A Rare Case of Eosinophilic Myalgia Syndrome

Abstract

Introduction: A 57-year-old female with a history of hypertension, hyperlipidemia, and osteoarthritis presented to a community hospital with altered mental status, severe bilateral upper and lower extremity myalgias, and arthralgias in her metacarpophalangeal joints bilaterally. Her only medications were hydrochlorothiazide and melatonin. She had no constitutional symptoms, rashes, nausea, vomiting, or diarrhea. At presentation, she was found to have WBC count of 14.5 with 43% eosinophils, ALT 1141, AST 630, total bilirubin 2.9 (predominantly direct bilirubin), and alkaline phosphatase 337. Abdominal ultrasound revealed mild gallbladder wall thickening with gallstones present, but no intra-/extra-hepatic ductal dilatation and normal common bile duct diameter; CT abdomen/pelvis was unremarkable. There was a weakly positive antismooth muscle antibody at titer of 1:40 as well as mildly elevated IgG of 1950 with negative ANA. Liver biopsy showed extensive eosinophilic infiltration, rare plasma cells, severe acute hepatitis with syncytial multi-nucleated giant cells, and focal centrilobular injury and piecemeal necrosis, which was not entirely consistent with autoimmune hepatitis. Bone marrow biopsy showed extensive eosinophilia not consistent with any hematologic malignancy, and flow cytometry was unrevealing. Further hematologic, neurologic, infectious, and rheumatologic studies were negative. She was diagnosed with eosinophilic myalgia syndrome. She was subsequently treated with oral steroids and discontinuation of melatonin, and her liver tests continued to improve, as did her confusion, myalgias, and arthralgias.