This is what the research shows…

The COVID-19 pandemic has now claimed as many lives as World War I, the Vietnam War, and the Korean War combined. Most of these deaths are due to the well-known pulmonary complications of the coronavirus. However, it has become increasingly recognised, that the virus also attacks the nervous system.

Research shows that patients with COVID-19 are experiencing an array of effects on the brain, ranging in severity from confusion to loss of smell and taste to life-threatening strokes. Younger patients in their 30s and 40s are suffering possibly life-changing neurological issues due to strokes.

Particularly troubling is increasing evidence that there may be mild — but very real — brain damage that occurs in many survivors, causing pervasive yet subtle cognitive, behavioural, and psychological problems.

Critical care physician and neurointensivist, Dr Robert Stevens, who is the associate director of the Johns Hopkins Precision Medicine Center of Excellence for Neurocritical Care, has been tracking cases at Johns Hopkins in which patients with COVID-19 also have neurological problems. As of July 2021, thanks to a new research consortium of more than 20 institutions and health systems in Europe, researchers, including Stevens, are using imaging and tests of blood and spinal fluid to understand how the coronavirus operates so they can prevent and treat effects on the brain. Although researchers don’t have answers yet as to why the brain may be harmed, they have reached significant conclusions.

COVID-19 infection – now a risk factor for STROKE

COVID-19 can cause damage to the brain directly by encephalitis, which may have devastating or subtle consequences. In one British study of 12 patients with encephalitis, one made a full recovery, 10 made a partial recovery, and one died. This study also found that a number of patients with COVID-19 suffered strokes. In fact, COVID-19 infection is a risk factor for strokes. A group of Canadian doctors found that individuals over 70 years of age were at particularly high risk for stroke related to COVID-19 infection, but even young individuals are seven times more likely to have a stroke from this coronavirus versus a typical flu virus.

Autopsy data from COVID-19 patients in Finland suggests that another major cause of brain damage is lack of oxygen. In one patient there was loss of taste, and in two there was “minimal respiratory distress,” but none of these patients were thought to have any brain damage while alive.

Another extensive research from Johns Hopkins University and Harvard Medical School found that large cells called megakaryocytes may be found in the brain capillaries of individuals who died from COVID-19 infection. Megakaryocytes make platelets — part of the body’s clotting system — and these cells should not be there. In fact, these neuropathologists had never seen megakaryocytes in the brain before, and this observation had never before been reported in the medical literature. These cells could be related to strokes observed in individuals with COVID-19.

In what ways does the coronavirus affect the brain?

Cases around the world show that patients with COVID-19 can have a variety of conditions related to the brain, including:

• Confusion

• Loss of consciousness

• Seizures

• Stroke

• Loss of smell and taste

• Headaches

• Trouble focusing

• Changes in behaviour

Major cognitive effects of COVID-19

In survivors of intensive care unit (ICU) stays due to acute respiratory failure or shock from any cause, one-third of people show such a profound degree of cognitive impairment that performance on neuropsychological testing is comparable to those with moderate traumatic brain injury.

In daily life, such cognitive effects on memory, attention, and executive function can lead to difficulties managing medications, managing finances, comprehending written materials, and even carrying on conversations with friends and family. Commonly observed long-term psychological effects of ICU stays include anxiety, depression, and post-traumatic stress disorder (PTSD). Effects due to COVID ICU stays are expected to be similar — a prediction that has already been confirmed by the studies in Britain, Canada and Finland.

Long-term cognitive effects of COVID-19 infection

As discussed above, strokes due to COVID-19 are common, particularly in those over 70. We know that silent strokes frequently occur, and are a risk factor for both large strokes and dementia. Silent strokes typically affect the brain’s white matter — the wiring between brain cells that enables different parts of the brain to communicate with each other. This wiring is essential for attention, and when it is damaged, sustained attention is impaired.

The bottom line

There is one inevitable conclusion from these studies: COVID-19 infection frequently leads to brain damage — more so in those over 70, but have also affected those in their 30s and 40s. While sometimes the brain damage is obvious and leads to major cognitive impairment, more frequently the damage is mild, leading to difficulties with sustained attention.

Although many people who have recovered from COVID-19 can resume their daily lives without difficulty, there are a number of people who may experience difficulty now or later, as another study suggested COVID-19 survivors are at high risk for Alzheimer’s disease in the future.

Survivors may need to be carefully evaluated with formal neuropsychological testing, including measures of sustained attention, to assure that their cognition has not been compromised.

“We need to balance treating their immediate medical needs with information gathering to better understand how we can help fight the virus in others who may develop this condition in the future” shares Dr Robert Stevens, John Hopkins University.