Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at January 27, 2016

Encephalitis describes brain swelling usually due to a viral infection. It is most common in very young children and the elderly. It is important to seek immediate medical attention for encephalitis because it can lead to permanent health problems or even death.


Definition & Facts

Encephalitis is swelling or inflammation of the brain that is most often caused by a viral infection. It is most commonly found in infants in their first year of life, in the elderly, and in those with weakened immune systems due to HIV or AIDS. Cases of encephalitis can be short and mild and the person fully recovers, or it can be severe, leading to hospitalization, chronic illness, or possibly death.

Symptoms & Complaints

Encephalitis usually has symptoms much like the flu such as fever, headache, body aches, and low energy. A mild case of encephalitis can easily persist for a week or two but will gradually go away. However, encephalitis can also be severe. Severe cases require medical attention. Symptoms of severe encephalitis include:

Symptoms of encephalitis in infants include:

Almost everyone who has a severe case of encephalitis will have at least one long-term complication associated with it especially if they are elderly or did not get prompt treatment. These complications can be memory loss, personality changes, epilepsy, and/or language problems, and speech problems.


The most common cause of encephalitis is a viral infection, and there are many types of viruses and bacterial infections that can cause it. People can be exposed to these viruses through contaminated food and contaminated water. If one makes skin contact with someone who is infected or breathes in the virus from another’s cough or sneeze, they may become infected. Other causes include:

Diagnosis & Tests

Encephalitis can be very dangerous. One should seek medical attention promptly if symptoms for this illness arise. It must be diagnosed quickly, and patients will begin to be treated before the diagnosis is confirmed. Patients will be treated with urgency due to its potentially serious nature.

A doctor will likely begin by asking some questions concerning the patient's history and symptoms. They will ask about recent illnesses and whether it is possible that the patient has been exposed to any of the viruses. This may be due to travel or any number or things. They may even want to know about exposure to mosquitoes or ticks. After learning the patient's history, they will need to run some tests. A battery of tests may be administered to look for abnormalities. Some of the tests doctors may use include:

Treatment & Therapy

Complications from encephalitis can be very serious and often require hospitalization. If the patient is only experiencing a mild case of encephalitis, the best medicine is rest, plenty of fluids, and acetaminophen.

Treatment will depend on a few factors: age, condition, and the form and cause of the encephalitis. There are no cures for viruses, so most treatment is administered to patients to alleviate symptoms and complications caused by the virus. If herpes is suspected to be the cause, the go-to treatment will be an antiviral drug called acyclovir. Some forms of encephalitis, such as those caused by biting insects, do not respond to antiviral drugs, and therefore must be treated differently.

Complications caused by severe cases can be treated. For example, some patients may need a ventilator or support machine. Some may need medication or sedatives to control seizures that accompany the encephalitis. Other medications may be given to reduce brain swelling.

Prevention & Prophylaxis

The most effective way to reduce the odds of contracting encephalitis is to get vaccinations. These include vaccines for measles, mumps, and rubella. If you will be traveling, talk to your doctor about any other vaccinations you may need. Other preventative measures for you and your children include: