Many kidney lesions are accompanied by massive loss of protein in the urine. As a result, the concentration of proteins decreases, the level of lipids in the blood increases, and edema occurs. This combination of clinical and laboratory signs is called “nephrotic syndrome.”

In this condition, protein loss exceeds 3.5 g per day in an adult with an average body surface of 1.73 m2.

The concept “syndrome” is not a diagnosis. When identifying its symptoms, it is necessary to determine the cause of the disease, and then treat it.

Causes of nephrotic syndrome

Nephrotic syndrome is often a manifestation of glomerulonephritis.

There are primary and secondary nephrotic syndrome:

• Primary occurs with initial disease of the kidneys themselves.
• Secondary complicates kidney disease resulting from some other disease.

Possible causes of primary nephrotic syndrome are various glomerulopathies, which are differentiated only after a biopsy of renal tissue.

Probable causes of kidney damage leading to the development of secondary nephrotic syndrome:

1. Infectious diseases: syphilis, leprosy, viral hepatitis, cytomegalovirus infection, malaria, toxoplasmosis, HIV infection, schistosomiasis.
2. Side effects of using medications: lithium, gold and bismuth salts, captopril overdose, penicillamine.
3. Rheumatoid and vascular diseases: rheumatoid arthritis, various vasculitis, amyloid lesions of internal organs, ulcerative colitis, cryoglobulinemia,.
4. Metabolic disorders: diabetes, preeclampsia.
5. Malignant tumors of the hematopoietic system, melanoma, tumors of the lungs, digestive tract, breast, thyroid gland, kidneys, reproductive system.
6. Allergic diseases and reactions.
7. Congenital diseases: Alporta, Fabry, sickle cell anemia, alpha-1 antitrypsin deficiency, renal artery stenosis.

In nephrotic syndrome, for one or a number of reasons, the glomeruli of the kidneys, the microscopic sections where water and salts are filtered out of the blood serum, are damaged. The protein remains in the blood. When various membrane structures are damaged, such a syndrome occurs.

Types of pathology

In addition to the cause and morphological (microscopic) characteristics, nephrotic syndrome is divided according to activity into:

• complete remission, when less than 0.3 g of protein is lost per day in the urine;
• partial remission, when protein losses in urine under the influence of treatment are reduced by 2 times or become less than 2 grams per day;
• relapse: appearance after an inactive phase or an increase in its number after partial remission.

Nephrotic syndrome also reflects the severity of kidney damage. This indicator takes into account the glomerular filtration rate (GFR) and various laboratory changes in the urine. Excretion of more than 30 grams of albumin in the urine is already a sign of chronic kidney disease.

Symptoms

With nephrotic syndrome, patients present a few complaints:

• swelling;
• decreased amount of urine output.

When questioning, you can identify the following facts that preceded the disease:

• the appearance and disappearance of edema for no apparent reason;
• periodic appearance of skin rash and redness;
• hair loss;
• joint pain without signs of inflammation;
• frequent, rhinitis, with bloody discharge from the nose, and redness of the urine is likely due to the large amount of blood in it;
• frequent pneumonia, attacks;
• periodic unexplained increase in body temperature;
• fast weight loss.

Of the concomitant diseases, the patient is often found to have:

• chronic pyelonephritis;
• intolerance to X-ray contrast agents or vaccines;
• habitual miscarriages in women.

It is important to find out whether the patient has taken gold, bismuth, lithium, high dose captopril (Capoten), non-steroidal anti-inflammatory drugs, probenecid, paramethadone, and heroin.

Characteristics of additional symptoms

Nephrotic syndrome is characterized by massive proteinuria, edema, high levels of lipids in the blood and a number of other signs.

Edema

Soft, can have different severity - from swelling under the eyes to complete swelling - anasarca. Fluid sometimes accumulates in the chest cavity, causing shortness of breath, and also in the abdominal cavity, causing an enlarged abdomen.

Redness and rash

Erythema (redness) resembles flame-shaped lesions, without clear localization, migrating. Their appearance is often associated with abdominal pain. This condition is often a harbinger of a serious complication - nephrotic crisis.

If redness and especially a rash are located on the face or décolleté, these are signs of systemic lupus erythematosus. Its localization on the trunk and limbs is more typical for various vasculitis and infectious diseases.

Rash and mouth sores

Quite typical for systemic rheumatic diseases with kidney damage.

Joint damage

If there is pain in the joints without inflammation or deformation, systemic connective tissue diseases should be assumed. If the joints of the hands are involved and their shape changes, the development of rheumatoid arthritis is likely, followed by the complication of renal amyloidosis.

Bloody issues

Such a runny nose or hemoptysis is a sign of vascular damage (vasculitis) and rapidly progressing glomerulonephritis.

Skin sensitivity disorder

Deterioration of temperature or tactile sensitivity in the arms and legs is characteristic of diabetes mellitus, which can be complicated by diabetic nephropathy. With the same disease, a sharp drop in blood pressure and fainting are possible when the patient tries to quickly get out of bed.

Enlarged lymph nodes

This sign helps to suspect a malignant tumor.

Diagnostics

In addition to clinical data, laboratory tests and instrumental studies are of great importance in recognizing nephrotic syndrome and its causes.

Basic Research	Changes	Possible reasons
Urine testing for protein content per day	More than 3.5 g	Nephrotic syndrome
Study of sediment in a general urine test	Deformed red blood cells, red blood cell casts	Rapidly progressive glomerulonephritis
	Increased ESR Decreased hemoglobin amount Increased white blood cell count Decreased white blood cell count Increased number of eosinophils Decreased platelet count	Nephrotic syndrome activity Systemic diseases, tumors, myeloma Infectious diseases, sepsis Rheumatic diseases, viral infections Churg-Strauss syndrome, rapidly progressive glomerulonephritis Systemic diseases
	Increased levels of urea, creatinine, changes in the level of sodium, potassium, calcium, phosphates, chlorides and carbonates Decrease in protein levels, in particular albumin Increased blood protein Increased uric acid levels Increased LDH levels Increased creatine kinase	Impaired renal function Nephrotic syndrome, liver cirrhosis Myeloma Gout, tumor decay Hemolytic anemia Injuries, metabolic diseases (metabolism)

More in-depth laboratory testing includes:

• determination of sodium and creatinine in urine;
• antinuclear antibodies;
• antibodies to double-stranded DNA;
• antineutrophil cytoplasmic antibodies (ANCA);
• anti-GBM antibodies;
• increased content of antistreptolysin-O;
• cryoglobulins;
• antiphospholipid antibodies;
• complement fractions;
• procalcitonin;
• anti PHLAR 2;
• immunoglobulins;
• Bence Jones protein;
• tumor markers as prescribed by a doctor.

An ultrasound of internal organs is also prescribed. However, the diagnosis cannot be made without a renal biopsy. Depending on the microscopic changes in the biopsy, doctors identify one of the following reasons pathologies:

• “minimal change disease”;
• focal segmental glomerulosclerosis;
• membranous nephropathy;
• mesangiocapillary glomerulonephritis type 1 or 3;
• dense deposit disease (or mesangiocapillary glomerulonephritis type 2);
• C3-glomerulopathy;
• extracapillary glomerulonephritis;

These names mean nothing to the average person. However, each of these conditions requires different treatments. We have presented this classification here so that each patient can learn more about his illness in the future.

In many cases, additional consultations are necessary:

• rheumatologist,
• ophthalmologist,
• oncologist,
• phthisiatrician,
• surgeon,
• infectious disease specialist
• neurologist,
• hematologist.

Differential diagnosis is carried out mainly with:

• severe heart failure (with swelling located in the legs, dense);
• (the abdomen mainly enlarges due to the accumulation of fluid in the abdominal cavity).

Treatment

If a patient has edema, he should limit his intake of table salt to 2 g per day.

Treatment begins in a hospital. Swelling usually appears suddenly and worsens over several days. In this case, the patient is hospitalized for a kidney biopsy, confirmation of the diagnosis and initiation of treatment. Subsequently, therapy continues on an outpatient basis.

Mode

Activity is limited by the patient's capabilities. There is no need to observe special bed rest. Moderate physical activity is recommended, for example, brisk walking for 30 minutes 5 days a week.

Quitting smoking and alcoholic beverages is mandatory.

Diet

A patient with nephrotic syndrome can eat anything. The protein content in his diet should be 1.5-2 grams per kilogram of weight. If there is swelling and increased blood pressure, table salt is limited to less than 2 grams per day.

Medicines

At severe swelling Diuretics are prescribed:

• torasemide,
• indapamide,
• spironolactone.

Sometimes in combination with albumin, in acute cases - hemodialysis.

If blood pressure increases and there is no acute kidney damage, the following is prescribed:

• perindopril,
• valsartan.

If they are contraindicated, calcium antagonists must be used. For palpitations, beta blockers may additionally be used.

The main treatment begins only after confirmation of the diagnosis. It may include glucocorticoids, immunosuppressants and others.

Observation

After discharge, the patient continues treatment. Additionally, he needs:

• measure blood pressure daily;
• weekly, and then once every 2 weeks, determine the amount of protein in the urine using special test strips;
• if the amount of protein increases, consult a doctor to correct the treatment regimen;
• at the beginning of treatment, examination by a nephrologist is scheduled monthly, then once every six months;
• in the active stage, general blood and urine tests, biochemical analysis, and determination of protein in the urine are monitored monthly;
• in the inactive phase, tests are repeated 2 times a year, and an ultrasound of the kidneys is performed annually.

The term “nephrotic syndrome” appeared relatively recently in clinical practice and is currently used by doctors in all countries. This name now refers to all conditions that, until the mid-20th century, were called lipoid nephrosis and nephrosis.

The concept of nephrotic syndrome combines a combination of certain pathological symptoms that appear when the glomerular system of the kidneys is damaged. Therefore, in most cases, this is not a diagnosis, but only a manifestation of some disease, and not necessarily urological.

However, there are situations when it is not possible to detect the underlying pathology that caused the decrease in the functionality of the renal glomeruli. In such cases, the patient is diagnosed with idiopathic nephrotic syndrome, that is, without an identified etiology.

What is nephrotic syndrome and its frequency

This serious condition in some cases becomes a consequence or complication of many diseases. The glomerular system of the kidneys can be affected by an infectious or autoimmune process not only in the urinary tract, but also by pathology of other internal organs or systemic diseases.

About 20-30% of urological diseases are complicated by nephrotic syndrome. It can develop both in adult patients and in children, and at a younger age, on average from 2 to 5 years. Read more about nephrotic syndrome in children. In adulthood, the pathology affects the working-age population, 20-40 years old. In addition, cases of this disease have been described in old age, after 70 years. If the cause of the syndrome is systemic pathologies (systemic lupus erythematosus, rheumatoid arthritis), then the predominant proportion of patients become women.

Pathology can also develop in children

Regardless of which causative factor became the main one, kidney damage of the nephrotic syndrome type has clear clinical and laboratory indicators. It is characterized by a combination of 4 characteristics:

1. Hyperproteinuria(increased protein levels in urine) more than 3.5 grams per day.
2. Hypoproteinuria with hypoalbuminuria (decrease in the amount of protein in the blood) less than 50 g/l.
3. Hyperlipidemia (increased cholesterol) more than 6.5 mmol/l.
4. Edema, which usually develops gradually and sometimes reaches the level of anasarca (swelling of the entire subcutaneous tissue of the body and most internal organs).

In most cases, all the signs of nephrotic syndrome are stated, but sometimes the severity of any of them is not clear. Therefore, the so-called incomplete, or reduced, nephrotic syndrome also occurs.

