A 35-year-old man with sickle cell disease presents with proteinuria 2.8 g/day and eGFR 55 mL/min. Renal biopsy shows focal segmental glomerulosclerosis (FSGS) on light microscopy and foot process effacement >80% on electron microscopy. The pattern is consistent with:
- A Secondary FSGS from sickle cell nephropathy — hypertrophy-adaptive FSGS pattern ✓
- B Primary (idiopathic) FSGS with podocyte injury as the initiating event
- C Membranous nephropathy — PLA2R-associated
- D FSGS secondary to heroin nephropathy
Explanation
Sickle cell nephropathy produces secondary FSGS through hyperfiltration and glomerular hypertrophy (adaptive FSGS), as sickling causes medullary ischemia and increased cortical blood flow with compensatory glomerular hypertrophy. On EM, adaptive FSGS shows partial foot process effacement (<80%) at the periphery of sclerotic lesions, in contrast to primary (idiopathic) FSGS which shows diffuse and global foot process effacement (>80%) as the primary podocyte injury. Greater foot process effacement correlates with primary FSGS and is steroid-responsive; adaptive is not steroid-responsive and treatment targets the underlying cause and ACEi/ARB.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.