Nephrotic Syndrome

Introduction

Nephrotic syndrome is a condition where the kidneys allow too much protein to leak into the urine. This happens because the tiny filters in the kidneys, called glomeruli, are damaged. When this occurs, the protein levels in the blood drop, leading to swelling in various parts of the body, particularly around the face, legs, and feet.

Causes

Most cases of nephrotic syndrome in children are idiopathic, meaning the exact cause is unknown. However, recent research suggests that it may be related to problems with the immune system.

Prevalence

This condition is more common in young children, especially boys, with an incidence of about 1.15 to 16.9 per 100,000 children. The median age of presentation is two to three years old.

Signs and Symptoms

The main signs of nephrotic syndrome include:

• Swelling in various body parts especially around the eyes and in the lower limbs
• Foamy urine
• Reduced urine output
• Abdominal pain

Diagnosis

To diagnose nephrotic syndrome, doctors will conduct blood and urine tests:

• Urinalysis for protein levels in urine.
• Blood tests for kidney function, blood protein level, lipid profile, clotting profile, immunological tests and infectious assessment.
• Investigations for potential underlying causes would be performed as well.

Common Complications

Nephrotic syndrome can lead to several complications:

• Increased risk of infection: Treatment with steroids weakens the immune system. Loss of antibodies in the urine also increases susceptibility to infection.
• High cholesterol levels: It is due to loss of protein that helps manage fats in the blood, especially if the nephrotic syndrome has lasted for a long time. The level of cholesterol usually returns back to normal when the child recovers from nephrotic syndrome.
• Blood clots in veins: Increased thickness of blood and loss of protein factors can lead to clots forming, especially in the legs. This may cause leg swelling and pain.
• Kidney injury: Rarely, co-existing infections, dehydration and use of certain medications can harm kidney function.

Management

General

• Dietary changes: Reducing salt intake and managing fluid consumption to control swelling and decrease the risk of developing high blood pressure.
• Medications:
  • Steroids like prednisolone are commonly used to reduce inflammation. It is usually given orally. The initial therapy usually comprises of four to six weeks of daily steroid followed by alternate-day dosing of steroid for four to six weeks. Your doctor will let you know the exact amount of medicine your child needs to take.
  • Diuretics may be prescribed to help remove excess fluid from the body.

Clinical course

Nephrotic syndrome can respond differently to treatment:

• Steroid sensitive nephrotic syndrome (SSNS): responds well to steroids.
• Steroid resistant nephrotic syndrome (SRNS): does not respond to standard steroid treatment.

Most children will eventually achieve remission, but about one-third may continue to have symptoms into adulthood.

Special treatment options available in HKCH

For children who experience relapses while on steroid treatment or do not respond to steroids, other immunosuppressants may be considered. Your doctor will determine the most suitable medication for your child, which may include:

• Levamisole
• Mycophenolate mofetil (MMF)
• Calcineurin inhibitors, such as Tacrolimus (FK)
• Biologics, like Rituximab or Obinutuzumab, for cases that are resistant to other treatments

At HKCH, we also provide therapeutic drug testing to monitor the effectiveness of treatments by measuring drug levels in the body.

HKCH serves as the tertiary referral center for patients with complicated nephrotic syndrome, including:

• Children under the age of one presenting with symptoms.
• Children who experience recurring protein in their urine after steroid treatment has been discontinued.
• Children who do not respond to steroid treatments.
• Children with significant complications or kidney function issues.

Genetic tests may be recommended for patients exhibiting unusual symptoms, as they help establish an accurate diagnosis, predict potential outcomes, customize treatment options, and provide support for family counselling.

For individuals over the age of 12 who are at higher risk of kidney inflammatory disorders or do not respond well to steroid treatments, a kidney biopsy might be suggested by doctor. This procedure involves removing a small tissue sample from the kidney using a needle, which is then examined in the laboratory under a microscope.

At HKCH, our paediatric nephrology team will develop a personalized management plan for your child after conducting a thorough evaluation.

Follow-up Care

It is important to have regular monitoring for protein levels in urine and ensure vaccinations (especially the pneumococcal and varicella vaccines) are up to date. Patient would also be regularly followed up in outpatient clinics with review of potential side effects of medications.

Useful Resources

infoKID

National Kidney Foundation

Acknowledgement

Dr Fanny Ho on behalf of Nephrology Team, HKCH

Initial posting: Nov 2025

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