Herpes Encephalitis

What is herpes encephalitis?

Herpes encephalitis is an uncommon but life-threatening complication of herpes virus infection. Encephalitis is an inflammation or infection of the brain and central nervous system (CNS).

How does it occur?

The herpes virus usually causes a skin infection, causing painful blisters. The blisters last for several days and the virus can be spread from the blisters to other people. The blisters may start as cold sores or fever blisters around the mouth, or they may start as sores in the genital area.

There are several ways the virus might infect the brain and nervous system.

• In between outbreaks on the skin, the herpes virus lives in nerve cells close to the spinal column. It's likely that the virus spreads from these areas into the fluid that cushions the brain and spinal cord.
• The herpes virus may enter the central nervous system through infections in the head and neck, including the ears. Many people have herpes infections inside their noses or inside their ears. These areas are separated from the central nervous system by very thin bones and membranes, which the virus can pass through.
• The virus may spread to a newborn during delivery if the mother has herpes sores in the genital area. When this happens, the baby may have a total body herpes infection, including the central nervous system.

What are the symptoms?

The symptoms of herpes encephalitis are similar to the symptoms of meningitis, a stroke, or epilepsy: They may change from mild to severe within several days or even several hours. At first the infection may cause flulike symptoms, including fever and aches, especially headache. The infection may then cause a gradual decrease in awareness. There may be disorientation, confusion, and seizures. Coma may follow.

When herpes encephalitis is suspected, it is very important to contact your healthcare provider right away.

How is it diagnosed?

The diagnosis can be difficult. Someone who has encephalitis is often not able to talk. Your provider will want to know your medical history, including:

• any history of herpes infections
• when and how long the symptoms occurred
• other medical conditions that might make it harder for the body to fight infection and easier for the virus to spread.

You will have a physical exam.

Spinal fluid collected from a lumbar puncture (spinal tap) can be tested for the herpes virus. Blood tests for herpes are also usually done. However, it can take days to weeks to get the test results.

How is it treated?

The main treatment is antiviral medicine given by IV (by vein), usually acyclovir. Because this infection can be life-threatening, the medicine may be started right away, before test results are known.

How long will the effects last?

It can take a long time to recover from herpes encephalitis. This is especially true if the infection has caused problems such as speech problems, weakness on one side, or balance problems. These effects usually require physical therapy. Because the brain controls all the basic functions of thinking and moving, there may be temporary or permanent loss of any of these functions. Herpes encephalitis can be fatal. If a newborn is infected and survives the infection, the baby is likely to have damage to the brain or other parts of the nervous system.

What can I do to prevent herpes encephalitis?

While we don't know how to prevent herpes encephalitis, there are ways to try to prevent getting the herpes virus.

• The herpes virus is everywhere in the environment. As with many other infections, frequent and careful hand-washing is the place to start, especially if your work brings you into contact with the general public.
• When herpes blisters are present, as in a cold sore on the lip, the liquid in the rash contains virus and can infect others. Avoid touching the blisters. If you do touch them, wash your hands as soon as possible. Wash your hands thoroughly but gently so as not to damage your skin and create an opening for the virus to enter.
• If you have genital herpes, the fluid in the blistery rash on the genitals is infectious. Do not touch the rash and then touch your eyes or nose, where the infection could be spread. Using condoms can help prevent spread of the herpes virus, but condoms do not cover all areas of the genitals that can have the rash. So it is best not to have intercourse when a rash is present.

It is not clear whether the herpes virus can be spread to others when there are no blisters or rash. This question is being studied by researchers.