Encephalitis

Introduction:

Encephalitis is the inflammation of the brain tissue, most often caused by a virus,
although it can also be due to bacteria, fungus, or protozoa. In the case of viral
encephalitis, the patient typically will have had viral symptoms prior to the current
illness. The virus enters the central nervous system via the bloodstream and begins
to reproduce. Inflammation in the area follows, causing damage to the neurons.
Demyelination of the nerve fibers in the affected area and hemorrhage, edema, and
necrosis occur, which create small cavities within the brain tissue. Herpes simplex
virus 1, cytomegalovirus, echovirus, Coxsackie virus, and herpes zoster can all
cause encephalitis. Some forms 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.

PROGNOSIS

Identification of the organism is important in order to individualize the treatment
for the patient. The earlier that symptoms are recognized and the earlier the patient
enters the healthcare system the better. Some patients will incur permanent dis-
ability 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


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
• furosemide
• mannitol

NURSING DIAGNOSES

• Impaired physical mobility
• Disturbed thought processes

NURSING INTERVENTION

• Range of motion exercises—active or passive.
• Turn and position patient.
• Administer diuretics to decrease cerebral edema, if indicated:
• Provide a quiet environment to decrease unnecessary stimulation.
• Monitor fluid input and output.
• Explain to the patient and family:
• Home care needs.
• Necessity of turning and positioning.
• Medication actions, side effects, and interactions.