Severe Covid infections can cause inflammation in the brain’s “control center”, researchers say, leading to damage that may explain the long-term breathlessness, fatigue and anxiety experienced by some patients.
High-resolution MRI scans of 30 people hospitalized with Covid early in the pandemic, before the introduction of vaccines, found signs of inflammation in the brainstem, a small but critical structure that controls life-sustaining body functions such as breathing, heartbeat and blood control. pressure.
The scans suggest that severe Covid infections can trigger an immune response that inflames the brainstem, with the resulting damage causing symptoms that can persist for months after patients are discharged.
“The fact that we see abnormalities in the parts of the brain associated with breathing strongly suggests that long-lasting symptoms are an effect of inflammation in the brainstem after Covid-19 infection,” says Dr Catarina Rua, a neuroscientist at the University of Cambridge and first author of the study.
The project was launched before researchers and public health officials knew about long Covid, the chronic post-viral disease estimated to affect 2 million people in England and Scotland and tens of millions worldwide. But many people with prolonged Covid report breathlessness and fatigue, raising the possibility that brain inflammation may also be involved in their symptoms.
“We haven’t studied people with long Covid, but they often have long-term effects of breathlessness and fatigue, which are similar to the symptoms these very severely affected people had six months after being admitted to hospital,” Rua said. . “This leads us to ask the question, do people with long Covid have any brain stem changes?”
Rua and her colleagues used powerful 7 Tesla MRI scanners to image the patients’ brains. This revealed enough detail to see inflammation and microstructural abnormalities in the brainstem tissue. All the patients were admitted to the hospital with severe Covid near the beginning of the pandemic.
The scans highlighted abnormalities related to inflammation in various parts of the brainstem, which began several weeks after patients were admitted to the hospital. The damage was still evident in scans more than six months later.
Damage to the brainstem may also contribute to the mental health problems that some patients experience after Covid infection. Of the patients in the study, those with the highest levels of brainstem inflammation had the most severe physical symptoms and the highest levels of depression and anxiety, according to the study published in Brain.
“While this study does not conclusively prove the causes of prolonged Covid, it does point a finger at one possible suspect for some of the symptoms experienced,” said Paul Mullins, a professor of neuroimaging at Bangor University. “It is not clear that this shows much in the way of possible treatments for prolonged Covid once it has occurred, but it may indicate the need to reduce inflammatory responses during initial Covid infection and response.”
