Encephalitis, or inflammation of the brain, usually occurs when the cerebral hemispheres, brainstem, or cerebellum is infected by a microorganism. Approximately 2000 cases of encephalitis are reported each year in the United States, but this is probably only a fraction of the cases. Most forms have mortality rates of less than 10%, with the exception of eastern equine encephalitis, where mortality is as high as 50%. Determining the true incidence is impossible because reporting policies are neither standardized nor rigorously enforced.
Encephalitis has two forms: primary and postinfectious (or parainfectious). The primary form of the disease occurs when a virus invades and replicates within the brain. Postinfectious encephalitis describes brain inflammation that develops in combination with other viral illnesses or following the administration of vaccines such as measles, mumps, and rubella. In that case, encephalitis occurs because of a hypersensitivity reaction that leads to demyelination of nerves.
When the brain becomes inflamed, lymphocytes infiltrate brain tissue and the meninges of the brain. Cerebral edema results, and ultimately, brain cells can degenerate, thus leading to widespread nerve cell destruction. Complications from encephalitis can be short term or lifelong. Bronchial pneumonia and respiratory tract infections may complicate the course of encephalitis. Patients may go into a coma and experience all the complications of immobility, such as contractures and pressure ulcers. Other complications include epilepsy, parkinsonism, behavioral and personality changes, and mental retardation. A comatose state may last for days, weeks, or months after the acute infectious state.
Most cases of encephalitis are related to viruses, and the most common cause is herpes simplex virus-1 (HSV-1) in adults. HSV-2 is more common in neonates and may be transmitted from a mother infected with genital herpes during childbirth. Herpes encephalitishas a range of clinical presentations and can be transmitted during birth, through the blood, or by neuronal transmission. Neuronal transmission often occurs from the peripheral neuron in retrograde fashion to the brain. Arboviruses are also common causes of encephalitis; although most people bitten by arbovirus-infected insects do not develop the disease, approximately 10% do have overt symptoms. Transmission of arboviruses requires an insect vector and usually occurs in the Northern Hemisphere between June and October. The two most common arboviruses cause La Crosse encephalitis and St. Louis encephalitis. In the United States, most cases of nonepidemic encephalitis are caused by the La Crosse virus, are most common in rural areas of the Midwest, and affect children. Epidemics of both St. Louis encephalitis (found mostly in the East and Midwest) and western equine encephalitis (WEE; found across North America) have contributed a large number of the total cases since 1955. Many sources cite the St. Louis encephalitis virus as the most common form in this country, although many forms of the disease exist. Although relatively uncommon, the deadliest arbovirus is the eastern equine encephalitis (EEE), which is mostly encountered in the New England region. Other viruses include the WEE (most common in rural communities west of the Mississippi River) and the Powassan (POW) virus, the only arbovirus known to be transmitted by ticks. Encephalitis has also been associated with many other diseases, including Creutzfeldt-Jakob disease, HSV (specifically HSV-1), kuru, malaria, mononucleosis, rabies, trichinosis, and typhus.
Nursing care plan assessment and physical examination
Obtain a history of recent illnesses, which may include an upper respiratory infection or a minor systemic illness that caused headache, muscle ache, malaise, sore throat, and runny nose. Note if the patient has other sites of infection, such as a recent skull fracture or head injury, middle ear infection, or sinus infection. Ask if the patient has had a recent immunization, exposure to mumps or HSV, animal bites, recent travel, or exposure to epidemic outbreaks or mononucleosis. Ask if a child has been playing in a rural area where exposure to ticks or mosquitoes was possible.
Encephalitis typically has an abrupt onset. The patient, parents, or family may describe altered respiratory patterns, fever, headache, nuchal (neck) rigidity, and vomiting. Neurological symptoms generally follow 24 to 48 hours after the initial onset; often, a seizure is the initial presenting symptom. The patient and family may describe other symptoms such as facial palsies, difficulty speaking, and decreased movement and sensation of the extremities.
The patient appears acutely ill with an altered mental status that may range from mild confusion to delirium and coma. The patient may have tremors, cranial nerve palsies, and absent superficial or exaggerated deep tendon reflexes. There may be a decrease in sensation, along with weakness or even paralysis of the extremities. The patient may have no sense of taste or smell and may have difficulty speaking and swallowing. Heart and respiratory rates may be rapid. The patient’s skin is often warm because of fever.
Encephalitis can be life-threatening and lead to permanent disability; therefore, determine the patient’s and family’s ability to cope with sudden illness, anxiety, and stress, as well as disability. If the patient is a child, the parents may be excessively anxious. Analyze the family structure, the number of children, the financial resources, and the role of parental support systems to determine the extent of the problem.
Nursing care plan primary nursing diagnosis: Risk for ineffective airway clearance related to unresponsiveness and inability to clear secretions.
Nursing care plan intervention and treatment plan
To maintain a patent airway, many patients require endotracheal intubation, oxygen therapy, and mechanical ventilation if gas exchange is impaired. One of the most important roles of the nurse and physician is ongoing neurological assessment. Using serial assessments, the healthcare team documents changes in the patient’s condition and initiates proper care immediately. Pupil size and reaction, level of consciousness, strength and motion of the extremities, and the patient’s response to noxious stimuli are all essential for patient assessment and management.
The maintenance of airway, breathing, and circulation is the foremost concern for the patient with encephalitis. If the patient is unable to clear secretions or maintain a patent airway as the disease progresses, notify the physician immediately, and prepare for endotracheal intubation. The family is likely to be anxious and need a great deal of support should intubation and mechanical ventilation be necessary. Once the airway is in place, maintaining an open airway with suctioning as needed is a primary nursing responsibility. Always take into account patient safety, and weigh it against the possibility of the patient’s further increase in intracranial pressure. Implement measures to limit the effects of immobility, such as skin care, range-of-motion exercises, and a turning and positioning schedule. Note the effect of position changes on intracranial pressure, and space activities as necessary. The patient and significant others need assistance in learning about the disease process and treatments. The patient’s behavioral and communication changes are often the most difficult to face and understand. Alterations can occur in thought processes when intracranial pressure begins to increase and the level of consciousness begins to decrease. Reorient the patient to time, place, and person as needed. Keep familiar objects or pictures around the patient. Allow visitation of significant others. Establish alternate means of communication if the patient is unable to maintain verbal contact (e.g., the patient who needs intubation).
Nursing care plan discharge and home health care guidelines
Although most patients recover fully before being discharged from the hospital, some have lifelong deficits following encephalitis. If the patient needs supportive care, teach the family, significant others, and caregivers how to plan and administer hygiene, nutrition, and medications. If arrangements need to be made for a nursing home or long-term facility, work with the family and social service to arrange for a careful transition. Teach the patient and family about the disease process and signs of recurrence. Make sure that the patient and family know when the follow-up visit with the healthcare provider is scheduled. Teach the patient and family about the route, dosage, mechanism of action, and side effects of all medications. Provide written information so that the patient and family have a permanent record of the communication.