Rasmussen Encephalitis

National Organization for Rare Disorders, Inc.

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  • Rasmussen syndrome (RE)
  • chronic encephalitis and epilepsy
  • chronic localized (focal) encephalitis
  • epilepsy, hemiplegia and intellectual disabilities

Disorder Subdivisions

  • None

General Discussion

Rasmussen encephalitis, sometimes referred to as Rasmussen syndrome, is a rare disorder of the central nervous system characterized by chronic inflammation (encephalitis) of one hemisphere of the brain. As a result, the patient experiences frequent episodes of uncontrolled electrical disturbances in the brain that cause epileptic seizures (epilepsy). Further symptoms may include progressive weakness of one side of the body (hemiparesis), language problems (if on the left side of the brain) and intellectual disabilities. The exact cause of this disorder is not known. The two leading ideas are that the brain inflammation might be a reaction of a foreign antigen (infection) or an autoimmune disease limited to one side of the brain resulting in brain damage.

It occurs mostly, but not always, in children between the ages of two and ten years, and in many cases the course of the disease is most severe during the first 8 to 12 months. After the peak inflammatory response is reached, the progression of this disorder appears to slow or stop and the patient is left with permanent neurological deficits.


Typically, affected individuals develop focal seizures that may progress to near continuous seizures termed epilepsia partialis continua (EPC). EPC is characterized by a rapid, rhythmic succession of contractions and relaxations of a muscle or muscle group (myoclonus), particularly of the arms, legs, and face, that may occur singularly or in a repetitive, continuous series. In Rasmussen this occurs consistently on one side of the body.

In most cases, affected children will exhibit progressive paralysis of one side of the body (hemiparesis) and if the seizures continue developmental disabilities. In many cases, the development of physical and mental abilities of affected children may cease (developmental arrest). In addition, affected children may lose previously acquired physical and mental abilities (developmental regression). In some cases, affected children may exhibit degeneration (atrophy) of one side of the brain and/or progressive confusion, disorientation, and deterioration of intellectual abilities (dementia).


The exact cause of Rasmussen encephalitis is not known. Most researchers now suspect that Rasmussen encephalitis is an autoimmune disorder following review of the tissue involved under the microscope. In autoimmune disorders, the body's natural defenses (antibodies) fight its own tissue, mistaking it for foreign organisms for no apparent reason.

Some researchers believe that Rasmussen encephalitis may be triggered by an unidentified infection such as influenza, measles, or cytomegalovirus.

Affected Populations

Rasmussen encephalitis mostly affects children ten years of age and younger. It is unusual to affect children under two years of age. Adolescents and young adults in much smaller proportions are also affected. There may be a history of some prior mild cold or flu prior to the onset of the seizures. The annual number of new-onset Rasmussen has been estimated as 2.4/107 persons less than or equal to 18 years of age.

Standard Therapies


Rasmussen encephalitis may be diagnosed based upon a thorough clinical evaluation, a detailed patient history, and a complete neurological evaluation including advanced techniques such as electroencephalography (EEG), and magnetic resonance imaging (MRI).

During an EEG, the brain's electrical impulses are recorded. Such studies may reveal brain wave patterns that are characteristic of certain types of epilepsy. During MRI, a magnetic field and radio waves are used to create cross-sectional detailed images of the brain. It is usual that the diagnosis is made after a minimum of two scans which will detail progressive shrinkage of the affected side of the brain


Treatment of Rasmussen encephalitis is mostly symptomatic and supportive. Special services that may be beneficial to affected children include special social support, physical therapy, and other medical, social, and/or vocational services.

Various anti-seizure medications (anticonvulsants) may be prescribed to treat seizures. However, in most cases, anticonvulsants have proven ineffective. Medical treatments targeted at possible autoimmune disease may be tried, including steroids, immunoglobulin and tacrolimus. Immunological therapies (tacrolimus, intravenous immunoglobulins, potentially others as well) may slow down the neurological and structural deterioration but usually does not improve the epilepsy. Its precise role in management of Rasmussen encephalitis remains to be determined

Surgery usually in the form of a cerebral hemispherectomy is the only way to cure the seizures and halt neurodevelopmental regression. However, there is the inevitable resultant functional deficits including hemiparesis (weakness of one side) and hemifield defect (impairment of vision to one side), and where the dominant side of the brain is affected, there may be an effect on language. The difficulty is often deciding on the necessary and best timing of surgery, dependent on the severity of epilepsy and degree of effect on learning. The decision needs to be made jointly by the family and specialist center who deal with this condition regularly.

Investigational Therapies

The RE Children's Project (http://www.rechildrens.org) a non-profit non-government organization has established a research consortium among US and international research laboratories to identify the cause of Rasmussen encephalitis and develop new more effective treatments. In order to develop new therapies, this group is soliciting families and patients to volunteer their brain tissue obtained at surgery for research. Contact RE Children's Project for more information.

