COVID-19 causes mainly cold and flu-like symptoms (such as fever, cough, chills, sore throat), but unlike most colds, COVID-19 can cause loss of taste and smell. However, COVID-19 sometimes affects many parts of the body and can cause many other symptoms. It can affect the brain and nerves, causing neurologic symptoms, such as confusion. COVID-19 can also cause disturbances in thinking, emotion, mood, and/or behavior, causing mental health (psychologic) symptoms.
Neurologic and psychologic symptoms may occur when people are first infected with COVID-19, while people are recovering, and/or after people have recovered from the initial infection.
People who become critically ill with COVID-19 can, as with other infections, develop delirium and become agitated or drowsy.
After recovering from the initial infection with COVID-19, many people have at least one persistent symptom, such as fatigue, impaired memory and cognition, headache, numbness and tingling, and/or loss of smell.
Doctors may do magnetic resonance imaging to check for changes in the brain and do blood and urine tests to rule out other disorders that can cause similar symptoms.
The main treatment for neurologic and psychologic symptoms is supportive care, but for people with depression, antidepressants may be useful.
Neurologic and psychologic symptoms may last a long time—for many weeks to months. Symptoms that occur during the first 4 weeks after the initial infection are called acute COVID-19. Symptoms that last longer or recur after a period of feeling well and then continue are commonly called long COVID (also referred to as chronic COVID).
How the virus that causes COVID-19 (SARS-CoV-2) causes neurologic and psychologic symptoms is unclear. These symptoms may result from
The infection itself
Problems that are common during severe illness or that result from hospital care, particularly in an intensive care unit (ICU)
An autoimmune reaction—when the immune system malfunctions and attacks its own tissues—triggered by the virus
For example, if COVID-19 (or any respiratory illness) is severe, it may reduce the level of oxygen in the blood. If the oxygen level is very low, the brain may not get enough oxygen and may malfunction, causing problems with thinking, memory loss, personality changes, difficulty walking, and lack of coordination.
Risk factors for developing neurologic and psychologic symptoms (such as delirium and agitation) due to COVID-19 include
Being critically ill, especially if treatment in an ICU is required
Being older
Having another disorder such as cerebrovascular disease, heart failure, or high blood pressure
In an ICU, people are easily disoriented and confused. They are often alone and frightened in a strange place without familiar landmarks and usual routines. There are often no windows or clocks, and they have none of their possessions to help orient them. Older people, whether they have dementia or not, are particularly affected when they are taken out of their usual environment and do not have the support of family and friends. People in an ICU tend to be drowsy because they are often given sedatives and their sleep is constantly interrupted by beeping monitors and by staff members checking on them, taking blood, and giving them drugs. People who are tired are more easily confused, sometimes leading to delirium.
Symptoms of Brain Dysfunction Related to COVID-19
About 80% of people hospitalized with COVID-19 have neurologic symptoms. Many people have neurologic and psychologic symptoms in the 6 months after being hospitalized for COVID-19, especially if it is severe.
Early symptoms
During the first 4 weeks of infection, neurologic symptoms of COVID-19 may include headache, dizziness, muscle aches, fatigue, and the more specific symptom of COVID-19—loss of smell and taste.
Several days after they are first infected, some people continue to become sicker and may become critically ill. They commonly become delirious. People with delirium cannot concentrate, and they become confused. They may alternate between being alert one moment and drowsy the next. Delirious people may be agitated and hostile or sluggish and subdued.
Occasionally, COVID-19 causes severe neurologic problems such as ischemic stroke, bleeding within the brain, meningitis, encephalitis, and seizures. Some symptoms persist for weeks to months. Persistent problems may require extensive rehabilitation.
Disorders that affect nerves and muscles, such as Guillain-Barré syndrome, may occur in people with COVID-19.
Later symptoms
During recovery and/or as part of post-COVID syndrome, many people have at least one long-lasting neurologic symptom, such as chronic fatigue, general muscle aches, numbness and tingling, and unrefreshing sleep. Some people, even those with a mild case of COVID-19, have brain fog, which may involve problems with concentration, memory, understanding spoken and written language, and planning and making decisions. Many people have migraine-like headaches (which often do not respond to treatment). These symptoms often significantly affect people's ability to do daily activities. Loss of taste and smell may persist for several months or longer after other symptoms resolve.
Mood disorders, mainly anxiety and depression, are common.
Posttraumatic stress disorder (PTSD) may develop. People with PTSD may have recurring intrusive memories.
More study is needed to determine how long neurologic and psychologic symptoms last and how well people recover from them.
Diagnosis of Brain Dysfunction Related to COVID-19
A doctor's evaluation
Testing for other causes
Magnetic resonance imaging (MRI) or computed tomography (CT) of the brain is done to evaluate neurologic and/or psychologic symptoms due to COVID-19 (or other causes). These tests can detect swelling in the brain, brain tumors, infection, and other abnormalities. Blood and urine tests are done to check for metabolic disorders and infections. Neuropsychologic testing is done to evaluate problems with thinking and behavior.
Doctors use the same specific criteria to diagnose mood disorders (such as depression), anxiety disorders, and PTSD in people with COVID as used in other people. Standard screening tools should be used to identify depression, anxiety disorders, sleep disturbances, PTSD, and fatigue. More extensive neuropsychologic evaluation may be needed in people with problems with thinking that persist after the initial infection resolves.
Treatment of Brain Dysfunction Related to COVID-19
Supportive care
Sometimes antidepressants
Supportive care is the main treatment for people with neurologic and psychologic symptoms due to COVID-19. Supportive care involves relieving symptoms and may include full life support in an ICU. It includes
Closely monitoring people to identify problems as they occur
Helping them breathe by giving them supplemental oxygen
Reducing fever
Keeping them hydrated by giving them fluids by vein (intravenously)
Providing intensive care, including mechanical ventilation, as needed
There is no specific treatment for long COVID, but supportive care provided by a team of doctors, rehabilitation specialists, counselors, nurses, and psychiatrists (a multidisciplinary team) can be helpful.
Treatments for COVID-19 are continually being developed and are rapidly evolving. However, currently, none specifically targets neurologic and psychologic symptoms.
