What happens in the kidneys
The glomerulus acts as a thin filter: it allows water and small substances to pass through, but retains blood proteins. When the filter is damaged, its permeability increases, and albumin is released into the urine in large quantities. The level of protein in the blood drops, oncotic pressure decreases, and fluid moves from the vessels into the tissues - edema appears. The liver responds by increasing the synthesis of lipoproteins and cholesterol increases. At the same time, proteins responsible for coagulation and immune defense are lost, so the risk of thrombosis and infections increases.
- Damage to the glomerular filter
- Loss of albumin in urine
- Decrease in blood protein and release of fluid into tissues
- Increased cholesterol levels
- Loss of anti-clotting proteins
- Decreased immune defense
Causes in children and adults
In children, the vast majority of cases are caused by minimal change disease, a form of glomerular disease that responds well to hormonal therapy and often does not require a biopsy. In adults, the spectrum is wider: membranous nephropathy, focal segmental glomerulosclerosis, diabetic nephropathy, amyloidosis. Nephrotic syndrome can be secondary - against the background of systemic lupus erythematosus, viral hepatitis, cancer, or taking certain medications. Therefore, the examination is always aimed at finding a specific cause, and not just at relieving swelling.
- In children, most often minimal change disease
- Membranous nephropathy in adults
- Focal segmental glomerulosclerosis
- Diabetic nephropathy
- Systemic lupus erythematosus and vasculitis
- Amyloidosis, hepatitis, drug-induced lesions
Symptoms
The first and most noticeable sign is usually swelling. In children, they often begin with the eyelids and face in the morning, in adults - with the feet and legs, and with severe loss of protein, fluid accumulates in the abdominal and pleural cavities. Urine may foam due to the large amount of protein, and its quantity decreases. Weakness, loss of appetite, sometimes nausea and abdominal pain appear. Blood pressure can be normal or high, depending on the cause. There is usually no blood in the urine in pure nephrotic syndrome.
- Swelling of the eyelids, face, feet, then the whole body
- Foamy urine
- Decreased urine output
- Rapid weight gain due to fluids
- Weakness, loss of appetite
- Shortness of breath due to fluid accumulation in the chest cavity
Survey
The diagnosis is based on a combination of massive loss of protein in the urine, low blood albumin, edema and high cholesterol. They start with a general urine test and quantitative assessment of protein - daily loss or the ratio of protein and creatinine in a single serving. Albumin, total protein, lipid profile, creatinine and filtration rate are assessed. An ultrasound of the kidneys shows their size and structure. To clarify the cause in adults and in case of an atypical course in children, a kidney biopsy is performed, and also examined for diabetes, lupus and hepatitis.
- General urine analysis and determination of protein in urine
- Daily protein loss or protein-creatinine ratio
- Albumin and total blood protein
- Lipid profile and creatinine
- Kidney ultrasound
- Kidney biopsy and screening for systemic diseases
Treatment and observation
Therapy is always prescribed by a nephrologist, and it consists of two parts: treatment of the syndrome itself and treatment of the cause. To reduce protein loss, drugs are used that reduce pressure in the glomerulus; in immune forms, glucocorticoids and other immunosuppressive drugs are used according to a strict regimen. Edema is reduced by limiting salt and diuretics under the supervision of a physician, but severe dehydration is dangerous. If the risk of thrombosis is high, prophylaxis is prescribed. It is important to control blood pressure and lipids, get vaccinated according to the calendar and avoid self-medication, especially painkillers.
- Treatment of the underlying disease
- Glucocorticoids and immunosuppression as indicated
- Drugs that reduce protein loss
- Salt restriction and controlled use of diuretics
- Prevention of thrombosis at high risk
- Regular monitoring of tests and pressure
