A 40-year-old woman with recurrent deep vein thrombosis, prolonged aPTT, and positive lupus anticoagulant develops proteinuria. Renal biopsy shows segmental glomerular capillary thrombosis, arteriolar fibrin thrombi, and focal cortical infarcts without immune complex deposits. Immunofluorescence is negative. This pattern corresponds to:
- A Thrombotic microangiopathy (antiphospholipid nephropathy) ✓
- B Lupus nephritis Class V (membranous)
- C Lupus nephritis Class IV (diffuse proliferative)
- D Thrombotic thrombocytopenic purpura affecting the kidney
Explanation
Antiphospholipid nephropathy is a distinct form of renal thrombotic microangiopathy (TMA) caused by antiphospholipid antibodies (including lupus anticoagulant) that promote endothelial activation and microvascular thrombosis. Renal biopsy shows glomerular capillary and arteriolar thrombi, cortical infarcts, fibrous intimal hyperplasia ('onion skinning'), and recanalizing thrombi, all without immune complex deposition on immunofluorescence. This distinguishes it from lupus nephritis (which has immune deposits) and TTP (which has ADAMTS13 deficiency and systemic microangiopathy with thrombocytopenia).
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.