New York, Feb 8 (IANS): Among the many hard lessons from the Covid-19 pandemic is that SARS-CoV-2, the virus that causes Covid infections, can affect every organ system in the body, including the brain.

Approximately one third of all patients with Covid may develop neurological complications from infection, and many patients present to hospitals with acute ischemic stroke (AIS) or "brain attack", caused by the sudden blockage of blood flow to or within the brain.

Clinicians from Massachusetts General Hospital (MGH) and 29 other stroke centres across the US and Canada report that patients with Covid-19 who experience AIS appear to be at higher risk for severe disability and death compared with stroke patients treated in the pre-Covid era.

A team of researchers looked at records of 230 patients with AIS who were seen at the stroke centers during the first wave of the pandemic, from mid-March through the end of August 2020.

The findings reported in the Journal of Neurology, Neurosurgery & Psychiatry, a little more than half (51 per cent) of all patients had poor outcomes, with 39.1 per cent dying either in hospital or within 30 days of being discharged.

In contrast, data from large clinical trials conducted before the pandemic show death rates of 27.6 per cent among all patients with ischemic strokes, and 11.6 per cent among patients with strokes caused by blockage of one or more large blood vessels that supply blood to much of the brain.

"There is an interaction that is still unknown between Covid respiratory disease and stroke, because the rate of poor outcomes or mortality is clearly greater than it would be in someone who had just an acute respiratory distress syndrome or Covid pneumonia, and also worse than someone who would have an equivalently large stroke in the pre-Covid era," said Adam A. Dmytriw, interventional neuroradiology & endovascular neurosurgery student at MGH.

The data also suggest that patients from less affluent areas may have been at greater risk for serious complications such as stroke because of their inability to carry out protective measures such as social distancing or working at home, Dmytriw said.