Diffuse alveolar haemorrhage in ANCA-negative pauci-immune crescentic glomerulonephritis

Pulmonary renal syndrome (PRS) is a combination of diffuse pulmonary haemorrhage and glomerulonephritis (GN). Though an established form of presentation in anti-neutrophil cytoplasmic autoantibody (ANCA)-associated GN and vasculitis, diffuse pulmonary haemorrhage is extremely unusual in those with ANCA-negative GN. We present here a case of a 76-year-old Hispanic female with stage IV chronic kidney disease (serum creatinine of 2 mg/dL), who presented with diffuse alveolar haemorrhage and nephritic syndrome. Less than 1 week prior to the full-blown PRS, she was treated for an apparent pneumonia as was evidenced by a right lower lobe infiltrate on her chest X-ray. Retrospectively, this was likely a focal pulmonary haemorrhage. ANCA were persistently negative, and the remainder of her immunologic workup was normal. Renal biopsy was diagnostic of crescentic pauci-immune GN. The patient required a ventilator and haemodialysis support (serum creatinine 6 mg/dL), and was successfully treated with methylprednisolone, cyclophosphamide and a total of six cycles of plasmapheresis. Once her oliguria resolved, the creatinine plateaued at 2.7 mg/dL. Our case illustrates that diffuse alveolar haemorrhage can be a distinct clinical feature even in patients with ANCA-negative pauci-immune crescentic glomerulonephritis.