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  • Meningoencephalitis

  • Acute disseminated encephalomyelitis


  • 323.9 Unspecified cause of encephalitis, myelitis, and encephalomyelitis


  • G04.90 Encephalitis and encephalomyelitis, unspecified


  • 5A: Primary Prevention/Risk Reduction for Loss of Balance and Falling1

  • 5C: Impaired Motor Function and Sensory Integrity Associated with Nonprogressive Disorders of the Central Nervous System—congenital origin or acquired in infancy or childhood2

  • 5D: Impaired Motor Function and Sensory Integrity Associated with Nonprogressive Disorders of the Central Nervous System—acquired in adolescence or adulthood3

  • 5I: Impaired Arousal, Range of Motion and Motor Control Associated with Coma, Near Coma, or Vegetative State4


Three weeks after a regimen of cyclosporine to treat his psoriasis, a 42-year-old man developed a fever, headache, and nausea that were unresponsive to medication or position change. Within a few days he struggled with balance and gait ataxia and became progressively more disoriented. By the end of the week he was comatose, with Glasgow Coma Scale score of 5. Magnetic resonance imaging (MRI) reveals mediotemporal lobe necrosis. The patient is placed on intravenous acyclovir.



  • Infection of the brain parenchyma

  • Most commonly results in infection of the entire brain, but some viruses attack specific nervous system structures

Essentials of Diagnosis

  • May occur with meningitis; some overlap of signs and symptoms

  • Two primary forms: Viral and bacterial

  • Postinfectious encephalitis: Autoimmune reaction to systemic viral infection

  • Causative factor must be identified to initiate appropriate medical treatment prior to physical therapy involvement

  • Common forms include

    • Herpes simplex encephalitis (most common cause of sporadic encephalitis in adults)

    • Arboviral encephalitis (most common epidemic forms): West Nile virus, Eastern and Western equine encephalitis, and rabies


Viral encephalitis, showing perivascular lymphocytic cuffing. (From Chandrasoma P, Taylor CR. Concise Pathology. 3rd ed. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

General Considerations

  • Rapid differential diagnosis of encephalitis versus meningitis should be made due to similarities of initial symptoms and response to medication.

  • Severity may progress over a period of 1 week; PT should monitor for changing neurologic signs and symptoms, refer accordingly.


  • Approximately 20,000 cases of acute viral encephalitis are reported annually in the United States.

  • Death occurs in 5% to 20%.

  • All ages and genders are susceptible; some forms are more common in specific geographic locations.


CT (A) and diffusion-weighted MRI (B) scans of the brain of a patient with left-temporal-lobe HSV encephalitis. (From Longo DL, Fauci AS, Kasper DL, et al., ...

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