Looks can be Deceiving: A Challenging Case of Anti-Neutrophil Cytoplasmic Autoantibody Associated Vasculitis.

[Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis] (AAV) is an autoimmune disease characterized by systemic vascular inflammation. We present a case of a 76-year-old man who presented with shortness of breath, fatigue, and weakness. He was eventually diagnosed with hydralazine-induced ANCA-associated renal limited glomerulonephritis. The presentation of this case was unique for a few reasons; the patient showed an initial improvement in kidney function, was non-oliguric, and had no systemic signs of vasculitis. This led to the patient being discharged prematurely with the diagnosis of acute tubular necrosis. We discuss educational features of this case and warn future clinicians about the possibility of waxing and waning renal function in these patients, as well as the importance of having a higher index of suspicion for glomerulonephritis in patients who take hydralazine.