Which of the following is a primary (idiopathic) cause of nephrotic syndrome?

Which of the following is a primary (idiopathic) cause of nephrotic syndrome?

• A. Minimal change disease
• B. Diabetes mellitus
• C. SLE (systemic lupus erythematosus)
• D. Amyloidosis

Answer: (A)

Nephrotic syndrome can arise from diseases of the kidney itself (primary) or from systemic diseases that affect the kidneys (secondary). The classic primary (idiopathic) cause is minimal change disease, especially in children. It presents with edema and heavy proteinuria, usually without hematuria, and with hypoalbuminemia. Light microscopy often looks nearly normal, but electron microscopy shows podocyte foot-process effacement, reflecting a reversible podocyte injury. Patients typically respond very well to steroids, often within weeks. The other conditions listed are systemic diseases that can cause nephrotic-range proteinuria, not primary idiopathic kidney disease: diabetes mellitus leads to diabetic nephropathy, SLE can cause lupus nephritis, and amyloidosis involves amyloid deposition in the kidneys.

Nephrotic syndrome can arise from diseases of the kidney itself (primary) or from systemic diseases that affect the kidneys (secondary). The classic primary (idiopathic) cause is minimal change disease, especially in children. It presents with edema and heavy proteinuria, usually without hematuria, and with hypoalbuminemia. Light microscopy often looks nearly normal, but electron microscopy shows podocyte foot-process effacement, reflecting a reversible podocyte injury. Patients typically respond very well to steroids, often within weeks.

The other conditions listed are systemic diseases that can cause nephrotic-range proteinuria, not primary idiopathic kidney disease: diabetes mellitus leads to diabetic nephropathy, SLE can cause lupus nephritis, and amyloidosis involves amyloid deposition in the kidneys.