Why does pathology develop, its classification

Factors predisposing to the formation of the disease are quite diverse. They can consist only of damage to the kidney tissue, without affecting the organ from other systems. In other cases, the glomerular structures of the kidneys are affected secondarily, in diseases of various internal organs.

Therefore, depending on the origin, nephrotic syndrome can be:

• primary, resulting from renal diseases;
• secondary, which is a complication of pathologies of other internal organ systems.

Among the primary factors that are the direct causes of nephrotic syndrome, pathologies that occur with local damage to the renal glomeruli should be noted. These are acute and chronic glomerulonephritis, which are expressed in various morphological variants. In terms of frequency, they occupy up to 80% of all primary causes.

Due to the special gene of the Finnish type, pathology is possible mainly among the peoples of Scandinavia

However, in this group there are factors that can be called congenital or hereditary. Therefore, primary nephrotic syndrome is in turn divided into:

• congenital, caused by the presence of a special gene mutation that is inherited; This group includes Finnish type syndrome (diagnosed mainly in Scandinavian countries) and Fabry disease, caused by a disorder of protein and fat metabolism.
• acquired, which can form at any age: along with AGN (acute glomerulonephritis), its causes are primary amyloidosis and kidney tumors.

The group of secondary factors is very diverse. First of all, these are quite common pathologies of internal organs such as diabetes mellitus, specific infectious processes (tuberculosis, malaria, syphilis), systemic connective tissue diseases (lupus erythematosus, periarteritis nodosa, scleroderma), neoplasms (lymphogranulomatosis, myeloma), allergic pathologies , as well as the state of pregnancy. Along with diseases, factors such as exposure of the human body to heavy metals, certain medications, and bee, wasp or snake bites can also lead to kidney damage.

Such an extensive list of diseases and conditions occurring with nephrotic syndrome suggests several mechanisms of pathogenesis of the pathology. Among them main role The immunological mechanism plays a role, which consists in activating the body’s own defenses, which leads to damage to the glomerular structures.

This argument is supported by the fact that most often kidney damage syndrome develops precisely in allergic and autoimmune conditions. In addition, good therapeutic results are also demonstrated when using drugs that suppress the immune system (immunosuppressors).

Therefore, depending on the predominance of the immunological mechanism in a particular patient and the degree of effectiveness of immunosuppressive treatment, nephrotic syndrome also has a clinical classification:

• hormone-sensitive, with excellent effect from the use of hormonal agents;
• hormone-resistant, when only cytostatic drugs that suppress cell growth are effective in therapy.

Any allergic reaction can lead to damage to the kidney glomeruli

The immunological mechanism consists in the formation of a large number of antigen-antibody complexes, and the role of antigens is played by both external factors(bacteria, toxins, food products, medications) and the body’s own structures. These are various organic compounds: proteins, DNA, globulins, elements of basal glomerular membranes. The formed immune complexes are deposited in the renal glomeruli, significantly damaging their filtration system, which leads to an increase in the permeability of the basement membranes. That is why acute nephrotic syndrome, for example, is manifested by a sharp increase in the level of protein in the urine and a decrease in its amount in the blood plasma, since even large protein structures with a high molecular weight can penetrate through the filtration mesh. The more intense and longer the damaging factor affects the glomeruli, the more pronounced the symptoms of nephrotic syndrome.

The immunological mechanism of pathogenesis is also manifested by biochemical changes in the body. Thus, lysosomal enzymes, serotonin, histamine, aldosterone, and renin penetrate into the free bloodstream in significant quantities. These factors additionally increase the permeability of basement membranes and also negatively affect the state of microcirculation in the renal glomeruli. As a result, the functionality of not only the filtration structures, but also the tubular system is disrupted, in particular, sodium reabsorption is disrupted. All these processes are the causes of edema, the most striking symptom of this pathology.

The destructive phenomena occurring in the renal tissue are expressed in its macroscopic and microscopic characteristics. A pathological process of infectious or autoimmune origin leads to the fact that the organ slightly increases in size, its surface remains smooth. In this case, the cortex becomes lighter in color, and the medulla becomes reddish. The organ is called the “great white kidney.” But these macroscopic signs change in diseases such as tumors, amyloidosis, tuberculosis and others.

In histological examination, changes also depend on what pathology caused the formation of nephrotic syndrome. Thus, under a microscope, dystrophy of epithelial cells, proliferation (proliferation) of capillary endothelial cells and Shumlyansky-Bowman capsule structures can be detected, and in the tubules - dystrophy or necrosis of the epithelium. The lumens of the tubules look dilated, they contain a large number of cylinders of various natures.

Changes in podocytes are a hallmark of the syndrome

Nephrotic syndrome itself also has a characteristic histological picture. Its criteria are as follows:

• the structure of podocytes (glomerular capsule cells) is disrupted with shortening and disappearance of pedicles (processes) and changes in the structure of the podocyte cytoplasm;
• the structure of the basement membranes of the glomerular capillaries is disrupted, with thickening, loosening and increasing their permeability.

The earliest microscopic sign is considered to be a change in the structure of podocytes. With the further development of pathology, violations of the basement membranes also join this indicator.

Symptoms of nephrotic syndrome

Depending on what disease led to damage to the renal glomeruli, clinical manifestations can develop at different rates, rapidly or gradually, passing through several stages, and have unequal intensity in patients. The clinical picture of nephrotic syndrome is distinguished by the presence of several obligatory signs. These include:

• significant proteinuria, sometimes reaching 10-15 g/day; the predominant part of the proteins lost in the urine is albumin;
• hypoproteinemia, with a decrease in total protein in the blood to 50 g/l, sometimes to critical values ​​of 25-30 g/l; in this case, dysproteinemia is observed (imbalance of protein fractions in the blood plasma);
• hyperlipidemia, mainly due to an increase in blood cholesterol, phospholipids, trilycerides; an increase in plasma fat levels gives the serum its characteristic white color;
• edema, which has individual characteristics for each patient.

Depending on the severity of the condition and the degree of kidney damage, swelling varies in intensity. As a rule, swelling first appears on the face (in the eye area), then spreads to the upper body, down to the lower back, genitals and legs. Edema can be located throughout the body (anasarca), in the cavities around the internal organs (ascites, hydrothorax, hydropericardium).

Swelling forms on the face and spreads throughout the body

Patients with nephrotic syndrome present the following complaints:

• dry mouth and thirst;
• general weakness and malaise, loss of appetite, headache;
• discomfort or feeling of heaviness in the lumbar or abdominal area;
• sometimes nausea and vomiting, severe flatulence, loose stools;
• the appearance of brittle nails and hair;
• decrease in the amount of urine excreted, less than 1 liter per day;
• muscle pain, possible cramps.

When examining the patient, attention is drawn to his lack of mobility, the presence of edema, and pale, pasty skin. At the same time, it is cold, dry, flaky, severe cases cracks are observed (the skin looks like mother of pearl). All these complaints and external examination data are taken into account by the doctor in the differential diagnosis of nephrotic syndrome, when identifying the factors that led to its occurrence.

Diagnostics

As a rule, it is the appearance of edema and deterioration in well-being that brings a sick person to a doctor’s appointment. This is typical for primary acquired and secondary nephrotic syndrome, when, for example, pathological symptoms appear after contact with an allergic agent or after exposure to industrial or household poisons. If the pathology has developed against the background of other diseases, then the patient will be concerned about the addition of new signs to the specific symptoms, which may indicate a complication such as kidney damage in the form of nephrotic syndrome.

The doctor’s task at the appointment is to find out not only all the patient’s complaints, but also the anamnesis, which includes the presence of predisposing factors (acute or chronic infectious pathologies, allergic mood of the body), and the possibility of similar diseases in relatives. In addition, the doctor must clarify how nephrotic syndrome develops, in what order its signs appeared and how quickly they increase.

Percussion of the abdomen reveals an enlarged liver

During an external examination, a set of characteristic manifestations of the pathology is noted: dry pearlescent skin, a light-coated tongue, the presence of edema of various locations, and an enlarged abdomen. Upon percussion (tapping), an expansion of the borders of the liver and its thickening (hepatomegaly) are noted. If fluid has accumulated in the pleural cavity (hydrothorax), the patient’s breathing becomes difficult and shallow, and fine rales are heard on auscultation. With hydropericardium, when fluid has accumulated around the heart and prevents it from working, the expanded boundaries of the organ are determined, and the ECG shows symptoms of cardiac muscle dystrophy and bradycardia (slowing the heart rate).

In most cases, upon initial treatment of a patient with the above complaints and clinical signs, the diagnosis of nephrotic syndrome is not too difficult. In this, in addition to the history, complaints and examination data, the results of blood and urine tests help. In a general urine test, in addition to the presence of elevated protein levels, the following parameters are determined:

• the specific gravity of urine increases to 1030-1040;
• the number of leukocytes exceeds the norm;
• cylinders of various origins appear (hyaline, granular);
• cholesterol appears in the form of crystals and neutral fat in the form of separate drops;
• sometimes single red blood cells are present.

When examining daily urine for protein content, a sharp increase is noted: more than 3.5 grams per day.

A clinical blood test, especially with underlying infectious diseases of the kidneys and other internal organs, will certainly show an increase in ESR, an increase in the number of leukocytes, as well as a shift in the leukocyte formula to the left, that is, with the appearance of young forms of leukocytes. In addition, a decrease in hemoglobin levels is also characteristic, below 100-110 g/l. A biochemical blood test reveals specific signs of nephrotic syndrome: a decrease in the amount of total protein and albumin, an increase in cholesterol.

Blood changes become a diagnostic criterion

Having received such laboratory results, the attending physician can already make a diagnosis of nephrotic syndrome. However, given that this pathology in most cases is just a consequence or complication of other diseases, diagnostic measures must continue. Their goal is to determine the underlying pathology. Therefore, the patient is then sent for an ECG, ultrasound of the kidneys, ultrasound of the renal vessels, nephroscintigraphy, and sometimes a biopsy is necessary.

Electrocardiography may detect dystrophic changes in the pericardium; a slow heart rate (bradycardia) is almost always observed. With an ultrasound scan of the kidneys, various diseases of the organ can be diagnosed, and during Dopplerography of the renal arteries and veins, their anatomical structure, the presence of narrowing, tortuosity or accessory vessels, as well as the state of blood flow. Additionally, the functionality and structure of the kidneys can be assessed with nephroscintigraphy, which involves introducing a certain amount of radioactive drug into the patient’s body. In other situations, it is necessary to perform an intravital biopsy of the kidney tissue (taking a sample and examining it under a microscope). For example, to confirm or exclude amyloidosis.

Treatment of nephrotic syndrome should be differentiated, that is, depending on the stage and severity of the underlying disease that caused its development. Therefore, all of the above diagnostic methods in each clinical case should provide the doctor with comprehensive and reliable information. If necessary, they are supplemented by immunological, allergological studies, and biopsies of other internal organs (mucosa of the rectum, submucosal layer of the gums). Only after a final diagnosis has been made can treatment of nephrotic syndrome as a manifestation of the underlying pathology begin.

The patient must be thoroughly examined

Treatment options

The syndrome is treated according to the same rules as most kidney diseases. Its characteristics in each patient are determined by the main diagnosis, but in general, the treatment of nephrotic syndrome has the following directions:

• diet;
• drinking regime;
• use of medications with different mechanisms of action.

The diet primarily involves limiting salt and protein. The menu is calculated so that the daily amount of salt is no more than 3 grams, and proteins, animal and plant origin, no more than 1 gram per kilogram of the patient’s weight. In addition, all foods containing sodium are limited. On the contrary, foods with large amounts of potassium and vitamins should prevail in the diet.

