The new coronavirus SARS-CoV-2, which causes atypical pneumonia COVID-19, can also penetrate into the brain, disrupt the work of the nervous system and cause other severe complications.
The disease may not be limited to respiratory infections only. As practical studies show, in a significant number of patients, the virus affects the nervous system. The mechanism of its impact on nerve cells has not been studied yet, but scientists believe that there is some connection: a temporary loss of taste or smell was recognized as specific symptoms of COVID-19 in the middle of March. To make matters worse, the virus may penetrate directly into the brain from the nasopharynx. In this case, the virus may trigger a series of complications, disrupting the normal functioning of almost any organ.
The list of possible concomitant diseases is extensive:
- deterioration of the respiratory tract (upper and lower),
- brain dysfunctions,
- heart failure,
- myocarditis,
- vascular occlusion
- blood clotting disorders
- digestive problems
- encephalitis,
- kidney dysfunction,
- deterioration of the liver
- Guillain-Barré syndrome (a rare disorder in which the immune system of the body attacks nerves)
- paralysis...
Four months into the epidemic scientists still know very little about SARS-CoV-2 virus and its effect on the human body. The overall picture of the infection is extremely disintegrated, as doctors from all over the world continue sharing their knowledge about the disease as they treat coronavirus-affected patients.
The list of possible symptoms of COVID-19 has been expanded
The list of possible symptoms of COVID-19 continues to expand. There are already more than a dozen of them: chills, sore throat, trembling, muscle aches, headache, fever, loss of taste and smell, skin rash and livedo reticularis (net-like bluish skin color), changed color of toes (blue or purple), conjunctivitis, redness of the eyes ...
This list may not include all the symptoms, as the virus constantly mutates and new strains emerge. In addition, one should suspect coronavirus if a person has several symptoms at a time. In no case should one engage in self-diagnosis.
New symptoms expand doctors’ knowledge about what other organs the virus can affect and what complications, other than pneumonia, the disease may lead to.
Most often, doctors describe disorders in the work of the nervous system. Two studies conducted in France and China found that more than a third of infected patients experience neurological symptoms in one form or another.
In general, the new infection is peculiar for its versatile and even individual approach. The list of described complications of COVID-19, which doctors had to face in practice, includes diseases of the gastrointestinal tract, heart problems and blood clotting disorders.
The virus may affect the human nervous system in very different ways. There were incidents, when the novel virus caused encephalitis (inflammation of the brain), as well as Guillain-Barré syndrome – a rare disorder, when the patient's immune system begins to attack its own nerve cells, which leads to muscle weakness and, in severe cases, to paralysis.
At least five cases of massive stroke were reported in coronavirus patients in New York City during the recent two weeks. The cases were reported in relatively young patients, who were under 50 years of age, and they did not have any other pronounced symptoms of COVID-19. Doctors believe that the coronavirus triggered the formation of blood clots in large vessels, which ultimately led to an acute disorder in cerebral circulation. At the same time, it was noted that neurological disorders were observed in severe patients. In such cases, symptoms at times remain even after patients recover from COVID-19.
The virus can disrupt the nervous system both indirectly, through excessive activation of the immune system (the so-called cytokine storm), and directly. This was revealed as a result of the autopsy of the bodies of COVID-19 victims. Viral particles were found in the brain. Doctors assume that the infection penetrates into the brain from the respiratory tract through olfactory receptors in the nose.
This is not a unique ability of the novel virus. Some other viruses, including influenza and measles, may cause a similar infection of the brain too. This may lead to neurological diseases, albeit quite rarely.
Still, if the virus enters the brain, further infection is almost inevitable: there are ACE2 membrane receptors on the surface of the brain cells, through which the virus easily penetrates into the tissue, causing inflammation.
The cells lining the inner surface of blood vessels have the same receptor, which enables the virus penetrate into general bloodstream from respiratory organs into the general bloodstream. Thrombotic complications occur in almost every third patient, who suffers from coronavirus-caused pneumonia. The blood can carry the virus to any other organs, including the brain.
However, according to most recent reports, almost 50% of all infected people carry COVID-19 without any symptoms at all.
For the time being, it is believed that the severity of the infection, many of its symptoms, and possibly the likelihood of contracting the infection dependent on genetic factors, i.e. heredity.
Those who had a severe form of the disease have many neurological symptoms, such as confusion and disorientation. It remains unclear how long the consequences of the disease persist.
After recovery, patients with coronavirus often have a decrease in the volume of their lungs by 20-30 percent. Clearly, survivors will need serious rehabilitation, including pulmonary.
The severity of the course of the disease may also depend on the number of viruses that enter the body. Relatively speaking, a person touches a counter in a grocery store and then touches their nose or mouth. In this case, the number of viruses that have entered the body is likely to be small, and the body can manage to develop an immune response to them. In case of high viral load (like in hospitals), the disease may take a severe form, develop rapidly and result in lethal outcome.
To crown it all, it was discovered that the coronavirus can be especially dangerous for people with blood type A (II blood group). The number of deaths is higher with those having blood type A, doctors say. In Russia, the number of such patients amounted to 40 percent.
No comments :
Post a Comment