Study presents early details of brain damage in COVID-19 patients
A new spectroscopic imaging-based study of neurological injury in novel coronavirus (COVID-19) patients has been reported by researchers at Massachusetts General Hospital (MGH) in the American Journal of Neuroradiology.
Looking at six patients using a specialized magnetic resonance (MR) technique, the researchers found that COVID-19 patients with neurological symptoms show some of the same metabolic disturbances in the brain as other patients who have suffered oxygen deprivation or hypoxia from other causes, but there are also notable differences.
While it is primarily a respiratory disease, COVID-19 infection affects other organs, including the brain. It is thought that the disease's primary effect on the brain is through hypoxia, but few studies have documented the specific types of damage that distinguish COVID-19-related brain injury. Several thousand patients with COVID-19 have been seen at the MGH since the outbreak began early this year, and this study included findings from three of those patients.
The severity of neurological symptoms varies, ranging from one of the most well-known, a temporary loss of smell, to more severe symptoms such as dizziness, confusion, seizures, and stroke, the researchers said.
The researchers used 3 Tesla Magnetic Resonance Spectroscopy (MRS), a specialized type of scanning that is sometimes called a virtual biopsy. MRS can identify neurochemical abnormalities even when structural imaging findings are normal, according to the study.
COVID-19 patients' brains showed N-acetyl-aspartate (NAA) reduction, choline elevation and myo-inositol elevation, like what is seen with these metabolites in other patients with white matter abnormalities (leukoencephalopathy) after hypoxia without COVID. One of the patients with COVID-19 who showed the most severe white matter damage with necrosis and cavitation had particularly pronounced lactate elevation on MRS, which is another sign of brain damage from oxygen deprivation, the researchers said.
Two of the three COVID-19 patients were intubated in the intensive care unit at the time of imaging, which was conducted as part of their care. One had COVID-19-associated necrotizing leukoencephalopathy. Another had experienced a recent cardiac arrest and showed subtle white matter changes on structural MR. The third had no clear encephalopathy or recent cardiac arrest. The non-COVID control cases included one patient with white matter damage due to hypoxia from other causes such as post-hypoxic leukoencephalopathy, one with sepsis-related white matter damage, and a normal, age-matched, healthy volunteer.
"Moving forward, we are also interested in understanding long-term lingering effects of COVID-19, including headaches, fatigue, and cognitive impairment,” said Eva-Maria Ratai, PhD, senior author of the study and an investigator in the Department of Radiology, in a statement. “So-called brain fog and other impairments that have been found to persist long after the acute phase.”