Version July 2025
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What is encephalitis? —
This is a rare condition that causes inflammation of the brain. It is most often caused by a virus.
What are the symptoms of encephalitis? —
Symptoms include:
●Fever
●Headache
●Confusion, or trouble thinking
●Trouble swallowing or speaking
●Saying things that do not make sense
●Clumsiness, or trouble walking
●Weak muscles on 1 side of the body
●Seizures – These are waves of abnormal electrical activity in the brain. They can make people pass out, or move or behave strangely.
Will I need tests? —
Yes. Your doctor will ask about your symptoms and do an exam. They will do tests to see what caused your encephalitis and to check that you do not have a different condition. Tests might include:
●Blood tests
●MRI or CT scan of the brain – These are imaging tests that create pictures of the inside of the brain.
●Lumbar puncture (also called a "spinal tap") – A doctor puts a thin needle into the lower back and removes a small sample of spinal fluid. This is the fluid that surrounds the brain and spinal cord. They do lab tests on the sample.
How is encephalitis treated? —
Some types of encephalitis can be treated with medicines to fight the infection. These are given in a hospital, usually through a thin tube that goes into a vein, called an "IV." They might include:
●Acyclovir (brand name: Zovirax) – This is used to treat infections caused by certain viruses.
●Antibiotics
When encephalitis is related to something other than an infection, doctors can try to treat the cause. Some types of encephalitis are not treated with medicines and must get better on their own.
Can encephalitis be prevented? —
Sometimes. Some of the viruses that cause encephalitis are spread by mosquito or tick bites. You can lower your chances of getting encephalitis by avoiding these types of bites. To do this:
●Stay inside at dawn and dusk, when mosquitoes are more likely to be around.
●Wear shoes, long-sleeved shirts, and long pants when outside, especially at dusk.
●Wear bug spray on your skin. On your clothes and gear, use bug repellents that have a chemical called "permethrin."
●Drain areas of standing water if possible, such as wading pools, buckets, and potted plants with saucers. Mosquitoes breed in standing water.
●Check your body for ticks after being outside or around dogs.
Patient education: Bacterial meningitis (The Basics)
Patient education: Viral meningitis (The Basics)
Patient education: Viral culture (The Basics)
Patient education: Insect bites and stings (The Basics)
Patient education: What you should know about antibiotics (The Basics)