Along with changes in nutrition, the patient’s physical activity is also adjusted. It should be moderate; the patient should not spare himself in the physical sense, unless, of course, his condition allows him to do so. Athletes should reduce their load, and people with a sedentary lifestyle should increase it.

The patient's drinking regime also requires special attention. It should be gentle, without a massive increase in circulating blood volume and, therefore, without increasing the load on the kidneys. The daily amount of fluid consumed should be 30 ml more than the daily diuresis.

Drinking regime occupies a special place in the treatment regimen

Clinical recommendations for the use of medications are different for each patient and are determined by the underlying disease. So, if nephrotic syndrome is the result of an infectious kidney disease, then antibacterial and anti-inflammatory drugs are prescribed. For many renal diseases, diuretics and antihypertensive drugs, replacement intravenous administration of protein drugs are necessary. Considering that it is the immunological mechanism that is leading in the syndrome, either immunosuppressants or cytostatics are selected for the patient.

It should be noted that therapy for nephrotic syndrome in the vast majority of cases is quite lengthy and requires not only regular hospitalization of patients, but also assistance in specialized sanatoriums and resorts. In many patients, it is combined with treatment of chronic renal failure. In these cases, we can say that therapy for chronic renal failure simultaneously affects the mechanisms of formation of nephrotic syndrome. In particular, Dr. Denisov, a well-known nephrologist in Moscow and the Moscow region, deals with precisely this complex treatment of renal pathologies.

Nephrotic syndrome is a condition that is very dangerous for the health and life of the patient. It can cause the development of serious complications, manifested by damage to the brain, heart, blood vessels, and lungs. Therefore, its timely diagnosis and competent treatment can be decisive for the patient.

Kidney diseases are not always limited to the appearance of other urinary disorders.

Secondary pathology of the glomerular filter is the responsibility of a specialized specialist, depending on the background pathology.

But treatment should be adjusted taking into account the opinion of the nephrologist. The pathology is serious, so the solution to this problem must be comprehensive.

What symptoms and complications require treatment?

Pathogenetic therapy is required in the presence of high activity of the process. Such situations include high loss of protein in the urine - proteinuria more than 3 g/l. The second situation is severe swelling. In this case, the use of amino acids is also required.

Chronic renal failure complicates the course of nephrotic syndrome sooner or later. High levels of creatinine and blood urea lead to hospitalization.

DIC syndrome is not treated in the nephrology department, but in intensive care. Treatment will require a whole range of drugs, as well as the interaction of doctors from different specialties.

Necessary medications

In a specialized nephrological or therapeutic hospital, several groups of drugs are used. Among them:

• cytostatic agents (Chlorobutin, Cyclophosphamide);
• glucocorticoids (Prednisolone, Dexamethasone);
• diuretics (Triamterene, or Inspra);
• antihypertensive therapy.

The main principle of treatment of nephrotic syndrome is immunosuppression or reducing the aggression of one’s own immune forces towards one’s own tissues. After all, the predominant mechanism of development of this condition is autoimmune. To do this, calculate the doses of glucocorticoid hormones or cytostatic drugs.

Diuretics are intended as symptomatic therapy.

If there is a large loss of protein in the urine, nephrologists recommend resorting to infusion of solutions containing amino acids and proteins. This will avoid fatal complications.

Hormonal and cytostatic drugs

Glucocorticoids and agents that affect cell division are indicated for the treatment of nephrotic syndrome.

The point of prescribing these medications is to reduce the activity of inflammation, cellular or humoral (antibody) aggression.

Among the hormonal drugs used:

• Triamcinolone;

The dosage of Prednisolone for adults with high activity of the process is 80 mg per day. 1 tablet contains 5 mg, that is, 16 tablets are used throughout the day. They are divided into 4 doses.

Then the dosage is gradually reduced to maintenance. They can be taken on an outpatient basis. If glucocorticoids are ineffective, the next group of drugs is prescribed - cytostatics.

Dietary requirements

Non-drug measures include dietary recommendations.

Limit the consumption of table salt as much as possible, because it can cause hypertension (increased blood pressure).

The second important aspect is limiting protein intake in food, despite its loss in urine from the body.

Maintenance therapy

Therapy does not end at the hospital level. At this stage, nephrologists select a maintenance dosage of pathogenetic drugs, which are then prescribed by a local therapist or outpatient.

The task of these specialists is to monitor the patient’s condition. If the condition worsens, they again refer the patient to inpatient treatment.

You should regularly visit your therapist and nephrologist. The frequency of visits is determined in each specific case individually. At the time of examination, the patient must take next row analyzes and research:

• general urine test;
• Nechiporenko's test;
• Zimnitsky test;
• daily proteinuria;
• twice a year - ultrasound examination of the kidneys;
• creatinine, urea, potassium, protein, albumin, blood globulins as part of a biochemical analysis.

It is important to monitor changes in dynamics in order to take measures for further treatment, its intensification or reduction in volume.

Prognosis for recovery

The prospects for therapy depend on the timeliness of started therapy.

In the earliest stages, with a minimal degree of proteinuria, pathogenetic treatment can achieve remission.

At the stage of complications, it is extremely difficult to treat the patient. Achieving remission is an almost impossible mission in this situation.

Disease prevention

There are no specific preventive measures for this pathology. However, undergoing preventive examinations will allow you not to miss changes in tests and clinical manifestations of nephrotic syndrome.

Nephrotic syndrome is difficult to prevent. The main thing is to find the cause and start etiotropic and pathogenetic treatment in a timely manner.

Self-medication can only do harm with this disease. Consultation with a qualified doctor is required.

(right and left respectively). Each kidney is bean-shaped and covered with fibrous ( connective tissue) and fat capsules ( shells), which protect kidney tissue from damage. Inner sides ( medial sides) kidneys are concave and are located next to the spine, external ( lateral) – convex and facing the walls of the abdomen and lower back. On the medial side of each kidney there is a gate, through which vessels and nerves enter the kidneys.

The inside of the kidneys is made up of connective tissue ( interstitium) and the system of formation and excretion of urine. If you make a cut, you can see that the entire parenchyma of the kidney is not homogeneous. It includes the so-called medulla and cortex, which differ from each other in color, location and density. The cortex occupies the outer part of each kidney; it is relatively smaller in volume and density than the medulla, which is localized in the central part of the organ. The cortex is yellowish-red, the medulla is bluish-red. The medulla structurally consists of cone-shaped formations ( renal pyramids), the bases of which are directed towards the cortex. The apices of these pyramids are directed towards the hilum of the kidney.

The system of formation and excretion of urine, in fact, begins in the cortex, where a huge number of nephrons are located - the main functional units of the kidneys. Each nephron consists of a vascular glomerulus ( glomeruli), capsules ( Shumlyansky-Bowman) and tubules. The choroidal glomerulus is a system of branching and repeatedly intertwining small arterial vessels located in the capsule. The arterial capillaries in the capsule are surrounded by mesangium ( type of connective tissue). The capsule itself looks like a bowl ( in which the glomerulus is immersed) and consists of two leaves - outer and inner. The outer leaf is formed by connecting flat cells to each other, forming a single-layer membrane.

The structure of the inner leaf is a little more complex. It consists of three shells. The first membrane is the cells of the capillary walls ( endothelial cells) choroid glomerulus. The second membrane is the basement membrane, to which endothelial cells are attached. This membrane is located outside the capillaries ( and outside of endothelial cells). The third layer of the inner layer of the Shumlyansky-Bowman capsule is the layer of podocytes ( special epithelial cells). They are localized on the basement membrane with reverse side from endothelial cells. Podocytes have processes that cover the capillaries of the vascular glomerulus. All three membranes of the inner layer of the Shumlyansky-Bowman capsule make up the so-called glomerular filter ( barrier). Through it, filtration occurs in each nephron of the kidneys ( straining) blood ( entering the kidney via the renal artery), resulting in the cavity of the capsule itself ( which is located between its outer and inner leaves) primary urine is formed ( glomerular ultrafiltrate).

Primary urine is blood plasma freed from formed elements and large molecular compounds ( mostly proteins). To prevent the body from losing everything valuable ( for example, water, mineral salts, vitamins, amino acids, etc.) that is in the primary urine, it must pass through the tubular system - the last component of each of the nephrons. Reabsorption occurs in the tubules ( reverse suction) substances useful for the body from primary urine back into the blood. Filtration and reabsorption are the main functions of the renal nephrons. Most of the tubules are located in the renal medulla. After passing through the tubule system, primary urine gradually turns into secondary urine, which is excreted from the tubules ( and, strictly speaking, from the nephrons themselves) into the renal calyces, localized in the area of ​​the apices of the renal pyramids. Connecting with each other, these calyces flow into the renal pelvis, through which the secondary ( final) urine penetrates further into the ureter and is excreted from the kidneys.

The arterial blood supply to the kidneys is provided by the renal arteries, which branch from the abdominal aorta. Venous blood from the kidneys flows through the renal veins. These veins then drain into the inferior vena cava. Lymphatic vessels deliver all lymph to the lumbar The lymph nodes. Innervation of the kidneys is provided through the branches of the renal plexus and nerves coming from the upper lumbar and lower thoracic nodes.

Causes and pathogenesis of nephrotic syndrome

Nephrotic syndrome is a set of clinical and laboratory abnormalities indicating a disorder of renal function. It is characterized by hypoproteinemia ( decreased protein levels in the blood), hypoalbuminemia ( decrease in blood albumin levels), proteinuria ( protein excretion in urine), edema and sometimes hyperlipidemia ( increased blood fat levels).
Nephrotic syndrome is not an independent disease. It can occur in various diseases and pathological conditions. Moreover, it is not necessary that they ( these diseases and conditions) originally appeared in the kidneys. For example, nephrotic syndrome often occurs with blood diseases, diabetes mellitus, rheumatic diseases, systemic vasculitis ( pathologies associated with vascular inflammation) etc. In some cases, it, of course, can develop against the background of primary kidney diseases - acute glomerulonephritis, some genetic kidney diseases ( congenital nephrotic syndrome). In any case, the main mechanism for the appearance of nephrotic syndrome is damage to the glomerular filter in the renal nephrons, against the background of which the process of filtration of blood plasma in the kidneys is disrupted.

The most common causes of nephrotic syndrome are:

• congenital nephrotic syndrome;
• acute glomerulonephritis;
• tubulointerstitial nephritis;
• amyloidosis;
• diabetes;
• infectious diseases;
• rheumatic diseases;
• blood diseases;
• systemic vasculitis;
• venous thrombosis;
• allergic diseases;
• poisoning with toxic substances.

Congenital nephrotic syndrome

Congenital nephrotic syndrome ( VNS) is a nephrotic syndrome that appears in children in the first 3 months of life. In addition to the congenital, there is also the infantile ( infant) nephrotic syndrome, which first occurs in children 4 to 12 months of age. The causes of congenital and infantile nephrotic syndrome, as a rule, are various genetic disorders, less often infections and metabolic disorders. The most common genetic disorders that provoke the appearance of congenital nephrotic syndrome are mutations in the fibrocystin genes ( polycystic kidney disease), collagen type IV ( Alport syndrome), nephrine ( NPHS1 gene), podocin ( NPHS1 gene), WT1 gene ( Denis-Drash syndrome), PLCE1 gene ( impaired secretion of nephrin and podocin), LamB2 gene ( Pearson syndrome).

