A 25-year-old man presents with nephrotic syndrome: 4+ proteinuria (protein:creatinine ratio 7 g/g), serum albumin 1.8 g/dL, and peripheral edema. Serum creatinine is normal. Renal biopsy on light microscopy shows no abnormality. Electron microscopy reveals diffuse effacement of podocyte foot processes. Immunofluorescence is negative. What is the MOST likely diagnosis?
- A Focal segmental glomerulosclerosis (FSGS)
- B Membranous nephropathy
- C Minimal change disease (MCD) ✓
- D IgA nephropathy
Explanation
Minimal change disease (MCD) is characterized by normal light microscopy, negative immunofluorescence, and diffuse foot-process effacement on electron microscopy. It is the most common cause of nephrotic syndrome in children and young adults. It responds dramatically to corticosteroids. FSGS also shows foot-process effacement on EM but demonstrates segmental sclerosis of glomeruli on light microscopy in at least one glomerulus. Membranous nephropathy shows subepithelial immune deposits ('spike and dome' pattern) and IgG/C3 on immunofluorescence. IgA nephropathy typically presents as nephritic syndrome or asymptomatic hematuria with mesangial IgA deposits on immunofluorescence.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.