Long Covid fatigue linked to changes in brain

The extreme fatigue and ‘brain fog’ that people with long Covid can experience may be down to the virus causing changes in the brain structure.

Long Covid, or the often debilitating long-term side-effects following a Covid-19 infection, is often associated with fatigue, difficulty concentrating, and forgetfulness.

A study of 50 patients by researchers from the Free University of Berlin has argued this could be the result of “distinct” structural changes in the brain left by the virus.

For the study, patients from post-Covid outpatient clinics were recruited between April and December 2021. They ranged from 18 to 69 years of age and underwent MRI, neuropsychiatric, and cognitive testing.

Of the 50, 47 said they were experiencing moderate or severe fatigue seven months after the initial infection.

The tests revealed changes in parts of the brain, including the thalamus, putamen and pallidum. Changes included shape deformations and decreased volumes of the left thalamus, putamen, and pallidum.

These changes correlate with fatigue severity and impairment in daily activities, daytime sleepiness, and short-term memory problems, the researchers argue in The Lancet.

“Importantly, this pattern of pathological changes emerged even though this cohort is relatively young, most patients were not hospitalised during their acute infection, and patients were in overall good health before Covid-19,” they said.

“Our novel finding – that post-Covid fatigue is associated with structural brain damage – highlights the importance of consequent therapeutic management of this debilitating postinfectious syndrome,” the research team added.

The findings add to growing evidence of the impact on the virus on the brain and associated functions. Last year, for example, a study by researchers from Oxford University concluded that millions of people who have had Covid-19 face a higher risk of neurological and psychiatric conditions, including ‘brain fog’, epilepsy and dementia, two years after catching the virus.

Equally, a study last year by Imperial College London, Cambridge University and the National Institute for Health Research concluded that severe illness from Covid-19 causes cognitive impairment equivalent to 20 years of ageing.

In the latest study, around 20%-30% of the patients were experiencing fatigue at 12 weeks after their acute infection, independent of whether or not they had previously been hospitalised.

“In line with this, we found that fatigue severity was independent of the severity of the acute disease course, such as the duration of Covid-19 and the number of acute symptoms,” the researchers argued.

“In contrast, post-Covid fatigue was strongly associated with the manifestation of depressive symptoms and sleep quality several months after the acute infection.

“Although fatigue is a subjective symptom based on self-report, it has substantial and relevant consequences for a patient’s everyday life. The continuous experience of overwhelming exhaustion and low energy levels impacts quality of life, and around 30-50% of patients are unable to return to their previous workplace,” they also said.

All this meant long Covid fatigue needed to be managed holistically, the researchers concluded, including considering sleep quality, mood alterations, and cognitive impairment.

“Future research will determine whether these fatigue symptoms are transient or persistent. The identification of distinct subcortical brain correlates provides a foundation for further research on the pathomechanisms of post-Covid fatigue,” the researchers said.