All these genes are responsible for the proper development of kidney tissue during fetal embryogenesis, as well as for its functioning after the birth of a child. For example, a mutation in the NPHS1 gene ( Finnish type nephrotic syndrome) leads to disruption of the formation of nephrin protein in kidney cells, which serves as an important component of the gap spaces located between the podocyte stalks ( glomerular cells covering arterial capillaries entering Bowman's capsule). This is accompanied by destructuring of the capsule and impaired filtration of blood plasma, resulting in the development of nephrotic syndrome.

Congenital nephrotic syndrome can develop against the background of a variety of infectious diseases. This is often observed with intrauterine infections ( syphilis, cytomegalovirus infection, herpes, rubella, hepatitis B, toxoplasmosis, etc.), damaging various organs of the fetus ( including the kidneys) during pregnancy. Congenital nephrotic syndrome can also be caused by various metabolic disorders ( metabolic disorders), such as Fabry disease ( mutation in the a-galactosidase gene, leading to fat deposition in the glomerular region), congenital forms of hypothyroidism ( decreased thyroid function), hypoadrenocorticism ( adrenal gland dysfunction) and etc.

Acute glomerulonephritis

Acute glomerulonephritis is a kidney disease in which inflammation of a large number of glomeruli occurs in them ( glomerulus). The reason for its development is a disruption of the immune system, as a result of which it attacks its own kidney tissue. Acute glomerulonephritis most often appears after streptococcal pharyngitis ( inflammation of the pharyngeal mucosa). As the body fights this infection, pathogenic streptococci are partially destroyed. The remaining bacterial particles settle in the glomeruli. After a few weeks, the immune system can detect deposited streptococcal particles and initiate an immune response that causes inflammation of the glomeruli.

Inflammatory changes in the glomeruli often lead to damage to them morphological structure and an increase in their permeability to various plasma components that normally do not penetrate into primary urine ( for example, large molecular proteins, blood cells). Therefore, kidney damage in acute glomerulonephritis is often accompanied by signs characteristic of nephrotic syndrome ( proteinuria, hypoalbuminemia and edema). In addition to streptococcal infection, acute glomerulonephritis can also be caused by infective endocarditis, rubella, pneumonia, measles, malaria, schistosomiasis, certain medications, etc.

Tubulointerstitial nephritis

Tubulointerstitial nephritis is a pathology that develops as a result of inflammation of the interstitial ( intermediate) kidney tissue, as well as renal tubules. With this disease, the function of the renal glomeruli is practically not impaired ( up to the most advanced clinical stages of the disease), so nephrotic syndrome is not so typical for him. However, there are cases when it was still observed with tubulointerstitial nephritis. The main causes of this renal pathology are pyelonephritis, leptospirosis, acute tubular necrosis ( immediate death of the renal tubular epithelium), caused by drugs, toxins ( lead, cadmium), ischemia ( impaired blood supply to the kidneys), radiation, obstructive nephropathy ( a pathology in which the normal flow of urine through the urinary tract is disrupted), tuberculosis, etc.

The occurrence of nephrotic syndrome in tubulointerstitial nephritis is associated with the spread of the inflammatory process from the renal tubules and interstitium ( intermediate kidney tissue) to glomeruli. The development of inflammation in the glomeruli is then accompanied by a violation of their filtration function and the penetration of excess amounts of protein from the blood plasma into the primary urine. In addition, inflammation in the glomeruli in tubulointerstitial nephritis may also be promoted by the same etiological factors that provoked the onset of the underlying disease. For example, if tubulointerstitial nephritis was caused by poisoning of the patient with salts of heavy metals ( lead, cadmium), then they can also serve as damaging agents in relation to the anatomical structures of the renal glomeruli.

Amyloidosis

Amyloidosis is a disease caused by a disorder of protein metabolism. It is characterized by the formation of a pathological protein in the body - amyloid, which over time settles in various tissues and organs ( liver, heart, kidneys, gastrointestinal tract, etc.), disrupting their basic functions. Today, many types of amyloidosis are known, which differ from each other depending on the origin of the amyloid protein. There are so-called genetically determined types of amyloidosis ( e.g. ATTR amyloidosis, Finnish type amyloidosis, AF amyloidosis), in which the appearance of amyloid is clearly associated with genetic mutations in certain proteins of the body. In addition to them, secondary forms of amyloidosis are known, associated with various diseases, for example, myeloma ( AL amyloidosis), Alzheimer's disease ( AB amyloidosis), chronic diseases ( AA amyloidosis), tumors ( AE amyloidosis) and etc.

In all of the above types of amyloidosis, an abnormal amyloid protein is formed, deposited in the kidney tissue and gradually causing kidney failure. At the initial stages, amyloid deposition occurs in the zone of the basement membranes of the renal glomeruli and their mesangium ( tissue located between capillaries in nephron capsules). The constant sedimentation of new masses of amyloid in the glomeruli leads to disruption of their structure ( which is accompanied by nephrotic syndrome) and progressive replacement of normal elements ( capillaries, mesangium, podocytes, etc.), forming nephron capsules. Amyloid accumulation may also be observed in the renal interstitium ( intermediate kidney tissue), peritubular ( near the tubules) and perivascular tissue. Thus, in the process of amyloid deposition, mechanical replacement of normal kidney tissue with abnormal – amyloid – is observed, resulting in the development of nephrotic syndrome.

Diabetes

Diabetes mellitus is an endocrine disease that is associated with an absolute or relative deficiency of the hormone insulin, produced in the pancreas and regulating metabolism in the body. Insulin primarily regulates blood glucose levels ( Sahara) and lowers its level if it goes off scale. In diabetes mellitus, either an insufficient amount of this hormone is produced, or the action of insulin is simply ineffective on the target tissue ( that is, those tissues on which it should exert its direct effect). Therefore, diabetes mellitus is accompanied by an increase in blood glucose.

Diabetes mellitus can cause the development of nephrotic syndrome. The fact is that with this endocrine disease due to hyperglycemia ( increased blood glucose levels) glycosylation occurs ( non-enzymatic addition of glucose to other chemical compounds) various proteins that make up the various structures of renal nephrons ( capillary walls, mesangium, basement membrane, etc.). This leads to an increase in the permeability of the glomerular filter for proteins, which is accompanied by the release of a significant amount of it into the primary urine and, as a consequence, the development of nephrotic syndrome.

The formation of nephrotic syndrome in diabetes mellitus is also facilitated by increased blood pressure, which disrupts intraglomerular blood flow ( blood pressure inside the glomeruli increases significantly, which creates additional stress on the walls of the intraglomerular capillaries). Since hyperglycemia is a constant phenomenon in diabetes mellitus, the glycosylation of proteins in the renal glomeruli gradually progresses, which creates the preconditions for the development of renal sclerosis ( ) and the appearance of renal failure. All pathological changes observed in the kidneys with diabetes are called diabetic nephropathy. It is one of the complications of diabetes mellitus and may not always occur in a patient suffering from this endocrine disease.

Infectious diseases

In some infectious diseases, the pathogen may be carried into the kidneys. This often happens with various bacterial ( tuberculosis, septic endocarditis, pneumonia, syphilis, abscesses, bronchiectasis, osteomyelitis, etc.), viral ( HIV infections, etc.) and fungal ( actinomycosis) pathologies. Penetration of pathogenic microorganisms ( viruses, bacteria, fungi) into the kidney tissue usually occurs through the blood ( hematogenously). Once in the kidneys, they damage their various tissue structures.

Most often in such cases, the cells of the glomerular capillaries are affected ( endothelial cells), mesangium and podocytes ( glomerular cells lining arterial capillaries). Since these cells are part of the glomerular filter, their gradual death is accompanied by a violation of its permeability and increased release of proteins from the blood plasma into the primary urine. It is this mechanism that underlies the appearance of nephrotic syndrome in infectious diseases. Also, the inflammatory process that develops immediately at the site of damage to endothelial cells, mesangium and podocytes can play some role in its appearance during infections. With such inflammation, the basement membrane of the glomerular filter is often damaged, which only further intensifies the disorders that arose before.

Rheumatic diseases

Nephrotic syndrome can develop in many rheumatic diseases ( systemic) diseases ( for example, systemic lupus erythematosus, rheumatoid arthritis, systemic scleroderma, rheumatism, etc.). In systemic lupus erythematosus, the kidneys are often affected due to the deposition of immune complexes ( connection between an antibody and an antigen - a molecule foreign to the body) in the region of the renal glomeruli. The accumulation of such complexes leads to the development of an immunoinflammatory response from the body, damage to the anatomical structures of the glomeruli and the development of nephrotic syndrome.

The appearance of this syndrome in rheumatoid arthritis, in most cases, is associated either with secondary renal amyloidosis, in which the renal glomeruli become clogged with an abnormal protein - amyloid, or with damage to glomerular tissue by antirheumatic drugs. In systemic scleroderma, nephrotic syndrome develops as a result of a disruption in the interaction of cells of the immune system with cells of other tissues ( vascular, connective, renal, etc.), which leads to the occurrence of inflammatory processes in the glomeruli and their sclerosis ( replacing them with connective non-functional tissue).

In fact, rheumatic diseases contribute to the development of inflammatory reactions in the glomeruli, which are accompanied by impaired permeability of the glomerular filter and the development of nephrotic syndrome. In fact, in such cases glomerulonephritis develops ( a disease in which diffuse inflammation of the renal glomeruli is observed), and this glomerulonephritis has a long course and is not acute, but chronic. Chronic glomerulonephritis can sometimes occur for a long time without any symptoms. The main danger of this disease is that over time it can lead to chronic renal failure. Therefore, all patients with rheumatic diseases should periodically monitor the functional state of their kidneys.

Blood diseases

Nephrotic syndrome can occur with certain blood diseases, for example, lymphogranulomatosis, myeloma, mixed cryoglobulinemia, thalassemia, sickle cell anemia, etc. With lymphogranulomatosis ( tumor developing from cells of the lymphoid system) the kidneys are rarely affected, but if this happens, then most likely this blood disease has been bothering the patient for a long time. Typically, renal tissue damage is observed in stages 3 or 4 ( final stage) lymphogranulomatosis, in which not only the lymphatic system, but also many other organs are involved in the pathological process ( besides the kidneys), which is associated with the spread of tumor cells throughout the body. Once in the kidney tissue, such cells actively multiply and replace normal tissue with malignant tissue, as a result of which the internal structure of the kidneys is disrupted and nephrotic syndrome develops.

For multiple myeloma ( malignant tumor of plasma cells - special blood cells) the so-called myeloma nephropathy develops, which is characterized by damage to intrarenal structures due to the penetration of abnormal myeloma proteins into them ( paraproteins), secreted by plasmacytoma cells ( myeloma tumor). Kidney damage in multiple myeloma is often accompanied by nephrotic syndrome, nephrosclerosis ( replacement of renal tissue with connective tissue) and renal failure. With mixed cryoglobulinemia, specific protein molecules, cryoglobulins, deposit on the walls of the vessels of the renal glomeruli, which initiate the local launch of inflammatory reactions ( via the complement system), which is accompanied by damage to the glomerular filter and the development of nephrotic syndrome in the patient. The appearance of cryoglobulins is caused by a disorder in the functioning of cells of the immune system, which occurs during certain viral infections ( hepatitis B, hepatitis C, cytomegalovirus infection, infectious mononucleosis, etc.).

Development of nephrotic syndrome in thalassemia ( genetic disease associated with impaired hemoglobin formation) is caused by damage to the glomeruli, against the background of periodic accumulation of iron in them, formed during the breakdown of pathological red blood cells. For sickle cell anemia ( a disease in which there is a disruption in the formation of normal hemoglobin) thrombosis often occurs in the kidneys ( blockages of blood vessels), due to the reduced resistance of red blood cells to destruction. Against the background of thrombosis in the glomeruli, blood flow is often disrupted, which often leads to hyperfiltration ( increased filtration) plasma through the glomerular filter and the appearance of nephrotic syndrome.

