Encephalitis
Encephalitis literally means an inflammation of the brain, but it usually refers to brain inflammation caused by a virus. It's a rare disease that only occurs in approximately 0.5 per 100,000 individuals - most commonly in children, the elderly, and people with weakened immune systems (i.e., those with HIV/AIDS or cancer).
Although several thousand cases of encephalitis (also called acute viral encephalitis or aseptic encephalitis) are reported to the Centers for Disease Control and Prevention (CDC) every year, experts suspect that many more may go unreported because the symptoms are so mild.
Signs and Symptoms
Symptoms in milder cases of encephalitis usually include:
- fever
- headache
- poor appetite
- loss of energy
- just a general sick feeling
In more severe cases of encephalitis, a person is more likely to experience high fever and any of a number of symptoms that relate to the central nervous system including:
- severe headache
- nausea and vomiting
- stiff neck
- confusion
- disorientation
- personality changes
- convulsions (seizures)
- problems with speech or hearing
- hallucinations
- memory loss
- drowsiness
- coma
It's harder to detect some of these symptoms in infants, but there are still some important signs to look for including:
- vomiting
- a full or bulging soft spot (fontanel)
- crying that doesn't stop or that seems worse when an infant is picked up or handled in some way
- body stiffness
Because encephalitis can follow or accompany common viral illnesses, there are sometimes characteristic signs and symptoms of these illnesses beforehand. But often, the encephalitis appears without warning.
Causes
Because encephalitis can be caused by many types of germs, the infection can be spread in several different ways.
Of the many different kinds of viruses that can cause encephalitis, one of the most dangerous and the most common cause of encephalitis is the ticks, or of measles, chickenpox, mononucleosis. Viruses like chickenpox spread mostly via the fluids of the nose and throat, usually during a cough or sneeze.
Less commonly, encephalitis can result from a bacterial infection, such as bacterial syphilis. Certain parasites, like immunization. Have your child immunized according to the tick bites:
- Limit your child's contact with soil, leaves, and vegetation.
- Have your child wear long-sleeved, light-colored shirts and long pants.
- Check your child and your pets frequently for ticks.
Duration
For most forms of encephalitis, the acute phase of the illness (when symptoms are the most severe) usually lasts up to a week. Full recovery can take much longer, often several weeks or months.
Diagnosis
Doctors use several tests to diagnose encephalitis, including:
- imaging tests, such as computed tomography (CT) scans or magnetic resonance imaging (MRI), to check the brain for swelling, bleeding, or other abnormalities
- blood tests to confirm the presence of bacteria or viruses in the blood, and whether a person is producing antibodies (specific proteins that fight infection) in response to a germ
- fever, especially if he or she also has a childhood illness (measles, mumps, chickenpox) or is recovering from one.
Seek immediate medical attention if your child has any of the following symptoms:
- severe headache
- convulsions (seizures)
- stiff neck
- inability to look at bright lights
- double vision
- difficulty walking
- problems with speech or hearing
- difficulty moving an arm or leg
- loss of sensation anywhere in the body
- sudden personality changes
- problems with memory
- extreme drowsiness or lethargy
- loss of consciousness
If your infant has any of the following symptoms, seek immediate medical care:
- high fever or any fever higher than 100.4 degrees Fahrenheit (38 degrees Celsius) in infants younger than 3 months of age
- fullness or bulging in the soft spot
- any stiffness
- floppiness or decreased tone
- lethargy
- poor appetite or reduced feeding
- vomiting
- crying that won't stop
Reviewed by: Joel Klein, MD