340 - Inflammatory Myopathy Following COVID-19 Infection: A Case Report

Case Diagnosis: 33 year old female with inflammatory myopathy following COVID-19 Infection.

Case Description: Patient is a 33 year old female without significant past medical history who was hospitalized with COVID pneumonia. During her hospitalization, she developed proximal muscle weakness. Her aldolase and CPK levels were significantly elevated. Patient's inflammatory myopathy was diagnosed by EMG of the tibialis anterior and vastus lateralis, which revealed decreased amplitude, decreased duration, and increased recruitment. Muscle biopsy was consistent with inflammatory myopathy. Patient received IVIG and rituximab infusions, and was also placed on azathioprine and prednisone taper. Patient was discharged to a skilled nursing facility, followed by readmission for acute hypoxic respiratory failure in the setting of pneumonia. Patient was subsequently admitted to inpatient rehab, where she stayed for one month. Patient made significant functional gains, and was able to proficiently use a power chair on day of discharge.

Discussions: Myopathy in the setting of COVID-19 infection is a relatively rare but concerning condition. The exact mechanisms behind COVID-associated myopathy are not fully understood, but several factors contribute to its development. SARS-CoV-2 primarily targets cells in the respiratory system through ACE2 receptors. However, these receptors are also found in various tissues, including muscle cells. It is possible that the virus may directly invade and damage muscle cells, leading to myopathy. COVID-19 also triggers a robust immune response, including the release of pro-inflammatory cytokines. In some cases, this immune response can become dysregulated, leading to a cytokine storm, which may lead to myopathy. Furthermore, limited mobility and insufficient O2 intake may contribute to myopathy.

Conclusions: COVID-19 associated myopathy is a multifactorial condition that can lead to significant disability. Diagnosis is made through electromyography and muscle biopsy. Treatment may include IV immunoglobulin, monoclonal antibodies, corticosteroids, disease-modifying anti-rheumatic drugs, and physical rehabilitation.