Polymyositis Presenting With Nontraumatic Rhabdomyolysis and Dysphagia: A Case Report

Abstract

Idiopathic inflammatory myopathies (IIMs) are a rare, heterogeneous group of diseases with a characteristic clinical presentation consisting of muscle inflammation and weakness. They often present with accompanying extra-muscular findings, most notably in the skin, lungs, and joints. Inflammatory myopathies are also identified by their characteristic laboratory abnormalities, including a 10- to 50-fold increase in creatinine kinase, elevated liver enzymes, and characteristic electromyography and magnetic resonance imaging findings. Distinct autoimmune markers and clinical phenotypes have advanced our understanding of IIMs and have led to the recognition of 5 distinct entities, each with its unique pathophysiology, autoimmune markers, and clinical features. While autoimmune panels and muscle biopsies help clinicians distinguish one entity from the other, their sensitivity and specificity vary. Of the various inflammatory myopathies, polymyositis remains the most elusive. Often, the diagnosis is ultimately made by combining clinical findings and laboratory data. As our case report illustrates, clinicians must use this constellation of data to initiate treatment for suspected polymyositis despite negative autoimmune panels and negative muscle biopsy.

Atraumatic Unilateral Myositis with Rhabdomyolysis of the Right Lower Extremity

“…2,3 Although this points towards rare drug-induced myositis, the patient was responsive to steroids given for refractory pain, suggesting a possible autoimmune etiology. 4 CT and ultrasound can visualize rhabdomyolysis as focal hypodensities and muscle with both decreased and increased echogenic areas, respectively. 5 Although nonspecific, MRI visualizes increased signal intensity with a sensitivity as high as 100% compared to 62% and 42% in CT and ultrasound, respectively.…”