Demyelinationof the nerve fibers in the affected area and hemorrhage,
edema, and necrosis occur, which creates small cavities within the brain
tissue. Herpes simplex virus 1, cytomegalovirus, echovirus, coxsackie virus,
and herpes zoster can all cause encephalitis. Some causes of encephalitis can
be transmitted by insects (such as mosquitoes or ticks) to humans, such as
West Nile virus, St. Louis encephalitis, or equine encephalitis.
Identification of the organism is important to individualize the treatment for
the patient. The earlier symptoms are recognized and the patient enters the
health-care system, the better. Some patients incur permanent disability from
the irreversible damage that occurs to the brain. These patients may be in need
of long-term custodial care.
Signs and Symptoms
Fever due to infection
Nausea and vomiting due to increased intracranial pressure
Stiff neck due to meningeal irritation
Drowsiness, lethargy, or stupor due to increased intracranial pressure
Altered mental status: irritability, confusion, disorientation, personality
change
Headache due to increased intracranial pressure
Seizure activity possible due to irritation of brain tissue
Bulging fontanels in infant
Test Results
Blood cultures used to help identify organism when patient febrile
CT scan
MRI
Analysis of CSF for microorganism that is causing the infection
Treatment
Monitor respiratory status for compromise.
Monitor vital signs for widened pulse pressure and bradycardia, signs of
increased intracranial pressure.
Monitor neurologic function for change.
Administer corticosteroid to decrease inflammation:
- Dexamethasone
Administer antipyretics to reduce fever: - Acetaminophen
Administer anticonvulsants to decrease chance of seizure activity: - Phenytoin, phenobarbital
Administer diuretics to decrease cerebral edema if indicated: - Furosemide
- Mannitol
CHAPTER 10/ Neurologic Conditions^209