**4. Hepatobiliary involvement**

The hepatic injury has been found in increasing number in COVID-19 patients [15–18]. It has been evident from altered liver enzymes and total bilirubin. It ranges from mild to severe hepato-cellular damage. It was observed and reported by American college of gastroenterology News Team, that 20-30% individuals with COVID-19 infection had raised transaminases on admission [15]. Liver injury can be attributed to multi-organ dysfunction or the disease process itself causing viral induced hepatitis. The mechanism underlying the liver injury is yet not clear, but few theories might explain the patho-physiology. Firstly, critical illness and immune mediated injury and secondly ACE2 mediated direct hepatocyte injury by the virus itself [16]. The role of ACE2 receptor in infecting the cells by COVID-19 virus has been well established and these receptors are highly expressed in gastrointestinal epithelial cells which can infect cholangiocytes as well [17]. With severe COVID-19 infection, severe hepatic injury has been observed [18]. In severe infection, liver failure can occur due to hypotension and immune mediated mechanisms. Liver dysfunction is heightened in COVID-19 infection due to cytokine storm. Patients who already have underlying chronic liver disease like hepatitis B infection, alcohol induced hepatitis, primary biliary cholangitis may get decompensated during COVID-19 infection. As these patients are at increased risk of acquiring infection due to their immuno-compromised status, liver enzymes should be carefully monitored [18].
