What Is Encephalitis?

Encephalitis is inflammation and swelling of the brain. This rare disease leads to changes in neurological function, resulting in mental confusion and seizures.

“The cause of encephalitis can vary depending on the season, the part of the country and the type of exposure,” explains neurologist Jonathan Cheponis, MD, with LVH Neurology–1250 Cedar Crest, part of Lehigh Valley Fleming Neuroscience Institute. “Vaccines for many viruses, like measles, mumps and chickenpox, have greatly lowered the rates of encephalitis from these diseases. Encephalitis can also occur from Lyme disease, West Nile virus, bacteria, cancer and autoimmune diseases.”

Encephalitis often follows a viral illness, such as an upper respiratory infection. Or it may occur after a gastrointestinal illness that causes diarrhea, nausea or vomiting.

“The symptoms of encephalitis depend on which part of the brain is being attacked,” Cheponis says. “These can be as mild as headaches, body aches and other flu-like symptoms, or can be more serious, causing weakness, paralysis or even coma.”

Other symptoms of encephalitis are:

• Sensitivity to light
• Neck stiffness
• Increased irritability
• Seizures
• Changes in alertness, confusion or hallucinations
• Loss of energy or appetite
• Unsteady gait
• Nausea and vomiting
• Personality changes

These symptoms may look like other health problems, so be sure to see your doctor or clinician for a diagnosis.

Your doctor or clinician can diagnose encephalitis based on your symptoms and certain tests. “During the exam, you will need to give your medical history, including what vaccines you’ve had. You should also tell your doctor or clinician whether you’ve recently had a respiratory or GI infection, a tick bite, or have traveled outside the area,” Cheponis explains.  

You may need these tests:

• MRI or CT scan. These procedures can take images of your brain and look for swelling, bleeding or other problems.
• Blood, urine, stool or sputum culture tests. These can find signs of infection.
• Electroencephalogram (EEG). This test looks for unusual brain waves.
• Spinal tap (lumbar puncture). For this test, a special needle is placed into the lower back to take a small amount of cerebrospinal fluid, which is examined for signs of an infection or other problems.

The key to treating encephalitis is early detection and quick treatment. A person with encephalitis needs to be watched closely in a hospital.

“The goal of treatment is to reduce the swelling in the brain and to prevent other related complications,” Cheponis says. “You may need medicines to treat the infection itself, or you may need other treatments to control symptoms like seizures or fevers. If the immune system itself is responsible, then medications to suppress the immune system may be needed, and if you have an associated cancer, that will need to be aggressively treated as well.”

Complications of encephalitis depend on the severity of inflammation and whether you have other organ problems. Most people fully recover from mild cases. People can die from encephalitis or suffer permanent impairment, including:

• Fatigue
• Irritability
• Problems concentrating
• Seizures
• Hearing loss
• Memory loss
• Blindness

Call your doctor or clinician if there are signs of another infection, including:

• Headache
• Fever
• Neck stiffness
• Drowsiness

Also call if you have signs of neurological issues, such as:

• Seizures
• Memory loss
• Visual problems
• Impaired hearing
• Behavioral changes