Encephalitis: Viral - Symptoms

Symptoms

Symptoms of encephalitis usually appear within 2 days to 2 weeks of exposure to the virus. In milder cases, symptoms may resemble the flu. In severe cases of full-blown encephalitis, symptoms may include:

• Behavioral and personality changes
• Sensitivity to light
• Fever
• Headache
• Vomiting
• Lethargy and reduced consciousness
• Seizures -- uncommon with West Nile virus
• Memory loss
• Stiff neck and back -- Stiff neck with fever and headache would indicate meningitis
• Confusion
• Speech, hearing, and vision problems
• Muscle weakness
• Seizures
• Partial paralysis
• Loss of consciousness
• Coma

Patients experiencing these types of symptoms, (especially if they may have recently been bitten by a mosquito or tick of if they have lesions on the lips or genitals), should immediately seek medical treatment.

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Symptoms in Infants. Infants with herpesvirus encephalitis may develop lesions in the mouth, in the eye, or on the skin within 1 - 45 days after birth. Other symptoms include lethargy, seizures, and changes in temperature. Their fontanels, the soft spots on their head where the skull has not yet closed, may bulge outward.

Review Date: 01/18/2007
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital