Using ultra-powered magnetic resonance imaging (MRI), researchers from the Universities of Cambridge and Oxford have demonstrated that COVID-19 infections can damage the brainstem, the brain’s "control center." The findings are published in Brain.
The study was based on the MRI images of 30 people who had been hospitalized with severe COVID-19 before the availability of COVID-19 vaccines. The images were captured with a 7-Tesla machine, which can measure inflammation levels in the brain. Typically, brainstems can only be imaged postmortem, but the 7-Tesla allows researchers to look at the nuclei of brainstems in living participants.
“Things happening in and around the brainstem are vital for quality of life, but it had been impossible to scan the inflammation of the brainstem nuclei in living people, because of their tiny size and difficult position.” said first author Catarina Rua, PhD, in a press release from the University of Cambridge.
Things happening in and around the brainstem are vital for quality of life, but it had been impossible to scan the inflammation of the brainstem nuclei in living people.
The COVID patients were scanned 93 to 548 days after hospital admission for COVID-19, and their images were compared to 51 age-matched controls without a history of COVID-19 infection.
Among the 30 participants, breathlessness, fatigue, and chest pain were common symptoms in the days and weeks after infection.
Brainstem inflamed
The authors found that certain areas of the brainstem, including the medulla oblongata, pons, and midbrain, showed signs of inflammation. The inflammation was greatest in patients with longer hospital stays, higher COVID severity, more prominent inflammatory responses, and worse functional outcomes, the authors said.
"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 following Covid-19 infection," said Rua. "These effects are over and above the effects of age and gender, and are more pronounced in those who had had severe Covid-19."
The authors said COVID-19 infection can result in a "brainstem insult" that results in clusters of physical long-COVID symptoms.
"A similar pattern is observed following post severe traumatic brain injury, with patients reporting fatigue and dizziness but also tachycardia, tachypnoea and hypertension, linked to acute or chronic brainstem dysfunction," they wrote.
The authors said further use of 7-Tesla imaging will provide further insight into the mechanisms of long COVID.
