eMedicine Specialties > Infectious Diseases > CNS Infections

Eastern Equine Encephalitis: Follow-up

Author: Mohan Nandalur, MD, Staff Physician, Department of Internal Medicine, Section of Cardiovascular Medicine, Washington Hospital Center
Coauthor(s): Andrew W Urban, MD, Chief, Section of Infectious Diseases, Middleton Memorial Veterans Hospital; Clinical Assistant Professor, Department of Internal Medicine, University of Wisconsin at Madison
Contributor Information and Disclosures

Updated: Oct 31, 2007

Follow-up

Further Inpatient Care

  • Transfer an infected patient to the ICU when appropriate.
  • Assess the many issues secondary to the high mortality rate of the disease.
  • Ensure that a social worker and appropriate hospital services staff are available to the patient's family.

Further Outpatient Care

  • Patients who survive infection usually need extensive rehabilitation.
  • Based on the duration of symptoms and the extent of neurospasticity, schedule the patient for physical therapy upon recovery.
  • Also, based on the specific defect, a patient may need consultations with speech and auditory therapists.
  • Because of the potential for high neurologic morbidity, arrange coordinated care and quality follow-up care.
  • Patients often require close neurodiagnostic follow-up care. The primary care physician must also be aware of subtle changes in behavior, intelligence, and motor skills.

Deterrence/Prevention

  • Environmental animal control
    • Monitoring the sources of infection may be possible by assessing serology of antibodies to eastern equine encephalitis (EEE) in certain wild birds or caged flocks of sentinel birds (eg, chickens).
    • The virus may also be recovered from adult mosquitoes and may provide an opportunity for screening in possible vector habitats.
    • Officials should control the vector mosquito population in areas where the virus has been isolated or where the risk of infection is high.
  • Environmental: Global factors also play a role in future prevention and spread. If global temperatures continue to rise and sea levels rise, the swampy breeding habitat of the C melanura mosquito and other bridge vectors may expand.
  • Public information: Warn individuals who live in high-risk areas to take the necessary precautions. This includes wearing appropriate clothing (eg, long pants, long-sleeved shirts), wearing mosquito repellant, avoiding areas with high mosquito activity, and avoiding outside activity during times of day when mosquitos are active. Mosquito netting at nighttime can also be used if appropriate.
    • Permethrin 5% cream on exposed skin areas can prevent arthropod bites for up to a week. The drug is not an effective repellant of arthropods, but it deters biting and causes the insect to die after contact with the treated skin.6
    • Permethrin rinse in clothing has been shown to be partially effective in the prevention of arthropod bites.
  • Future prevention: Currently, a vaccine is available for the North American subtype of EEE is not in widespread use and may not be effective against certain antigenic variants that are found primarily in other countries. Current use is limited to environmental workers at high risk of exposure. Recent advances in experimental vaccination have yielded equivocal results. The current vaccine has a weak antigen and requires multiple immunizations to achieve protection.
  • Surveillance: EEE is reportable under the National Notifiable Diseases Surveillance System. Additionally, electronic surveillance is conducted through ArboNet, a CDC site used to assist states in tracking mosquito-borne viruses.
  • Screening: To enable appropriate precautions, states with known mosquito-borne illnesses are now also screening vectors to determine if certain counties contain an increased number of carriers.

Complications

  • The primary complication, other than death, is often a variable level of CNS impairment. Numerous factors, including location and specific inflammatory cell response may determine the result.
  • Demyelination is a known by-product of this disease and can be radiologically detected. Often, these areas heal well, unless overlying fibrosis is present or cell death occurs.
  • Additional complications
    • Mental retardation
    • Behavioral changes
    • Paralysis
    • Permanent focal neurologic deficits
    • Seizure disorders
    • Emotional lability
    • Adjustment disorders

Prognosis

  • Currently, no clinical or radiographic prognostic indicators are available for EEE. The location and the type of lesion on imaging do not correlate with long-term sequelae or mortality.
  • Additionally, although younger patients with longer prodromes tend to have better outcomes, no study has proven any statistical significance.
  • The initial history and physical examination often do not reveal any prognostic variables.
  • Changes in treatment regimens do not commonly affect outcome; in fact, one series revealed a poorer outcome with the use of steroids and anticonvulsants, but many confounding variables were involved in this determination.
  • Certain laboratory findings may have some significance. The outcome in a patient with an elevated CSF WBC count (>500 cells/μL) is poorer than in a patient with a CSF WBC count of less than 500 cells/μL. Also, the prognosis in a patient with hyponatremia whose sodium level is less than 130 mmol/L is poorer than in patients with a higher sodium level.

Patient Education

Miscellaneous

Medicolegal Pitfalls

  • Failure to carefully stabilize the patient before any other activity, as with all critically ill patients
  • Because of the similarity in presentation between encephalitis and meningitis, failure to implement broad-spectrum antibiotics and antivirals in patients with eastern equine encephalitis (EEE)
 


More on Eastern Equine Encephalitis

Overview: Eastern Equine Encephalitis
Differential Diagnoses & Workup: Eastern Equine Encephalitis
Treatment & Medication: Eastern Equine Encephalitis
Follow-up: Eastern Equine Encephalitis
References
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Further Reading

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Keywords

eastern equine encephalitis, EEE, western equine encephalitis, WEE, St Louis encephalitis, La Crosse encephalitis, West Nile encephalitis, meningoencephalitis, viral encephalitis, herpes simplex virus, arboviruses, alphavirus, Togaviridae family, Culiseta melanura, Coquillettidia perturbans, Aedes canadensis, Venezuelan equine encephalitis, North American eastern equine encephalitis, South American eastern equine encephalitis

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Contributor Information and Disclosures

Author

Mohan Nandalur, MD, Staff Physician, Department of Internal Medicine, Section of Cardiovascular Medicine, Washington Hospital Center
Mohan Nandalur, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, American College of Physicians-American Society of Internal Medicine, and Phi Beta Kappa
Disclosure: Nothing to disclose.

Coauthor(s)

Andrew W Urban, MD, Chief, Section of Infectious Diseases, Middleton Memorial Veterans Hospital; Clinical Assistant Professor, Department of Internal Medicine, University of Wisconsin at Madison
Andrew W Urban, MD is a member of the following medical societies: American College of Physicians-American Society of Internal Medicine
Disclosure: Nothing to disclose.

Medical Editor

Gary L Gorby, MD, Program Director of Adult Infectious Diseases Fellowship, Associate Professor, Department of Internal Medicine, Division of Infectious Disease, St Joseph Medical Center, Creighton University School of Medicine
Gary L Gorby, MD is a member of the following medical societies: Alpha Omega Alpha, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, and New York Academy of Sciences
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

John L Brusch, MD, FACP, Assistant Professor of Medicine, Harvard Medical School; Consulting Staff, Department of Medicine and Infectious Disease Service, Cambridge Health Alliance
John L Brusch, MD, FACP is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

CME Editor

Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital
Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Chief Editor

Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

 
 
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