ENCEPHALITIS

Encephalitis

It is an acute inflammation of the brain.

Encephalitis with meningitis is known as meningoencephalitis.

Types of Encephalitis

• Herpes Simplex Virus Encephalitis

• Arthropod-Borne Virus Encephalitis

• Fungal Encephalitis

Clinical Manifestations

• Fever• Headache• Stiff neck• Vomiting• Drowsiness• Dysphasia• Focal Seizure

• Hemiparesis• Altered LOC• Personality Changes• Maculopapular Rash• SIADH with hyponatremia• Increased ICP

Pathophysiology

Nsg Diagnosis:

• Acute Pain may be related to inflammation/irritation of the brain and cerebral edema, possibly evidenced by verbal reports of headache, distraction behaviors, restlessness, and autonomic response (changes in vital signs).

Nsg Interventions:• INDEPENDENT:• Anticipate need for pain relief. • * Respond immediately to complaint of

pain. In the midst of painful experiences a patient’s perception of time may become distorted. * Eliminate additional stressors or sources of discomfort whenever possible.

• * Provide rest periods to facilitate comfort, sleep, and relaxation.

o Imagery The use of a mental picture or an imagined event involves use of the five senses to distract oneself from painful stimuli.o Distraction techniques Heighten one’s concentration upon nonpainful stimuli to decrease one’s awareness and experience of pain.

o Relaxation exercises Techniques are used to bring about a state of physical and mental awareness and tranquility. The goal of these techniques is to reduce tension, subsequently reducing pain.

o Biofeedback, breathing exercises, music therapy

Dependent:

• Give analgesics as ordered, evaluating effectiveness and observing for any signs and symptoms of untoward effects. Pain medications are absorbed and metabolized differently by patients, so their effectiveness must be evaluated from patient to patient. Analgesics may cause side effects that range from mild to life-threatening.* Notify physician if interventions are unsuccessful or if current 

Nsg Diagnosis:

• Hyperthermia may be related to increased metabolic rate, illness, and dehydration, possibly evidenced by increased body temperature, flushed/warm skin, and increased pulse and respiratory rates.

Nsg Interventions:

Nsg Diagnosis

• Risk for Trauma/Suffocation: risk factors may include restlessness, altered LOC, cognitive impairment; generalized weakness

Nsg Interventions• INDEPENDENT:• 1. Explore with client the various stimuli that may precipitate seizure

activity.• Rationale: Alcohol, various drugs, and other stimuli, such as loss of

sleep, flashing lights, and prolonged television viewing, may increase the potential for seizure activity. Client may or may not have control over many precipitating factors, but may benefit from becoming aware of risks.

• 2. Discuss seizure warning signs, if appropriate, and usual seizure pattern. Teach SO to recognize warning signs and how to care for client during and after seizure.

• Rationale: Can enable client or SO to protect individual from injury and to recognize changes that require notification of physician and further intervention. Knowing what to do when seizure occurs can prevent injury or complications and decreases SO’s feelings of helplessness.

• 3. Keep padded side rails up with bed in lowest position, or place bed up against wall, and add floor pad if rails are not available or appropriate.

• Rationale: Minimizes injury should frequent or generalized seizures occur while client is in bed.

• 4. Maintain strict bedrest if prodromal signs or aura is experienced. Explain necessity for these actions.

• Rationale: Client may feel restless, need to ambulate or even defecate during aural phase, thereby inadvertently removing self from safe environment and easy observation. Understanding importance of providing for own safety needs may enhance client cooperation.

• 5. Stay with client during and after seizure.• Rationale: Promotes client safety and reduces sense of

isolation during event.

6. Turn head to side and suction airway as indicated. Insert soft bite block per facility protocol, only if jaw relaxed.

• Rationale: Helps maintain airway and reduces risk of oral trauma but should not be “forced” or inserted when teeth are clenched because dental and soft-tissue damage may result. Note: Current practice is mixed regarding the use of airways during seizure activity.

• 7. Cradle head, place on soft area, or assist to floor if out of bed. Do not attempt to restrain.

