Published online Aug 21, 2020. doi: 10.3748/wjg.v26.i31.4579
Peer-review started: May 6, 2020
First decision: May 26, 2020
Revised: June 2, 2020
Accepted: August 12, 2020
Article in press: August 12, 2020
Published online: August 21, 2020
Processing time: 106 Days and 16.3 Hours
The pandemic of coronavirus disease 2019 (COVID-19), caused by a newly identified β-coronavirus (SARS-CoV-2) has emerged as a dire health problem, causing a massive crisis for global health. Primary method of transmission was firstly thought to be animal to human transmission. However, it has been observed that the virus is transmitted from human to human via respiratory droplets. Interestingly, SARS-CoV-2 ribonucleic acid (RNA) has been isolated from patient stools, suggesting a possible gastrointestinal (GI) involvement. Most commonly reported clinical manifestations are fever, fatigue and dry cough. Interestingly, a small percentage of patients experience GI symptoms with the most common being anorexia, diarrhea, nausea and vomiting. The presence of viral RNA in stools is also common and fecal tests can be positive even after negative respiratory samples. The exact incidence of digestive symptoms is a matter of debate. The distribution of Angiotensin converting enzyme type 2 receptors in multiple organs in the body provides a possible explanation for the digestive symptoms’ mechanism. Cases with solely GI symptoms have been reported in both adults and children. Viral RNA has also been detected in stool and blood samples, indicating the possibility of liver damage, which has been reported in COVID-19 patients. The presence of chronic liver disease appears to be a risk factor for severe complications and a poorer prognosis, however data from these cases is lacking. The aim of this review is firstly, to briefly update what is known about the origin and the transmission of SARS-CoV-2, but mainly to focus on the manifestations of the GI tract and their pathophysiological background, so that physicians on the one hand, not to underestimate or disregard digestive symptoms due to the small number of patients exhibiting exclusively this symptomatology and on the other, to have SARS-CoV-2 on their mind when the “gastroenteritis” type symptoms predominate.
Core tip: Although respiratory transmission and symptoms are still the primary route and expression of coronavirus disease 2019 (COVID-19), the gastrointestinal system could be an alternative or additional way for COVID-19 to be transmitted and manifested, most likely due to the presence of Angiotensin converting enzyme type 2 receptors which are observed throughout its length. The main aim of this article is mainly to focus on the manifestations of the gastrointestinal tract and their pathophysiological background, so that physicians on the one hand, not to underestimate or disregard digestive symptoms due to the small number of patients exhibiting exclusively this symptomatology and, on the other, to have severe acute respiratory syndrome coronavirus 2 on their mind when the “gastroenteritis” type symptoms predominate.