CNS complications in COVID-19: 1 in 100 hospitalized patients affected

A large retrospective study conducted in the US and Europe and presented at RSNA 2021 has suggested that central nervous system (CNS) complications may affect approximately one in 100 patients hospitalized with COVID-19.

“Of all the inpatients who had imaging such as MRI or a CT scan of brain, the exam was positive approximately 10 percent of the time,” said study lead author Professor Scott Faro, director of the Division of Neuroradiology/Head & Neck Imaging, Thomas Jefferson University, Philadelphia, Pennsylvania, US.

The participants were 37,950 patients aged ≥18 years (average age 65.8 years, male-to-female ratio 2:1) with laboratory-confirmed COVID-19 hospitalized at seven US and four European university hospitals, of whom 4,342 underwent neuroimaging. All included patients were required to have brain CT or MRI acute neuroimaging findings that were not attributable to any cause other than COVID-19. The most common causes of hospitalization were confusion, altered mental status, and fever. Comorbidities such as hypertension, cardiovascular disease, and diabetes were also common in this population.

Acute neuroimaging findings, indicative of CNS complications, were present in 10.1 percent (n=442) of the 4,342 patients, specifically 7.9 percent (n=294) of the 3,701 patients in the US and 22.8 percent (n=148) of the 647 patients in Europe.

This amounted to a 1.16-percent incidence of CNS complications in the overall group of patients hospitalized with COVID-19.

“The incidence of 1.2 percent means that a little more than one in 100 patients admitted to the hospital with COVID-19 are going to have a brain problem of some sort,” Faro pointed out.

Among patients with positive neuroimaging findings, the most common CNS complications were ischaemic stroke (62.4 percent), intracranial haemorrhage (37.1 percent), and encephalitis (5.2 percent). Ten patients (2.3 percent) experienced sinus venous thrombosis, eight (1.8 percent) experienced acute demyelinating encephalomeningitis (ADEM), seven (1.6 percent) experienced posterior reversible encephalopathy syndrome, and two (0.5 percent) had vasculitis.

The incidence of ischaemic stroke was more common in the US than Europe (74.1 percent vs 39.2 percent), while intracranial haemorrhage, encephalitis, and ADEM were more common in Europe than the US (46.6 percent vs 32.3 percent, 10.1 percent vs 2.7 percent, and 4.7 percent vs 0.3 percent, respectively).

In terms of lesions, distal unilateral lesions were the most common (59.7 percent). Thirty-one percent of patients had bilateral asymmetric lesions and 11.3 percent bilateral symmetric lesions. Frontal lobe lesions were detected in 55.2 percent, parietal and temporal lobe lesions in 49.1 and 33.9 percent, respectively, and cerebellum and brainstem lesions in 19.2 and 13.3 percent, respectively. White matter, cortical, and subcortical lesions were detected in a comparable proportion of patients (57, 56.8, and 53.6 percent, respectively).

“Much has been written about the overall pulmonary problems related to COVID-19, but we do not often talk about the other organs that can be affected,” said Faro. “It is important to know an accurate incidence of all the major CNS complications.”

“[In this] large international, multi-institutional cohort, incidence and spectrum of acute neuroimaging findings helped to characterize the neurological complications of COVID-19 thereby assisting in understanding the full extent of this disease process beyond the devastating pulmonary complications,” he continued.

“Our study shows that CNS complications represent a significant cause of morbidity and mortality in this devastating pandemic … There should probably be a low threshold to order brain imaging for patients with COVID-19,” Faro concluded.