An Unusual Performance of Polymyositis

Abstract

Rationale Polymyositis (PM), which usually occurs in young and middle-aged females, is an inflammatory myopathy characterized by symmetrical proximal limb weakness, neck muscular weakness, and muscle soreness. Severe kidney injury performance caused by the primary disease is uncommon among patients with PM. In this case report, we described the clinical features and pathological clues to help diagnose this disease, furthermore, a review of the literature is provided. Patient concerns A 26-year-old female suffered from persistent weakness and pain in the limb muscles for 1 month and anuria for 1 week before admission. Diagnosis and interventions Serum creatine kinase (CK) level elevated five times above the limit of normal levels and the myositis autoantibody test was positive. Typical clinical symptoms and signs, laboratory results, and significant therapeutic efficacy of hormone therapy and biological therapy all revealed PM complicated with rhabdomyolysis (RML) clinically. After admission, the patient underwent renal replacement therapy, glucocorticoid treatment and was infused with tocilizumab. And the patient recovered and was discharged 4 months later. Outcomes During the conventional treatment, the patient remained in an unstable state. After glucocorticoid pulse treatment and biotherapy, her muscle force enhanced significantly and her general condition improved gradually. Lessons PM combined with RML is rare in clinics and easily misdiagnosed as simple RML, which delays the timing of treatment. This study was to explore the disease by reviewing one case and literatures, which would help for early diagnosis of this disease and then give a reasonable basis for future treatment. Glucocorticoids are still the first-line treatment for the disease.