Encephalitis is a viral infection that may cause inflammation of the brain. In rare cases, encephalitis can be life-threatening. Early diagnosis and treatment must be done to avoid complications.

Encephalitis can also cause confused thinking, seizures, or problems with senses or movement.

Most people with viral encephalitis have mild flu-like symptoms, including:

  • Headache
  • Fever
  • Fatigue or weakness
  • Aches in muscles or joints

Severe symptoms may include:

  • Seizures
  • Muscle Weakness
  • Loss of Consciousness
  • Confusion, Agitation or Hallucinations
  • Problems with Speech or Hearing
  • Loss of Sensation or Paralysis in Certain Areas of the Face or Body

In infants and young children, symptoms may also include:

  • Nausea and Vomiting
  • Body Stiffness
  • Irritability
  • Poor Feeding or Not Waking for a Feeding
  • Bulging in the Soft Spots (Fontanels) of an Infant’s Skull


To diagnose Encephalitis, your doctor might check your medical history and perform a physical exam. He or she might also recommend the following.

  • Brain imaging. MRI or CT images can reveal any swelling of the brain tumors.
  • Spinal tap (lumbar puncture). A needle inserted into your lower back removes cerebrospinal fluid (CSF). It is the protective fluid that surrounds the brain and spinal column. If the fluid changes, this may indicate inflammation and infection in the brain. In some cases, samples of CSF can be tested to identify the virus or other infectious agent.
  • Other lab tests. Samples of blood, urine or excretions from the back of the throat are tested.
  • Electroencephalogram (EEG). Electrodes affixed to your scalp record the brain’s electrical activity. Certain abnormal patterns may indicate a diagnosis of encephalitis.
  • Brain biopsy. A small sample of brain tissue might be removed for testing. It is usually done 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 to relieve headaches and fever, including:
    • Acetaminophen (Tylenol)
    • Ibuprofen (Advil, Motrin IB)
    • Naproxen Sodium (Aleve)

Encephalitis caused by certain viruses usually requires antiviral medications, such as:

  • Acyclovir (Zovirax)
  • Ganciclovir (Cytovene)
  • Foscarnet (Foscavir)

Insect-borne viruses and some other viruses, don’t respond to these treatments. In that case, 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. Rare side effect of this drug can include kidney damage.

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