In the wake of the Spanish flu pandemic that killed some 50 million people worldwide at the end of World War I, a strange crippling disease spread across Europe, causing severe lethargy, nervous problems, headaches and confusion.
According to the journal Brain, scientists called it lethargic encephalitis syndrome, and it is estimated that it affected more than a million people at the time.
Thousands of people were left with permanent neurological damage that left them all but comas. The hit film Awakenings dramatized attempts by neurologist and author Oliver Sacks to revive victims who had been trapped for decades in motionless, wordless passivity.
Many experts believe that lethargic encephalitis was a side effect of the Spanish flu and that the virus traveled to the victims’ brains through the nose, causing the devastating symptoms of the syndrome.
We are now beginning to witness something alarmingly similar in the wake of the Covid-19 pandemic, and neurology experts fear that history may repeat itself.
Many experts believe that lethargic encephalitis was a side effect of the Spanish flu and that the virus traveled to the victims’ brains through the nose, causing the devastating symptoms of the syndrome.
Several studies have warned that coronavirus can invade patients ’brains by traveling through the olfactory nerve, which runs from the top of the nose to the olfactory bulb, the center of the brain’s sense of smell. From here, the virus can establish an infectious base and can spread dangerously to other regions.
A Chinese study published in April in the journal Signal Transduction and Targeted Therapy found that the virus used this pathway to the brain in infected rhesus monkeys.
In July, a study by the University of Southampton in the journal Brain Communications stated the ability of Covid-19 to cause serious mental problems. The study of 267 patients infected with neurological symptoms found that 11% had delirium, 9% had psychosis and brain inflammation, and 7% had other encephalopathies (any generalized brain disease that impaired their function or function). structure).
“It was amazing that some of these conditions occurred together within the same patients,” says lead author and neurology specialist Dr. Amy Ross-Russell. “This suggests that Covid-19 may affect several parts of the nervous system in a single patient.”
These symptoms often subside after Covid infection has subsided. However, in some, the virus can cause lasting neurological problems.
The National Institute for Excellence in Health and Care, the NHS treatment watchdog, says the long Covid, which is estimated to affect more than two million people in the UK, could lead to neurological problems such as “brain fog” (loss of concentration or memory problems), insomnia, nervous problems and delirium.
Dr David Strain is Co-Chair of the Medical Medical Staff Committee of the British Medical Association and Professor of Clinic at the University of Exeter.
Several studies have warned that coronavirus can invade patients’ brains by traveling through the olfactory nerve, which runs from the top of the nose to the olfactory bulb, the center of the brain’s sense of smell.
He told a BMA expert meeting in July: “Most of these patients had relatively minor initial infections, such as a flu-like illness, although they have been left with a catalog of symptoms such as fatigue, brain fog. and pain in every muscle. “
Dr. Strain said there are many historical precedents, adding: “The biggest example of how a virus can leave lasting neurological damage is the Spanish flu. Since then, there have been many other postviral manifestations of others. epidemics [such as the Middle East respiratory syndrome outbreak in 2012]. So it was no surprise how long Covid appeared. ”
Long-term brain problems caused by Covid infection can be unprecedented in scale and depth, according to a U.S. report in The Lancet in July that warned of an impending dementia epidemic. The study, led by Roy Parker, a professor of biochemistry at the University of Colorado Boulder, predicts that patients with substantial chronic brain inflammation (as can occur in a long Covid) could develop high levels of abnormal brain proteins. These proteins, known as tau, are strongly related to dementia.
“There could be similarities between postcovide complications and the 1918 pandemic,” Professor Parker told Good Health.
“The long – term consequences of infectious diseases remain possible [such as long Covid] would include some types of neurodegenerative diseases. “The large number of covid infections means we could see an increase in the number of dementia cases,” he added. “Monitoring studies of neurological dysfunction in Covid-19 survivors are essential,” the report warns.
“These studies should persist for at least a decade and focus on young people [aged 30 to 40],’ he says. These should include blood tests to check for tau proteins.
To prevent mistaken detection of people who may already experience tau protein accumulation and cognitive problems due to early-onset dementia.
Unfortunately, he adds, this control cannot help people with dementia caused by Covid. “Nothing can be done (at least right now) to stop the formation or progression of tau problems,” he says.
Dr Dennis Chan, principal investigator at the Institute of Cognitive Neurosciences at University College London, also warned of the appearance of ‘Cognitive Covid’ in the journal World Psychiatry earlier this year.
“There’s a big risk for younger people, such as something with Covid, as it can cause dementia at later ages that otherwise wouldn’t have developed,” he told Good Health. “In 20 years we may see emerging people with new mental problems.”
Some other viruses are known to cause dementia. If HIV enters the brain, “it is associated with a 50% increased risk of dementia due to the accumulation of tau protein,” says Dr. Chan.
“Given the much larger number of people infected with Covid-19, an increased risk that it was even a fraction of HIV would result in a very large number of people being affected,” he warns.
He is especially concerned about the fact that Covid-19 appears to enter through the olfactory nerve, which carries it to the olfactory bulb of the brain.
“I was alarmed when this was discovered, because there is a large fat pathway that goes from the olfactory bulb to many parts of the brain associated with Alzheimer’s,” he says. “It’s like a highway and we know viruses can run through it.”
In particular, the olfactory bulb is linked to the hippocampus, which participates in the formation of memories, and to the entorinal cortex, a center of memory, navigation, and perception of time. Studies show that this cortex is the area of the brain most damaged by Alzheimer’s disease.
As for when generalized neurological problems associated with a long Covid may begin to arise, Dr. Chan says, “We don’t know the time period because of the uncertainty about how long it will take for the virus to interact with the tau proteins in the brain, and then the dementia to develop.”
Regardless, Dr. Chan says the threat of dementia underscores the need for us to continue to take precautions against Covid.
“You really don’t want to catch him,” he says. “If you are an adult after the age of 40, there is a significant chance that this may increase your risk of dementia.”
For those who have already had Covid, “there are things that can change the risk of developing dementia,” he adds.
“We are beginning to see new so-called biological drugs on the horizon that may help stop dementia in the future. In 2035, when Covid-driven dementia may appear, there is a possibility that these are in place to help them.” .
Biological products are proteins that are genetically targeted to the parts of the immune system that fuel inflammation. It is hoped that by reducing the damage caused by brain inflammation, medications can help prevent dementia.
A study last year examined more than 140,000 patients taking biologics for their rheumatoid arthritis. The research, presented at the American College of Rheumatology by researchers at New York Special Surgery Hospital, found that people who took the drugs had a 17% lower incidence of dementia than conventional medications.
Until then, we should focus on the lifestyle changes that build our cognitive reserve: the brain’s ability to resist damage, says Dr. Chan. “The more cognitive reserve you have, the lower the risk of debilitating symptoms if you develop dementia-related brain changes,” says Dr. Chan.
His research on Neurobiology of Aging in 2018 found that being sociable has by far the most important preventive benefit.
‘Try new activities instead of watching TV, exercise regularly, and maintain a healthy weight. We’ve been lost doing these things for over a year of social isolation. We all need to do more, ”he says.