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June 17, 2020

'Silent' neurological damage caused by COVID-19 may lead to future health problems

Researchers recommend hospitalized coronavirus patients undergo a brain MRI

Illness COVID-19
Brain deficits with COVID Raman Ozar/Pixabay

Researchers have identified three stages of neurological deficits caused by the coronavirus. Because many of them can be easily missed by medical providers, researchers suggests hospitalized COVID-19 patients undergo a brain MRI.

When a patient is admitted to the hospital with respiratory distress related to COVID-19, the critical care team is focused on life-saving measures and may miss more subtle signs of neurological damage that can lead to longterm problems, according to a new medical paper. 

Strokes and brain hemorrhages in COVID-19 patients have been well-documented in studies, but milder neurological damage often can be missed by health care providers, said Dr. Majid Fotuhi, medical director of NeuroGrow Brain Fitness Center in Northern Virginia.

That is why his research team recommends all hospitalized COVID-19 patients undergo a brain MRI before they are discharged. Doing so will help doctors catch any "silent" deficits.

The researchers conducted a comprehensive review of the neurological effects of COVID-19, identifying three stages of neurological deficits caused by the coronavirus. Their findings were published in the Journal of Alzheimer's Disease

"We are learning that a significant number of hospitalized COVID-19 patients have various degrees of brain impairment," Fotuhi said. "As a medical community, we need to monitor these patients over time as some of them may develop cognitive decline, attention deficit, brain fog or Alzheimer's disease in the future.

"There is a lot we can do to promote brain healing in COVID-19 patients, but first we must understand the nature and severity of their neurological deficits. At the patient level, getting a baseline MRI before leaving the hospital is imperative so we have a starting point to evaluate and treat them."

Fotuhi pointed to a French study that found 84% of intensive care unit patients with COVID-19 had positive abnormalities on their neurological examinations. Plus, 15% of patients who leave the ICU have residual neurological deficits, including poor attention and difficulties with decision-making and behavior control.

Anywhere from one-third to 59% of hospitalized COVID-19 patients will experience confusion, dizziness, headaches, mini strokes and paralysis, he added. Even these milder neurological deficits need to be documented and monitored.

Mini strokes might lead to a slowness in thinking, Fotuhi said. An MRI can alert the doctor that the patient had a mini stroke, necessitating a followup visit three months later. Patients who have had a mini stroke are put on an aspirin regimen and are counseled on their vascular risk factors. 

How the coronavirus affects the nervous system

The three stages of neurological deficits caused by the coronavirus begin with damage primarily limited to the epithelial cells of the nose and mouth. The main symptoms of this first stage are temporary losses of smell and taste. 

In the second stage, a flood of inflammation caused by a cytokine storm begins in the lungs. But it can spread to other organs and cause blood clots that could lead to a stroke.

In the final stage, inflammation damages a protective insulation layer in the blood vessels of the brain, allowing blood content, inflammation markers and virus particles to invade the brain. 

Patients with severe inflammation develop seizures, confusion, coma or encephalopathy – a disease that alters the function and structure of the brain. These patients have a higher risk for developing Parkinson's disease, Alzheimer's and multiple sclerosis.

Fotuhi recommends any patients with second or third-stage neurological deficits undergo an MRI. 

It's not just patients with stroke and brain hemorrhages that can benefit from interventions, Fotuhi said. Even the milder neurological damage that some COVID-19 patients develop can be reversible. That's why documenting them is important.

People often attribute mild neurological symptoms to aging, assuming that nothing that can be done, he said. But that leaves them operating at a deficit for the rest of their lives.

"The exciting thing for me is that we can grow the capacity and volume of the brain with vigorous exercise, good sleep, eating a Mediterranean diet, reducing stress as well as targeted brain training and neurofeedback therapy," Fotuhi said.

Younger COVID-19 patients are developing strokes

In addition to causing "silent" neurological deficits, the coronavirus also may be making younger adults more prone to strokes, researchers at Jefferson Health in Philadelphia have found. 

"We were seeing patients in their 30s, 40s, and 50s with massive strokes, the kind that we typically see in patients in their 70s and 80s," said Dr. Pascal Jabbour, chief of Jefferson's division of neurovascular and endovascular neurosurgery.

The researchers examined the strokes of 14 patients with COVID-19. Half of them were already being treated for the infection when they suffered a stroke. The others did not know they had COVID-19 at the time of their strokes. 

Six of the patients were under the age of 50 – a surprising finding given that more than 75% of strokes in the U.S. occur in people over the age of 65, Jabbour said. 

Their study, published in the journal Neurosurgery, also revealed two other unusual findings: Massive strokes were occurring in both hemispheres of the brain. Plus, they were occurring in both arteries and veins.

Additionally, the mortality rate of stroke patients with COVID-19 was 42.8% – significantly higher than the 5-10% rate typically associated with stroke.

There are a couple theories why younger COVID-19 patients are experiencing strokes, Jabbour said. 

Researchers believe the coronavirus gains access to human cells by attaching to a particular protein abundant on the cells that line the body's blood vessels, heart, kidney and lungs. 

In addition to using this protein as an entry point, the virus could be affecting the cells' ability to to control blood flow to the brain, Jabbour said. Another possibility: inflammation of the blood vessels causes mini blood clots in the vessels. 

"Our observations, though preliminary, can serve as a warning for medical personnel on the front lines, and for all of those at home," Jabbour said. "Stroke is occurring in people who don’t know they have COVID-19, as well as those who feel sick from their infections. We need to be vigilant and respond quickly to signs of stroke."

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