Published: 18 Jun 2025

ICD9: 581.9      ICD10: N04.9      ICD11: GB41

Nephrotic syndrome is a kidney disorder characterized by a specific set of abnormalities that result in the body excreting too much protein in the urine.
This protein loss leads to several other problems, including:

The main features, often remembered as the "hallmarks" of Nephrotic Syndrome, are:

Proteinuria: High levels of protein in the urine (specifically, albumin). This is the defining characteristic. Normal kidneys keep protein in the blood; in nephrotic syndrome, the kidney's filtering system is damaged, allowing protein to leak into the urine. Usually measured as >3.5 grams of protein per day.

Hypoalbuminemia: Low levels of albumin in the blood. Albumin is a protein that helps maintain fluid balance in the blood vessels. Because it's being lost in the urine, the blood albumin level drops.

Edema: Swelling, particularly in the ankles and feet, but can also occur in the face, around the eyes (periorbital edema), and even in the abdomen (ascites). This swelling happens because the low albumin levels reduce the osmotic pressure in the blood vessels, causing fluid to leak into the tissues.

Hyperlipidemia: High levels of cholesterol and triglycerides in the blood. The liver attempts to compensate for the protein loss by producing more proteins, including lipoproteins (which carry cholesterol and triglycerides). Also, the decreased oncotic pressure stimulates hepatic synthesis of lipoproteins.

Other possible features and complications:

Hypercoagulability: Increased risk of blood clots (thrombosis). This is due to changes in clotting factors caused by protein loss.

Increased risk of infection: Loss of immunoglobulins (antibodies) in the urine can weaken the immune system, making people more susceptible to infections.

Anemia: May develop due to loss of transferrin (a protein that carries iron) in the urine.

Elevated blood pressure (hypertension): Can occur, often related to underlying kidney disease.

Acute Kidney Injury (AKI): In severe cases, kidney function can rapidly decline.

Causes:

Nephrotic syndrome can be caused by a variety of factors, including:

Glomerular diseases: These are diseases that affect the glomeruli, the filtering units of the kidneys. Examples include:
Minimal change disease (most common in children)
Focal segmental glomerulosclerosis (FSGS)
Membranous nephropathy
Membranoproliferative glomerulonephritis (MPGN)
Diabetic nephropathy (caused by diabetes)
Lupus nephritis (caused by lupus)
Amyloidosis
Infections: Certain infections, such as hepatitis B, hepatitis C, HIV, and malaria, can trigger nephrotic syndrome.
Medications: Some medications, such as NSAIDs (nonsteroidal anti-inflammatory drugs) and certain antibiotics, can cause nephrotic syndrome.
Systemic diseases: Diseases that affect the whole body, such as diabetes, lupus, and amyloidosis, can also cause nephrotic syndrome.
Genetic factors: Some forms are inherited.

Diagnosis:

Diagnosis is typically made based on the following:

Urine test: To check for protein in the urine. A 24-hour urine collection is often used to measure the amount of protein excreted per day.
Blood test: To check for low levels of albumin and high levels of cholesterol.
Kidney biopsy: A small sample of kidney tissue is examined under a microscope to determine the cause of the nephrotic syndrome. This is often necessary to guide treatment.

Treatment:

Treatment depends on the underlying cause and severity of the condition. The goals of treatment are to:

Reduce protein in the urine: Medications such as ACE inhibitors or ARBs are often used to lower blood pressure and reduce protein leakage. Immunosuppressants (like steroids, cyclophosphamide, cyclosporine, tacrolimus, mycophenolate mofetil) are used for certain glomerular diseases.
Relieve edema: Diuretics (water pills) are used to help the body get rid of excess fluid.
Lower cholesterol: Statins (cholesterol-lowering medications) may be prescribed.
Prevent blood clots: Anticoagulants (blood thinners) may be used in some cases.
Treat underlying cause: Addressing the underlying condition (e.g., controlling diabetes, treating lupus) is crucial.
Dietary changes: A low-sodium, moderate-protein diet is often recommended.

Prognosis:

The prognosis of nephrotic syndrome varies depending on the underlying cause and the response to treatment. Some people with nephrotic syndrome can achieve complete remission, while others may develop chronic kidney disease.

In summary, Nephrotic Syndrome is a serious kidney disorder marked by significant protein loss in the urine, leading to low blood albumin, swelling, and high cholesterol. Prompt diagnosis and treatment are important to manage the condition and prevent complications.

Important note: This information is for general knowledge and informational purposes only, and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment. Self-treating can be dangerous.