Minimal change disease nearly always presents as nephrotic syndrome, accounting for 75% of cases in children and 25% in adults.

Most common cause of nephrotic syndrome in children

Causes:

Usually idiopathic, in around 10-20% a cause is found:

• Drugs: NSAIDs, antibiotics (amoxicillin, rifampicin), lithium, bisphosphonates, sulfasalazine
• Hodgkin’s lymphoma, thymoma
• infectious mononucleosis

Pathophysiology:

• T-cell and cytokine-mediated damage to the glomerular basement membrane → polyanion loss
• the resultant reduction of electrostatic charge → increased glomerular permeability to serum albumin

Features

• nephrotic syndrome - oedema is common in children, occurs around the face
• normotension - hypertension is rare
• highly selective proteinuria
  • only intermediate-sized proteins such as albumin and transferrin leak through the glomerulus

Investigations

• renal biopsy
  • Only indicated if response to steroids is poor
  • normal glomeruli on light microscopy
  • electron microscopy shows fusion of podocytes and effacement of foot processes