As the number of cases of COVID-19, grows globally, neurologists are vigilant for possible signs of the virus. COVID-19 although is a respiratory disease marked by cough, fever, and shortness of breath, there are reports that it might have a neurologic component as well.

Similar to other coronaviruses (like MERS, SARS) that affect humans have been shown to invade the brain and central nervous system. Early reports from three COVID-19-designated hospitals in Wuhan, China, indicated that one-third of coronavirus patients had some type of neurologic symptom, including altered consciousness, evidence of skeletal muscle damage, and acute cerebrovascular disease. These symptoms were far more common in severe disease.

Early reports indicate some COVID-19 patients experience symptoms of headache, stiff neck, and muscle ache, which, he said, may be suggestive of viral meningitis. However, it is still not understood whether the neurologic symptoms/complications are reflective of direct viral injury or due to the secondary or systemic effects of infection.

Experts say that perhaps, the respiratory/lung aspect of COVID-19 is so overwhelming in patients who end up dying that they don't live long enough "for the virus to cause damage to the brain". However, the extent to which COVID-19 can affect the brain and central nervous system will become clearer as epidemiologic data emerges.

Based on epidemiological studies from Wuhan, the median time from the first symptom to shortness of breath was 5 days, to hospital admission was 7 days, and to the intensive care (when worsened) was 8 days. Experts believe that the latency period of up to 8 days may be enough for the virus to enter and destroy the medullary neurons (a group of specialized brain cells).

Emerging reports also suggest that neurological signs were observed in more than one-third of all patients diagnosed with COVID-19. Importantly, neurological symptoms were observed in about 88% of all patients with severe COVID-19 who had to be admitted into the intensive care unit. The reported neurologic complications included acute cerebrovascular diseases (brain stroke) and impaired consciousness.

The dissemination of corona virus in the blood circulation or across the cribriform plate of the ethmoid bone (upper part of the nose) during the course of infection may lead to involvement of brain and higher centres of respiration. Although the exact pathway of dissemination to the brain is not proven yet, the proposed pathway was reported in the past for coronavirus that resulted in SARS.

Other pathway of coronavirus reaching the brain is through the general circulation. The flow of blood in the arteries of brain (cerebral circulation) is sluggish. This sluggish movemnt of the blood within the cerebral circulation may facilitate the interaction of the COVID-19/ corona virus to spike the protein with ACE2 expressed in the capillary endothelium (a layer/lining inside the blood vessel).

Subsequent, budding of the virus from the capillary endothelium leads to damage to the endothelial lining which may favor viral access to the brain. Once within the reach of the brain tissues, the virus can initiate a cycle of viral budding accompanied by neuronal/brain tissue damage without substantial inflammation. Simultaneously, the endothelium of the blood vessels supplying to the brain may rupture thus leading to bleeding within the brain tissue which can have fatal consequences in patients with COVID-19 infections.

Since catching the symptoms early may help avoid clinical deterioration, it is now frequently reported that findings like an altered sense of smell in an uncomplicated early stage COVID-19 patient should be investigated thoroughly for involvement of brain.

Another important reason why patients with neurological (Brain & Central Nervous system ) ailments need to stay more careful is because many of them fall into high-risk categories that include older persons (generally 60 or older) and those with underlying medical conditions such as hypertension, lung disease, and diabetes.

In fact, Centers for Disease Control and Prevention (CDC) has advised “people with neurologic conditions such as brain stroke, Parkinson's disease, Alzheimer's disease, tumors and myasthenia gravis, could also be at high risk of COVID 19 infection.

It is important to observe that though younger people feel that they are not at risk of COVID-19, it has to be remembered that they could be active carriers and spread the virus among elderly and high-risk patients. Therefore, physical/social distancing play a major role in stopping the spread. Not only during lock-down period but also subsequently people should ensure hygiene practices and sufficient social distancing to prevent a pandemic.

Due to the varying severity of COVID and an undetermined incubation period, currently asymptomatic individuals may subsequently test positive for the COVID 19 virus. This uncertainty has put the Neurosurgeons, the staff in operating rooms and post-operative intensive care units are placed at high risk of contracting the virus, especially from the asymptomatic individuals. Particularly, in brain surgeries that require transsphenoidal surgeries (surgery of the brain through the nose) there is a higher risk of transmission, based on preliminary reports out of China.

For emergency surgeries in patients in whom the COVID 19 status is undetermined, the surgeon could delay to operate. However, in patients who cannot be safely delayed, the surgeon should utilize a transcranial approach (through the head or skull), instead of approaching through the nose. Experts say that the nasal and oral passages have high viral loads and therefore non-emergency procedures should be delayed until adequate testing is available. These recommendations have been adopted by several national and inter-national organizations.

During the recent COVID-19 pandemic, there is an urgent need to understand the potential of the COVID-19 virus to affect brain and central nervous system. This understanding may help to prioritize and individualize the treatment protocols based on the severity of the disease.