How does encephalitis affect my body?

Encephalitis is a brain inflammation that occurs due to an infection such as a virus or bacteria, medication or immune system malfunction. Encephalitis is a rare, often serious condition that requires timely care.

Encephalitis causes physical symptoms like fever, headaches and neck pain. It can also affect brain (cognitive) functioning, leading to confusion and behavior changes. In some cases, cognitive encephalitis symptoms linger long after physical symptoms go away.

How is encephalitis different from meningitis?

Both conditions are uncommon but severe.

Some important differences are that:

Encephalitis occurs in the brain.

Meningitis affects the meninges. This delicate layer of tissue protects the brain and spinal cord.

What causes encephalitis?

The type of encephalitis you experience depends on the cause. And there are many causes, including:

Viruses: Infections from herpes, enteroviruses, human immunodeficiency virus (HIV), West Nile and tick-borne viruses lead to viral encephalitis. This is the most common cause.

Problem with the immune system: The immune system can mistakenly attack the brain, causing autoimmune encephalitis.

Bacteria and parasites: On rare occasions, these germs can cause bacterial encephalitis.

What are encephalitis symptoms?

You’ll likely experience physical and neurologic symptoms.

Physical symptoms may include:

• Fever.
• Headache.
• Joint pain.
• Muscle weakness.
• Nausea.
• Stiff neck.
• Neurologic encephalitis symptoms may include:
• Behavior changes.
• Confusion.
• Difficulty speaking or moving.
• Loss of consciousness.
• Memory issues.
• Seizures.
• Sensitivity to light.

How is encephalitis diagnosed?

Healthcare providers take many steps to diagnose brain infections.

Your care may include:

• Physical exam to learn more about your symptoms.
• Neurologic exam to assess brain functioning.
• Lab tests and imaging studies, which help confirm or rule out encephalitis.

How is encephalitis treated?

The brain infection treatments you need depend on the type of encephalitis and how severe it is.

You may need:

• Antibiotics to treat bacterial infections.
• Antiviral medications for viral infections.
• Antiseizure medicines if you are having seizures.
• Breathing assistance, including supplemental oxygen or a breathing machine (mechanical ventilation).
• Immunomodulators, which are medications that quiet immune system attacks.
• Intravenous (IV) fluids to keep you hydrated.
• Steroids, which reduce swelling and brain pressure.
• Tube feeding to deliver nutrition if you are unconscious.