Gastrointestinal manifestations of COVID-19: a review article in adults

Background and Aim: Although COVID-19 patients typically present with respiratory symptoms such as cough, dyspnea, and bilateral pulmonary infiltration, there have been numerous reports of gastrointestinal manifestations such as diarrhea, nausea, vomiting, anorexia, and abdominal pain in these patients. The aim of this study was to review the gastrointestinal manifestations in COVID-19 patients. Materials and Methods: In this systematic review, we searched the key-words in PubMed, Embase, Web of Science, and Google Scholar for studies published between 2019, and July 22, 2020. We selected the studies on epidemiological and clinical manifestations of COVID-19 including gastrointestinal symptoms, and excluded, duplicate publications, review articles, meta-analysis, guidelines, comment or editorials, case reports, studies with unavailable data, and studies in children. Finally, 35 articles were selected for our systematic review. Results: In our study, 6119 COVID-19 patients were evaluated for gastrointestinal manifestations. Four studies showed COVID-19 patients can merely present with gastrointestinal symptoms (highly variable, ranging from 10.1 to 100 percent). In these patients, the prevalence of gastrointestinal symptoms included anorexia (91.3%), nausea or/and vomiting (79.13%), diarrhea (41.73%), and abdominal pain (18.89%), respectively. Among 6119 patients, the most common gastrointestinal symptoms were nausea or/and vomiting (12.45%), diarrhea (11.47%), anorexia (9.56%), and abdominal pain (2.25%). Conclusion: This review study showed that despite the preliminary opinions, SARS-CoV-2 does not always present with respiratory symptoms. Knowledge of pathophysiology, type, and prevalence of gastrointestinal manifestations can lead to early diagnosis (considering fecal viral RNA testing for diagnosis), timely treatment, and hence better prognosis for the patients. On the other hand, gastrointestinal manifestations can raise the possibility of oral-fecal transmission, which requires necessary recommendations to reduce the risk of transmission.