Severe Refractory Diarrhea Associated with COVID-19: A Case Report.

Introduction: Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is frequently associated with various gastrointestinal symptoms, including abdominal pain, vomiting, and diarrhea. Moreover, several cases of refractory diarrhea have been reported after COVID-19 recovery. Herein, we present a case of severe refractory diarrhea associated with COVID-19. Case Presentation: A 50-year-old man with no comorbidities was admitted to our hospital with SARS-CoV-2 pneumonia. His respiratory status deteriorated, and ventilatory management, including extracorporeal membrane oxygenation, was needed. The patient's respiratory condition improved, resulting in a transfer to another hospital for rehabilitation. However, the patient developed diarrhea that worsened to 6,000-7,000 mL/day, and he was transferred to our hospital. We diagnosed the patient with enterocolitis caused by cytomegalovirus infection and treated him with ganciclovir on day 5 after transfer to our hospital. The diarrhea did not improve. We suspected enterocolitis associated with COVID-19 and administered a methylprednisolone pulse (intravenous injection, 1,000 mg/day for 3 days) on day 10 after transfer, resulting in a marked improvement in his symptoms. The prednisolone dose was tapered, and no recurrence of diarrhea was observed thereafter. Conclusion: The prevalence of COVID-19-associated enterocolitis is low, and the pathogenesis of the disease remains unclear. Prednisolone administration should be considered in cases of post-COVID-19 symptoms of severe diarrhea due to a possible abnormal immune response related to COVID-19.