Introduction

A 56-year-old man with COVID-19 pneumonia, requiring mechanical ventilation and extracorporeal membrane oxygenation, was transferred to our hospital. He was successfully treated with dexamethasone and remdesivir, followed by favipiravir, and he was extubated on day 30. Eighteen days after admission, he developed severe watery diarrhoea (passing more than 7000 mL/day). Subsequently, he went into shock due to hypovolaemia and hypoalbuminaemia (2.3 g/dL), and norepinephrine and albumin administration were commenced. Contrast-enhanced CT showed thickening of the small and large intestinal walls without findings suggesting intestinal ischaemia, such as decreased bowel wall enhancement and mesenteric thrombosis (figure 1A). Sigmoidoscopy on day 32 (figure 1B) showed prominent detachment of the colonic mucosa, and peroral enteroscopy …