Systemic vasculitis

Systemic vasculitis is a group of diseases in which inflammation of the walls of blood vessels located in various tissues and organs is observed. The renal vessels are most often damaged in several systemic vasculitis ( polyarteritis nodosa, Henoch's Schonlein's purpura and Wegener's granulomatosis). The mechanism of origin of all three pathologies is associated with disruption of the immune system. For example, Henoch's Schonlein purpura occurs as a result of the deposition of immune complexes on the walls of blood vessels, as a result of which the complement system is activated, which triggers a local inflammatory reaction and promotes them ( vessel walls) damage. The origin of the immune complexes themselves has not yet been precisely established; it is assumed that they may be molecules remaining in the patient’s body after certain diseases ( allergies, streptococcal infection, mycoplasma infection, etc.).

The mechanism of development of inflammation of the walls of renal vessels in polyarteritis nodosa is in general similar to that observed in Henoch Schönlein purpura, however, the occurrence of immune complexes in this pathology may also be associated with some other viruses ( for example, hepatitis B virus, hepatitis C virus, HIV infection, cytomegalovirus) or certain drugs ( bismuth preparations, antibiotics, sulfonamides, etc.). The pathogenetic mechanism of origin of Wegener's granulomatosis is even more complex. It includes not only precipitation ( deposition) on the walls of blood vessels of glomeruli of immune complexes, but also various disorders of interaction between cells of the immune system. Neutrophils play an important role in damage to the walls of blood vessels in this disease ( blood cells), which accumulate in the area of ​​the renal glomeruli and produce various enzymes that have a damaging effect on them. Damage to blood vessels in all three types of systemic vasculitis leads to impaired permeability of the glomerular filter and the development of nephrotic syndrome.

Venous thrombosis

Nephrotic syndrome can be detected in patients with thrombosis of large venous vessels ( inferior vena cava, renal veins). Such thromboses are a common occurrence in diseases and conditions associated with blood clotting disorders ( taking oral contraceptives, pregnancy, congenital diseases of the blood coagulation system, etc.). In addition, thrombosis is periodically observed in heart failure, systemic vasculitis, tumor diseases ( when the venous vessels are compressed from the outside by malignant formations).

With thrombosis in the venous vessels, blood flow is disrupted, which contributes to blood stagnation and retrograde ( the opposite) increased pressure in the renal arteries. An increase in pressure in the glomerular arterial system leads to dilation of the vessel walls and increased plasma filtration. Therefore, thrombosis of large venous vessels, such as the inferior vena cava, renal and other veins, is quite often associated with nephrotic syndrome. Other common causes of thrombosis in these veins include malignant kidney tumors, metastases, severe dehydration ( in children), aortic aneurysm, severe trauma, sepsis, peritonitis ( inflammation of the peritoneum), antiphospholipid syndrome, etc.

Allergic diseases

For some allergic pathologies ( for example, hay fever, food allergies, cosmetical tools, allergic reactions that occur after insect bites, etc.) nephrotic syndrome can sometimes develop. The mechanism of its appearance is, in general, similar to that which occurs in rheumatoid diseases ( for example, systemic lupus erythematosus) and is caused by the accumulation of immune complexes on the walls of the vessels of the renal glomeruli, as a result of which their immunoinflammatory damage unfolds, leading to disruption of the normal permeability of the glomerular filter and hyperfiltration ( increased filtration) the liquid part of the blood through it. Unlike systemic lupus erythematosus, damage to the glomeruli in allergic diseases is most often temporary. Nephrotic syndrome immediately ( or after a short period of time) disappears after eliminating the allergen ( etiological factor that caused the allergy).

Poisoning with toxic substances

Poisoning with toxic substances quite often leads to kidney damage and the development of nephrotic syndrome. This is often observed when various pesticides and toxic poisons enter the patient’s body ( ethylene glycol, oxalic acid, arsenic, acetic acid, chromium, lead, radioactive elements, copper sulfate, arsine, etc.). In rare cases, the use of certain medications ( for example, antiepileptic drugs, bismuth drugs, gold, mercury, antibiotics, anticoagulants, sulfonamides, vitamins, D-penicillamine) can also cause nephrotic syndrome.

The mechanism of development of nephrotic syndrome itself in case of poisoning with toxic substances always depends on their type. For example, poisoning with substances containing mercury is accompanied by impaired cellular respiration of glomerular cells of the kidneys, which inevitably leads to their death. In case of acetic acid poisoning, copper sulfate, arsine, which, by their nature, are hemolytic poisons ( that is, substances that destroy red blood cells), excessive deposition of free hemoglobin occurs ( released when red blood cells break down) in the area of ​​glomerular filters, which leads to nephrotic syndrome.

Damage to kidney tissue by toxic substances is called toxic nephropathy. It can be acute or chronic. Acute toxic nephropathy usually leads to the development of acute glomerulonephritis ( inflammation of the kidney glomeruli) and then to acute renal failure. Chronic nephropathy is accompanied by the appearance of chronic glomerulonephritis and chronic renal failure. Nephrotic syndrome in toxic nephropathy is caused precisely by acute or chronic glomerulonephritis.

Classification of nephrotic syndrome

Nephrotic syndrome is of two types - primary and secondary. The division into these types is due to the root cause of its development. Primary nephrotic syndrome is caused by kidney disease. In the secondary type, nephrotic syndrome appears due to the presence of pathologies in the patient that primarily affect other organs rather than the kidneys. There is also a classification of nephrotic syndrome depending on the degree of its response to treatment with hormonal drugs ( prednisone). In this classification, nephrotic syndrome is divided into steroid-resistant and steroid-sensitive types.

Primary nephrotic syndrome

Primary nephrotic syndrome develops with acute or chronic glomerulonephritis ( inflammation of the glomeruli of the kidneys) and some genetic kidney diseases ( congenital nephrotic syndrome). Idiopathic nephrotic syndrome is also classified as primary nephrotic syndrome. In idiopathic nephrotic syndrome, the cause of kidney damage is unknown.

Secondary nephrotic syndrome

Secondary nephrotic syndrome occurs with a variety of diseases of other organs and tissues, for example, allergies, systemic vasculitis, toxic substance poisoning, venous thrombosis, blood diseases, diabetes mellitus, amyloidosis, infectious and rheumatic diseases, tubulointerstitial nephritis. Damage to the kidney tissue in these pathologies is not always accompanied by nephrotic syndrome, and, in some cases, the kidneys are not affected at all, therefore it is believed that the development of this syndrome in these pathologies is secondary.

Steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome is a nephrotic syndrome that does not disappear in humans ( not in remission) after an eight-week course of steroid therapy with prednisone.

Steroid-sensitive nephrotic syndrome

Steroid-sensitive nephrotic syndrome ( SCNS) is observed in those patients who have a positive response to treatment with prednisolone. Usually remission ( disappearance of symptoms and signs of the disease) This syndrome occurs after 2 to 4 weeks of steroid treatment. In some cases, the period may be extended to 4–8 weeks. Relapses ( reappearance of symptoms and signs of the disease) nephrotic syndrome may occur after it goes into remission during treatment, or may not appear at all.

Steroid-sensitive nephrotic syndrome is divided into several types ( non-relapsing, infrequently relapsing, frequently relapsing, steroid dependent). With non-recurrent SSNS, relapses of the disease do not occur, remission of the pathology is very long. With infrequently recurrent SSNS, relapses occur less than twice every 6 months, and with frequently recurrent SSNS, relapses occur at least twice every six months. In steroid-dependent SSNS, the appearance of relapses is usually associated with cessation of the course of hormonal therapy with prednisolone; sometimes such relapses may be due to a reduction in the dose of the drug ( prednisone) taken during treatment.

Symptoms of nephrotic syndrome

The only specific symptom of nephrotic syndrome is swelling. Other symptoms ( for example, nausea, vomiting, pain in the heart, weakness, decreased performance, shortness of breath, impaired growth and development, etc.), which may occur in a patient with this pathology, are classified as its nonspecific manifestations. These symptoms are additive. They may or may not occur with it. Swelling always serves as one of the mandatory clinical criteria for nephrotic syndrome.
The difficulty in diagnosing nephrotic syndrome is that this syndrome is more laboratory than clinical, since most of its signs are determined using laboratory tests and are not recognized during a routine examination of the patient. Therefore, to establish the fact that a patient has nephrotic syndrome, it is not enough to simply detect swelling on his body. In such cases, he must prescribe the necessary laboratory tests.

Main symptoms observed in patients with nephrotic syndrome

Symptom	The mechanism of appearance of this symptom	How does this symptom manifest itself?
Edema	In nephrotic syndrome, the patient's body loses huge amounts of protein through the kidneys. This protein comes into the urine from blood plasma. Such constant losses are accompanied by a decrease in the amount of proteins in the blood. One of the functions of plasma proteins is to maintain blood oncotic pressure. This pressure determines in which direction the intravascular fluid will move. The less proteins in plasma, the lower its oncotic pressure. If the oncotic pressure in the vessels is low, then the liquid does not stay in them for a long time and leaves them, then entering the intercellular spaces ( because the pressure is higher in them) various tissues rich in subcutaneous fat, resulting in the formation of edema.	The severity of edema usually correlates ( tied) with a degree of proteinuria ( that is, the intensity of the patient’s loss of protein in the urine). Swelling, as a rule, first appears in the area of ​​the face, eyelids, lower back, and genitals. Further, the swelling spreads to the arms and legs, less often to the torso. The rate of occurrence and distribution of edema may vary. They can develop instantly, literally overnight, or they can appear gradually over several days, weeks and even months. When palpated, the swollen skin is soft ( loose). If you press on it, then immediately after that a hole is formed at the site of the depression. Edema areas in nephrotic syndrome move easily. Swelling of the external genitalia makes urination difficult.
Heartbeat	In most patients with nephrotic syndrome, fluid accumulates not only externally ( under the skin), causing peripheral edema, but also in various cavities of the body. If fluid accumulation occurs in the pericardial cavity ( cardiac sac), then the patient experiences palpitations and pain in the heart area. Accumulation of fluid in the chest cavity ( hydrothorax) causes shortness of breath. Fluid entering the abdominal cavity contributes to the development of ascites and the appearance of nausea, vomiting, diarrhea and bloating.	Cardiac symptoms ( pain, palpitations), are slightly less common than from the gastrointestinal tract ( nausea, vomiting, diarrhea) and lungs ( dyspnea). The intensity of these symptoms is always individual and is largely determined by the degree of proteinuria. The sequence of appearance of all these symptoms may vary. Gastrointestinal symptoms usually appear after eating. Shortness of breath, pain in the heart and palpitations are present in patients both at rest and during physical activity.
Pain in the heart area
Dyspnea
Nausea
Vomit
Diarrhea
Tearing	The appearance of lacrimation is caused by swelling of the conjunctiva ( mucous membrane) eye.	Watery eyes are an intermittent symptom of nephrotic syndrome.
Disorders of growth and development	Impaired growth and development occurs as a result of various metabolic disorders that can be identified in nephrotic syndrome. For example, with this pathology the amount of microelements in the body decreases ( iron, zinc, cobalt) and macroelements ( calcium), playing a great role in the development and growth of various tissues ( bones, nervous system, skin, cartilage, etc.).	Impaired growth and development are quite clearly observed in children suffering from nephrotic syndrome for a long time. Such children often lag behind their peers in development, both in general physical and intellectual terms.
Tetany	In nephrotic syndrome due to calcium metabolism disorders ( there is very little of it in the blood) convulsive attacks may be observed ( tetany). Hypocalcemia ( decrease in blood calcium) occurs as a result of a metabolic disorder of metabolites ( products of exchange) vitamin D in the body, which is involved in the regulation of phosphorus-calcium metabolism.	Tetany does not occur in all patients. It is more often observed in children and is combined with signs of osteomalacia and osteoporosis ( slowdown in the growth and development of bones, their excessive fragility, skeletal deformation, development of fractures, the appearance of pain in bones and muscles, etc.).
Skin paleness	Pallor of the skin, headache, decreased ability to work and weakness appear with nephrotic syndrome due to the presence of anemia ( decrease in the amount of hemoglobin and red blood cells in the blood).	These symptoms are quite common in patients with nephrotic syndrome. They appear periodically or are present to them constantly. Their intensity is always individual.
Headache
Decreased ability to work
Weakness
Weight gain	Weight gain is caused by the accumulation of additional fluid in the subcutaneous fat and various cavities of the body ( chest, abdominal, etc.).	An increase in body weight occurs as free fluid accumulates in the tissues. The rate of its increase cannot be predicted, since it depends on many factors ( the patient’s nutrition, the presence of additional diseases, the severity of nephrotic syndrome, etc.).
Dystrophic changes in the skin and its appendages	Dystrophic changes in the skin and its appendages ( nails, hair) in nephrotic syndrome are caused by disturbances in the metabolism of microelements ( zinc, iron, cobalt, copper) and a decrease in their concentration in the blood.	The skin with nephrotic syndrome is dry, rough, and often peels off. You can see cracks on it. Hair and nails become brittle and dull.

