Definition

Encephalitis is swelling of the brain.

Encephalitis Copyright © Nucleus Medical Media, Inc.

Causes

Encephalitis can often be caused by an infection. Some common ones are:

• Herpes simplex virus (HSV)
• The varicella zoster virus, which causes chickenpox, shingles, Measles, Mumps, and rubella
• Viruses carried by mosquitoes such as West Nile or Eastern equine encephalitis

It can also be caused by a problem with the immune system, such as a prior infection in the body or a tumor.

Risk Factors

Some things that may raise the risk of encephalitis are:

• Spending time in an area where mosquito- or tick-borne viruses are common
• Not getting vaccinated for diseases that can cause encephalitis
• Having a weakened immune system

Symptoms

Symptoms may range from mild to severe. They may be:

• Nausea and vomiting
• Diarrhea
• Belly pain
• Fever
• Headache
• Sleepiness
• Loss of feeling or numbness in the body
• Stiff neck
• Personality changes
• Confusion
• Seizures

Diagnosis

The doctor will ask about your symptoms and health history. A physical exam will be done.

Blood tests will be done to look for signs of infection. A lumbar puncture may be done to test the fluid around the spine.

Images may be taken of the brain to look for changes. This can be done with:

• CT scan
• MRI scan

Treatment

There are not many ways to treat viruses. They take time to leave the body. Most treatment will focus on supporting the body until the virus has passed.

These medicines may be given:

• Antiviral drugs to shorten the length of the illness
• Steroids to ease swelling in the brain
• Diuretics to ease pressure in the head
• Anti-seizure medicine to prevent and treat seizures

Prevention

To lower your chances of getting encephalitis:

• Make sure your vaccinations are up to date.
• Protect yourself from mosquito and tick bite, especially in high risk areas.