COVID-19
There is increasing recognition of GI symptoms in COVID-19 patients (up to 50%).84 Patients may present only with GI symptoms.20 , 84 Loss of appetite and diarrhea have been the most commonly reported symptom (in up to 78.6% cases), and less often vomiting (up to 5%), and abdominal pain (up to 2%) (Table 3).20, 21, 22 , 84 Vomiting has been shown to be a more common presenting symptoms in children. The GI features seem to worsen with overall disease severity and the presence of abdominal pain has been associated with about 4 times higher odds of severe COVID.22 , 24 The delayed recognition of GI symptoms and lack of awareness may lead to a delay in seeking medical care.22 Patients who present later during their illness were more likely to suffer from hepatic dysfunction but without a difference in mortality, ICU days or time to discharge.22 Patients with obesity are at significantly higher risk for severe disease requiring critical care and invasive mechanical ventilation. Compared with patients with a BMI <25 kg/m2, patients with BMI >35 kg/m2 have been seen to have 7 times the odds for requiring invasive mechanical ventilation.25 , 26
COVID-19 virus enters enteric epithelial tissue through ACE 2 and transmembrane protease, serine 2, but the exact mechanism of GI symptoms is not known.85 The virus is detectable in stool in up to half of COVID-19 patients,86 , 87 and the feces remains positive for as much as 4 weeks.87 ACE 2 and viral protein have been detected in GI epithelial cells, and infectious virus particles were isolated from feces.88 Fecal polymerase chain reaction (PCR) testing has been shown to be as accurate as PCR detection from a sputum sample, and in some cases, fecal PCR is positive before sputum PCR.88 It remains unclear if the fecal-oral route is a significant mode of transmission.