Nephrotic syndrome is a complex of symptoms that occurs with kidney damage and includes severe proteinuria, edema, disturbances in the metabolism of proteins and lipids. Nevertheless, pathology does not always accompany secondary and primary disorders of the kidney function, sometimes it acts as an independent nosological form.
The term has been used since 1949, replacing concepts such as nephrosis or lipoid nephrosis, and has been introduced into the modern WHO nomenclature. Statistics indicate that this syndrome occurs among all kidney diseases in about 20% of cases, other data indicate 8-30% of cases. Most often, the disease is found in childhood from 2 to 5 years, less often adults, whose average age is from 20 to 40 years old. But in medicine, a case of the development of the syndrome in the elderly and in new-borns is described. The frequency of its occurrence depends on the ethological factor by which it is caused. Women suffer more often than men in the case when the pathology develops against the background of rheumatoid arthritis and systemic lupus erythematosus.
- Causes of nephrotic syndrome.
- Symptoms of the nephrotic syndrome.
- Forms of nephrotic syndrome.
- Complications of nephrotic syndrome.
- Diagnostics of the nephrotic syndrome.
- Treatment of nephrotic syndrome.
- Prevention and prognosis of nephrotic syndrome.
Causes of Nephrotic Syndrome
The causes of nephrotic syndrome are diverse, distinguishing between both primary and secondary pathology.
Causes of primary nephrotic syndrome:
- The most common kidney disease caused by this syndrome is glomerulonephritis, both chronic and acute. In this case, nephrotic syndrome develops in 70-80% of cases.
- Other independent kidney diseases, against the background of which nephrotic syndrome occurs, are: primary amyloidosis, nephropathy of pregnant women, hypernephroma.
Causes of secondary nephrotic syndrome:
- Infections: syphilis, tuberculosis, malaria.
- Connective tissue diseases of a systemic nature: scleroderma, lupus erythematosus, rheumatoid arthritis.
- Diseases of an allergic nature.
- Hemorrhagic vasculitis.
- Periodic illness.
- Septic endocarditis with a protracted course.
- Exposure to the body of toxic substances, including heavy metals, bee and snake bite poisons, etc.
- Oncology of other organs.
- Thrombosis of the inferior vena cava, renal veins.
- Taking some medicines.
The idiopathic variant of the development of the disease (when the cause cannot be established) most often develops in childhood.
Turning to the pathogenesis of the syndrome, it can be noted that the most common is the immunological theory of its development.
This confirms several facts, including:
Experiments on animals showed that the introduction of nephrotoxic serum against the background of absolute health caused them to develop nephrotic syndrome.
Often the pathology develops in people who have allergic reactions to plant pollen, hypersensitivity to various drugs.
In addition to this syndrome, patients often have autoimmune diseases. Immunosuppressive treatment is beneficial.
Immune complexes that have a damaging effect on the basement membranes of the renal glomeruli are formed as a result of the contact of blood antibodies with external antigens (viruses, allergens, bacteria, pollen, etc.) and internal antigens (DNA, tumor proteins, cryoglobulins, etc.). Sometimes immune complexes are formed as a result of the production of antibodies to a substance that is reproduced by the basement membranes of the kidneys themselves. Whatever the origin of immune complexes, the degree of kidney damage will depend on what is their concentration inside the body and how long they affect the organs.
Another negative effect of immune complexes is their ability to activate inflammatory responses at the cellular level. As a result, histamine, serotonin and enzymes are released. This leads to the fact that the permeability of the basement membranes becomes higher, microcirculation in the capillaries of the kidneys is disturbed, and intravascular coagulation is formed.
Macroscopic examination shows that the kidneys are enlarged, their surface remains smooth and even, the cortical substance has a pale gray color, and the medulla is red.
Histology and optical microscopy reveal pathological changes with fatty and hyaline dystrophy of the kidneys, focal proliferation of the endothelium of organs, protein dystrophy of the renal tubules. If the disease has a severe course, then visualization of atrophy and necrosis of the epithelium is possible.
