Review article: COVID-19 and liver disease-what we know on 1st May 2020

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of coronavirus disease 2019 (COVID-19), became a global threat to human health. Liver impairment has been frequently reported as a common manifestation, although its clinical significance is still unclear, particularly in patients with underlying chronic liver disease (CLD). Aims To summarise the changes in liver function tests during SARS-CoV-2 infection and the impact of COVID-19 in patients with underlying CLD. Methods A literature review using online database PubMed was done using the search terms "SARS-CoV-2", "COVID-19", "liver", "cirrhosis" and "liver transplantation". Results COVID-19 is frequently associated with different degrees of abnormal liver function tests, most notably transaminases, which are usually transitory and of mild degree. Available evidence suggests that liver injury may result from direct pathogenic effect by the virus, systemic inflammation or toxicity from commonly used drugs in this subset of patients. SARS-CoV-2 infection in children is associated with minimal or no increase in liver enzymes, thus the presence of abnormal liver function tests should trigger evaluation for underlying liver diseases. Although it seems that patients with CLD are not at greater risk for acquiring the infection, those with cirrhosis, hepatocellular carcinoma, non-alcoholic fatty liver disease, autoimmune liver diseases or liver transplant may have a greater risk for severe COVID-19. Conclusions Abnormal liver function tests during the course of COVID-19 are common, though clinically significant liver injury is rare. Further research is needed focusing on the effect of existing liver-related comorbidities on treatment and outcome of COVID-19.