Inflammation, lack of oxygen can play a role
On the one hand, Goldstein pointed out that the 10 patients who had suffered from delirium also had lung infections. However, in the context of COVID-19, he said that the delirium could be caused by “a decrease in oxygen in the blood, a direct infection [and/or] drugs, among a number of other potential causes. “
As to whether COVID’s delirium could result from direct brain damage, Zandi noted that brain scans and cerebrospinal fluid test results “were largely normal” among those battling delirium, adding to the mystery.
Despite this, Zandi emphasized that delirium was not the only neurological complication faced by COVID patients. In fact, many of those who have not experienced delirium fact develop disorders of brain inflammation, including encephalitis. In some cases, these disorders were the main feature of the COVID experience, sometimes without severe respiratory illness.
In fact, 12 of the patients were diagnosed with brain inflammation, the British team noted. Three-quarters of this group (nine patients) were diagnosed with a rare, potentially fatal and largely pediatric disease known as ADEM (acute disseminated encephalomyelitis).
In addition, eight COVID patients suffered a stroke, while eight others suffered nerve damage. Most cases of nerve damage have involved Guillain-Barré syndrome, a rare disease that develops when the body’s own immune system is unleashed and begins to attack the patient’s nervous system.
Since the British team has found no evidence of coronavirus in their patients’ cerebrospinal fluid, this may provide a clue to what is actually going on. This could signal that the brain complications associated with COVID – be it inflammation or delirium – are the product of an out of control immune response.
In any event, Zandi and his colleagues suggest that physicians should be alert for the early signs of neurological disorders in their COVID patients, to intervene early and reduce the risk of long-term brain damage.
Can delirium during COVID infection cause lasting problems? Zandi and Goldstein said the jury was still away.
It all depends, said Goldstein. “Delirium can be transient, with no long-term consequences,” he said. But he warned that it can also have long-lasting effects when caused by something like a small stroke. The ultimate impact of COVID-induced delirium will require further research, he said.
Meanwhile, Zandi has suggested that brain inflammation is more likely to complicate COVID recovery than delirium, although “we know that some elderly people with delirium have poor outcomes and an accelerated decline in function. For the moment, we do not know the long-term result of delirium in COVID-19. “
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