Critical illness with fatal muscle weakness and gastrointestinal perforation after COVID-19.

A 43-year-old man reported with upper respiratory tract symptoms and tested positive for coronavirus disease 2019 (COVID-19) antigens. The symptoms improved quickly, but 1 month later, myalgia in both shoulders and from both thighs to both lower legs, pharyngeal pain, and dyspnoea appeared. His muscle strength was low, and laboratory tests showed an elevated serum creatine kinase level at 1273 U/l. A COVID-19 polymerase chain reaction test was positive on the day of admission, and a diagnosis of multisystem inflammatory syndrome in adults was considered. The patient received high-dose intravenous immunoglobulin (30 g for 5 days) for myositis due to multisystem inflammatory syndrome in adults with muscle weakness refractory to glucocorticoids, but progressive dysphagia led to a gradual reduction in the ability to swallow saliva. The patient choked due to sputum, resulting in cardiopulmonary arrest on Day 31. Lifesaving measures were immediately performed, and the patient's heartbeat resumed. However, on Day 39, the patient experienced a gastrointestinal perforation and underwent emergency surgery. Since antinuclear matrix protein 2 antibody-positive dermatomyositis (DM) is known as a severe form of DM that can cause gastrointestinal perforation, we measured the antibody and found it to be positive. We report the case of gastrointestinal perforation in a patient with antinuclear matrix protein 2 antibody-positive DM that developed after a COVID-19 infection and was successfully managed through multidisciplinary therapy.