Irritable Bowel and COVID-19

The first symptoms of Coronavirus disease  (day 0) begin from two to 14 days after exposure to the virus (marked as day –5 in the figure below, since median time is about five days). The disease affects

different people in different ways. A recent article identified 6 distinct types of COVID-19 with different symptoms,  some of which are hallmarks of the most severe forms of the disease. SARS-CoV-2-infected patients usually first experience a fever. The fever is often followed by a dry cough or fatigue and muscle pain, followed by GI tract symptoms, if they ever occur. Some people, experience nausea or have diarrhea in the days just before the fever begins. 

Gastrointestinal symptoms are reported in about one third of COVID-19 cases, the most common is loss of appetite  - it can happen even in the mildest form of the disease. Nausea/vomiting and diarrhea are slightly less common. Abdominal pain is even less widely known in COVID-19, yet it is  - along with shortness of breath and confusion - is a potential sign of the most severe form of COVID-19. In children, having gastrointestinal symptoms was more frequently associated with severe and critical phenotype (Giacomet et al, 2020). Hyperinflammatory syndrome was presenting with both cardiac and significant GI symptoms (diarrhea, vomit, abdominal pain).

Some researchers suggest that gut dysfunction may exacerbate the severity of infection by enabling the virus to access the surface of the digestive tract and internal organs. These organs are vulnerable to infection because they have widespread ACE2—a protein target of SARS-CoV-2 for its possible routes of entry —on the surface.  ACE2 is abundantly present in the epithelia of the lung and small intestine.

Yet, even if SARS-CoV-2 reaches the GI tract, it may not cause GI problems. An inflamed leaky gut, however, may be associated with a higher risk of severe illness and the microbial imbalance of the gut affecting gut barrier integrity can allow pathogens and pathobionts easier access to cells in the intestinal lining.

Several studies have already demonstrated that, when compared with healthy individuals, COVID-19 patients present a significantly reduced bacterial diversity and higher abundancy of opportunistic Streptococcus, Rothia, Veilonella, and Actinomyces compared to depleted levels of beneficial Agathobacter, Fusicatenibacter, Roseburia, and Ruminococcaceae UCG-013. Rothia was preeviously thought to contribute to the pathogenesis of pneumonia. Critically ill patients on mechanical ventilation who were given probiotics experienced decrease in viral colonization when compared with placebo. However, the efficacy of probiotics use in COVID-19 patients and other bowel remedies remains to be proved.

REFERENES

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Riphagen S, Gomez X, Gonzalez-Martinez C, et al. Hyperinflammatory shock in children during COVID-19 pandemic. Lancet. 2020;395:1607–1608.

Giacomet V, Barcellini L, Stracuzzi M, Longoni E, Folgori L, Leone A, Zuccotti GV. Gastrointestinal Symptoms in Severe COVID-19 Children. The Pediatric infectious disease journal. 2020 Aug 10;39(10):e317-20.

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Gu, S.; Chen, Y.; Wu, Z.; Chen, Y.; Gao, H.; Lv, L.; Guo, F.; Zhang, X.; Luo, R.; Huang, C.; et al. Alterations of the Gut Microbiota in Patients with COVID-19 or H1N1 Influenza. Clin. Infect. Dis. 2020, 71, 2669–2678.

Dhar, D.; Mohanty, A. Gut microbiota and Covid-19- possible link and implications. Virus Res. 2020, 285, 198018. 

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Kim HS. Do an Altered Gut Microbiota and an Associated Leaky Gut Affect COVID-19 Severity?. mBio. 2021 Feb 23;12(1).

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