COVID-19 could starve the brain of oxygen and cause “a terrifying side effect”, scientists have warned.
The three main symptoms of Covid-19 are a new persistent cough, a high temperature and a loss of taste and smell but some people who contract the virus also experience brain fog – creating a “significant burden”.
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Some people who have contracted Covid-19 have suffered from brain fog and deliriumCredit: Getty Images – Getty
People who overcome Covid-19 can often be left with long Covid, a condition which has seen many people struggle to recover.
Many people with long Covid have difficulty concentrating and thinking and some have even experienced short-term memory loss as a result of the virus.
In a handful of cases, some patients have also reported psychosis and delrium.
In order to understand the impact that Covid-19 has on the brain, scientists have autopsied brains of patients who died from coronavirus.
What the experts found was large cells called megakaryocytes which were taking up space and leaving less room for blood to pass through the brain freely.
Professor of pathology at the Johns Hopkins University School of Medicine, David Nauen said this could be key to understand how the brain is impacted by the Covid-19 virus.
Speaking to ABC News he said if these cells are blocking blood flow to the brain then it would starve it of the nutrients and oxygen it needs to work at full capacity.
Prof Nauen added that the “findings on autopsy suggest that the burden could be significant”.
He said: “The brain cortex is richly vascularized with capillaries, if some proportion of capillaries are blocked or occluded by these cells, it blocks some level of blood flow.
“An alteration in flow of blood in a system that is so precisely delivering oxygen based on time and need could be leading to impaired cognitive function, like a brain fog picture.”
Prof Nauen said it was key that researchers learn how the cells are getting into the brain and what they are doing once they are in there.
Other scientists claim that people who experience brain fog are likely to have inflammation.
Adrienne A. Boire, MD, PhD, a Neuro-Oncologist & Neurologist at Memorial Sloan Kettering Cancer Center explained that cytokines (a type of protein) swirl around the tissue that surrounds both the brain and the spinal cord.
They are usually associated with the immune system and can cause damage to vital organs.
Many people who contract Covid suffer from inflammation and some patients often develop skin conditions caused by this.
Prof Boire said that patients who recover from Covid without suffering from any side effects could help to determine why some develop brain fog and others don’t.
A recent study also found that 44 per cent of people who had Covid suffered from attention disorder.
Several “neuropsychiatric symptoms” – mental disorders linked with disease of the nervous symptom – were discovered by the research team in the US.
These were headaches (44 per cent), attention disorder (27 per cent) and loss of smell (21 per cent).
They could be a result of the coronavirus directly impacting the brain, oxygen deprivation during Covid, medications, or the stress of having Covid – a deadly disease.
A UK study also suggested that patients worst-hit by Covid could see their brain age by 10 years.
Researchers found that in the worst cases the infection can cause mental decline equivalent to an 8.5-point fall in IQ or the brain ageing a decade.
Even people who showed only mild symptoms scored lower on the tests than those who had not got Covid.
Scientists suggest that the “brain fog” reported by many people weeks and month after recovering may be a sign of more serious cognitive deficits.