The purpose of this case study is to review the clinical presentation and medical workup of a young adult male presenting with rhabdomyolysis in the setting of suspected contributing factors, including treatment with mirtazapine and history of COVID-19 infection.

This case study involves a 19-year-old male in a residential setting with a psychiatric history of major depressive disorder and post-traumatic stress disorder who had been stabilized on mirtazapine for 9 months. Then, the patient exhibited fever, sore throat, cough, nausea, diarrhea, and malaise and was diagnosed with COVID-19 infection; he did not require hospitalization, was treated with supportive care, and signs and symptoms resolved uneventfully. Approximately 2 months later, in the winter, the patient presented for clinical assessment due to hematuria and painful urination. History revealed that he had been exercising excessively exercising over the past 24 hours, completing hundreds of push-ups and sit-ups. The patient presented to a nearby community hospital and was found to have creatine kinase of over 500,000. He was transferred to a large Midwestern university hospital for further evaluation and management.

The patient’s serum creatine kinase level was found to be 510,000 U/L. Patient’s ALT, AST, and alkaline phosphatase were 283, 79, and 76 IU/L, respectively, while creatinine was 0.92. Patient received vigorous hydration, supportive care, and further evaluation. Treatment with mirtazapine was discontinued. The following week he developed severe nausea and vomiting; creatine kinase had decreased to 920, while hepatic function tests remained mildly elevated. Evaluation for hepatitis, cytomegalovirus, and Epstein-Barr virus were negative, as was Wilson’s disease and hemochromatosis. Further medical workup for other potential causes of rhabdomyolysis was negative. The patient recovered and is asymptomatic with return to normal lab values. He remains in psychiatric follow-up.

The patient’s presentation of rhabdomyolysis may have been attributable to multiple factors. Independently, sustained excessive physical activity, COVID-19 infection, and treatment with mirtazapine have all been implicated in the development of rhabdomyolysis. Caution should be taken when prescribing mirtazapine in individuals at higher risk of developing rhabdomyolysis, including those engaged in excessive exercise or who have had COVID-19 infection.

No funding