Encephalitis, Herpes Simplex

Encephalitis, Herpes Simplex

National Organization for Rare Disorders, Inc.

Important

It is possible that the main title of the report Encephalitis, Herpes Simplex is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

  • Herpes Encephalitis
  • HSE
  • Herpetic Brainstem Encephalitis
  • Herpetic Meningoencephalitis

Disorder Subdivisions

  • None

General Discussion

Herpes simplex encephalitis (HSE) is a rare neurological disorder characterized by inflammation of the brain (encephalitis). Common symptoms include headaches, fevers, drowsiness, hyperactivity, and/or general weakness. The disorder may have some symptoms similar to those associated with meningitis, such as a stiff neck, altered reflexes, confusion, and/or speech abnormalities. Skin lesions usually are not found in association with herpes simplex encephalitis. Herpes simplex encephalitis is caused by a virus known as herpes simplex virus (HSV).

Symptoms

Symptoms associated with herpes simplex encephalitis usually develop over several days, often without warning. Early symptoms include headaches, fevers, and seizures. Additional symptoms include drowsiness with general weakness (stupor), and confusion or disorientation.



After the initial symptoms appear, affected individuals may develop speech abnormalities such as a diminished ability to communicate by speech, writing, and/or signs (aphasia), absence of the sense of smell (anosmia), and memory loss. In some cases, behavioral changes such as hyperactivity or psychotic episodes occur. Some symptoms of herpes simplex encephalitis may mimic meningitis. These symptoms may include a stiff neck, altered reflexes, confusion, convulsions, and paralysis.



Individuals with herpes simplex encephalitis may develop more severe symptoms, including loss of consciousness, hallucinations, and partial paralysis (hemiparesis). In some rare cases, herpes simplex encephalitis may affect the nerve-rich membrane lining the eyes (retina), resulting in inflammation of the retina (retinitis).

Causes

Herpes simplex encephalitis is a complication of infection with the herpes simplex virus. In most cases, the disorder results from herpes simplex virus type I (HSV-I). In rare cases, usually in newborns (neonatals), the disorder is caused by herpes simplex virus type II (HSV-II).



Herpes simplex infection is an acute viral disease usually spread from person to person. It is marked by small fluid-filled blisters appearing on the lips or genitals often accompanied by fever. Herpes simplex encephalitis rarely occurs in conjunction with oral or genital lesions. The herpes virus may become immediately active or remain in the body in an inactive (dormant or latent) state. After being active, the virus may become inactive and then recur (reactivate).



Symptoms associated with herpes simplex encephalitis may occur due to tissue degeneration associated with bleeding (hemorrhagic necrosis) of a tongue-shaped lobe (i.e., temporal lobe) of the cerebral hemisphere.

Affected Populations

Herpes simplex encephalitis usually occurs during early childhood or adulthood. It affects males and females in equal numbers. The disorder is the most common form of acute encephalitis in the United States with approximately 2,000 cases occurring per year. It accounts for 10 percent of all cases of encephalitis in the United States per year.

Standard Therapies

Diagnosis

A diagnosis of idiopathic herpes simplex encephalitis is made based upon a detailed patient history, a thorough clinical evaluation, identification of classic symptoms, and a variety of specialized tests. These tests include polymerase chain reaction (PCR) in cerebrospinal fluid (CSF), which may confirm infection of CSF with the herpes simplex virus. In some cases, advanced imaging techniques such as computed tomography and magnetic resonance imaging (MRI) can also be beneficial in diagnosing a case of herpes simplex encephalitis.



Treatment

Prompt treatment of individuals with herpes simplex encephalitis is important as it improves the efficiency of treatment options.



Treatment with the antiviral drug Zovirax (acyclovir) has resulted in a dramatic improvement of symptoms in most individuals with herpes simplex encephalitis. It is manufactured by GlaxoSmithKline.



Another antiviral drug that has been used to treat herpes simplex encephalitis is vidarabine. However, antiviral therapy may not benefit affected individuals in advanced stages of the infection. Antiviral therapy should be started as soon as herpes simplex encephalitis is suspected.



