Not Lupus Nephritis but a Rare Case of Drug-Induced Pauci-Immune Glomerulonephritis

Hydralazine-induced pauci-immune glomerulonephritis is a rare cause of glomerulonephritis. It is an anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis that can be rapidly progressive and potentially life-threatening. However, most cases are found to be asymptomatic, and patients often present with acute renal failure and painless hematuria. It has been confused with lupus nephritis but treatment differs, thus, necessitating the need for differentiation. A case report of an 80-year-old African American woman with a history of hypertension, diabetes mellitus type 2, and hypothyroidism, who presented with generalized weakness and weight loss of 30-40 lbs. The patient had been treated with hydralazine for months for hypertension. She presented to the hospital with acute renal failure that worsened over the course of several months eventually requiring hemodialysis. The patient was found to have drug-induced ANCA vasculitis from hydralazine. This etiology was confirmed with pauci-immune glomerulonephritis seen on renal biopsy. This presentation has the potential of being confused with lupus nephritis. Despite the initial serology being suggestive of lupus, this type of nephritis does not have positive immunofluorescence. The treatment of nephritis in this patient was generally supportive. However, it was important to identify the underlying cause of renal failure. Equally important to initiating immunosuppressive therapy, it was imperative to discontinue the offending drug in a timely manner to prevent rapid organ failure. The causative agent, hydralazine, may have otherwise gone unnoticed without a thorough investigation into other causes of renal failure. Thus, it is important to consider this as a diagnosis with a patient who presents with rapidly progressive renal failure on hydralazine and may mimic lupus nephritis.