Symptoms of The Nephrotic Syndrome
The symptoms of nephrotic syndrome are typical and always appear monotonously, regardless of what triggered the development of the pathological process.
Among them are:
Massive proteinuria. It is expressed in a large amount of protein (mainly albumin) in the urine. This is the main symptom of this pathology, but it is not the only symptom of the disease.
In the blood serum, the level of cholesterol and triglycerides increases, while the number of phospholipids decreases. As a result, the patient develops hyperlipidemia. At the same time, the amount of lipids is so high that it can stain the serum part of the blood in a milky white color. As a result, only one appearance of blood can be judged on the presence of hyperlipidemia. It is assumed that the increase in blood lipids is due to their increased production in the liver with their retention in the vessels due to their high molecular weight. Disorders of kidney metabolism, a drop in the level of albumin in the blood, etc., also affect.
There is a jump in blood cholesterol. Sometimes its level can reach 26 mmol / l and even more. But most often the increase in cholesterol is moderate and does not exceed 10.4 mmol / l.
Swelling. They can be of varying severity, but they are present in all patients, without exception. The swelling is sometimes very severe, to such an extent that it limits the patient’s mobility, becoming an obstacle to the performance of work duties.
The patient has general weakness, increased fatigue. Weakness tends to increase, especially when nephrotic syndrome has been present for a long time.
Appetite suffers, the need for fluid increases, since thirst and dry mouth are present on an ongoing basis.
The amount of urine excreted becomes less. Nausea, vomiting, flatulence, abdominal pain, and loose stools are rare. Mostly these symptoms indicate severe ascites.
Characterized by headaches, pulling sensations in the lumbar region. With the course of the disease for many months, paresthesias, convulsions against the background of potassium loss, painful sensations in the muscles develop.
Hydropericarditis is indicated by shortness of breath, which disturbs the patient even during a state of rest, and not only against the background of physical exertion.
Patients, as a rule, are inactive. The skin is pale, the body temperature can be kept at normal levels, and maybe less than normal. As a result, the skin is cold and dry to the touch. Possibly peeling, brittle nails, hair loss.
Tachycardia develops against the background of heart failure or with anemia. Blood pressure is either lowered or normal.
A dense plaque is found on the tongue, the abdomen is enlarged.
The general metabolism is disturbed, as the function of the thyroid gland suffers.
A decrease in the volume of excreted urine is also a constant companion of pathology. At the same time, the patient excretes no more than a liter of urine per day, and sometimes 400-600 ml. Visible impurities of blood in the urine, as a rule, are not detected, but it is detected during microscopic examination.
Another clinical sign of the syndrome is blood hypercoagulation.
Symptoms of nephrotic syndrome can increase slowly and gradually, and sometimes, on the contrary, violently, which most often occurs in acute glomerulonephritis.
In addition, a distinction is made between pure and mixed syndrome. The difference lies in the absence or presence of hypertension and hematuria.
Forms of Nephrotic Syndrome
It is worth noting also three forms of the syndrome, among which:
Recurrent syndrome. This form of the disease is characterized by a frequent change of exacerbations of the syndrome to its remission. In this case, remission can be achieved through drug therapy, or it happens spontaneously. Nevertheless, spontaneous remission is observed quite rarely and mainly in childhood. The share of recurrent nephrotic syndrome accounts for up to 20% of all cases of the disease. Remissions can be quite long in duration and sometimes reach 10 years.
Persistent syndrome. This form of the disease is the most common and occurs in 50% of cases. The course of the syndrome is sluggish, slow, but constantly progressive. Stable remission cannot be achieved even with persistent therapy, and after about 8-10 years, the patient develops renal failure.
Progressive syndrome. This form of the disease differs in that nephrotic syndrome develops rapidly and can lead to chronic renal failure within 1-3 years.
Complications of Nephrotic Syndrome
Complications of nephrotic syndrome can be associated both with the syndrome itself, and be provoked by the drugs used to treat it.