Seizures that are often associated with herpes simplex encephalitis may be treated with drugs that reduce, prevent, or suppress seizures (anticonvulsants).

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.



For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:



Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov



For information about clinical trials sponsored by private sources, contact:

www.centerwatch.com

References

ARTICLES

McJunkin JE, et al. La crosse encephalitis in children. N Engl J Med. 2001;11:801-807.



Maertzdorf J, et al. Herpes simplex virus type 1 (HSV-1) induced retinitis following herpes simplex encephalitis: indications for brain-to-eye transmission of HSV-1. Ann Neurol. 2000;48:936-39.



Sauerbrei A, et al. Virological diagnosis of herpes simplex encephalitis. J Clin Virol. 2000;17:31-36.



Garcia de Tena J, et al. The value of polymerase chain reaction in cerebrospinal fluid for the diagnosis of herpetic encephalitis: a report of 2 cases and a review of the literature. An Med Interna. 2000;17:81-83.



Chan PK, et al. Use of oral valaciclovir in a 12-year-old boy with herpes simplex encephalitis. Hong Kong Med J. 2000;6:119-21.



Garcia-Barragan N, et al. An unusual presentation of herpetic encephalitis. Rev Neurol. 2000;30:441-44.



Pavone P, et al. Early relapse of herpes simplex encephalitis. Clinical and therapeutic implications. Minerva Pediatr. 1999;51:395-98.



Ito Y, et al. Exacerbation of herpes simplex encephalitis after successful treatment with acyclovir. Clin Infect Dis. 1999;30:185-87.



Kaplan CP, et al. Cognitive outcome after emergent treatment of acute herpes simplex encephalitis with acyclovir. Brain Inj. 1999;13:935-41.



Levitz RE. Herpes simplex encephalitis: a review. Heart Lung. 1998;27:209-12.



McGrath N, et al. Herpes simplex encephalitis treated with acyclovir: diagnosis and long term outcome. J Neurol Neurosug Psychiatry. 1997;63:321-26.



Hokkanen L, et al. Cognitive recovery instead of decline after acute encephalitis: a prospective follow up study. J Neurol Neurosurg Psychiatry. 1997;63:222-27.



Paillard C, et al. Recurrence of herpes simplex encephalitis. Arch Pediatr. 1999;6:1081-85.



Foucher A, et al. Herpetic encephalitis: prognostic elements in adults and children (49 cases). Rev Electroencephalogr Neurophysiol Clin. 1985;15:185-93.



Taylor WB, et al. Ocular infection with herpes simplex virus type 1: prevention of acute herpetic encephalitis by systemic administration of virus-specific antibody. J Infect Dis. 1979;140:534-40.

Resources

Transverse Myelitis Association

1787 Sutter Parkway

Powell, OH 43065-8806

USA

Tel: (614)766-1806

Email: info@myelitis.org

Internet: http://www.myelitis.org



Centers for Disease Control and Prevention

1600 Clifton Road NE

Atlanta, GA 30333

Tel: (404)639-3534

Tel: (800)232-4636

TDD: (888)232-6348

Email: cdcinfo@cdc.gov

Internet: http://www.cdc.gov/



NIH/National Institute of Allergy and Infectious Diseases

Office of Communications and Government Relations

6610 Rockledge Drive, MSC 6612

Bethesda, MD 20892-6612

Tel: (301)496-5717

Fax: (301)402-3573

Tel: (866)284-4107

TDD: (800)877-8339

Email: ocpostoffice@niaid.nih.gov

Internet: http://www.niaid.nih.gov/



NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801

Bethesda, MD 20824

Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

TDD: (301)468-5981

Internet: http://www.ninds.nih.gov/



Encephalitis Global

18 North Broadway #404

Tarrytown, NY 10591

USA

Tel: 604-980-2236

Fax: (604)904-0809

Email: admin@encephalitisglobal.org

Internet: http://www.encephalitisglobal.org



Encephalitis Society

32 Castlegate

Malton

North Yorkshire, YO17 7DT

United Kingdom

Tel: 4401653692583

Internet: http://www.encephalitis.info



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223

Internet: http://rarediseases.info.nih.gov/GARD/



For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.

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