What is encephalitis?

Illustration of the nervous system
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Encephalitis is a term used to describe inflammation of the brain. This condition causes problems with the brain and spinal cord function. The inflammation causes the brain to swell, which leads to changes in the person's neurologic condition, including mental confusion and seizures.

What causes encephalitis?

The cause of encephalitis varies depending on the season, the area of the country, and the type of exposure. Viruses are the leading cause of encephalitis. Although vaccines for many viruses, including measles, mumps, rubella, and chickenpox have greatly lowered the rate of encephalitis from these diseases, other viruses can cause encephalitis. These include herpes simplex virus and rabies.

Encephalitis can also occur following infection by disease-carrying agents including ticks (Lyme disease), mosquitoes (West Nile virus), and cats (toxoplasmosis).

What are the symptoms of encephalitis?

Encephalitis often is preceded by a viral illness such as an upper respiratory infection, or a gastrointestinal problem, such as diarrhea, nausea, or vomiting. The following are the most common symptoms of encephalitis. However, each individual may experience symptoms differently. Symptoms may include:

The symptoms of encephalitis may resemble other problems or medical conditions. Always consult your doctor for a diagnosis.

How is encephalitis diagnosed?

The diagnosis of encephalitis is made after the sudden or gradual onset of specific symptoms and after diagnostic testing. During the examination, your doctor obtains a complete medical history, including your immunization history. Your doctor may also ask if you have recently had a cold or other respiratory illness, or a gastrointestinal illness, and if you have recently had a tick bite, have been around pets or other animals, or have traveled to certain areas of the country.

Diagnostic tests that may be performed to confirm the diagnosis of encephalitis may include the following:

Treatment for encephalitis

Specific treatment for encephalitis will be determined by your doctor based on:

The key to treating encephalitis is early detection and treatment. A person with encephalitis requires immediate hospitalization and close monitoring.

The goal of treatment is to reduce the swelling in the head and to prevent other related complications. Medications to control the infection, seizures, fever, or other conditions may be used.

The extent of the problem is dependent on the severity of the encephalitis and the presence of other organ system problems that could affect the person. In severe cases, a breathing machine may be required to help the patient breathe easier.

As you recover, physical, occupational, or speech therapy may be necessary to help regain muscle strength and/or speech skills.

The health care team educates the family after hospitalization on how to best care for the patient at home, and outlines specific clinical problems that require immediate medical attention by his or her doctor. A person with encephalitis requires frequent medical evaluations following hospitalization.

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