Rasmussen Encephalitis Fast Facts

 Rasmussen encephalitis (RE), also sometimes called Rasmussen syndrome, is a neurological disorder in which inflammation causes damage to the brain.

RE most commonly affects children under the age of 10, but it can also occur later in life.

Seizures are the most common symptom of RE, but other neurological and cognitive symptoms are also common.

The cause of RE is not well understood, but many scientists believe it occurs when the body’s immune system mistakenly attacks healthy brain cells.

Eastern equine encephalitis usually affects fewer than ten people in the United States each year, but the disease’s fatality rate can be as high as 30%.

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Seizures are the most common symptom of RE, but other neurological and cognitive symptoms are also common.

What is Rasmussen Encephalitis?

Rasmussen encephalitis (RE) is a neurological disorder characterized by inflammation and swelling of brain tissue. The inflammation is chronic, meaning it continues over a long period, and it eventually causes damage to the brain. The disorder most often affects children younger than 10, but it sometimes affects older children and adults.

Usually, only one side of the brain is affected by RE. This can cause neurological symptoms, such as paralysis, that only affect one side of the body. In some cases, the disorder eventually progresses to involve both sides of the brain.

Symptoms of Rasmussen Encephalitis

Common symptoms of RE include:

  • Severe, prolonged seizures, often affecting only one side of the body
  • Paralysis on one side of the body
  • Slowed physical and mental development, or loss of skills already acquired
  • Speech difficulties
  • Vision impairment
  • Difficulty swallowing
  • Deterioration (atrophy) of brain tissue
  • Confusion, disorientation, or dementia

What Causes Rasmussen Encephalitis?

Scientists don’t know precisely what causes RE, but many believe that the body’s immune system causes the disorder’s inflammation. In this case, the immune system mistakes proteins in nerve cells for infectious invaders, causing the immune system to attack the healthy nerve cells. This type of encephalitis is called autoimmune encephalitis.

Researchers haven’t discovered why the immune system targets healthy cells in RE. Some scientists think the immune-system action is an inappropriate response to an actual infection. Infections that may trigger autoimmune encephalitis include:

  • Influenza
  • Cytomegalovirus
  • Childhood diseases such as measles, mumps, and rubella

Is Rasmussen Encephalitis Hereditary?

RE seems to be caused by external environmental factors (such as infections), and it is not likely to be caused directly by an inherited genetic component. However, because the immune system is involved in the development of the disorder and because genetic factors can influence the immune system‘s behavior, some scientists suspect a genetic connection to RE. However, no conclusive evidence of a genetic link has been discovered.

How Is Rasmussen Encephalitis Detected?

Seizures are usually the first sign of RE. Common characteristics of early seizures include:

  • Infrequent seizures that become more frequent over weeks or months
  • Seizures that affect one side of the face or body
  • Progression to near-continuous seizures that may last for hours

How Is Rasmussen Encephalitis Diagnosed?

If you exhibit symptoms consistent with RE, your healthcare provider will move through a series of diagnostic steps to see if you have the condition.

  • Physical exam and medical history. The doctor will look for signs that you may be at risk for encephalitis. For example, they may ask if you’ve recently had a gastrointestinal or respiratory illness (cold or flu).
  • Laboratory tests. Tests of your blood, urine, stool, and throat cultures can determine whether or not there is an infection in your body that could lead to encephalitis.
  • Electroencephalogram (EEG). This test monitors your brain’s electrical activity and can help detect abnormalities in brain function.
  • Imaging tests. Magnetic resonance imaging (MRI) and computed tomography (CT) scans can detect brain swelling or deterioration of brain tissue caused by RE. Diagnosis of RE is usually made when progressive loss of brain tissue is observed in two different imaging scans.

How Is Rasmussen Encephalitis Treated?

RE seizures typically don’t respond well to anticonvulsant medications used to treat epilepsy and other types of seizures. In addition, no non-surgical treatment has yet proven consistently effective at stopping seizures or controlling the long-term deterioration of brain tissue caused by the disorder.

Medical Treatments

Common drug-based treatment approaches for RE include:

  • Medications to suppress the immune system, such as corticosteroids, immunoglobulin, and tacrolimus
  • Intravenous immune-suppression therapies such as IV immunoglobulin and blood plasma transfusions

Surgical Treatments

Surgery may be an option in cases of RE in which seizure activity is confined to one well-defined area of the brain. Surgical intervention, when possible, is the only reliable way to relieve seizures and stop the progression of the disorder.

Surgery is likely to cause permanent side effects, such as muscle weakness or vision impairment. It may be more effective in young children whose brains can more easily recover from the surgical procedure.

Possible surgical interventions include:

  • Functional hemispherectomy. This procedure removes the part of the brain where the seizures are centered.
  • Functional hemispherotomy. This procedure severs the neurological connections between the brain’s hemispheres.


Supportive therapies may be used to manage the complications of RE. Commonly used treatments include:

  • Physical therapy
  • Occupational therapy
  • Speech therapy

How Does Rasmussen Encephalitis Progress?

