Non-Anti-Neutrophil Anti-Cytoplasmic Antibodies Associated Methimazole-Induced Nephritis: Case and Review of Literature

Current anti-thyroid therapy is rarely associated with adverse effects such as vasculitis or nephritis. Historically, vasculitis associated with anti-thyroid therapy is associated with anti-neutrophil anti-cytoplasmic antibodies (ANCA). Here, we report a rare case of ANCA-negative interstitial nephritis secondary to methimazole, resulting in end organ renal failure. A 27-year-old male with a history of Graves' hyperthyroidism on methimazole anti-thyroid therapy presented to the hospital with shortness of breath and chest pain, complicated by a pericardial effusion and acute kidney injury (AKI) requiring emergent hemodialysis. The diagnosis of drug-induced ANCA-negative vasculitis was based on the temporal relationship between clinically evident vasculitis and treatment with methimazole, after excluding other causes of vasculitis. The lack of ANCA-associated positivity should not deter clinicians from considering stopping the offending agent and pursuing more definitive therapy (radioactive iodine or surgery as appropriate).