Viral Encephalitis

What is Viral Encephalitis

Viral encephalitis is inflammation of the brain that is caused by a virus. It can result in an illness with flu-like symptoms. Sometimes the illness may be severe and require immediate treatment in a hospital.

What are the causes?

This condition may be caused by many types of viruses. These viruses can be spread in different ways. You can get a virus by:

• Breathing in droplets that have been coughed or sneezed into the air by an infected person.
• Sharing drinking glasses, eating utensils, or personal items like toothbrushes or lipstick with an infected person.
• Having contact with infected animals or insects. A bite from a mosquito or tick can pass certain types of viruses that may cause viral encephalitis.

What increases the risk?

You may be more likely to develop viral encephalitis if your body’s defense system (immune system) is weak. This may be the case with:

• People who have HIV.
• People who are taking medicines to reduce the strength of the immune system (immunosuppressants).
• People who are receiving chemotherapy treatments.

What are the signs or symptoms?

Symptoms of this condition may vary depending on how severe the illness is.

Mild symptoms

• Fever.
• Muscle aches.
• Headache.
• Eye pain caused by light.
• Stiff neck.
• Backache.
• Nausea and vomiting.

Severe symptoms

• Confusion.
• Unusual drowsiness.
• Difficulty speaking.
• Irritability.
• Clumsiness.
• Uncontrolled stiffening, twitching, or jerking of your body (seizures).
• Loss of consciousness (coma).

How is this diagnosed?

This condition may be diagnosed based on:

• Your symptoms and medical history.
• A physical exam.
• Results of tests, which may include:
  • Blood tests.
  • A test of the fluid that surrounds and protects your brain and spinal cord (cerebrospinal fluid). The fluid is removed by inserting a needle into your lower back (lumbar puncture).
  • Imaging studies of the brain, such as a CT scan or MRI.

How is this treated?

Most cases need to be treated in the hospital. Hospitalization is needed to treat symptoms and to watch for complications of this condition. The condition may be treated with:

• Medicines to treat the infection (antiviral medicines).
• Medicines to treat symptoms such as seizures, fever, and pain.
• Fluids given through an IV. These may be given if:
  • Vomiting has led to dehydration.
  • You cannot eat or drink without vomiting.
• Medicines to treat bacterial infections (antibiotics). This may be given for a day or two to make sure that the infection is not from bacteria.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Rest in a quiet room while you are recovering. Keep the room dark if you are sensitive to light.
• Drink enough fluid to keep your urine pale yellow.
• Take steps to avoid spreading the infection if it can be spread from person to person.
  • Wash your hands often.
  • Stay away from other people as much as possible during your recovery.
  • Avoid sharing food, utensils, glasses, and other objects with others.
• Return to your normal activities as told by your health care provider. Ask your health care provider what activities are safe for you.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• You develop new symptoms.

Get help right away if:

• You have a seizure.
• You faint or lose consciousness.
• You have weakness in your arm or leg.
• You have confusion or memory loss.
• You have signs of dehydration, including:
  • Increased thirst.
  • Weakness.
  • Drowsiness.
  • Dizziness.
  • Not urinating or only urinating a small amount of very dark urine in 6–8 hours.

Summary

• Viral encephalitis is inflammation of the brain that is caused by a virus.
• This condition may be caused by many types of viruses. These viruses can be spread from person to person or through contact with infected animals or insects.
• Symptoms vary depending on how severe the illness is. They may include fever, headache, muscle aches, and confusion.
• Treatment includes medicines to treat the infection and medicines to treat symptoms such as seizures, fever, and pain.