INTRODUCTION: The SARS-CoV-2 is the virus responsible for the COVID-19 pandemic While SARS-CoV-2 infection predominantly results in respiratory illness, the effect on the GI system is emerging This review summarizes what is known about the effects of SARS-CoV-2 infection in the GI system It also identifies knowledge gaps and suggests future research directions METHODS: Relevant articles from a Pubmed search were reviewed and the findings summarized RESULTS: Manifestations of SARS-CoV-2 infection in the GI system include non-specific symptoms such as nausea, vomiting, abdominal pain, and diarrhea Incidence of liver injury ranges between 15 - 53%, with marked dysfunction in liver chemistry seen in severe infections The exact mechanism(s) for the GI effects seen in SARS-CoV-2 infection remains unclear CONCLUSION: Several plausible mechanisms have been hypothesized and the leading theory suggests SARS-CoV-2, utilizes the angiotensin-converting enzyme-II receptor expressed in hepatocytes, cholangiocytes, and other regions of the GI tract as a functional receptor for cellular entry, and ultimately induces direct cellular damage Other proposed mechanisms include immunological damage from excessive inflammatory responses - cytokine storm, drug-related injury, as well as hypoxia secondary to pneumonia SARS-CoV-2 has 80% genomic sequence homology with SARSCoV, and it demonstrates viral shedding from the GI tract that may precede respiratory and other clinical symptoms and persist long after resolution of respiratory symptoms This fecal source could lead to infective aerosol generation and fomite transmission There is paucity of research on the interaction of existing liver conditions with SARS-CoV-2 infection and the effect on treatment outcomes In conclusion, a clearer understanding of the specific mechanisms through which the virus attacks the GI tract will be helpful in directing timely and effective treatment options, as well as possibly mitigating long-term complications In patients with GI affectation with concomitant liver injury, treatment choices should be tailored to limit further hepatic injury Clinicians need to be alert to GI symptoms of SARS-CoV-2, especially in the absence of respiratory symptoms and this knowledge should influence personal protective equipment strategy during triage and GI procedures More research into the role liver pathologies play in modulating hepatic injury in patients with SARSCoV- 2 infection is needed
SARS-COV-2 and the gastrointestinal (GI) system: A structured review