[Diaphragmatic dysfunction post-COVID-19 infection: report of two cases]

Following the global outbreak of COVID-19, many patients have suffered from multi-system complications and long-term sequelae caused by the virus. Diaphragm dysfunction is an obscure post-COVID-19 symptom. Although a few cases of diaphragm dysfunction caused by COVID-19 infection have been reported abroad, there are no relevant reports in China. Herein, we present two cases of patients with respiratory distress after COVID-19 infection. On admission, dynamic chest radiographs revealed diaphragm dysfunction in these patients. Further investigations including diaphragm ultrasound, neurophysiological examinations, transdiaphragmatic pressure measurements cranial MRI, and antibody testing for autoimmune diseases, were conducted. The final diagnoses were severe myasthenia gravis induced by COVID-19 infection and diaphragmatic nerve and muscle involvement caused by COVID-19 infection. Both patients showed improvement in symptoms after treatment. Therefore, we summarized our case, with a review of the relevant literature to improve the understanding of the disease and to provide clinical evidence for future diagnosis and treatment.