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What Is Encephalitis?

Encephalitis is inflammation of the brain. While most cases cause flu-like symptoms, in rare instances the condition can be life-threatening and/or cause severe brain damage. Rapid diagnosis and treatment are the best ways to ensure a full recovery without complications. 

Some cases of encephalitis have no known cause, but the most common cause of encephalitis is viral infection, including herpes viruses. Other causes include: 

  • Mosquito and tick-borne viruses
  • Rabies
  • Enteroviruses, such as polio
  • Childhood infections, such as measles and mumps, that are preventable through vaccination
  • Bacterial infection or a non-infectious inflammatory condition

Older people and those with weaker immune systems are more susceptible to encephalitis, as are people who live in climates where mosquitoes and ticks are common. 


Primary encephalitis occurs when a virus or other agent attacks the brain directly. Secondary encephalitis occurs when an infection elsewhere in the body triggers a faulty immune response that targets healthy brain cells, typically two or three weeks after the initial infection. Mild encephalitis symptoms tend to be flu-like and can include:

  • Fatigue — This unexplained tiredness causes mental exhaustion and lack of energy.
  • Fever — Body temperature greater than 98.6˚F is a fever, a biological response that helps the body clear infections.
  • Headache — Sensations associated with balance disorders can lead to the development of throbbing mild or chronic headaches.
  • Sore muscles and joints — White blood cells produce chemicals in response to infection, and those chemicals cause soreness and pain.

Severe Symptoms

More severe symptoms may include:

  • Seizures — Disturbances to the brain’s electrical system can cause episodes of uncontrolled behavioral and movement changes.
  • Temporal lobe effects — The temporal lobe in the brain controls memory and speech, so confusion, hallucinations, and difficulty speaking or hearing may develop when that part of the brain is affected.
  • Loss of consciousness — Fainting and loss of awareness may develop.
  • Partial paralysis — Encephalitis may result in the inability to move parts of the body.

Treatment Options

Seek immediate medical care for severe symptoms, including severe headache or fever. Treatment for encephalitis typically involves:

  • Antiviral drugs These are prescribed if the cause is determined to be a type of virus that responds to medication.
  • At-home treatment — Getting plenty of rest and increasing fluid intake are frequently recommended.
  • Hospitalization — Generally reserved for severe cases, hospitalization may involve surgery to remove the swelling in the brain, anti-inflammatory and/or anticonvulsant medications, as well as intravenous fluids.

Ready for an Appointment?

If you're experiencing signs or symptoms of encephalitis, schedule an appointment or call 800-TEMPLE-MED (800-836-7536) today.

Learn more about our doctors and care team who diagnose and treat encephalitis.