Overview
What is Nephrotic syndrome?
- Nephrotic syndrome is a kidney disorder in which excessive protein leaks into the urine
- It usually occurs due to damage to the kidney’s filtering units, called glomeruli
- Glomeruli filter waste products and extra fluid from the blood to form urine
- Common waste products filtered by the kidneys include urea, creatinine, and acids
- In healthy kidneys, glomeruli prevent important proteins and blood cells from passing into the urine
- When the glomeruli are damaged, proteins such as albumin leak into the urine
- In nephrotic syndrome, more than 3 grams of protein may be lost in the urine within 24 hours
- This amount of protein loss is nearly 20 times higher than what is normally seen in healthy kidneys
Why is it important?
- Nephrotic syndrome is considered a relatively uncommon kidney disorder
- In children, it affects approximately 1 in 50,000 individuals each year
Who is commonly affected?
- Most cases in children are diagnosed between 2 and 5 years of age
- Boys are nearly twice as likely to develop nephrotic syndrome compared to girls
- In adults, nephrotic syndrome occurs in about 3 out of every 100,000 people annually
Causes / Why it Happens
Underlying causes
- Diabetic kidney disease: Diabetes can damage the kidney filters (glomeruli), leading to protein loss in urine
- Minimal change disease: Kidney tissue may appear normal under a microscope, despite abnormal kidney function
- Focal segmental glomerulosclerosis (FSGS): It involves scarring of parts of the glomeruli, which may occur due to genetic factors, medications, or other diseases
- Membranous nephropathy: Caused by thickening of the glomerular membranes due to immune deposits. It may be associated with hepatitis B, malaria, or cancer.
- Systemic lupus erythematosus (SLE): A chronic inflammatory disorder that can cause significant kidney damage.
- Amyloidosis: A disorder in which abnormal amyloid proteins accumulate in organs and damage the kidneys’ filtering system.
Risk factors for nephrotic syndrome include
- Kidney-damaging medical conditions: Diseases such as diabetes and other kidney disorders increase the risk of nephrotic syndrome.
- Certain medications: Long-term use of some drugs, including nonsteroidal anti-inflammatory drugs (NSAIDs) and certain anti-infective medications, may contribute to kidney damage.
- Infections: Infections such as HIV, hepatitis B, hepatitis C, and malaria can increase the likelihood of developing nephrotic syndrome.
Signs & Symptoms
Common symptoms
- Severe swelling: Commonly seen around the eyes, ankles, and feet due to fluid accumulation
- Foamy urine: Caused by excessive protein loss in the urine
- Weight gain: Results from increased fluid retention in the body
Warning signs include
- Blood clots: Increased risk of clot formation in the veins
- High cholesterol and triglycerides: Elevated blood lipid levels are common.
- Malnutrition: Excessive protein loss may lead to poor nutrition, anaemia, and low vitamin D and calcium levels
- High blood pressure: Kidney damage can contribute to hypertension
- Acute kidney failure: Severe glomerular damage may suddenly impair kidney function, sometimes requiring emergency dialysis.
- Chronic kidney disease: Progressive loss of kidney function can occur over time.
- Infections: Individuals with nephrotic syndrome are more prone to infections.
Diagnosis & Investigations
Diagnosis of nephrotic syndrome
- Urine tests: Urine albumin-to-creatinine ratio (uACR) is measured to detect excess protein in the urine, an early sign of kidney damage and nephrotic syndrome.
- Blood tests: Blood investigations help calculate the estimated glomerular filtration rate (eGFR), which assesses how effectively the kidneys filter waste products. A low eGFR may indicate impaired kidney function.
Additional diagnostic tests
- Ultrasonography: Helps identify structural kidney abnormalities, including a single kidney.
- Renal biopsy: Kidney biopsy commonly shows glomerular diseases as the cause of nephrotic-range proteinuria.
What patients should expect
- Taking medications regularly as prescribed is essential for controlling symptoms and protecting kidney function
- Recovery and improvement depend on the underlying cause of nephrotic syndrome
- Some patients may notice symptom relief within a few days of starting treatment
- In others, improvement may take several weeks or months
Treatment Options
Medication
- No definitive cure: Treatment mainly focuses on controlling symptoms and protecting kidney function
- Blood pressure and cholesterol medicines: Help reduce the risk of heart attack, stroke, and further kidney damage.
- Diuretics (water pills): Help remove excess fluid from the body, reducing swelling and controlling blood pressure.
- Injection therapies: Certain injectable medications may be used to reduce inflammation and improve kidney function.
- Blood thinners: Prescribed to prevent or treat blood clot formation.
Lifestyle changes
- Protein intake: Patients may benefit from limiting protein intake
- Salt restriction: Reducing sodium intake helps control swelling and maintain healthy blood pressure levels
- Low-fat diet: Limiting saturated fats and cholesterol may help manage high cholesterol associated with nephrotic syndrome
- Healthy protein choices: Lean protein sources such as fish and low-fat meat can support better cholesterol control
Non-surgical management
- Regular physical activity lowers the risk of blood clots; prolonged bed rest should be avoided.
- Regular follow-up required (every 3 months), during steroid therapy, to monitor side effects such as growth suppression.
- Steroid therapy may weaken bones; therefore, calcium and vitamin D supplementation can help maintain bone health.
- Annual eye examinations are recommended to screen for cataracts associated with long-term steroid use.
- Patients should ensure routine vaccination monitoring and updates to reduce the risk of infections.
When a procedure/surgery is needed
- If nephrotic syndrome progresses to kidney failure, dialysis or kidney transplantation may be required.
- Nephrotic syndrome can recur even after a kidney transplant if the underlying kidney disease is not adequately treated.
- Ongoing management of the original disease is important to protect the transplanted kidney from further damage.
Myths and Facts
Nephrotic syndrome only affects children.
Nephrotic syndrome affects both children and adults, though the underlying causes often differ between age groups.
Foamy urine always means someone has nephrotic syndrome.
Foamy urine can have other causes, but persistent foaminess is worth a medical evaluation, since it may be a sign of excess protein loss.
Nephrotic syndrome always leads to kidney failure.
Many patients respond well to treatment and maintain kidney function. Kidney failure generally occurs only in severe or untreated cases.
The swelling caused by nephrotic syndrome will go away on its own.
Swelling usually requires treatment, such as diuretics and dietary changes, to be managed effectively.
References
1. Nephrotic syndrome. Available from https://my.clevelandclinic.org/health/diseases/5989-nephrotic-syndrome. Accessed on 11 May 2026
2. Nephrotic syndrome. Overview. Available from https://www.mayoclinic.org/diseases-conditions/nephrotic-syndrome/symptoms-causes/syc-20375608. Accessed on 11 May 2026
3. Nephrotic syndrome. Available from https://www.uclahealth.org/programs/core-kidney/conditions-treated/glomerulonephritis/nephrotic-syndrome. Accessed on 11 May 2026
4. Nephrotic syndrome symptoms, causes and treatment. Available from https://www.kidneyfund.org/all-about-kidneys/other-kidney-problems/nephrotic-syndrome-symptoms-causes-and-treatment. Accessed on 11 May 2026
5. Tapia C, Bashir. Nephrotic Syndrome. Available from https://www.ncbi.nlm.nih.gov/books/NBK470444/. Accessed on 11 May 2026
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