TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Hydralazine is a widely used medication for blood pressure control. Hydralazine-induced anti-neutrophilic cytoplasmic antibody (ANCA) vasculitis is dose dependent and has an incidence of 5.4% in patients with 100 mg/day to 10.4% with 200 mg/day for greater than 3 years. The pathogenesis is unknown, however some theories include hydralazine binding to myeloperoxidase (MPO) leading to neutrophil apoptosis, causing autoantibodies and the other being hydralazine-induced reversal of epigenic silencing of MPO and proteinase3 (PR3) leading to increased expression of neutrophil autoantigens. This case is of severe vasculitis due to hydralazine with primarily pulmonary involvement. CASE PRESENTATION: Patient is 69-year-old female with a past medical history of fibromyalgia, hypertension, systemic lupus erythematosus, and rheumatoid arthritis who presented with a productive cough, moderate respiratory distress, fever of 38.9C, and dyspnea on exertion of four days. Chest x-ray showed multifocal patchy opacities bilaterally. The patient was treated empirically with antibiotics for community acquired pneumonia. Her hypoxemia worsened and she ultimately required bilevel positive airway pressure. Urine studies showed moderate blood, 1+ protein, 6 RBCs, and a urine protein creatinine ratio of 1.1 g/g of creatinine. Serologies were positive for ANCA 1:1280, MPO IgG 169, anti-dsDNA IgG 68, and lupus anticoagulant panel. PR3 IgG and C3/C4 complement levels were negligible. Renal biopsy revealed no identifiable immune complex deposits. Hydralazine was suspected as the etiology by rheumatology given her long history use which was discontinued. The patient was treated with high dose systemic steroids and rituximab infusions while hospitalized. The patient's clinical condition improved significantly during the 24-day hospitalization; required 4L of oxygen supplementation on discharge. DISCUSSION: Hydralazine induced ANCA vasculitis, specifically microscopic polyangiitis, has been documented as a rare cause of pulmonary-renal syndrome. This case, however, demonstrates interstitial pneumonitis with minimal renal involvement as the acute kidney injury resolved within two days after hydralazine was discontinued. Many documented cases show patients placed on dialysis indefinitely. In severe cases like this, aggressive management with immunosuppressive regiments such as using corticosteroids and rituximab or cyclophosphamide are needed. CONCLUSIONS: Early suspicion of an agent causing an autoimmune response from commonly used agents such as hydralazine must be recognized early. Individualizing organs systems such as pulmonary and renal prevent ruling out disease processes that may occur thinking that two or more systems are required in the diagnosis. Early cessation of such agents can lead to preserving organ functionality. Higher dosages of hydralazine have higher incidence of causing vasculitis. REFERENCE #1: Aeddula, N., Pathireddy, S., Ansari, A., & Juran, P. (2018, November 8). Hydralazine-associated antineutrophil cytoplasmic antibody vasculitis with pulmonary-renal syndrome. Retrieved November 21, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6229221/ REFERENCE #2: M. Farag, T., MR. Kandler, G., N. Yokogawa, F., F. Babar, J., S. Bjorck, C., WF. Pendergraft, J., . . . G. Almroth, S. (1970, January 01). Hydralazine-induced antineutrophil cytoplasmic antibody-associated vasculitis with pulmonary–renal syndrome: A case report. Retrieved November 21, 2020, from https://jmedicalcasereports.biomedcentral.com/articles/10.1186/s13256-020-02378-w REFERENCE #3: Timlin, H., Liebowitz, J., Jaggi, K., & Geetha, D. (2018, March). Outcomes of hydralazine induced renal vasculitis. Retrieved November 21, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5895152/ DISCLOSURES: No relevant relationships by Oluseyi Abidoye, source=Web Response No relevant relationships by Christopher Chew, source=Web Response No relevant relationships by Aman Kaur, source=Web Response