Encephalitis

Your doctor will start with a thorough physical examination and medical history.

Your doctor might then recommend:

Brain imaging. MRI or CT images can reveal any swelling of the brain or another condition that might be causing your symptoms, such as a tumor.

Spinal tap (lumbar puncture). A needle inserted into your lower back removes a small amount of cerebrospinal fluid (CSF), the protective fluid that surrounds the brain and spinal column. Changes in this fluid can point to infection and inflammation in the brain. Sometimes samples of CSF can be tested to identify the cause. This may include a virus, other cause of infection or autoimmune disorder.

Other lab tests. Samples of blood, urine or excretions from the back of the throat can be tested for viruses or other infectious agents.

Electroencephalogram (EEG). Electrodes affixed to your scalp record the brain's electrical activity. Certain abnormal patterns may indicate a diagnosis of encephalitis.

Brain biopsy. Rarely, a small sample of brain tissue might be removed for testing. A brain biopsy is usually done only if symptoms are worsening and treatments are having no effect.

Treatment for mild encephalitis usually consists of:

Bed rest

Plenty of fluids

Anti-inflammatory drugs — such as acetaminophen (Tylenol, others), ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve) — to relieve headaches and fevers

Antiviral drugs

Encephalitis caused by certain viruses usually requires antiviral treatment.

Antiviral medications commonly used to treat encephalitis include:

Acyclovir (Zovirax)

Ganciclovir (Valcyte, Zirgan, others)

Foscarnet (Foscavir)

Some viruses, such as insect-borne viruses, don't respond to these treatments. But because the specific virus may not be identified immediately or at all, doctors often recommend immediate treatment with acyclovir. Acyclovir can be effective against HSV, which can result in significant complications when not treated promptly.

Antiviral medications are generally well tolerated. Rarely, side effects can include kidney damage.