Review
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jun 6, 2021; 9(16): 3796-3813
Published online Jun 6, 2021. doi: 10.12998/wjcc.v9.i16.3796
COVID-19 and the digestive system: A comprehensive review
Ming-Ke Wang, Hai-Yan Yue, Jin Cai, Yu-Jia Zhai, Jian-Hui Peng, Ju-Fen Hui, Deng-Yong Hou, Wei-Peng Li, Ji-Shun Yang
Ming-Ke Wang, Ju-Fen Hui, Deng-Yong Hou, Wei-Peng Li, Department of Disease Control and Prevention, Naval Medical Center of PLA, Naval Medical University, Shanghai 200052, China
Hai-Yan Yue, Department of Digestive Diseases, Naval Medical Center of PLA, Naval Medical University, Shanghai 200052, China
Jin Cai, Department of Geriatrics, Naval Medical Center of PLA, Naval Medical University, Shanghai 200052, China
Jin Cai, Department of Infectious Diseases, Naval Medical Center of PLA, Naval Medical University, Shanghai 200052, China
Yu-Jia Zhai, Department of Outpatient Services, Naval Medical Center of PLA, Naval Medical University, Shanghai 200052, China
Jian-Hui Peng, Department of Quality Management, Guangdong Second Provincial General Hospital (Pazhou Campus), Guangzhou 510317, Guangdong Province, China
Ji-Shun Yang, Medical Care Center, Naval Medical Center of PLA, Naval Medical University, Shanghai 200052, China
Author contributions: Wang MK, Yue HY, and Cai J contributed equally to this work and wrote the draft; Zhai YJ, Peng JH, Hui JF, Hou DY, and Li WP collected the literature; Wang MK and Yang JS conceptualized the article and revised manuscript; All authors have read and approved the final manuscript.
Conflict-of-interest statement: All authors declare that they have no conflicts of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ji-Shun Yang, MD, PhD, Director, Medical Care Center, Naval Medical Center of PLA, Naval Medical University, No. 338 Huaihai West Road, Shanghai 200052, China. jasunyang@foxmail.com
Received: January 23, 2021
Peer-review started: January 23, 2021
First decision: February 8, 2021
Revised: February 10, 2021
Accepted: March 24, 2021
Article in press: March 24, 2021
Published online: June 6, 2021
Processing time: 110 Days and 18.3 Hours
Abstract

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is spreading at an alarming rate, and it has created an unprecedented health emergency threatening tens of millions of people worldwide. Previous studies have indicated that SARS-CoV-2 ribonucleic acid could be detected in the feces of patients even after smear-negative respiratory samples. However, demonstration of confirmed fecal-oral transmission has been difficult. Clinical studies have shown an incidence rate of gastrointestinal (GI) symptoms ranging from 2% to 79.1% in patients with COVID-19. They may precede or accompany respiratory symptoms. The most common GI symptoms included nausea, diarrhea, and abdominal pain. In addition, some patients also had liver injury, pancreatic damage, and even acute mesenteric ischemia/thrombosis. Although the incidence rates reported in different centers were quite different, the digestive system was the clinical component of the COVID-19 section. Studies have shown that angiotensin-converting enzyme 2, the receptor of SARS-CoV-2, was not only expressed in the lungs, but also in the upper esophagus, small intestine, liver, and colon. The possible mechanism of GI symptoms in COVID-19 patients may include direct viral invasion into target cells, dysregulation of angiotensin-converting enzyme 2, immune-mediated tissue injury, and gut dysbiosis caused by microbiota. Additionally, numerous experiences, guidelines, recommendations, and position statements were published or released by different organizations and societies worldwide to optimize the management practice of outpatients, inpatients, and endoscopy in the era of COVID-19. In this review, based on our previous work and relevant literature, we mainly discuss potential fecal-oral transmission, GI manifestations, abdominal imaging findings, relevant pathophysiological mechanisms, and infection control and prevention measures in the time of COVID-19.

Keywords: COVID-19; SARS-CoV-2; Gastrointestinal manifestations; Abdominal imaging; Mechanisms; Prevention

Core Tip: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 has led to an unprecedented global public health crisis. Based on our previous work and the relevant literature, the aim of this review is to discuss mainly the current status and progress, the problems that have been resolved and those that remain to be resolved, and the future research directions in the field of COVID-19 and the digestive system, with special focus on potential fecal-oral transmission, gastrointestinal manifestations, abdominal imaging, pathophysiological mechanisms, and infection control and prevention measures in outpatient visits, inpatient ward, and endoscopy centers in the time of COVID-19.