Signs of nephrotic syndrome

Nephrotic syndrome is characterized by the appearance of certain symptoms in the patient. Almost all of these signs relate to laboratory indicators, so they are determined by conducting special studies. The main changes observed in nephrotic syndrome can be identified using a complete blood count, biochemical blood test, examination of the hemostatic system and a general urinalysis. The main sign of nephrotic syndrome in a general urinalysis is massive proteinuria ( protein excretion in urine), in which the total protein content in the urine should exceed 3.0 - 3.5 grams per day. Such protein losses are one of the main criteria for nephrotic syndrome in adults ( in addition to edema, hypoproteinemia and hypoalbuminemia).

In children, the degree of proteinuria is calculated based on their body weight. In nephrotic syndrome, the amount of protein lost by their kidneys should be more than 50 mg per kilogram of body weight per day. In addition to proteinuria, leukocyturia can be observed quite often in a general urinalysis in nephrotic syndrome ( the appearance of leukocytes in the urine) and hematuria ( the appearance of red blood cells in the urine). Hyperaminoaciduria is much less common ( ), glucosuria ( ), hyperphosphaturia ( ).

The main signs of nephrotic syndrome in a biochemical blood test are hypoproteinemia ( ), hypoalbuminemia ( decrease in albumin in the blood), hyperlipidemia ( ), and secondary - an increase in urea, a decrease in the amount of iron, zinc, cobalt, calcium in the blood. The occurrence of hypoproteinemia in nephrotic syndrome is caused not only by damage to the glomerular filter and direct loss of plasma protein in the urine, which is observed in all diseases that cause this syndrome. Part of the plasma protein in nephrotic syndrome is removed from the vascular bed and undergoes intense catabolism ( the process of decay) in various tissues. In addition, with this syndrome, a lot of proteins, as a result of the development of peripheral edema, tend to leave the vessels into the interstitial ( intercellular) textile.

The total protein content in the blood serum in nephrotic syndrome decreases to 25–40 g/l. Such changes indicate a fairly pronounced degree of hypoproteinemia. The mechanisms of development of hypoalbuminemia in nephrotic syndrome are similar to those that cause the occurrence of hypoproteinemia. The concentration of albumin in blood plasma with this pathology can drop to 8–35 g/l. Since albumins perform many important functions in the circulatory system ( for example, they transport hormones, drugs, minerals, bind various toxic metabolites and transfer them to the liver, etc.), then a drop in their concentration leads to metabolic disorders ( metabolism) throughout the body. Albumin also helps maintain blood oncotic pressure. Therefore, their decrease is accompanied by an even greater increase in peripheral edema.

Hyperlipidemia does not serve as a baseline ( optional) criterion for diagnosing nephrotic syndrome, but it is one of the main ( very frequent, but not always occurring) its signs. Hyperlipidemia is a general term for an increase in the amount of fat in a patient's blood, but at its core it includes abnormal changes in several parameters ( some of which include not only fats). In particular, with nephrotic syndrome there is an increase in the blood levels of total cholesterol, non-esterified fatty acids, triglycerides, and low-density lipoproteins ( LDL), apoprotein B.

The origin of hyperlipidemia in this syndrome is explained by several theories. The main one is the one based on the mechanism of hypoalbuminemia. The fact is that hypoalbuminemia stimulates the synthesis in the liver of an increased amount of blood plasma proteins and special transporters ( lipoproteins), which transport fats in the blood. Since the patient has nephrotic syndrome, most of the protein produced in the liver is lost through the kidneys ( while the increased amount of lipoproteins in the blood persists and gradually increases, which indirectly contributes to the accumulation of fats).

Another theory suggests that hyperlipidemia in nephrotic syndrome is partly due to impaired breakdown processes ( catabolism) fats, due to disruption of certain enzymes ( for example, lipoprotein lipases) responsible for this process. The presence of hyperlipidemia in nephrotic syndrome has a detrimental effect on the state of the cardiovascular system ( promotes the development of atherosclerosis) and worsens the prognosis of the syndrome itself, since the increased content of fats in the blood ultimately leads to their deposition in the structures of the renal glomeruli ( especially those that are damaged). The accumulation of fat in the glomeruli stimulates the development of inflammatory and sclerotic changes in them, which contribute to the strengthening of nephrotic syndrome.

Changes in the hemostatic system ( that is, the blood clotting system) in nephrotic syndrome affect its cellular and plasma-coagulation link. If we talk about changes in the cellular unit, then here, mainly, pathological changes are observed in platelets, which acquire an increased ability to adhesion ( adhesion to any surface, usually to the vascular endothelium) and to aggregation ( platelets sticking together). This is caused by an increase in the amount of fibrinogen in the blood plasma, as well as hyperlipidemia ( increased amount of fats in the blood), hypoalbuminemia ( decrease in the amount of albumin in the blood) and a decrease in the production of nitric oxide in vascular endothelial cells, which prevents excessive platelet aggregation.

In the plasma-coagulation link of hemostasis, in addition to increasing the fibrinogen already mentioned just above, the concentration of some coagulation factors in the blood also increases ( ). In addition to the functioning of the blood coagulation system in nephrotic syndrome, the functioning of the anticoagulation system, which normally balances with the coagulation system and controls its activity, is also disrupted. Disturbances in the anticoagulant system occur in the fibrinolysis system, which is responsible for the decomposition ( resorption) new blood clots in the vessels. These disorders are caused by the loss in urine of the main components of the fibrinolysis system ( mainly plasminogen). In nephrotic syndrome, the patient loses a sufficient amount of natural anticoagulants through the kidneys ( antithrombin III, protein S), preventing the formation of blood clots in blood vessels. Due to such extensive and serious changes in the hemostatic system, patients with nephrotic syndrome very often experience thrombosis of the deep veins of the legs, renal veins, coronary arteries and thromboembolic complications ( most often - pulmonary embolism - PE).

Diagnosis of nephrotic syndrome

The diagnosis of nephrotic syndrome is made based on clinical results ( taking anamnesis, palpation, examination of the patient) and laboratory ( general, biochemical blood test, general urine test, study of the state of the hemostatic system) research. An important part of diagnosing this syndrome is establishing its cause ( since nephrotic syndrome is not an independent disease, but appears against the background of various other diseases). For this purpose, not only the methods used to diagnose nephrotic syndrome itself are prescribed, but also some other examinations, for example, radiation research methods ( ultrasound, computed tomography, magnetic resonance imaging), other laboratory tests ( immunological, genetic blood test, urine test according to Nechiporenko, according to Zimnitsky, etc.), kidney biopsy, electrocardiogram ( ECG), urography, scintigraphy, pulmonary radiography, etc. These additional studies help not only to detect the underlying pathology, but also to establish various complications of nephrotic syndrome.

Methods for diagnosing nephrotic syndrome

Method name	Methodology	What signs of nephrotic syndrome does this method reveal?
History taking	History ( anamnestic data) is information obtained by a doctor when questioning a patient during a medical consultation. The anamnestic data includes not only the patient’s complaints, but also other important information regarding the circumstances of the onset of the disease, its clinical course, as well as the living conditions of the patient himself.	In the process of collecting anamnesis, you can detect the main symptoms of nephrotic syndrome ( for example, swelling, nausea, vomiting, pain in the heart, weakness, decreased performance, shortness of breath, impaired growth and development, etc.), the sequence of their appearance and intensity. An important step in collecting anamnesis is to establish whether the patient has kidney or pancreas diseases ( diabetes mellitus), blood vessels, rheumatic diseases, and the use of various toxic substances that could contribute to the development of nephrotic syndrome.
Patient examination	The patient is examined by a doctor during a consultation. The essence of the method is a visual examination of the external integument of the patient’s body to identify abnormal changes.	In nephrotic syndrome, changes are most often found in the skin and its derivatives ( hair, nails), muscular system, joints. The skin of patients is usually swollen, with dystrophic changes ( peeling, covered with cracks, pale color, dry), hair and nails are brittle and dull. After swelling subsides, muscle atrophy can be detected ( decrease in muscle mass). Some joints may become enlarged due to fluid accumulation in them.
Palpation	Palpation ( palpation) the doctor examines certain areas of the patient’s body during his examination.	The main signs that can be detected by palpation are hepatomegaly ( liver enlargement) and swelling. Edema is the main clinical sign of nephrotic syndrome. Some swelling may not be detected during normal visual examination. In such cases, palpation helps. The doctor needs it to clarify the nature of the edema. Edema in nephrotic syndrome is soft, easily moved and has a dough-like consistency.
General blood analysis	Blood for general and biochemical blood tests is taken from the ulnar vein, in the morning, on an empty stomach. Then it is delivered to the laboratory, where it is analyzed in special biochemical and hematological analyzers.	A general blood test for nephrotic syndrome can reveal anemia ( decrease in the number of red blood cells and hemoglobin), increase in ESR ( erythrocyte sedimentation rate), eosinophilia ( increased levels of eosinophils in the blood), leukocytosis ( increase in white blood cell count) and lymphocytosis ( increase in the number of lymphocytes).
Blood chemistry		A biochemical blood test helps detect certain changes in the patient’s blood biochemical composition, for example, hypoproteinemia ( decrease in total protein in the blood), hypoalbuminemia ( decrease in albumin in the blood), an increase in the concentration of cholesterol, non-esterified fatty acids, triglycerides, low-density lipoproteins ( LDL), apoprotein B, urea, creatinine, decreased amount of iron, zinc, cobalt, calcium.
General urine analysis	Urine collection is carried out in the morning. Urine should be collected in sterile 200 ml plastic containers. The collected urine must then be delivered to the laboratory, where it will be biochemically and microscopically analyzed.	The main sign of nephrotic syndrome in a general urinalysis in adults is severe proteinuria ( protein excretion in urine), in which the total protein content in the urine exceeds 3.0 - 3.5 grams per day. In children, proteinuria, characteristic of nephrotic syndrome, should reach 50 mg/kg body weight/day or higher. Sometimes leukocyturia occurs with this syndrome ( the appearance of leukocytes in the urine), hematuria ( the appearance of red blood cells in the urine), hyperaminoaciduria ( excretion of increased amounts of amino acids in urine), glucosuria ( increased levels of glucose in urine), hyperphosphaturia ( excretion of increased amounts of phosphate in the urine).
Study of the hemostasis system	To study the hemostasis system, venous blood is taken on an empty stomach from the ulnar vein in the morning. After this, the blood is placed in special devices ( coagulometers and aggregometers), which calculate the main indicators of the hemostasis system.	In nephrotic syndrome, an increase in platelet adhesion and aggregation, hyperfibrinogenemia ( increase in the amount of fibrinogen in the blood), increased concentrations of some coagulation factors ( II, V, VII, VIII, XIII, von Willebrand factor), decrease in plasminogen, antithrombin III and protein S. Thrombocytosis ( increase in platelet count) is rarely detected in nephrotic syndrome.

