Multisystem inflammatory syndrome in adults following COVID-19 infection: A case report presenting with colitis

Background Multisystem Inflammatory Syndrome in Adults (MIS-A) is a recently emerging condition that occurs as a delayed complication of COVID-19 infection. It involves inflammation of multiple extra-pulmonary organ systems. Diagnostic criteria and treatment recommendations have yet to be clearly defined. We present a case of a young adult with suspected MIS-A who initially displayed symptoms and radiological findings of colitis.Case: A 22-year-old male with no past medical history suffered a minor respiratory illness for a few days and tested positive on SARS-CoV-2 RT-PCR. Approximately 6 weeks later, he presents after 3 days of right-sided abdominal pain, diarrhoea and fever. He is initially admitted with a working diagnosis of gastroenteritis. Sustained fever and escalating blood markers of illness led to abdominal CT; showing inflammation of ascending colon as well as some loops of small bowel. Hypotension becomes increasingly pronounced and on the fourth day of admission he developed type 1 respiratory failure with evidence of fluid overload. He was transferred to critical care for vasopressor and respiratory support. All microbiological and autoimmune screens performed return negative results but inflammatory markers were significantly elevated, he was diagnosed as MIS-A. IVIg was added to the antibiotics on day 4. His clinical condition dramatically improved and he was discharged home after 10 days in hospital. His blood tests have returned to normal and he has no lasting complications from his illness. Discussion This case displays the potential for MIS-A to present in various ways, with this example a primarily gastroenterological illness. It therefore highlights the importance of physicians in different fields having an awareness of the condition, in order to identify when MDT input is required to guide treatment. We review the current literature on various presentations and treatments of MIS-A, and discuss the need for clear case definition.