Sunday, February, 12, 2012

Encephalitis

Table of Contents

Symptoms

Some patients may have symptoms of a cold or stomach infection before encephalitis symptoms begin.

When a case of encephalitis is not very severe, the symptoms may be similar to those of other illnesses, including:

  • Fever that is not very high
  • Mild headache
  • Low energy and a poor appetite

Other symptoms include:

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

Symptoms in newborns and younger infants may not be as easy to recognize:

  • Body stiffness
  • Irritability and crying more often (these symptoms may get worse when the baby is picked up)
  • Poor feeding
  • Soft spot on the top of the head may bulge out more
  • Vomiting

Emergency symptoms:

  • Loss of consciousness, poor responsiveness, stupor, coma
  • Muscle weakness or paralysis
  • Seizures
  • Severe headache
  • Sudden change in mental functions:
    • "Flat" mood, lack of mood, or mood that is inappropriate for the situation
    • Impaired judgment
    • Inflexibility, extreme self-centeredness, inability to make a decision, or withdrawal from social interaction
    • Less interest in daily activities
    • Memory loss (amnesia), impaired short-term or long-term memory

Signs and tests

An examination may show:

  • Abnormal reflexes
  • Increased intracranial pressure
  • Mental confusion
  • Mouth ulcers
  • Muscle weakness
  • Neck stiffness
  • Signs in other organs, such as the liver and lungs
  • Skin rash
  • Speech problems

Tests may include:

  • Brain MRI
  • CT scan of the head
  • Culture of cerebrospinal fluid (CSF), blood, or urine (however, this test is rarely useful)
  • Electroencephalogram (EEG)
  • Lumbar puncture and CSF examination
  • Tests that detect antibodies to a virus (serology tests)
  • Test that detects tiny amounts of virus DNA (polymerase chain reaction -- PCR)

Review Date: 07/26/2010
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, Unviersity of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)