A new paper, published last month in the journal JAMA Neurology, has discussed the potential complications of COVID-19 on the nervous system.
COVID-19 has been causing severe lung complications such as pneumonia and respiratory distress; however, there is strong evidence that the virus has also been affecting other organs, such as the heart and the nervous system.
The current paper aims to contribute to knowledge about the neurologic complications from COVID-19.
This coronavirus infects humans via the ACE2 receptor in various tissues, including the epithelium of airways, lungs, kidneys, small intestine, and endothelial cells.
Since endothelium is found within blood vessels, offering a potential route for coronavirus to invade and localize the brain. In addition, one report shows that the ACE2 receptor is also found in the neurons (nerve cells) and the other brain cells, such as astrocytes, oligodendrocytes. The receptor is also found in brain ventricles, gyrus, and olfactory bulb.
It has been found that the new coronavirus can infect neurons and glial cells in the central nervous system.
There a variety of possibilities on how the virus enters the nervous system. It may cross the synapses of infected cells and enter the brain through the olfactory nerve. The virus may cross the blood-brain barrier (BBB) through the infected vascular endothelial cells or through the infected white blood cells.
Although there is limited data on the association between COVID-19 and neurological implications, it is clear that the most common neurological symptoms caused by the virus include headaches, anosmia (loss of smell), and ageusia (loss of taste). Other neurological implications include stroke and impairment of consciousness.
The researchers said, “Given the reports of anosmia presenting as an early symptom of COVID-19, dedicated testing for anosmia may offer the potential for early detection of COVID-19 infection.”
Abnormal states of consciousness may occur in up to 37 percent of COVID-19 patients due to direct brain infection or injury, toxic-metabolic encephalopathy, and demyelinating disease.
If patients already have underlying neurological conditions that require special attention and care, they are more likely to be at greater risk for COVID-19 because of co-existing lung, heart, liver, or kidney disease. And the risk is more if they are on immunosuppressive medications. The paper concluded, “Clinicians should continue to monitor patients closely for neurological disease. Early detection of neurological deficits may lead to improved clinical outcomes and better treatment algorithms.”
