COVID-19 and the Nervous System.

Neurological effects of SARS-CoV-2

During these days, We are hearing that the patients with infection SARS-CoV-2 displayed neurological symptoms such as loss of sense of taste or smell, numbness in limbs and memory deficit.

Three months after the infection , their MRI scan revealed enlarged volumes of the olfactory cortex, hippocampus, insula and the cingulate cortex and we know that together these areas of the brain regulate the sense of smell, memory formation and emotional processing.

Researchers across the world are assembling more evidence around the neurological manifestation of COVID-19. The conditions like hemorrhage, acute stroke like conditions and heart complications are already associated with COVID-19 symptoms.

INVADING THE BRAIN

As we know that the blood brain barrier(BBB) is the fence between the brain and the rest of the body. It protects the brain against viral infections. However, SARS-CoV-2 creates an immune reaction that can damage the barrier.

The virus could cross the BLOOD BRAIN BARRIER via two separate mechanisms:-

1. In the first case the infected vascular endothelial cells could transport the virus across the blood vessels into the neurons.
2. The second mechanism is via the infected white cells passing through the BBB. The inflamed BBB allows the influx of immune cells and cytokines and even the viral particles into the brain. T-lymphocytes however do not allow the virus to replicate though they can be infected.

RESEARCH

Autopsy studies of COVID-19 mortalities have revealed SARS-CoV-2 viral load in neurons and also in other non-neural tissues. The loss of taste and smell senses, headache, nausea, dizziness in COVID-19 patients can be strongly correlated to the brain function.