Gastrointestinal Perspective of COVID-19 in Children - an Updated Review.

ABSTRACT: Gastrointestinal symptoms are common findings in children with SARS-CoV-2 infection, including vomiting, diarrhoea, abdominal pain, and difficulty in feeding, although these symptoms tend to be mild. The hepato-biliary system and the pancreas may also be involved, usually with a mild elevation of transaminases and, rarely, pancreatitis. In contrast, a late hyper-inflammatory phenomenon, termed multisystem inflammatory syndrome (MIS-C), is characterized by more frequent gastrointestinal manifestations with greater severity, sometimes presenting as peritonitis.Gastrointestinal and hepato-biliary manifestations are probably related to a loss in enterocyte absorption capability and microscopic mucosal damage caused by viral infection of intestinal epithelial cells, hepatocytes and other cells through the angiotensin conversion enzyme 2 receptor resulting in immune cells activation with subsequent release of inflammatory cytokines. Specific conditions such as inflammatory bowel disease (IBD) and liver transplantation may pose a risk for more severe presentation of COVID-19 but as adult data accumulate, paediatric data is still limited.The aim of this review is to summarise the current evidence about the effect of COVID-19 on the gastrointestinal system in children, with emphasis on the emerging MIS-C and specific considerations such as patients with IBD and liver transplant recipients.