Among the complications are:
Infections: pneumonia, peritonitis, furunculosis, pleurisy, erysipelas, etc. The most serious complication is considered to be pneumococcal peritonitis. Untimely antibiotic therapy can be fatal.
Nephrotic crisis is another rare but severe complication of nephrotic syndrome. It is accompanied by an increase in body temperature, abdominal pain, the appearance of cutaneous erythema with previous vomiting, nausea, loss of appetite. A nephrotic crisis often accompanies rapidly growing nephrotic shock with a marked drop in blood pressure.
Renal artery thrombosis leading to kidney infarction.
There is evidence that nephrotic syndrome increases the risk of cardiac ischemia and myocardial infarction.
Complications from taking medications for the treatment of nephrotic syndrome are expressed in allergic reactions, in the formation of gastric and intestinal ulcers with ulcer perforation, in diabetes mellitus, in drug psychoses, etc.
Almost all of the above complications are life-threatening for the patient.
Diagnostics of The Nephrotic Syndrome
Clinical laboratory research is the leading method for the diagnosis of nephrotic syndrome. However, examination and instrumental examination methods are required. During the examination of the patient, the doctor visualizes the coated tongue, edema, dry and cool skin, as well as other visual signs of the syndrome.
In addition to examining a doctor, it is possible to prescribe the following types of diagnostics:
The general analysis of urine will reveal an increase in relative density, cylindruria, leukocyturia, cholesterol in the sediment. Proteinuria in the urine is usually severe.
A blood test will indicate an increase in ESR, eosinophilia, an increase in platelets, a drop in hemoglobin and erythrocytes.
A coagulogram is necessary to assess blood clotting.
A biochemical blood test reveals an increase in cholesterol, albumin, and proteinmia.
To assess the degree of damage to the kidney tissue, it is necessary to conduct an ultrasound scan with an ultrasound scan of the renal vessels, nephroscintigraphy.
It is equally important to determine the cause of nephrotic syndrome, which requires an in-depth immunological examination, it is possible to conduct a biopsy of the kidneys, rectum, gums, and perform angiographic studies.
Treatment of Nephrotic Syndrome
Treatment of nephrotic syndrome is carried out in a hospital under the supervision of a nephrologist.
General recommendations for doctors practicing in urological departments are reduced to the following points:
- Compliance with a salt-free diet with restriction of fluid intake and selection, depending on the age of the patient, the amount of protein.
- Infusion therapy using Repoliglukin, Albumin, etc.
- Reception of cytostatics.
- Taking diuretics.
- Immunosuppressive treatment.
Diuretic drugs play an important role in the treatment of kidney disease. However, their intake must be strictly controlled by specialists, otherwise serious health problems may develop. Among those: metabolic acidosis, hypokalemia, sodium leaching from the body, a decrease in the volume of circulating blood. Since taking large doses of diuretics in the presence of renal failure or with hypoalbuminemia is often complicated by shock, which is difficult to correct, patients should be treated with caution. The shorter the duration of taking diuretics, the better. Their repeated reception is advisable to prescribe only with an increase in edema and with a decrease in the amount of urine separated.
To relieve the patient of edema, it is recommended to take Furosemide, either intravenously or orally. It is a very powerful decongestant, but its effects are short-lived.
Ethacrynic acid may also be prescribed to relieve swelling. Hypothiazide has a less pronounced effect. Its effect will be noticeable 2 hours after the initial intake.
Another important link in the fight against edema is diuretics, which help to preserve potassium in the body. These are drugs such as Amiloride, Triamteren, Aldactone, Veroshpiron. Veroshpiron is especially effective in combination with Furasemide.
If the edema is due to amyloidosis, then they are difficult to correct with the help of diuretics.
Glucocorticosteroids such as Prednisolone and Methylprednisolone are the drugs of choice for immunosuppressive treatment of nephrotic syndrome. These drugs have a direct effect on immune complexes, suppressing their susceptibility to inflammatory mediators, reducing their production.
