Individuals with encephalitis often show mild flu-like symptoms. In more severe cases, people may experience:

• Problems with speech or hearing
• Double vision
• Hallucinations
• Personality changes
• Loss of consciousness
• Loss of sensation in some parts of the body

• Muscle weakness
• Partial paralysis in the arms and legs
• Impaired judgment
• Seizures
• Memory loss

Important signs of encephalitis to watch for in an infant include fever, lethargy, not waking for feedings, vomiting, body stiffness, unexplained/unusual irritability, and a full or bulging fontanel (the soft spot on the top of the head).

Diagnosis of autoimmune encephalitis can be made when all three of the following criteria have been met:

1. Subacute onset (rapid progression of less than 3 months) of working memory deficits (short-term memory loss), altered mental status, or psychiatric symptoms

2. At least one of the following:

• New focal CNS findings
• Seizures not explained by a previously known seizure disorder
• CSF pleocytosis (white blood cell count of more than five cells per mm3)
• MRI features suggestive of encephalitis

3. Reasonable exclusion of alternative causes

For more on diagnosis, visit the following link to the International Autoimmune Encephalitis Society Web site:
https://autoimmune-encephalitis.org/diagnosis

People who are suspected of having encephalitis should receive immediate, aggressive medical treatment. The disease can progress quickly and has the potential to cause severe, irreversible neurological damage.

Antiviral drugs used to treat viral encephalitis include acyclovir and ganciclovir. For most encephalitis-causing viruses, no specific treatment is available.

Autoimmune causes of encephalitis are treated with additional immunosuppressant drugs and screening for underlying tumors when appropriate. Acute disseminated encephalomyelitis, a non-infectious inflammatory brain disease mostly seen in children, is treated with steroids.

Anticonvulsants may be prescribed to stop or prevent seizures. Corticosteroids can reduce brain swelling. Affected individuals with breathing difficulties may require artificial respiration.

Once the acute illness is under control, comprehensive rehabilitation should include cognitive rehabilitation and physical, speech, and occupational therapy.