NEW YORK (NYTIMES) - Nearly a third of hospitalised Covid-19 patients experienced some type of altered mental function - ranging from confusion to delirium to unresponsiveness - in the largest study to date of neurological symptoms among coronavirus patients in a US hospital system.
And patients with altered mental function had significantly worse medical outcomes, according to the study, published on Monday (Oct 5) in Annals of Clinical and Translational Neurology.
The study looked at the records of the first 509 coronavirus patients hospitalised, from March 5 to April 6, at 10 hospitals in the Northwestern Medicine health system in the Chicago area.
These patients stayed three times as long in the hospital as patients without altered mental function.
After they were discharged, only 32 per cent of the patients with altered mental function were able to handle routine daily activities like cooking and paying bills, said Dr Igor Koralnik, senior author of the study and chief of neuro-infectious disease and global neurology at Northwestern Medicine.
In contrast, 89 per cent of patients without altered mental function were able to manage such activities without assistance.
Patients with altered mental function - the medical term is encephalopathy - were also nearly seven times as likely to die as those who did not have that type of problem.
"Encephalopathy is a generic term meaning something's wrong with the brain," Dr Koralnik said.
The description can include problems with attention and concentration, loss of short-term memory, disorientation, stupor and "profound unresponsiveness", or a coma-like level of consciousness.
The researchers did not identify a cause for the encephalopathy, which can occur with other diseases, especially in older patients, and can be triggered by several different factors including inflammation and effects on blood circulation, said Dr Koralnik, who also oversees the Neuro Covid-19 Clinic at Northwestern Memorial Hospital.
There is very little evidence so far that the virus directly attacks brain cells, and most experts say neurological effects are probably triggered by inflammatory and immune system responses that often affect other organs, as well as the brain.
Some experts said President Donald Trump, who was hospitalised with Covid at Walter Reed National Military Medical Centre beginning on Friday, is of the age and gender of the patients in the study who were more likely to develop altered mental function and therefore could be at higher risk for such symptoms.
Mr Trump returned to the White House on Monday evening.
