3. DISCUSSION
Although, COVID-19 mostly affects the respiratory system, GI-related
complaints are seen in up to 38% of patients [11]. A large
meta-analysis of more than 18,000 patients from around the world
suggested that diarrhea was the most common (11.5%) GI symptom,
followed by nausea and vomiting (6.3%), then abdominal pain (2.3%)
[12]. In critically ill patients with COVID-19, GI-complications are
seen in 74 to 86% which can include transaminitis, feeding intolerance,
cholecystitis, pancreatitis, colonic pseudo-obstruction, and even
life-threatening mesenteric ischemia [7]. AMI is the sudden onset of
small intestinal hypoperfusion and patients most commonly present with
acute abdominal pain requiring emergent surgical intervention.
The exact pathophysiology of bowel ischemia in critically ill patients
with COVID-19 remains uncertain. Pathogenesis of thrombotic events in
the context of COVID-19 include endothelial inflammation, thrombin
formation, complement activation and initiation of the immune response
[13,14]. Gross arterial and venous thrombosis, microvascular
thrombosis and even non-occlusive mesenteric ischemia have been
suspected responsible for fatal bowel wall necrosis [9].
Additionally, ICU admissions, high doses of vasopressors, hemodynamic
instability, metabolic derangements, positive pressure ventilation, and
viral enteritis should also be considered as contributory factors for
bowel wall ischemia in COVID-19 patients [7,9].
A systematic review showed radiologically detectable arterial/venous
thrombosis was not identified in more than half of patients with
ischemic bowel [9]. Such patients develop mesenteric ischemia
despite patent and well-perfusing proximal and mesenteric vessels on CT
[7,8,15]. Likewise, CECT of our patient showed patent mesenteric
vessels suggestive of non-occlusive mesenteric ischemia. Nevertheless,
CECT should be considered in any
cases of COVID-19 with prominent GI signs and symptoms, especially those
admitted in ICU. CECT can also be helpful in detecting associated
vascular findings and identifying those patients who may benefit from
percutaneous endovascular thrombectomy as well [16].
The most common finding in COVID-19 associated coagulopathy is an
increase in D-dimer levels. Abnormally elevated D-dimer has been found
to be reported in up to 46.4% of all COVID-19 patients with prevalence
higher among critically ill ICU patients (60%) than non-severe patients
(43%) [17]. Various studies have reported different cutoff scores
of D-dimer correlating with poor outcomes. Zhang et al. [18]
examined 343 cases and showed that D-dimer levels of over 2.0 µg/mL
could predict mortality with a sensitivity of 92.3% and a specificity
of 83.3%. Furthermore, study by Rostami et al. [19] showed an
increase in D-dimer and fibrinogen concentrations in the early stages of
COVID-19 disease with a 3 to 4-fold rise linked to poor prognosis. A
meta-analysis by Parisi et al., on 25,719 hospitalized COVID-19 patients
showed that anticoagulant use was associated with 50% reduced
in-hospital mortality risk [20]. Therefore, D-dimer and fibrinogen
levels should be monitored, and all hospitalized patients should undergo
thromboembolism prophylaxis with an increase in therapeutic
anticoagulation in certain clinical situations [5].