• Rationale: Gentle guiding of extremities reduces risk of physical injury when client lacks voluntary muscle control. Note: If attempt is made to restrain client during seizure, erratic movements may increase, and client may injure self or others.

•

• 8. Perform neurological and vital sign checks after seizure: level of consciousness, orientation, ability to comply with simple commands, ability to speak, memory of incident, weakness or motor deficits, blood pressure (BP), pulse, and respiratory rate.

• Rationale: Documents postictal state and time and completeness of recovery to normal state. May identify additional safety concerns to be addressed.

• 9. Reorient client following seizure activity.• Rationale: Client may be confused, disoriented, and

possibly amnesic after the seizure and need help to regain control and alleviate anxiety.

• Monitoring pupils and vital signs frequently for increased intracranial pressure (ICP; irregular pupils, widening pulse pressure, tachycardia, irregular breathing hyperthermia).

• Monitor the patient’s response to medications and observe for adverse reactions.

• Monitor neurologic status closely. Watch for subtle changes, such as behavior or personality changes, weakness, or cranial nerve involvement.

• Monitor fluid intake and output to ensure adequate hydration.• Maintain quiet environment and provide care gently, to avoid

excessive stimulation and agitation, which may cause increase ICP.

• Maintain seizure precautions; pad side rails of bed and have airway and suction equipment available at bedside.

• Maintain standard precautions and additional isolation according to hospital policy to prevent transmission.

• Administer antipyretics and other cooling measures as indicated.• Provide fluid replacement through I.V. lines as needed.• Reorient patient frequently.• Provide supportive care if coma develops; may last several weeks.• Encourage significant others to interact with patient with even

while in coma and to participate in care to promote rehabilitation.

Nsg Management:

Pharmacologic Management

• Antiviral medications, such as acyclovir (Zovirax) and foscarnet (Foscavir) -- to treat herpes encephalitis or other severe viral infections (however, no specific antiviral drugs are available to fight encephalitis)

• Antibiotics -- if the infection is caused by certain bacteria

• Anti-seizure medications (such as phenytoin) -- to prevent seizures.

• Steroids (such as dexamethasone) -- to reduce brain swelling (in rare cases)

• Sedatives -- to treat irritability or restlessness• Acetaminophen -- for fever and headache

Diagnostic Tools

• MRI• CT scan • Culture of cerebrospinal fluid (CSF),

blood, or urine (however, this test is rarely useful)

• Electroencephalogram • 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)

New Trends

Tobacco Plant-Made Therapeutic Thwarts West

Nile Virus

• Feb. 3, 2010 -The study examined antibodies against West Nile virus derived from mammalian cell lines and compared their effectiveness with those extracted from plants. The plants used to produce the antibodies are a relative of common tobacco, a member of the Solanceae family of plants, which produce abundant leaves for harvesting material and are also prolific seed producers. Seven days after the introduction of antibody genes into plants, the leaves are harvested, homogenized and purified to remove extraneous material.

• The strategy for gene insertion is to use the specific machinery of the tobacco mosaic virus and potato virus X (PVX) to carry the genes of interest into the plants, where they can be expressed, yielding a human monoclonal antibody known as hu-E16. The gene expression occurs in just a week's time, making the production process highly efficient.

• The monoclonal antibody, once injected into the recipient, binds to a particular surface protein of the virus. That binding site is also the one used by the virus to attach itself to mammalian host cells, and once it is occupied, the virus' cell-binding (and infectious) capacity is neutralized.

• Cell-derived versions of this antibody have already demonstrated impressive effectiveness, protecting mice from WNV-induced mortality even several days after infection. Chen's research shows comparable effectiveness using tobacco-plant derived monoclonal antibodies. Indeed, the results in the groups of mice tested, were essentially indistinguishable. The therapeutic, Chen emphasizes, is effective in very small dosages, (50-200 micrograms), and only one dose is required to clear the virus from an infected individual's system.

