A 38-year-old woman with SLE on hydroxychloroquine develops new heavy proteinuria 3.8 g/day, serum creatinine 1.9 mg/dL, and low complement. Renal biopsy shows mesangial and subendothelial deposits with wire-loop lesions and fibrinoid necrosis. Based on ISN/RPS 2003 and 2018 classifications, what class of lupus nephritis is this?
- A Class IV — diffuse proliferative nephritis ✓
- B Class III — focal proliferative nephritis
- C Class V — membranous nephropathy
- D Class II — mesangial proliferative nephritis
Explanation
Wire-loop lesions (subendothelial immune deposits creating thickened capillary loops), fibrinoid necrosis, and global or diffuse involvement of > 50% of glomeruli are hallmarks of Class IV diffuse proliferative lupus nephritis — the most severe and most common form leading to progressive renal failure. Class III involves < 50% of glomeruli (focal). Class V (membranous) shows subepithelial deposits and spike-and-dome pattern. Class II is purely mesangial without endocapillary proliferation or wire-loops. Class IV requires induction with mycophenolate or cyclophosphamide plus high-dose corticosteroids.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.