While respiratory issues are a well-documented symptom of coronavirus, researchers have found that over 80% of hospitalized COVID-19 patients experience some type of neurological manifestation as well. In examining 509 patients admitted to a Chicago hospital network, researchers found that 419 of them presented a neurological issue at some point during the course of their COVID-19 infection.
Though the central nervous system (CNS) is a highly protected organ from most viral infections by virtue of external multilayer barriers, the blood-brain barrier, and effective immune responses, some viruses can still enter the CNS through the hematogenous or neuronal retrograde routes resulting in debilitating direct immune-mediated pathologies, although invasion of the nervous system has no selective advantage for the host or the pathogen. The virus can infect the PNS or CNS either by direct infection of nerve endings in the tissues and using axonal transport machinery to gain access to the CNS, or by infecting cells of the circulatory system that ultimately carry the infection through the blood-brain barrier into the CNS.
For the study, researchers at Northwestern Medicine looked at the records of 509 patients who’d been hospitalized in the hospital’s network between March 5 and April 6, 2020.
They found 42.2% of patients experienced neurological symptoms when they first became sick, 62.7% reported such symptoms by the time they were hospitalized, and 82.3% had them at any time over the course of their disease. People who had severe COVID-19 cases and who were younger were most likely to experience any of these symptoms.
- Muscle pain, experienced by 45% of patients
- Headaches, experienced by 37.7% of patients
- Encephalopathy, experienced by 32% of patients
- Dizziness, experienced by 30% of patients
- Impaired sense of taste, experienced by 16% of patients
- Loss of smell, experienced by 11.4% of patients
“The most frequent neurologic manifestations were myalgias, headaches, encephalopathy, dizziness, dysgeusia [impaired sense of taste] and anosmia [loss of smell],” the authors wrote in their study published this week in the Annals of Clinical and Translational Neurology. “Strokes, movement disorders, motor, and sensory deficits, ataxia and seizures were uncommon.”
After they were discharged, only 32% of the patients with altered mental function were able to handle routine daily activities like cooking and paying bills, said Dr. Igor Koralnik, the senior author of the study and chief of neuro-infectious disease and global neurology at Northwestern Medicine.
Several human respiratory viruses can have neuroinvasive and neurotropic capabilities, leading to neuropathological consequences in vulnerable populations. Understanding the consequences of neuroinvasion and the underlining mechanisms of respiratory viruses (including coronaviruses) and their interactions with the central nervous system is essential as it can be used to better understand the potential pathological relevance of the infection, in addition to the design of novel diagnosis and intervention strategies that will help uncover the potential draggability of molecular virus-host interfaces highly relevant to symptoms of various neurological diseases with a viral involvement.
Liotta EM, et al. Frequent neurologic manifestations and encephalopathy‐associated morbidity in Covid‐19 patients. Ann Clin Transl Neurol.