Nephrotic Syndrome in Children

Nephrotic syndrome is a kidney disorder that causes the kidneys to excrete large amounts of protein in the urine, leading to low levels of protein in the blood. It is characterized by four main features: massive proteinuria (excretion of >3.5 grams of protein per 1.73m² body surface area per day), hypoalbuminemia (low albumin levels in the blood), hyperlipidemia (elevated lipid levels in the blood), and edema (swelling).

Causes

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

• Minimal change disease: This is the most common cause of nephrotic syndrome in children, accounting for approximately 80% of cases. The exact cause is unknown, but it is thought to be related to an abnormal immune response.
• Focal segmental glomerulosclerosis (FSGS): This is a type of kidney disease that can cause nephrotic syndrome. It is characterized by scarring of the glomeruli, which are the filtering units of the kidneys.
• Membranous nephropathy: This is a type of kidney disease that can cause nephrotic syndrome. It is characterized by thickening of the glomerular basement membrane, which leads to proteinuria.
• Post-streptococcal glomerulonephritis (PSGN): This is a type of kidney disease that can occur after a streptococcal infection, such as strep throat. It can cause nephrotic syndrome in some cases.

Symptoms

The symptoms of nephrotic syndrome in children may include:

• Edema (swelling) of the face, arms, legs, and abdomen
• Weight gain due to fluid retention
• Fatigue
• Loss of appetite
• Nausea and vomiting
• Diarrhea or constipation

Diagnosis

The diagnosis of nephrotic syndrome in children is based on a combination of clinical evaluation, laboratory tests, and imaging studies. The following tests may be used to diagnose nephrotic syndrome:

• Urinalysis: This test checks for the presence of protein in the urine.
• Serum albumin level: This test measures the level of albumin in the blood.
• Lipid profile: This test measures the levels of lipids, such as cholesterol and triglycerides, in the blood.
• Renal ultrasound: This imaging study uses sound waves to evaluate the size and structure of the kidneys.
• Kidney biopsy: This procedure involves removing a small sample of kidney tissue for examination under a microscope. It is used to determine the underlying cause of nephrotic syndrome.

Treatment

The treatment of nephrotic syndrome in children depends on the underlying cause and severity of the condition. The following treatments may be used:

• Corticosteroids: These medications, such as prednisone, are often used to treat minimal change disease and other forms of nephrotic syndrome.
• Immunosuppressive agents: These medications, such as cyclophosphamide or rituximab, may be used to treat FSGS, membranous nephropathy, and other forms of nephrotic syndrome that do not respond to corticosteroids.
• Diuretics: These medications, such as furosemide, may be used to reduce edema and fluid retention.
• Albumin infusions: In some cases, albumin infusions may be used to replace lost protein and help improve blood volume.

Prognosis

The prognosis for children with nephrotic syndrome varies depending on the underlying cause and response to treatment. Children with minimal change disease tend to have a good prognosis, with approximately 80% achieving complete remission within 8 weeks of starting corticosteroid therapy. However, children with FSGS or other forms of nephrotic syndrome may have a poorer prognosis, with a higher risk of developing end-stage renal disease (ESRD) and requiring dialysis or kidney transplantation.