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:

Toll-free: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

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


Contacts for additional information about Rasmussen encephalitis:

Gary W. Mathern, MD

Professor and Neurosurgical Director, Pediatric Epilepsy Surgery Program

Departments of Neurosurgery and Psychiatry & Biobehavioral Medicine

Mattel Children's Hospital

David Geffen School of Medicine

University of California, Los Angeles

Telephone: 310-825-7961

Fax: 310-825-0922

Email: gmathern@ucla.edu

William Davis Gaillard, MD

Professor, Pediatrics and Neurology

George Washington University School of Medicine

Professor Neurology

Georgetown University

Chief, Epilepsy, Neurophysiology, and Critical Care Neurology

Children's National Medical Center

Associate Director, Center for Neuroscience Research

Children's Research Institute

Telephone: 202-476-2120

Email: wgaillar@childrensnational.org

J. Helen Cross

The Prince of Wales's Chair of Childhood Epilepsy UCL-Institute of Child Health, Great Ormond Street Hospital for Children & Young Epilepsy

Head of Neurosciences Unit

UCL-Institute of Child Health

4/5 Long Yard

London WC1N 3LU

Telephone number: 0207 599 4105

Fax Number: 0207 430 0032

Mobile: 07983420692


PA Anne Brown: anne.brown@ucl.ac.uk

The Neville Epilepsy Centre

Young Epilepsy

St Piers Lane,


Surrey RH7 6PW

PA: Louise Jones ljones@youngepilepsy.org.uk

Tel: 01342 831212




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Menkes JH, Pine Jr JW, et al. eds. Textbook of Child Neurology. 5th ed. Baltimore, MD: Williams & Wilkins; 1995:479-80, 749, 776.


Bien CG et al., Rasmussen encephalitis: Incidence and course under randoized therapy with tacrolimus or intravenous immunoglobulins, Epilepsia in press.

Bauer J, Vezzani A, Bien CG. Epileptic encephalitis: the role of the innate and adaptive immune system. Brain Pathology. 2012: 22(3):412-21.

Bien CG, Granata t, Antozzi C, et al. Pathogenesis, diagnosis and treatment of Rasmussen encephalitis: a European consensus statement. Brain. 2005:128, 454-71.

Koh S. Mathern GW, Glasser g, et al. Status ellipticus and frequent seizures: incidence and clinical characteristics in pediatric epilepsy surgery patients. Epilepsia. 2005;46:1950-54.

Korkman M, Granstrom ML, Kantola-Sorsa E, et al. Two-year follow-up of intelligence after pediatric epilepsy surgery. Pediatr Neurol. 2005;33:173-78.

Gaynor Y, Freilinger M, Dulac O, Levite M. Monozygotic twins discordant for epilepsy differ in the levels of pathogenic antibodies and cytokines. Autoimmunity. 2005;38:139-50.

Freeman JM. Rasmussen's syndrome: progressive autoimmune multi-focal encephalopathy. Pediatr Neurol. 2005;32:295-99.

Tubbs RS, Nimjee SM, Oakes WJ. Long-term follow-up in children with functional hemispherectomy for Rasmussen's encephalitis. Childs Nerv Syst. 2005;21:461-65.

Hart Y. Rasmussen's encephalitis. Epileptic Disord. 2004;6:133-44.


NINDS Rasmussen's Encephalitis Information Page. National Institute of Neurological Disorders and Strokes. National Institutes of Health. www.ninds.nih.gov/disorders/rasmussen/rasmussen.htm. Last Updated December 19, 2011. Accessed November 14, 2012.

Rasmussen's encephalitis. Wikipedia. http://en.wikipedia.org/wiki/Rasmussen's_encephalitis. Last modified November 9, 2012. Accessed November 14, 2012.

Rasmussen's Encephalitis. The Hemispherectomy Foundation. http://hemifoundation.intuitwebsites.com/rasmussen.html. Accessed November 26, 2012.


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NIH/National Institute of Neurological Disorders and Stroke

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Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

TDD: (301)468-5981

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

Rasmussen's Syndrome and Hemispherectomy Support Network

8235 Lethbridge Road

Millersville, MD 21108


Tel: (410)987-5221

Email: rssnlynn@aol.com

Encephalitis Society

32 Castlegate


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/

Madisons Foundation

PO Box 241956

Los Angeles, CA 90024

Tel: (310)264-0826

Fax: (310)264-4766

Email: getinfo@madisonsfoundation.org

Internet: http://www.madisonsfoundation.org

Hemispherectomy Foundation

P.O. Box 1239

Aledo, TX 76008

Tel: (817)307-9880

Email: info@hemifoundation.org

Internet: http://www.hemifoundation.intuitwebsites.com/welcome.html

RE Children's Project, LLC

79 Christie Hill Road

Darien, CT 06820

Tel: (917)971-2977

Fax: (212)840-1233

Email: swohlberg@rechildrens.com

Internet: http://www.rechildrens.org

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.