Corticosteroids are prescribed in three ways:
Oral administration of drugs with the issuance of the maximum dose in the morning and subsequent dose reduction in 2-4 doses. The total dose is calculated taking into account the work of the adrenal cortex. Treatment is carried out at the very start of therapy.
An alternative administration of Prednisolone is used as a maintenance therapy. The daily dose of the drug is offered to the patient with an interval of one day. This allows you to maintain the achieved effect and reduce the severity of side effects from taking corticosteroids. Also, the alternative regimen for taking Prednisolone includes a scheme for dispensing the drug to the patient daily for 3 days, after which they take a break of 3 or 4 days. As for the effect, these modes, as a rule, have no differences in this regard.
The last option for taking glucocorticoids is pulse therapy. For this, a very high concentration of the hormone is created in the blood, since it is administered intravenously, drop by drop, over 20-40 minutes. The dropper is placed once, no more than once every 48 hours. The number of approaches and the exact dosage must be calculated by the doctor.
Naturally, you need to remember about the abundance of side effects that glucocorticoids give, among them: insomnia, edema, obesity, myopathy, cataracts. It is necessary to cancel drugs very carefully, as there is a risk of developing acute adrenal insufficiency.
As for the treatment with cytostatics, for this purpose, drugs such as Cyclophosphamide (Cytoxan, Cyclophosphamide) and Chlorambucil (Leukeran, Chlorbutin) are used. These drugs are aimed at suppressing cell division, and they do not have a selective ability and affect absolutely all dividing cells. The drug is activated in the liver.
Cyclophosphamide is treated with the method of pulse therapy, administered intravenously, against the background of pulse therapy with corticosteroids.
Chlorambucil is taken orally for 2-2.5 months. The drug is prescribed mainly for the recurrent form of the disease.
Antibiotic therapy is necessary if the syndrome develops against the background of chronic glomerulonephritis. For this purpose, drugs such as Cefazolin, Ampicillin, Doxycycline are most often used.
If the disease has a severe course, then it is necessary to carry out plasmapheresis, hemosorption, intravenous administration of Dextran, Rheopolyglutin, protein solutions.
After the patient is discharged from the hospital, he is shown observation by a nephrologist in the clinic at the place of residence. Supportive pathogenetic therapy is carried out for a long time. Only a doctor can make a decision about the possibility of its completion.
Also, patients are recommended sanatorium treatment, for example, on the southern coast of Crimea. You need to go to sanatoriums during the remission of the disease.
As for the diet, patients should adhere to a therapeutic diet number 7. This allows you to reduce swelling, normalize metabolism and urine output. It is strictly forbidden to include fatty meats, foods containing salt, margarine, trans fats, all legumes, chocolate products, marinades and sauces in the menu. Meals should be fractional; cooking methods should be gentle. Water is consumed in limited quantities, its volume is calculated on an individual basis, depending on the patient’s daily urine output.
Prevention and Prognosis of Nephrotic Syndrome
Preventive measures include persistent and early treatment of glomerulonephritis, as well as other kidney diseases. It is necessary to carry out a thorough sanitation of foci of infection, as well as to engage in the prevention of those pathologies that serve as etiological factors for the onset of this syndrome.
Medications should only be taken as recommended by the attending physician. Particular care should be taken in relation to those drugs that are nephrotoxic or may cause an allergic reaction.
If the disease manifested itself once, then in the future, medical supervision, timely delivery of tests, avoidance of insolation and hypothermia are necessary. With regard to employment, the work of people with nephrotic syndrome should be limited in terms of physical exertion and nervous strain.
The prognosis for recovery depends mainly on what caused the development of the syndrome, as well as on how long the person went without treatment, what is the patient’s age and on other factors. It is worth considering that complete and lasting recovery is rarely achieved. This is possible, as a rule, in childhood with primary fat nephrosis.
In other groups of patients, sooner or later, a relapse of the disease is observed with an increase in signs of renal impairment, sometimes with malignant hypertension. As a result, the patient develops renal failure, followed by azotemic uremia and death. Therefore, the earlier treatment is started, the more favorable the prognosis.