A new review of Covid-19 research has found that about half of hospitalized patients experience neurological symptoms, which the authors say suggests that the illness is one that threatens the entire nervous system, rather than solely being a respiratory infection.
The review by researchers from Northwestern University Feinberg School of Medicine and the University of Colorado School of Medicine found that patients who were hospitalized had neurological manifestations of Covid-19 ranging from milder symptoms such as headaches, dizziness, decreased alertness, weakness, muscle pain, difficulty concentrating, and loss of smell and taste, to more serious medical complications like seizures and strokes.
The disease can affect the brain, spinal cord, nerves, and muscles in several different ways, according to the research published in the Annals of Neurology. The disease attacks the lungs and heart, which can lead to a lack of oxygen in the brain, or clotting disorders that can lead to strokes. The virus may also directly infect the brain, as was shown in a recent case study in JAMA Neurology. Neurological symptoms can also be caused by the reaction of the immune system, which may cause damage to the brain and nerves through inflammation.
"Due to its worldwide distribution and multifactorial pathogenic mechanisms, COVID‐19 poses a global threat to the entire nervous system," the authors write in the paper. "As we hope for a vaccine or a cure, neurologists will play an important role in diagnosing, investigating, and treating the many neurologic manifestations of COVID-19."
Though neurological symptoms were found in around half of the hospitalized patients, more severe effects were less common. Overall, 25 percent of patients showed evidence of central nervous system dysfunction including dizziness (17 percent), headache (13 percent), and impaired consciousness (7.5 percent). Three percent had acute cerebrovascular disease (disorders that affect the blood vessels and blood supply to the brain), 0.5 percent experiencing ataxia (the loss of full control of bodily movements), and 0.5 percent had seizures.
“It’s important for the general public and physicians to be aware of this, because a SARS-COV-2 infection may present with neurologic symptoms initially, before any fever, cough or respiratory problems occur,” lead author Dr Igor Koralnik, chief of neuro-infectious diseases and global neurology at Northwestern Medicine, said in a statement.
Little is known about the long-term implications of the neurological impacts of Covid-19, and the team will now follow some patients to try to determine if neurological problems are temporary or permanent.