Announcement of the Israel Neurological Association – May 12th., 2020

Beyond stroke – What does COVID-19 do to the brain?

Many Corona patients experience neurological complications. Carmel Armon, MD, MHS,
Member of the Israel Neurological Association, and Chairman, Department of Neurology,
Shamir (Assaf Harofeh) Medical Center discusses COVID-19’s numerous and diverse
neurological effects.

In some patients the first Corona symptoms are neurological – loss of the sense of smell and
taste.

The most common long-term neurological complication is cognitive impairment. It affects an
estimated 40% of patients who experience the severe forms of the disease. The cognitive areas
that may be affected include the ability to focus or concentrate; motivation and initiative;
memory and comprehension. The reason for these complications is the vulnerability of brain
nerve cells to any infectious process or fever, particularly if associated with poor oxygenation or
multi-system failure. This vulnerability is common in patients more than 60 years old, who may
have experienced subtle forms of cognitive difficulties even before they were ill, or who were
on the verge of developing them.

The most common acute neurological complication is stroke. It is due to an increased tendency
of the blood to clot in severely affected COVID-19 patients. If a clot occludes a large blood
vessel in the brain the patient will have a stroke. Doctors looking after Corona patients have
started using blood thinners in severely-affected patients to reduce the risk of complications
due to blood clots.

Fairly common acute complications are muscle pain and muscle breakdown, usually mild and
reversible. Infrequently, changes are seen in imaging studies in the brain’s wrappings
(“meninges”); so far these have not been associated with isolation of COVID-19 itself from the
cerebrospinal fluid. This implies, that we are seeing a result of the hyperimmune state induced
by the virus, rather than meningitis caused by the virus directly.

Guillain Barre syndrome, a disease affecting the peripheral nervous system, is a rare
complication that may develop after or before COVID-19 is identified. It is an autoimmune
disease that attacks the nerves to the limbs or the head, causing progressive weakness. When
GBS is detected before COVID-19 is identified, it is attributed to the subclinical course of the
disease in many patients: the infected patient is not ill in terms of showing Corona symptoms,
but sufficiently infected for antibodies to develop against the virus, rarely cross-attacking the
body’s nerves.
Rarely the brain tissue itself is affected by an immune response to the virus (“post-infectious
encephalitis”).

The most significant longterm effect, in severely affected, older patients will be the impact on
cognitive function.

Professor Armon expects that increased awareness of the neurological complications of COVID19 will lead to greater recognition of these complications, and of new ones. “It may help plan
the rehabilitation program for those impacted most severely by the disease,” he says.

Professor David Tanne, President, the Israel Neurological Association, and Director of the Stroke
and Cognition Institute at the Rambam Health Care Campus concludes: The most common
symptoms of COVID-19 are pulmonary, but some of the patients experience neurological
symptoms as well, ranging from headaches and changes to the sense of smell to severe
complications affecting the brain and the peripheral nervous system. It will be important, says
Professor Tanne, to follow up on the long-term effects on memory, concentration and thought
processes in the severely-affected patients. Most of them are elderly, with pre-existing medical
conditions that place them at risk for brain disease.