The complications regarding the effect of COVID-19 started when a doctor at Strasbourg University Hospital in northeast France came across alarming symptoms from the patients admitted to her intensive care unit in early March.

“They were extremely agitated, and many had neurological problems; mainly confusion and delirium,” the doctor says. “We are used to having some patients in the ICU who are agitated and require sedation, but this was completely abnormal. It has been very scary, especially because many of the people we treated were very young, many in their 30s and 40s, even an 18-year-old.”

Since then, more than 300 studies from around the world have found a prevalence of neurological abnormalities in Covid-19 patients. The estimates of exact prevalence vary, but it seems that roughly 50% of patients diagnosed with Sars-CoV-2 virus responsible for causing the illness Covid-19 have experienced neurological problems.

The studies highlight that the neurological problems includes mild symptoms like headaches, loss of smell (anosmia) and tingling sensations (Arcoparasthesia), up to more severe outcomes such as aphasia (inability to speak), strokes and seizures.

Further, it is anticipated that when the coronavirus comes to the brain and nerves, it could result in four main sets of effects.

1. A confused state (known as delirium or encephalopathy), sometimes with psychosis and memory disturbance.
2. Inflammation of the brain (known as encephalitis). This includes a form showing inflammatory lesions, together with the effects of low oxygen in the brain.
3. Blood clots, leading to stroke (including in younger patients).
4. Potential damage to the nerves in the body.

To date, the pattern of the effect is found to be the same all over the world and some of these illnesses are fatal. And neurologists anticipate that, for those who survive, many will bear long term consequences.

In one study, patterns found included signs of inflammation and a shower of small spots of bleeding, often in the deepest parts of the brain. Some of these findings were similar to those seen in divers or altitude sickness.

The study says that they might represent the profound lack of oxygen being delivered to the brain in some patients with COVID-19. Yet we are only starting to understand the full scope of the brain’s involvement in the disease. Brain-imaging and postmortem studies for those killed by COVID-19 have been limited to date.

The scariest point is that most people including physicians may not recognize the neurological abnormalities for what they are and when they appear. Simply a person experiencing a seizure might look like dazed without any trembling or shaking. With its beeping machinery, sedative drugs and bed-bound isolation, an ICU environment can exacerbate and induce delirium, confounding the ability to link any symptom to the virus.

“In fact, there is a significant percentage of Covid-19 patients whose only symptom is confusion”, they don’t have a cough or fatigue”, says Robert Stevens, associate professor of anesthesiology and critical care medicine at Johns Hopkins Medicine in Baltimore, Maryland.

This trend of COVID-19 illness raises an important question: will COVID-19 be associated with a large epidemic of brain illness, in the same manner, that the 1918 influenza pandemic was linked to the epidemic of encephalitis lethargica (sleeping sickness) that took hold until the 1930s?

The 1918 influenza pandemic may have killed 50-100 million people and that is around six times the number killed in the First World War. Yet it’s not often mentioned that this pandemic was linked to an outbreak of brain disease known as the “sleeping sickness” encephalitis lethargica.

In those who died from influenza, postmortems revealed a pattern of inflammation in the seat of the brain, known as the brainstem. Some patients who had damage to areas of the brain were unable to move for decades and were only “awakened” by treatment with L-Dopa, a chemical that naturally occurs in the body by Oliver Sacks in the 1960s.

It is too early to tell if we will see a similar outbreak associated with the COVID-19 pandemic, though early reports of encephalitis in COVID-19 have shown features similar to those in encephalitis lethargica.

The aftermath of this global event has many lessons for us now in the time of COVID-19. One, of course, is that we may see widespread brain damage following this viral pandemic.

By Jumana Jabeer