A 55-year-old woman was admitted to a London hospital a few weeks ago after 14 days with fever, cough, muscle aches, shortness of breath and loss of the senses of smell (anosmia) and taste (hypogeusia). The typical picture of the covid. They released him three days later. The worst of the disease had passed or so he thought. The next day, her husband called the doctors, alarmed. His wife was behaving strangely. He put on and took off his coat repeatedly. She claimed to see lions and monkeys at home and claimed that someone was chasing her. She was even aggressive towards her family and medical staff. She only got better after treating her with haloperidol and risperidone, two antipsychotic drugs. It is an extreme case, but it is part of what the coronavirus is doing to the brains of some of the people it infects.
British researchers created a unit last March focused on detecting and studying COVID cases involving neurological problems. Although it is a respiratory disease, its impact is being seen to go far beyond the lungs and airways. The work has focused on 43 patients. They did not pretend to know how many of the patients end up having an affected brain. Its objective was to identify the alterations and disorders it is causing.
Its first results, published yesterday in the magazine Brain, show a broad spectrum of impacts of the coronavirus on the brain. The authors of this follow-up have classified them into five categories: encephalopathies with delusions and psychosis such as that of the 55-year-old woman, inflammatory processes in the central nervous system, cerebrovascular accidents such as stroke, neurological disorders in the peripheral nervous system and a last group who do not know how to classify. What they have not seen is that there is a relationship between the degree of severity of the covid and the appearance of neurological problems.
The study has not found a relationship between the severity of the covid and the appearance of neurological problems
In addition to the encephalopathies already detailed, the most common are neuro-inflammatory syndromes such as autoimmune encephalitis, caused by the immune system itself in its fight against the coronavirus. Another manifestation that has attracted attention is the high incidence (24%) of ADEM, or acute disseminated encephalomyelitis. Although rare, ADEM almost always affects children and adolescents. Here, the sample ranged from 16 to 85 years old.
In another group of patients, all under 65, the coronavirus ended up causing a stroke. Either in the blood vessels of the lungs or those that reach the brain, the virus, which is primed with the endothelial cells, which forms the inner wall of the blood capillaries, would facilitate the formation of thrombi, of clots that get stuck in the brain. Another seven patients developed the so-called Guillain-Barré syndrome, in which the defenses themselves attack the nerves. Among the cases that are difficult to classify, they report alterations in the spinal cord, cerebral microbleeds or intracranial hypertension.
“We are still working on what causes brain and nervous diseases in these patients,” says the researcher at University College London and lead author of the study Michael Zandi in an email. “The aim of this study was to describe the syndromes in detail to raise awareness about them and drive further research,” he adds. But Zandi, from the Queen Square Institute of Neurology at the British university, does provide clues: “The patients and their diagnoses have more to do with the effects of low oxygen levels in the brain on encephalopathies.” It also points out that the action of the immune system on the brain and nerves better explains neuroinflammatory and nervous disorders than the arrival of the virus in the brain area. In fact, in their study they did not detect any case in which the coronavirus had crept into the brain.
“It is not the virus that directly affects the central nervous system”, comments the neurologist and vice president of the Spanish Society of Neurology (SEN) Jesús Porta. Everything indicates that, as with other complications of covid, the cause of these disorders would be in the exaggerated response of the immune system. “In its defense, the immune system unleashes a storm of cytokines that can break the blood-brain barrier,” says Porta, who was not involved in the study. This barrier allows blood and only blood to flow from the blood vessels to the nerve cells.
Another unwanted effect of the defense system response is the autoimmune derivative. Antibodies designed to neutralize the virus can also attack myelin, a substance that covers the branches of nerve cells and that, in addition to protecting them, works as a lubricant for synapses. “We have learned,” says Porta, “that the coronavirus affects the lung but in its response, it has an impact on the entire organism.” The SEN published in April a manual for neurologists which estimated at least 36% of patients infected by covid who could suffer any of these impacts.
As the researcher at the University of Exeter David Strain recalls, “the main limitation is that we do not know what they have in common and how frequent these complications are”. But he believes it is necessary to delve into these disorders to see if they are rare cases or just the end of a long line of cases.
Information about the coronavirus
– Here you can follow the last hour on the evolution of the pandemic
– This is how the coronavirus curve evolves in Spain and in each autonomy
– Search engine: The new normal by municipalities
– Questions and answers about the coronavirus
– Guide to action against the disease
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