• The effectiveness of the plant expression system is dependent in part on the optimization of the antibody DNA sequence, which helps to ensure a high level of expression in the plants. "The goal is to make more of the protein and for it to persist longer before it is degraded, " said Chen. "Optimization helps." The strategy permitted the group to set a record for the antibody yield produced by the transgenic tobacco plants -- an increase from 500 micrograms of antibody per gram of leaf tissue to 800 micrograms per leaf.

• Because the monoclonal antibody therapeutic binds to a conserved region of the viral surface, it can be effective against a variety of West Nile virus stains and potentially against other flaviviral strains. Here, another advantage of plant-derived as opposed to animal-derived antibodies becomes important. If an individual is exposed to a variant strain of virus differing in some particulars from the antibody used to treat it, there is a chance in the case of the mammalian cell-derived therapy to actually worsen the condition, through an effect known as antibody dependent enhancement. The process has been studied in some detail in dengue fever, a related flavivirus. Chen emphasizes that plant-based antibodies lack the capacity to bind with a critical receptor implicated in the antibody dependent enhancement effect, making them potentially safer for use.

• The completion of this research relied on the efforts of a large, interdisciplinary team, including lead author Huafang "Lily" Lai. Michael Diamond of Washington University collaborated in studies with the mouse model. In addition to Chen's ASU scientist colleagues, Thomas Keller, an undergraduate in ASU's School of Life Sciences Undergraduate Research program appears as a co-author of the PNAS paper, having carried out much of the critical protein expression and characterization work. "This was a very remarkable achievement for an undergraduate student," Chen points out. The research was supported by grants from the National Institute of Allergy and Infectious Diseases, and Keller's work was supported in part through the Howard Hughes Fellowship for Undergraduate Research.

• While the group's focus has been on West Nile Virus, Chen believes the plant-based antibody approach could provide highly effective, cost efficient therapeutics for other diseases, including related flavivirus infections such as dengue fever and Japanese encephalitis, if the successes in mice can be replicated in humans.

• One challenge in treating a virus like West Nile, which targets the central nervous system, is that current antibody therapeutics are unable to pursue the virus into its sanctuaries in the human brain, due to the existence of the blood brain barrier. If this obstacle can be overcome, it may be possible to produce therapeutics capable of eradicating the infection even after 6 or 7 days, when a significant amount of virus has colonized brain tissue.

• Toward this end, Chen is now working on bifunctional antibodies, capable of binding with virus particles as well as attaching to receptors in the brain, allowing the antibody to migrate past the blood brain threshold. If successful, the technique may allow treatment of other, currently intractable infectious and neurological diseases. "If we can find a way to deliver therapeutics of this sort into the brain it will be really significant," said Chen.

Visualizing Brain Invasion by a Fungus

• Apr. 27, 2010) — Infection with the fungus Cryptococcus neoformans can cause meningitis (inflammation of the membranes surrounding the brain) and encephalitis (inflammation of the brain itself), conditions that are often lethal. To elicit these effects, the fungus must somehow leave the blood stream and enter the brain, but little is known about how it does this.

• A team of researchers, at the University of Calgary, Canada, has now used a form of microscopy known as intravital microscopy, which enables researchers to observe events in real-time in live animals, to visualize in mice the process of brain invasion by Cryptococcus neoformans.

• A key observation of the team, led by Christopher Mody, was that Cryptococcus neoformans stops suddenly in mouse brain capillaries that are similar or smaller in diameter than it is. Only after stopping abruptly was the fungus seen to cross the wall of the blood vessel and enter the brain. Interestingly, the protein urease was required for Cryptococcus neoformans to invade the brain, and treatment with a urease inhibitor reduced brain infection. The authors therefore suggest that therapeutics that inhibit urease might help prevent meningitis and encephalitis caused by infection with Cryptococcus neoformans.

• In an accompanying commentary, Arturo Casadevall, at Albert Einstein College of Medicine, New York, suggests that such inhibitors might not be applicable in the clinic, because most patients already have substantial brain infection when they first seek medical help. However, he highlights that the study opens up numerous new avenues of research that could be exploited in the clinic in the future.

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