Treatment of nephrotic syndrome

Treatment of nephrotic syndrome should be carried out in three main areas. The underlying pathology should be treated first ( for example, allergies, diabetes, infectious disease, etc.), which provoked the appearance of this syndrome. The dosages of all drugs and their choice, in such cases, depend on the disease that caused the nephrotic syndrome, its severity, the severity of the syndrome itself, the general condition of the patient, the presence of impaired function of various organs in the patient ( heart, kidneys, liver, intestines, etc.), his age, etc.
The second direction of treatment is symptomatic and pathogenetic therapy of the syndrome itself, which is aimed at eliminating edema and reducing proteinuria ( protein excretion in urine), restoration of lipid balance and maintenance of normal functioning of the hemostatic system.

To reduce edema, diuretics are prescribed ( furosemide, veroshpiron). Sometimes diuretics ( diuretics) are prescribed together with dextran preparations ( reopolyglucin and reogluman), which improve microcirculation and are plasma substitutes. For very severe edema, salt-free albumin is prescribed ( to correct the total protein level in the blood plasma). To reduce protein excretion in urine, glucocorticoids are prescribed ( prednisolone, methylprednisolone), cytostatics ( azathioprine, cyclosporine, cyclophosphamide, chlorobutine, mycophenolate mofetil, etc.), ACE inhibitors ( ramipril, enalapril, lisinopril). Glucocorticoids and cytostatics have an immunosuppressive effect on the patient’s immune system, due to which they help reduce inflammatory processes in the renal glomeruli and, thereby, reduce proteinuria.

The antiproteinuric effect of ACE inhibitors is that these drugs help reduce intraglomerular pressure in the capillaries of the glomeruli, and also reduce the permeability of the glomerular filter for large proteins. In addition, ACE inhibitors are used for nephrotic syndrome in cases where the patient's systemic blood pressure increases. To restore lipid balance, doctors usually prescribe HMG-CoA reductase inhibitors ( lovastatin), fibrates ( fenofibrate, gemfibrozil), probucol, nicotinic acid. Anticoagulants ( heparin) and antiplatelet agents ( dipyridamole, aspirin) are necessary for such patients to maintain the normal functioning of the hemostatic system and prevent thrombosis.

The third direction of treatment of nephrotic syndrome is therapy aimed at preventing and eliminating its complications ( nephrotic crisis, thrombosis, infectious diseases, acute renal failure, allergies, cerebral and retinal edema). The choice of drugs and their dosage in this direction depends on many factors ( the patient’s condition, the severity of nephrotic syndrome, the body’s response to the ongoing etiotropic therapy, the presence of diseases of other organs in the patient, etc.), determining the possibility of developing a particular complication.

Diet for nephrotic syndrome

In case of nephrotic syndrome, it is necessary to limit the intake of table salt to 3 grams per day. This is necessary then to reduce the amount of sodium chloride entering the body, which is one of the factors causing the development of edema in nephrotic syndrome. It is advisable to exclude all salty foods from the diet ( pickles, marinades, seasonings, fish, etc.). It is especially important not to eat salty foods when swelling increases. Despite the fact that with this syndrome there is a significant loss of protein in the urine, the consumption of significant amounts of protein or intravenous administration of proteins does not improve the condition of such patients, so it is recommended to take a low-protein diet.

The daily protein intake for such patients should be calculated based on their body weight ( 0.8 – 1.0 g/kg). In addition to salt and protein, all patients with nephrotic syndrome should also reduce their fat intake ( up to 70 – 85 g) per day. This measure allows you to level the intensity of hyperlipidemia ( a condition associated with increased amounts of fat in the blood), which quite often occurs in patients with nephrotic syndrome and serves as a risk factor for the development of atherosclerosis.

Foods you can and cannot eat if you have nephrotic syndrome

Can be consumed	Cannot be consumed
eggs ( fried or hard-boiled); vegetable and butter; fruits and berries; fruit and vegetable juices; milk, skim ( or low fat) cottage cheese and sour cream; cereals ( semolina, wheat, rice, pearl barley) and pasta; broths ( meat and fish); jam; lean meats ( chicken, rabbit, veal) and fish ( for example, pike perch, hake, crucian carp).	beverages ( coffee, tea, cocoa, alcohol, carbonated drinks); nuts; legumes ( peas, soybeans, lentils); chocolate; vegetables ( spinach, horseradish, parsley, garlic, radish, radish, dill); ice cream; custard; raisin; pickled or pickled vegetables; seasonings; dairy ( cream, cottage cheese, sour cream, cheese); fatty meats ( lamb, pork, beef) and fish ( mackerel, salmon, herring, etc.).

How long can nephrotic syndrome last?

It is quite difficult to say exactly how long nephrotic syndrome can last, since its course and prognosis depend on many different factors ( the age of the patient, the nature of the kidney damage, the type of underlying disease, its duration, the adequacy of the medications used, the presence of complications, etc.). One of the important clinical prognostic indicators of nephrotic syndrome is the level of its response to hormonal and immunosuppressive therapy. If a patient develops steroid-resistant nephrotic syndrome, the prognosis of the disease is unfavorable. If the same activity is maintained, nephrotic syndrome will reach the terminal stage of chronic renal failure in 5–10 years.

In steroid-sensitive nephrotic syndrome, remission ( transition of pathology to an inactive form), in most cases, observed after 2–8 weeks of intensive treatment. The only drawback of this form of nephrotic syndrome is that after entering remission, it may reappear, that is, a relapse may occur ( re-exacerbation). Predicting the risk of recurrence of steroid-sensitive nephrotic syndrome is as difficult as predicting the total duration of this syndrome in a patient.

Is nephrotic syndrome treated with folk remedies?

Nephrotic syndrome is not recommended to be treated with folk remedies, due to their terribly low effectiveness. In addition, these drugs are not able to eliminate most of the main pathologies that contribute to the appearance of nephrotic syndrome. It is also worth recalling that the patient is most often unable to independently identify the presence of nephrotic syndrome in him or his loved ones, since for those close to him this syndrome is more laboratory than clinical. Peripheral edema is observed not only with nephrotic syndrome, but also with other diseases, for example, heart failure, liver cirrhosis, Parhon syndrome, intestinal amyloidosis, liver tumors, Crohn's disease, etc. Therefore, when edematous syndrome occurs, you should not immediately think about that the patient has developed nephrotic syndrome.

Edema is only one of the main criteria for diagnosing this syndrome. Without laboratory tests, it is impossible to say for sure whether a patient has it or not. If the patient knows for sure that he has nephrotic syndrome and still wants to try some folk remedies, then in this case he needs to consult with his doctor before using them, since many folk remedies have side effects, which may adversely affect the course of drug therapy.

What is the difference between nephritic and nephrotic syndromes?

Nephritic syndrome, like nephrotic syndrome, is not a separate disease. It appears when the glomeruli become inflamed. The inflammatory process in nephritic syndrome is usually caused by damage to the glomerular structures by the patient's immune system. In nephritic syndrome, unlike nephrotic syndrome, the patient must have arterial hypertension ( high blood pressure) and urinary syndrome ( the appearance in the urine of red blood cells, protein in quantities less than 3.0 - 3.5 g/l, leukocytes and casts). Edema may also occur with nephritic syndrome. However, they are, for the most part, barely noticeable and are localized mainly on the face, especially in the eyelid area. Sometimes, with nephritic syndrome, the phalanges of the fingers and forearms of both hands become severely swollen. The development of edema in this syndrome is more due to sodium retention in the body than to a lack of proteins in the blood ( severe deficiency of proteins in the blood in nephritic syndrome, as a rule, is not observed), as occurs in nephrotic syndrome.

What are the possible complications of nephrotic syndrome?

The occurrence of complications in nephrotic syndrome depends on many factors ( the type of underlying pathology that caused this syndrome, its severity, the presence of additional diseases in the patient, the patient’s age, etc.). Most of these complications are quite serious and can threaten the patient's life, so it is very important to be aware of the possibility of their occurrence and prevent their development. In the vast majority of cases, complications of nephrotic syndrome appear with systemic lupus erythematosus, systemic vasculitis, renal amyloidosis, and diabetes mellitus.

The main complications of nephrotic syndrome are:

• infections;
• swelling of the retina and brain;
• acute renal failure;
• nephrotic crisis;
• allergy;
• vascular disorders.

Infections
With nephrotic syndrome, patients often experience various infectious complications. This is due to a decrease in general resistance ( resistance) of their body against the background of constant losses in urine of protein and the gamma globulin fraction ( antibodies). In addition, when treating this pathology, doctors often prescribe steroidal anti-inflammatory drugs ( glucocorticoids), one of the side effects of which is immunosuppression ( suppression of immune system activity). Nephrotic syndrome usually involves a variety of bacterial infections, such as pneumonia ( pneumonia), pleurisy ( inflammation of the pleura), pleural empyema ( accumulation of pus in the pleural cavity), peritonitis ( inflammation of the peritoneum), sepsis, erysipelas of the skin. Sometimes viral and fungal infections can occur.

Swelling of the retina and brain
In some cases, nephrotic syndrome can cause vision problems. This is due to swelling of the retina. The retina is one of the layers of the eye in which the photoreceptor cells responsible for vision are located. The more pronounced the retinal edema, the more impaired the visual function of the eyes. Prolonged swelling can lead to vision loss, so it is very important to detect and eliminate it in time. Retinal edema in nephrotic syndrome is a temporary phenomenon; it immediately disappears when the required level of albumin in the blood is replenished and edema in other parts of the body disappears. Swelling of brain tissue is a very serious complication of nephrotic syndrome. Such swelling appears very rarely and, as a rule, occurs with massive swelling of the body. Its main symptoms are lethargy and severe lethargy of the patient. In such cases, mandatory medical intervention is required, since cerebral edema can develop into cerebral coma.

Acute renal failure
Acute renal failure ( surge arrester) is a pathology in which the kidneys suddenly stop performing their main functions ( carry out filtration and reabsorption) in full. AKI is not common in nephrotic syndrome. The causes of its appearance are usually renal vein thrombosis, sepsis, hypovolemic shock ( syndrome caused by a decrease in circulating blood volume), some medications ( non-steroidal anti-inflammatory drugs, diuretics). This complication is mainly observed in children or the elderly. Its main symptoms are oliguria ( decrease in the volume of urine excreted during the day), tachycardia ( increased heart rate), weakness, yellowing of the skin, increased blood pressure, nausea, abdominal pain, hyperkalemia ( increase in blood potassium), shortness of breath, increased blood concentrations of creatinine and urea.

