Introduction

Rhabdomyolysis results from skeletal muscle injury leading to release of creatine kinase (CK), myoglobin, and intracellular electrolytes into the circulation [1]. While trauma, exertion, medications, and toxins are the most common causes, autoimmune-mediated necrotizing myopathies (IMNM) represent a rare but important etiology, particularly in patients with prior statin exposure [2]. Antibody assays, such as anti-HMGCR and anti-SRP, can facilitate diagnosis; however, a subset of patients remain seronegative. We present a case of severe rhabdomyolysis with acute kidney injury in which diagnostic reasoning suggested seronegative autoimmune-mediated myopathy.