Ischemic gastrointestinal complications of COVID-19: a systematic review on imaging presentation

Post-COVID-19 Gastrointestinal Invasive Mucormycosis

Thrombo-embolic episodes and invasive mucormycosis (IM) have shown a sudden surge after the second wave of novel coronavirus infection in India. Acute mesenteric ischemia secondary to coronavirus-19 is rare and that too due to invasive mesenteric mucormycosis has not yet been reported in Indian literature. We present a case of post-COVID diabetic woman who was on steroids and had mesenteric thrombosis with IM. The disease is associated with high mortality. Treatment of choice is wide surgical resection and iv liposomal amphotericin B. Since the pre-operative as well as intra-operative diagnosis is difficult, high index of suspicion for IM is necessary in post-COVID-19 patients presenting with mesenteric ischemia or bowel perforation.

COVID-19 and the digestive system: A comprehensive review

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.

Prospects of Intraoperative Multimodal OCT Application in Patients with Acute Mesenteric Ischemia

INTRODUCTION

Despite the introduction of increasingly multifaceted diagnostic techniques and the general advances in emergency abdominal and vascular surgery, the outcome of treatment of patients with acute impaired intestinal circulation remains unsatisfactory. The non-invasive and high-resolution technique of optical coherence tomography (OCT) can be used intraoperatively to assess intestine viability and associated conditions that frequently emerge under conditions of impaired blood circulation. This study aims to demonstrate the effectiveness of multimodal (MM) OCT for intraoperative diagnostics of both the microstructure (cross-polarization OCT mode) and microcirculation (OCT angiography mode) of the small intestine wall in patients with acute mesenteric ischemia (AMI).

METHODS AND PARTICIPANTS

A total of 18 patients were enrolled in the study. Nine of them suffered from AMI in segments II-III of the superior mesenteric artery (AMI group), whereby the ischemic segments of the intestine were examined. Nine others were operated on for adenocarcinoma of the colon (control group), thus allowing areas of their normal small intestine to be examined for comparison. Data on the microstructure and microcirculation in the walls of the small intestine were obtained intraoperatively from the side of the serous membrane using the MM OCT system (IAP RAS, Russia) before bowel resection. The MM OCT data were compared with the results of histological examination.

RESULTS

The study finds that MM OCT visualized the damage to serosa, muscularis externa, and blood vessels localized in these layers in 100% of AMI cases. It also visualized the submucosa in 33.3% of AMI cases. The MM OCT images of non-ischemic (control group), viable ischemic, and necrotic small intestines (AMI group) differed significantly across stratification of the distinguishable layers, the severity of intermuscular fluid accumulations, and the type and density of the vasculature.

CONCLUSION

The MM OCT diagnostic procedure optimally meets the requirements of emergency surgery. Data on the microstructure and microcirculation of the intestinal wall can be obtained simultaneously in real time without requiring contrast agent injections. The depth of visualization of the intestinal wall from the side of the serous membrane is sufficient to assess the volume of the affected tissues. However, the methodology for obtaining MM OCT data needs to be improved to minimize the motion artefacts generated in actual clinical conditions.

Colon ischemia in patients with severe COVID-19: a single-center retrospective cohort study of 20 patients

PURPOSE

Thromboembolic complications due to COVID-19 are common in patients requiring critical care and are associated with high morbidity and mortality rates. The aim of this study was to evaluate clinical manifestations and postoperative outcomes after colectomy for COVID-19-associated colonic ischemia in the first versus the second wave of the pandemic.

METHODS

A retrospective cohort study of patients with severe COVID-19 at our institution between 1 March 2020 and 31 January 2021 was performed. All patients with severe COVID-19, requiring critical care and surgical treatment of colonic ischemia, were included. The main outcomes were surgical complications and mortality rate.

RESULTS

A total of 190 patients were included of whom 20 (10.5%) patients underwent surgery for colon ischemia. Preoperatively, D-dimer was elevated, especially in the first wave (median 15.24 (interquartile range 6.00-32.00) vs. 2.09 (1.42-4.28) mg/L, p = 0.025). Twelve (60%) patients underwent a (sub)total colectomy, 7 (35%) a right hemicolectomy, and one patient (5%) an ileocecal resection. Grade 3b complications occurred in one of 5 patients (20%) in the first and in 9 of 15 patients (60%) in the second wave. The overall in-hospital mortality was similar in both waves (40% vs. 47%), with death occurring after a median stay of 21 days.

CONCLUSION

In this cohort study of patients with severe COVID-19 and colonic ischemia, clinical presentation and laboratory findings varied. However, the majority of patients required (sub)total colectomy. Despite a lower threshold to surgery in the second wave, mortality remained high.