Nephrotic crisis
Nephrotic crisis is one of the most severe complications of nephrotic syndrome, which sometimes leads to death. Nephrotic crisis is a situation in which there is a sharp deterioration in the general condition of patients with severe nephrotic syndrome, characterized by widespread edema of various parts of the body, massive effusions in the cavity ( chest, abdominal), significant hypoalbuminemia ( at which the concentration of albumin in the blood plasma drops to 10 g/l) and hypovolemia ( when the total volume of circulating blood decreases by 50–60% below normal). In a significant number of cases, this crisis develops spontaneously and unexpectedly.

The main symptoms of nephrotic crisis are severe abdominal pain, migrating erysipelas-like erythema ( redness) on the skin, changes in blood pressure ( it can increase or decrease), increased body temperature, leukocytosis ( increase in the number of leukocytes in the blood), leukocyturia ( presence of leukocytes in urine). Most often, nephrotic crisis occurs with nephrotic syndrome caused by chronic glomerulonephritis, diabetes mellitus, lupus nephritis ( kidney damage due to systemic lupus erythematosus).

Provoking factors that contribute to its occurrence are inadequate therapy with diuretics ( in which there is a rapid and significant decrease in the total volume of circulating blood), as well as diarrhea, some infectious complications of nephrotic syndrome ( intestinal infections, pneumonia, skin infections, etc.). The final stage of the nephrotic crisis is hypovolemic shock - an abnormal condition in which there is a significant decrease in the amount of fluid circulating in the vessels, which leads to insufficient blood supply to tissues and organs and the development of multiple organ dysfunction ( dysfunction of various organs) due to a lack of oxygen that threatens the patient's life.

Allergy
In nephrotic syndrome, some patients may experience hypersensitivity ( increased sensitivity) to certain medications ( most often - to antibiotics) and food ( for example, chocolate, citrus fruits, milk, eggs, red fish, etc.). Allergic complications of this syndrome manifest themselves in the form of rashes of various types and locations. They may be similar to the rashes observed with erysipelas, psoriasis, lichen planus, eczematous dermatitis.

Vascular disorders
Vascular disorders in nephrotic syndrome arise due to various disorders in the hemostatic system ( increased platelet aggregation and adhesion, increased concentrations of fibrinogen, some blood clotting factors, decreased plasminogen levels, etc.) and the presence of severe hyperlipidemia ( increase in the amount of fats in the blood). The most common vascular disorders in this pathology are venous thrombosis lower limbs, renal, coronary ( heart) and cerebral ( brain) arteries and pulmonary embolism ( TELA). Thrombosis of the heart vessels often leads to the development of coronary heart disease and myocardial infarction.

Hyperlipidemia does not directly contribute to the development of thrombosis. In this condition, the walls of blood vessels change, lipids are deposited in them ( mainly cholesterol), which causes the appearance of atherosclerotic plaques that interfere with normal blood flow. Atherosclerotic changes underlie the development of cerebral and kidney strokes, coronary heart disease and myocardial infarction in such patients.

Nephrotic syndrome is a disorder of the functioning of the kidneys, characterized by severe loss of protein, which is excreted from the body along with urine, a decrease in albumin in the blood and impaired metabolism of proteins and fats. The disease is accompanied by edema localized throughout the body and increased blood clotting ability. Diagnosis is made based on changes in blood and urine tests. Treatment is complex and consists of diet and drug therapy.

The disease can occur at absolutely any age, but nephrotic syndrome most often occurs in children aged one to four years, mostly in boys more often than in girls, and in adults up to forty years. The pathogenesis of the disease is that a large amount of proteins and lipids accumulate in a person’s urine, which seep into the cells of the skin, resulting in a symptom such as edema, which is characteristic of both acute and chronic forms of the disease. Without proper treatment, the disease can lead to complications that are dangerous to human health and life.

Etiology

The causes of the disease are not fully understood, but it is known that they can be primary and secondary. Primary sources include:

• hereditary predisposition;
• congenital pathologies of the structure and functioning of the kidneys;
• diseases of the urinary system, and kidneys in particular. These include: in pregnant women, etc.

Secondary causes are considered:

• viral infectious diseases occurring in the body, including;
• or its complicated form -;
• abuse of certain drugs that affect the functioning of the kidneys or liver;
• various allergic reactions;
• chronic heart failure;
• poisoning of the body with chemical compounds;
• autoimmune diseases;
• oncological tumors in the kidneys.

In some cases, but most often in children, it is quite difficult to determine the cause of the disease, but this is associated with the child’s weak immunity and his high susceptibility to a wide range of diseases. The pathogenesis of the disease directly depends on the etiological factors.

Varieties

As mentioned above, nephrotic syndrome can be classified into:

• primary– caused by various kidney diseases. It, in turn, can be hereditary or acquired. If with the first type everything is clear, it is inherited from close relatives, then with the second type a person is born healthy, but during his life he becomes ill with various kidney ailments, which causes the appearance of nephrotic syndrome;
• secondary– in which the disease develops against the background of other inflammatory processes in the body;
• idiopathic– the reasons for which are extremely difficult or even impossible to establish. This type is very common in children.

There are several types of nephrotic syndrome, which are classified according to how responsive they are to treatment with hormones:

• hormone sensitive– responds well to treatment;
• insensitive to hormones– in this case, other drugs are used aimed at suppressing the intensity of the pathological process.

Classification based on the volume of blood that circulates through the vessels:

• hypervolemic type – volume increased;
• hypovolemic– significant decrease in blood volume.

According to the severity of symptoms:

• spicy nephrotic syndrome - symptoms are expressed once;
• chronic– pathogenesis manifests itself with periods of remission and exacerbation. It often appears in adults due to improper or incomplete treatment in childhood.

Symptoms

Edema in nephrotic syndrome is the main symptom of the disease. At the first stage, they appear on the face, in particular on the eyelids, then spread to the genitals and lower back. After this, the exudate accumulates in the abdominal cavity, free space between the ribs and lungs, the pericardium, and often throughout the subcutaneous tissue. Other signs of nephrotic syndrome include:

• general weakness of the body;
• feeling of dryness in the mouth, despite strong thirst;
• severe headaches and dizziness;
• heaviness in the lower back;
• nausea and vomiting;
• diarrhea;
• urinary obstruction. The daily volume is reduced to one liter. Rarely, blood may be present;
• increase in abdominal volume;
• decreased appetite;
• the appearance of shortness of breath not only when moving, but also at rest;
• the skin takes on a pale tint and becomes dry, causing it to peel;
• seizures;
• fragility and hair loss;
• delamination of the nail plates.

If nephrotic syndrome has become chronic, the symptoms will be less pronounced, while in acute cases they will be more pronounced.

Complications

Untimely or inadequate treatment of nephrotic syndrome in children and adults can lead to the following consequences:

• infections that attack specifically weakened immunity during the treatment of the main illness. This happens due to the fact that during therapy, unwanted protective reactions of the immune system are avoided (special drugs are prescribed);
• nephrotic crisis - in which proteins in the body drop to a critical level and blood pressure rises. In some cases it causes the death of the patient;
• – occurs due to the accumulation of fluid and increased pressure in the intracranial box;
• , which is characterized by the death of heart tissue;
• the formation of blood clots in the arteries of the lungs;
• blood vessels, which becomes an impetus for circulatory disorders;
• – in which an insufficient amount of blood enters the internal organs;
• increased ability of blood to clot, as a result of which blood clots actually form;

If nephrotic syndrome is diagnosed in a pregnant woman, this will be fraught with additional complications for her and the newborn:

• gestosis, i.e. complicated course of pregnancy. The patient develops eclampsia with pronounced symptoms, which can cause death of the baby and coma of the mother;
• manifestation of congenital nephrotic syndrome in an infant;
• forced termination of pregnancy;
• premature birth.

Complications from the disease can occur not only in chronic cases, but also in acute ones.

Diagnostics

Differential diagnosis of nephrotic syndrome consists of a set of measures:

• collecting information about the disease - carried out to determine chronic or acute course;
• conducting an examination of the patient;
• laboratory tests;
• hardware examination of the patient.

When collecting a complete history of the disease, its pathogenesis, the degree of intensity of the symptoms and the time of their onset are taken into account, whether there were cases of detection of a similar disease in relatives, whether the patient underwent any treatment, what it was based on and what methods were used.

Diagnosis is carried out by a urologist. When examining a patient, he determines general state of the patient, examines the skin and palpates edema, which is characterized by some features:

• the skin at the site of swelling is pale;
• soft in density;
• the location depends on the stage of the disorder;
• most intense in daytime, and decrease towards evening.

And the patient undergoes laboratory diagnostics, during which general and examinations are carried out. Nephrotic syndrome is characterized by the detection of proteins in the urine, and low or increased levels of proteins, albumin, and cholesterol in the blood. The ability of the kidneys to filter is also determined. Urine analysis is carried out using the Nechiporenko and Zimnitsky test.

In order for blood and urine to show reliable results, it is best to take tests in the morning, on an empty stomach, having previously given up alcohol and smoking. Blood is taken from the cubital vein, and urine is collected immediately after a night's sleep.

Hardware examination of the patient consists of:

• kidney biopsy, during which a small part of the organ tissue is sampled for research;
• carried out to determine the presence of malignant neoplasms in this organ - cysts or cancerous tumors;
• Scintigraphy using contrast. The ability of the kidneys to filter the injected substance is determined;
• EGC – determines heart rate; nephrotic syndrome is characterized by its decrease;
• X-ray of the lungs can detect the accumulation of fluid in this area and the presence of blood clots.

After receiving all diagnostic results, the specialist prescribes treatment. It is also important to conduct a full differential diagnosis to exclude similar pathologies and prescribe the correct treatment.

Treatment

Therapy for nephrotic syndrome, similar to diagnosis, is not limited to one remedy. The patient is prescribed:

• glucocorticosteroid drugs - they help reduce swelling, have anti-inflammatory and antiallergic properties;
• cytostatic substances – prevent an increase in the number of pathological cells;
• immunosuppressants - prescribed to artificially lower immunity, which is considered normal for the treatment of this disorder;
• diuretic medications are in a great way relieve swelling;
• introduction into the blood of special solutions of a certain volume and concentration, which are calculated for each person individually. Among them are albumin, plasma-replacing substances and plasma itself, only in fresh frozen form;
• antibiotics, with different dosages for children and adults.

In some cases, hospitalization of the patient may be necessary; this is necessary:

• to determine the underlying disease that caused the syndrome;
• in case of respiratory dysfunction;
• for the treatment of complications.

In addition, patients are prescribed a diet, but only with certain differential diagnostic indicators:

• pronounced edema;
• depending on the protein content in urine;
• kidney filtration ability.

The diet consists of normalizing metabolism and preventing edema. This treatment method consists of:

• consuming no more than three thousand kilocalories per day;
• food intake should be done in small portions six times a day;
• excluding fried and spicy foods;
• salt restriction. Reduce its addition to food (no more than four grams per day);
• enriching food with protein, carbohydrates and potassium;
• reducing fluid intake to one liter.

Foods that can be consumed in any quantity during the diet:

• bran bread;
• lean fish and meat, steamed or baked in the oven;
• dairy and dairy products, but only with a low percentage of fat content;
• porridge and pasta;
• oil;
• vegetables and fruits, in any form, except fried;
• compotes, fresh juices, fruit drinks, herbal and berry teas;
• jam, sugar and honey.

During the diet you should give up:

• baked goods that have been prepared with added salt;
• fatty and fried foods;
• hard cheeses and fatty dairy products;
• margarine;
• legumes;
• confectionery products;
• pickles;
• onions and garlic;
• hot sauces and seasonings;
• sweet carbonated drinks;
• strong tea and coffee.

Prevention

Preventive measures for nephrotic syndrome include: