May 13, 2020

Imaging reveals bowel abnormalities in patients with COVID-19

Patients with COVID-19 can have bowel abnormalities, including ischemia, according to a study published in the journal Radiology.

Rajesh Bhayana, MD, Massachusetts General Hospital, Boston, Massachusetts, and colleagues conducted a retrospective study which included 412 patients who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and were consecutively admitted to a single quaternary care center from March 27 to April 10, 2020. The cohort included 241 men (58%) and 171 women (42%), with an average age of 57 years. Of these patients, 136 (33%) were admitted to the intensive care unit (ICU). 

The proportion of patients who initially presented with at least one gastrointestinal (GI) symptom was 34% (n=142/412). Patients were followed for an average of 16.8 days (range 11-25 days) after admission.

According to study data, of the patients, 17% had cross-sectional abdominal imaging, including 44 ultrasounds, 42 CT scans, and 1 MRI. Bowel abnormalities were seen on 31% of CT scans (3.2% of all patients) and were more frequent among patients in the intensive care unit (ICU) versus other in-patients. Bowel findings included thickening and findings of ischaemia such as pneumatosis and portal venous gas. Surgical correlation in 4 patients revealed unusual yellow discoloration of bowel in 3 of the patients, and bowel infarction in 2 patients.

“We found bowel abnormalities on imaging in patients with COVID-19, more commonly in sicker patients who went to the ICU,” said Dr. Bhayana. 

In 2 patients who had bowel resection, pathology demonstrated ischaemia with patchy necrosis. Both had fibrin thrombi in submucosal arterioles, suggesting bowel ischaemia in these patients might be caused by these blood clots. 

Lung base findings led to a diagnosis of COVID-19 in 1 patient who presented with abdominal symptoms only. 

Of right upper quadrant ultrasounds, 87% were performed for liver laboratory findings, and 54% demonstrated a dilated sludge-filled gallbladder suggestive of cholestasis, or a decrease in bile flow.

“Some findings were typical of bowel ischaemia, or dying bowel, and in those who had surgery we saw small vessel clots beside areas of dead bowel,” said Dr. Bhayana. “Patients in the ICU can have bowel ischaemia for other reasons, but we know COVID-19 can lead to clotting and small vessel injury, so bowel might also be affected by this.”

According to the researchers, possible explanations for the spectrum of bowel findings in patients with COVID-19 include direct viral infection, small vessel thrombosis, or nonocclusive mesenteric ischaemia. 

The authors added that further studies are required to clarify the cause of bowel findings in patients with COVID-19 and to determine whether SARS-CoV-2 plays a direct role in bowel or vascular injury.

“Our study is preliminary, and more work is needed to understand the cause of bowel findings in these patients,” said Dr. Bhayana.

SOURCE: Radiological Society of North America