-Saksham Shrestha
In March, four elderly patients who came into Danbury Hospital in Connecticut, USA with severe brain infection (encephalopathy) ultimately tested positive for Covid-19, although they had no other symptoms. It is not uncommon for elderly people to experience confusion when they develop other infection but Dr. Paul Nee, an infectious disease specialist at the hospital said, “The striking thing is we have not seen any real respiratory illness in these patients.”
Other studies also suggest that many young people with the infection died from stroke rather than respiratory related complications which are thought to be the major symptoms of Covid-19 infection.
Doctors around the world are now growing concerns that patients currently dealing with the coronavirus may also eventually suffer brain damage from the disease, which may or may not play part in causing acute respiratory failures as noted in one recent paper by the Chinese scientists giving evidences that Covid-19 infections were not confined to the respiratory tract.
Dr. Sherry H-Y. Chow, a neurologist at the University of Pittiburgh School of Medicine said, “There’s no ventilator for the brain. If the lungs are broken we can put the patient on a ventilator and hope for recovery. We don’t have that luxury with the brain.” These words are concerning with context to the extent of damage the virus is able to cause.
After the WHO’s announcement of Covid-19 as a pandemic disease on March 11, 2020 there has been about 3.85 million cases worldwide as of 8th May, 2020 out of which 36.4% patients had neurological symptoms like headaches, dizziness, loss of smell, stroke, seizures and hallucinations. Estimated 46-84% of severe cases showed neurological symptoms like changes in consciousness, disorientation, inattention and movement disorders, which were even persistent in the patients after recovery.
Although headaches and dizziness are common problems seen as a result of body’s immune system trying to demolish the foreign bodies but other neurological symptoms are major and unavoidable. This brings us to the study from 2002 and 2003 SARS outbreak that note the presence of viral particles in the brain cells including medulla oblongata, responsible for maintaining body’s breathing mechanism. Since, SARS and Covid-19 both belong to the same family of viruses namely coronaviruses, they have a similar genetic structure and mechanism of host infection.
By the previous studies and witnesses of 2002 and 2003; and similarities between SARS-CoV and SARS-CoV 2 (Covid-19), it was sure that the virus caused neurological disorders either by directly infecting the brain or as a result of strong activation of the immune system caused by Guillain-Barré syndrome or because of decrease in oxygen supply to the brain indicated by Dyspnea.
Now recent study has found the presence of SARS-CoV 2 viral particles on the brain of fatal cases. This brought a big question in the scientific community – how can a virus that infected alveolar progenitor cells infect the Central Nervous System (CNS)? The study suggested that infection of olfactory neurons in the nose may enable the virus to spread from the respiratory tract to the brain.
Cells in the Human brain express the Angiotensin-converting enzyme 2 (ACE2) protein on their surface. This protein is the receptor for the virus used to enter and infect the cells. ACE2 protein is also found on the cell surface of lungs, kidneys, arteries, heart, intestines and on the endothelial cells that line the blood vessels. Infection in the endothelial cells may allow the virus to pass from the respiratory tract to the blood and across the blood-brain barrier into the brain. Once into brain, replication of virus occurs by binding to the receptor protein causing neurological disorders, leading into complications discussed above.
In other hand, there are psycho-socio problems and mental health problems including the “Fear of Death” among confirmed patients and patients with suspected infection that causes complications like that in Italy. But until we are aware of the possible psychological manifestations of Covid-19, its effects can be eradicated.