Encephalitis

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• Fever
• Headache
• Vomiting
• Light-sensitivity
• Stiff neck and back (occasionally)
• Confusion , disorientation
• Drowsiness
• Clumsiness , unsteady gait
• Irritability or poor temper control

• Loss of consciousness , poor responsiveness, stupor, coma
• Seizures
• Muscle weakness or paralysis
• Sudden onset of:
  • Memory loss (amnesia), impaired short-term memory or impaired long-term memory
  • "Flat" mood or lack of discernible mood, or mood inappropriate for the situation
  • Diminished interest in daily activities
  • Inflexibility, extreme self-centeredness, indecisiveness, or withdrawal from social interaction
  • Impaired judgment

Various symptoms resembling meningitis may be present. An examination may show signs of meningeal irritation (especially neck stiffness), increased intracranial pressure, or other neurologic symptoms such as muscle weakness, mental confusion, speech problems, and abnormal reflexes. The patient may have a skin rash, mouth ulcers, and signs of involvement of other organs such as the liver and lungs.

• A lumbar puncture test and cerebrospinal fluid (CSF) examination may show clear fluid, high pressure, high white blood cell count and high protein levels -- indications of inflammation. Blood may be present in the CSF.
• Sometimes the virus can be detected in CSF, blood, or urine through a laboratory test called viral culture. However, this test is cumbersome and rarely useful. In some cases, viral PCR (polymerase chain reaction, a test able to detect very tiny amounts of viral DNA) may identify the virus. Health care providers also rely on serology tests to provide evidence of viral infection. Serologies detect proteins called antibodies, which are produced in response to a specific virus or other foreign invader.
• An EEG (a test of the electrical activity of the brain) may provide indirect clues for the diagnosis of encephalitis. Some EEG wave patterns may suggest a seizure disorder, or point to a specific virus as cause of the infection. Certain EEG wave patterns can suggest encephalitis due to herpes, for instance.
• A brain MRI, which provides high-quality pictures of the brain, or a CT scan of the head may be used to determine internal bleeding or specific areas of brain inflammation.

Review Date: 09/07/2006
Reviewed By: Kenneth Gross, M.D., Neurology, North Miami, FL. Review provided by VeriMed Healthcare Network.