Coronavirus could also affect the brain

news-single-imgcaption" style="width:240px">Virologists are not entirely surprised that the new coronavirus, SARS-CoV-2, can affect the brain and nervous system, as this link has been observed with other viruses, including the AIDS virus, HIV. (Keystone)

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New York doctors treating patients with Covid-19 increasingly observe that with fever, cough and shortness of breath, another symptom appears: some are confused, to the point of not knowing where they are are, nor what is the current year.

This loss of bearings is sometimes linked to the lack of oxygen in the blood, but in some patients the level of confusion seems to be out of proportion compared to the level of affection of their lungs.

For Jennifer Frontera, a neurologist at Langone University Hospital in Brooklyn, the question arises of the impact of the new coronavirus on the brain and nervous system.

Neurological symptoms

Studies are beginning to describe the phenomenon. In the journal of the American Medicine Association (Jama), last week, doctors reported that 36% of 214 Chinese patients had neurological symptoms, ranging from loss of smell to nerve pain, and up to seizures and strokes.

In the New England Journal of Medicine, the most highly rated American medical journal, French doctors in Strasbourg described that more than half of 58 intensive care patients were confused or agitated. Brain scanners revealed possible inflammations.

“Everyone says it’s a breathing problem, but it also affects something that is very precious to us, the brain,” says S. Andrew Josephson, head of the department of neurology at the University of California San Francisco.

“If you feel confused, if you have problems thinking, these are good reasons to see a doctor,” he adds. “The old idea that you should only come if you are out of breath is probably no longer valid.”

Viruses and the brain

Virologists are not entirely surprised that the new coronavirus, SARS-CoV-2, can affect the brain and nervous system, as this link has been observed with other viruses, including the AIDS virus, HIV.

Viruses can affect the brain in two main ways, says Michel Toledano, neurologist at the Mayo Clinic in Minnesota. The first is by triggering an abnormal immune response called “cytokine storm”, which causes inflammation of the brain: this is called autoimmune encephalitis.

The second is by direct infection of the brain: this is called viral encephalitis. The brain is protected by what is called the blood-brain barrier: its role is to block intruders, but it can be pierced.

Some speculate that the nose could be the path to the brain, since loss of smell is common in many Covid-19 patients. But this is not verified, and many patients who lose their sense of smell do not have serious neurological problems.

The main track is actually that of the overheated immune response. To find out, the virus should be detected in the cerebrospinal fluid. This was done once, in a 24-year-old Japanese man, whose case was described in the International Journal of Infectious Disease.

He suffered from confusion and seizures and imagery of his brain showed inflammation. But the test is not yet validated and the scientists remain cautious.

To be continued

To unravel these mysteries, Jennifer Frontera, who teaches at New York University School of Medicine, is collaborating on an international research project to standardize data collection.

His own team has documented seizures in Covid-19 patients who never had them before they fell ill. The researchers also observed tiny cerebral hemorrhages described as “new”.

They also want to take cerebrospinal fluid from a fifties whose white matter in the brain is badly affected. But these samples, like MRIs, are difficult to do on patients on artificial respirators. And as the majority die, there is little study of neurological damage.

Those who survive, however, end up consulting neurologists. “We see a lot of patients in states of confusion,” says Rohan Arora, neurologist at Long Island Jewish Forest Hills Hospital. He claims that 40% of coronavirus survivors are affected.

It is not known if these disorders are lasting. The transition to resuscitation is, in itself, a source of confusion, especially because of medication. But the neurologist finds that the return to normal, for Covid patients, seems to take longer than for those who survived a heart attack or stroke. (ats)

* AFP

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