What is the most common cause of nephrotic syndrome in children?

• A. Minimal change disease
• B. Focal segmental glomerulosclerosis
• C. Membranous nephropathy
• D. Acute interstitial nephritis

Answer: (A)

Minimal change disease is the most common cause of nephrotic syndrome in children. This condition typically presents with edema, hypoalbuminemia, heavy proteinuria, and often normal blood pressure with preserved kidney function. It accounts for the large majority of idiopathic nephrotic syndrome in kids. The underlying change is podocyte injury that causes foot process effacement, which disrupts the glomerular filtration barrier and allows large amounts of protein to leak into the urine; light microscopy is usually normal, while electron microscopy shows the foot process changes. Clinically, it responds very well to corticosteroids, with most children achieving remission within a couple of weeks, which also supports this diagnosis. Other causes like focal segmental glomerulosclerosis, membranous nephropathy, or acute interstitial nephritis are less common in children or present differently (for example, FSGS may be more steroid-resistant and show sclerosis on biopsy; membranous nephropathy is rare in kids and more common in adults; acute interstitial nephritis typically features inflammation and often impaired kidney function rather than classic nephrotic-range proteinuria).