Background: Cocaine adulterated with levamisole has been implicated in anti-neutrophil cytoplasmic antibody (ANCA) vasculitis previously (Pendergraft 2014, Alvarez-Diaz et al 2013). We present a cocaine-related ANCA vasculitis with an unexpectedly severe clinical course. Case report: A 66-year old male with limited prior exposure to medical care presented with new onset shortness of breath, profound anemia, and renal failure. Extensive work-up including renal biopsy revealed anti-myeloperoxidase (MPO) and antiproteinase-3 (PR3) ANCA vasculitis with crescentic glomerulonephritis (image 1). Nephrology, rheumatology, and hematology were consulted, and collaborative work-up revealed only hepatitis C and a history of cocaine abuse without active use. No emergent indication for hemodialysis was present. On hospital day (HD) #9 pulse methylprednisolone was initiated; rituximab was deferred absent evidence of systemic vasculitis. On HD #13 he became dyspneic over the morning hours. Peripheral oxygen saturations remained normal. Hemoglobin returned that morning at 10.6 g/dL and chest radiograph was unchanged. His abdomen became progressively distended and firm. Bi-level ventilation failed to alleviate his symptoms. Obtundation ensued and he was emergently intubated for airway protection. Hemoglobin dropped over 10 hours from 10.6 to 4.6 g/dL. Paracentesis revealed 700,000 red blood cells. In the operating suite, an actively bleeding aneurysmal omental vessel was excised and 3.5 L of blood evacuated. Pathology revealed acute necrotizing vasculitis (image 2). HD #14 urine cocaine metabolite returned positive, suggesting active in-hospital use. Discussion: Cocaine-mediated ANCA vasculitis rarely presents with severe late complications. In this case, ongoing in-house cocaine use coupled with renal failure and hypertension conspired to result in delayed life-threatening intraperitoneal hemorrhage. In the setting of cocaine use, levamisole-mediated ANCA vasculitis was strongly suspected by consulting rheumatologists. Serum levamisole, although drawn three days after his acute event, returned negative. Markedly positive MPO and PR3 strongly suggested drug-induced vasculitis (McGrath et al 2011). Conclusion: We present a rare complication of cocaine-associated ANCA vasculitis. Although serum levamisole returned negative, this was expected, in light of the relatively short serum half-life (5.6 hours). Clinicians should be aware of potential late complications of this disease process, particularly among patients with ongoing cocaine use.