Acute Viral-Induced Myopathy Following Covid-19

Coronavirus disease 2019 (COVID-19) has been associated with myopathies that may arise from immune dysregulation, autoimmunity, or possible direct viral injury, though the exact mechanisms remain unclear. Recognizing these cases is clinically important, as they can resemble primary autoimmune myopathies but may follow a different course and prognosis.

We report a 59-year-old previously healthy woman who developed acute myopathy shortly after COVID-19. She presented with diffuse myalgia, fatigue, exertional dyspnoea, dizziness, fine motor difficulties, and urinary incontinence. Neurological examination showed preserved reflexes, no sensory deficits, and normal cerebrospinal fluid, excluding Guillain-Barré syndrome and transverse myelitis. Laboratory tests revealed elevated lactate dehydrogenase (616 U/l; ref. 105-205), alanine aminotransferase (239 U/l; ref. <70), and plasma myoglobin (60-74 μg/l; ref. <45). The myositis antibody panel was negative except for isolated CHD4 (anti-Mi-2) positivity, deemed non-specific. She was treated with intravenous fluids, paracetamol, ibuprofen, and physiotherapy. Symptoms resolved within 1 week, and she was discharged on day 10. At 6-month follow-up, she remained fully recovered without recurrence.

This case illustrates that COVID-19 can cause acute, self-limiting viral myopathy in otherwise healthy individuals, emphasizing the need for clinical awareness and supportive management.

Coronavirus disease 2019 can cause acute, self-limiting viral myopathy that mimics autoimmune myositis with positive anti-Mi-2 even in previously healthy individuals.Careful exclusion of neuropathic and autoimmune causes prevents misdiagnosis, overtreatment, and avoiding unnecessary invasive tests.Supportive management with hydration, analgesia, and physiotherapy leads to full recovery.