Nephrotic syndrome

Seek urgent medical help for sudden shortness of breath, chest pain, coughing blood, fainting, or a painful swollen limb, because nephrotic syndrome increases blood-clot risk. Fever with feeling very unwell, rapidly worsening swelling, very little urine, severe weakness or confusion also needs urgent assessment. During pregnancy or after birth, urgent warning signs include a severe headache, vision changes, pain high in the abdomen, sudden swelling or difficulty breathing. Do not delay care to try a home remedy.

What is nephrotic syndrome?

Nephrotic syndrome is a pattern of findings caused by damage to the kidney’s glomeruli—the tiny filters that normally keep important proteins in the blood. It includes heavy protein loss in the urine, low blood albumin and swelling (oedema), often with high blood lipids. It is a syndrome rather than a single disease, so finding the cause is essential.

In adults, “nephrotic-range” protein loss traditionally means more than about 3.5 grams in 24 hours or an equivalent result from a spot urine ratio. Definitions and interpretation differ in children and in particular clinical settings. A urine dipstick can screen for protein but cannot safely establish the diagnosis or cause by itself.

Symptoms and why swelling occurs

Swelling may first be noticed around the eyes, then in the feet, ankles or legs; fluid can also collect in the abdomen or elsewhere. Foamy urine, rapid weight gain from fluid, fatigue and reduced appetite may occur. Loss of albumin changes fluid movement between blood vessels and tissues, while the kidneys may also retain sodium and water. Other kidney diseases, heart or liver disease, medicines and pregnancy-related conditions can cause similar swelling.

Causes in adults and children

Primary kidney causes include minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy. Minimal change disease is the leading cause in children; the pattern of adult causes varies with age, ancestry and other health conditions. Secondary causes include diabetes, lupus, amyloidosis, certain infections, some medicines and genetic conditions.

Give the clinician a complete medicine and supplement list, including non-steroidal anti-inflammatory drugs, but do not stop a prescribed medicine on your own. New protein in the urine, high blood pressure or swelling during pregnancy or after birth may signal pre-eclampsia and needs prompt maternity assessment rather than being assumed to be kidney disease.

Tests and diagnosis

After a dipstick finding, protein is quantified with a urine protein-to-creatinine or albumin-to-creatinine ratio, or sometimes a timed collection. Urine microscopy can look for blood cells, casts or other clues. Blood tests usually assess albumin, kidney function, electrolytes and lipids. Further tests for diabetes, autoimmune disease, infection, paraproteins or genetic disease are chosen from the history and findings rather than ordered indiscriminately.

A kidney ultrasound may be useful. Biopsy decisions depend on age and the clinical pattern. Most children with a typical initial presentation are treated without an immediate biopsy, while atypical features, steroid resistance or another suspected diagnosis may lead to biopsy or genetic testing. In adults, biopsy is often considered when it will clarify the cause and change treatment, after weighing risks. A nephrologist should guide this work-up.

Treatment targets the cause and complications

Treatment is individualised to the underlying disease, kidney function, severity and complications. A diuretic may reduce swelling, but too-rapid fluid removal can lower blood pressure or worsen kidney function, so weight, symptoms, electrolytes and kidney tests need monitoring. Medicines that block the renin–angiotensin system, such as an ACE inhibitor or ARB, can reduce protein loss and treat blood pressure in selected patients; they also require kidney and potassium monitoring and a pregnancy-safety review.

Immunosuppressive treatment, including corticosteroids, is appropriate only for particular diagnoses and protocols. It should not be started, copied from another person or adjusted without specialist supervision. Lipid-lowering treatment may be offered according to cardiovascular risk and whether nephrosis persists.

Confirmed blood clots require medical treatment. Preventive anticoagulation is not automatic: the clinician balances albumin level, diagnosis, immobility and other clot risks against bleeding risk. Do not self-treat with aspirin or an anticoagulant. Vaccination and prompt assessment of possible infection are important because the syndrome and some treatments increase infection risk.

Food, fluid and everyday monitoring

A clinician or renal dietitian may recommend limiting sodium and, in selected people, fluid to control swelling. The plan should reflect kidney function, medicines, blood pressure and nutritional status. Eating large amounts of protein does not replace urinary protein losses and can increase the kidney’s workload; avoid high-protein “cures,” extreme diets and unreviewed supplements. Maintain adequate nutrition with professional guidance, especially for children.

At home, record weight and swelling as advised and report a rapid increase. Follow the plan for blood-pressure and urine-protein checks, and attend blood tests for albumin, kidney function, electrolytes and treatment effects. Ask how to handle illness, missed medicines and vaccines, and when to contact the kidney team.

Outlook and follow-up

Complications can include infection, blood clots, high blood pressure, acute kidney injury, malnutrition and chronic kidney disease. Outcome depends on the cause and response to treatment. Some people enter remission; some relapse; others have persistent protein loss or progressive loss of kidney function. Regular nephrology follow-up helps detect recurrence, treatment toxicity and complications early. Seek review if swelling, foamy urine or weight gain returns rather than restarting old treatment yourself.