Anti-GBM Disease🔥: High Yield Nephrology Board Review!

🚨 Rapidly rising creatinine, hematuria, and hemoptysis? Recognize anti-GBM disease before irreversible kidney and lung injury occurs! In this high-yield nephrology board review, we cover the pathophysiology, clinical presentation, diagnostic tests, classic kidney biopsy findings, and emergency treatment of anti-glomerular basement membrane (anti-GBM) disease. 🧠 1. PATHOPHYSIOLOGY Autoantibodies target the alpha-3 chain of type IV collagen in basement membranes. The glomerular basement membrane is the major renal target; pulmonary alveolar basement membranes may also be affected. This causes rapidly progressive glomerulonephritis and, in some patients, pulmonary hemorrhage. ⚡ 2. CLINICAL PRESENTATION Rapidly progressive AKI Hematuria, dysmorphic red blood cells, and RBC casts Proteinuria, usually less prominent than the kidney dysfunction Hemoptysis, hypoxemia, or diffuse alveolar hemorrhage in pulmonary involvement Some patients have kidney-limited disease without lung manifestations 🔬 3. DIAGNOSIS Serum anti-GBM antibodies Urinalysis, creatinine, CBC, and chest imaging when pulmonary involvement is suspected Kidney biopsy for confirmation when feasible Test ANCA as well, because dual-positive anti-GBM and ANCA disease can occur. 🩺 4. CLASSIC KIDNEY BIOPSY Light microscopy: necrotizing crescentic glomerulonephritis. Immunofluorescence: strong, smooth linear IgG staining along the GBM. This contrasts with the pauci-immune pattern typically seen in ANCA-associated GN. 💊 5. EMERGENCY TREATMENT Plasma exchange to remove circulating pathogenic antibodies. Glucocorticoids plus cyclophosphamide to suppress antibody production and inflammation. Provide supportive care and dialysis when indicated. Treatment should begin urgently when suspicion is high; do not delay life-saving therapy while waiting for every result. ⚠️ 6. IMPORTANT PROGNOSTIC PEARL Patients presenting with dialysis-dependent kidney failure, extensive irreversible crescentic injury, and no pulmonary hemorrhage may have limited renal recovery. Decisions about treatment must be individualized; active pulmonary hemorrhage remains an important reason to treat even when renal recovery is unlikely. 🎯 BOARD PEARLS Anti-GBM disease: rapidly progressive GN with or without pulmonary hemorrhage. Linear IgG on immunofluorescence is the classic finding. ANCA-associated GN is typically pauci-immune. Anti-GBM disease is a nephrologic emergency requiring prompt specialist-directed therapy. 📚 Educational content for nephrology fellows, residents, and clinicians. #AntiGBM #GoodpastureDisease #RapidlyProgressiveGN #CrescenticGN #PulmonaryHemorrhage #KidneyBiopsy #PlasmaExchange #NephrologyBoardReview #Nephrology #MedicalEducation