Crescentic Glomerulonephritis with Anti-GBM and p-ANCA Antibodies

PULMONARY HEMORRHAGE AND CRESCENTIC GLOMERULONEPHRITIS IN A PATIENT WITH SEROPOSITIVE ANTI-GLOMERULAR BASEMENT MEMBRANE DISEASE AND ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODIES

Anti-glomerular basement membrane (anti-GBM) disease is an acute and life-threatening systemic autoimmune disorder. The coexistence of circulating anti-neutrophil cytoplasmic antibodies (ANCA) and anti-GBM disease, the so-called double-positive disease (DPD), is exceptionally rare. We report a unique case of DPD manifesting as pulmonary-renal syndrome (PRS) in a 46-year-old woman who first presented with clinical and radiological suspicion of pneumonia. Chest computed tomography scan later revealed bilateral alveolar hemorrhage. Kidney biopsy showed necrotizing crescentic (100% glomeruli) glomerulonephritis. On immunofluorescence microscopy, glomeruli were global linear positive for IgG, confirming anti-GBM disease. Double positivity was detected for circulating anti-myeloperoxidase ANCA (p-ANCA) and anti-GBM antibodies. Acute renal failure evolved rapidly. Therapeutic plasma exchange (TPE) and hemodialysis (HD) were initiated early in combination with intravenous pulse corticosteroid therapy followed by oral methylprednisolone and cyclophosphamide. Pulmonary hemorrhage resolved, but renal function could not be preserved. The patient remains HD dependent. This case report highlights that pulmonary symptomatology may be the leading clinical presentation of PRS, with initially normal renal function at DPD onset. Early recognition and diagnosis are therefore crucial to timely clinical intervention. The role of prompt kidney biopsy and initiation of TPE and HD in PRS must not be underestimated.

A Rare Case of Pulmonary-Renal Syndrome With Triple-Seropositive for Myeloperoxidase-Anti-Neutrophil Cytoplasm Antibody (MPO-ANCA), Proteinase 3 (PR3)-ANCA and Anti-Glomerular Basement Membrane (GBM) Antibodies

Anti-glomerular basement membrane (anti-GBM) disease and anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis are the main causes of pulmonary-renal syndrome (PRS). The concurrence of both ANCA - myeloperoxidase (MPO) and proteinase 3 (PR3) - and anti-GBM antibodies has been described, although positivity for all three antibodies has rarely been reported. The natural history of triple-positive patients as well as the best therapeutic approach remains unknown. We describe a case of an 80-year-old woman that presented to the emergency department with a 3-month history of progressive fatigue, malaise and anorexia, and 5 weeks of cough with blood-streaked sputum and progressive peripheral edema. Through the complementary study, a rare diagnosis of PRS with triple-seropositive for both ANCA (MPO and PR3) and anti-GBM antibodies was made in a patient with untreated chronic hepatitis B virus infection. She was treated with glucocorticoid, cyclophosphamide, plasma exchange and entecavir, with pulmonary recovery. Renal function did not improve. After 2 years, the patient is still in dialysis, but did not have relapse of alveolar hemorrhage and ANCA and anti-GBM antibody titers remain negative. The authors intend to warn to PRS, in particular this rare cause, since delaying diagnosis can lead to significant morbidity and mortality for patients.