Symptoms of RE get progressively worse after they first appear. Seizures typically become more frequent, and many children with RE eventually develop near-continuous seizures called epilepsia partialis continua (EPC).

The disorder also usually produces neurological and developmental problems that worsen over months. These problems can include:

  • Paralysis on one side of the body
  • Loss of motor skills
  • Loss of cognitive or intellectual skills
  • Slowed motor and cognitive development
  • Loss of speech skills
  • Neurological symptoms such as confusion or dementia

Young children with RE often experience stabilization of their symptoms within 8-12 months of the disorder’s initial onset. At this point, the worsening of the symptoms slows or stops, but the impairments already present are permanent. In adolescents and adults, RE may slowly progress indefinitely.

How Is Rasmussen Encephalitis Prevented?

Because the precise cause of RE remains unknown, there is no sure way to prevent it. However, if it is true, as some scientists believe, that infections trigger some cases of RE, avoiding viral infections may reduce the risk of developing the condition.

To protect yourself from the common viruses that could cause encephalitis, take these steps:

  • Vaccinate yourself and your children against common viruses such as measles, mumps, rubella, and chickenpox.
  • Wash your hands and practice good hygiene to prevent the spread of viruses. Teach your children these practices, too.

Rasmussen Encephalitis Caregiver Tips

The brain-related complications of RE are permanent. Even if the progression of the disorder stops, its lingering effects can make every day difficult, and caregivers can help sufferers to return to their everyday daily routines as much as possible.

  • Learn as much as you can about the disease and its long-term effects. The sufferer may need help with ongoing therapies, such as physical therapy, occupational therapy, speech therapy, or psychotherapy.
  • Understand that although your loved one may look as if everything is fine, they may be struggling with subtle, unseen complications. Depression and anxiety often result from these struggles, and daily tasks may be difficult. As a caregiver, be aware that these apparently unrelated problems result from the disease, and be alert for warning signs.
  • Create an environment free of distraction and confusion to help the sufferer cope with any problems with concentration or focus.
  • Find a support group for both the sufferer and yourself as a caregiver. It always helps to know that you’re not alone in what you’re going through.

Many people with RE also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with RE:

Rasmussen Encephalitis Brain Science

Encephalitis research includes studies to find ways to prevent or cure the infections that cause the condition, effective ways to treat the condition when it occurs, and ways to help patients recover from the effects of encephalitis long term.

One current study examines the early symptoms of anti-NMDA receptor encephalitis, specifically psychiatric and speech symptoms that occur in the early phases of the condition. These early symptoms often progress to more severe symptoms such as seizures and movement abnormalities. The study hopes to help practitioners better recognize the very early signs so that treatment can begin before the condition becomes more severe.

Another study looks at the recovery obstacles faced by survivors of autoimmune encephalitis and their caregivers. Researchers hope that practitioners will develop more effective therapies and support systems by having a more thorough understanding of what it means to live with the effects of encephalitis.

Rasmussen Encephalitis Research

Title: Use of a Tonometer to Identify Epileptogenic Lesions During Pediatric Epilepsy Surgery

Stage: Recruiting 

Principal Investigator: Aria Fallah, MD   

University of California, Los Angeles

Los Angeles, CA

Refractory epilepsy, meaning epilepsy that no longer responds to medication, is a common neurosurgical indication in children. In such cases, surgery is the treatment of choice. Complete resection of affected brain tissue is associated with the highest probability of seizure freedom. However, epileptogenic brain tissue is visually identical to normal brain tissue, complicating complete resection. Modern investigative methods are of limited use.

An important subjective assessment during surgery is that affected brain tissue feels stiffer. However, there is presently no way to determine this without committing to resecting the affected area. It is hypothesized that intraoperative use of a tonometer (Diaton) will identify abnormal brain tissue stiffness in the affected brain relative to the normal brain. This will help identify stiffer brain regions without having to resect them.

The objective is to determine if intra-operative use of a tonometer to measure brain tissue stiffness will offer additional precision in identifying epileptogenic lesions.

In participants with refractory epilepsy, various locations on the cerebral cortex will be identified using standard pre-operative investigations like magnetic resonance imaging (MRI) and positron emission tomography (PET). These are presumed normal and abnormal brain areas where the tonometer will be used during surgery to measure brain tissue stiffness. Brain tissue stiffness measurements will then be compared with the results of routine pre-operative and intra-operative tests. Such comparisons will help determine the extent to which intra-operative brain tissue stiffness measurements correlate with other tests and help identify epileptogenic brain tissue.

Twenty-four participants have already undergone intra-operative brain tonometry. Results in these participants are encouraging: abnormally high brain tissue stiffness measurements have consistently been identified and significantly associated with abnormal brain tissue.

If the tonometer adequately identifies epileptogenic brain tissue through brain tissue stiffness measurements, it is possible that resection of identified tissue could lead to better postoperative outcomes, lowering seizure recurrences and neurological deficits.


Title: Autologous Peripheral Blood Stem Cell Transplant for Neurologic Autoimmune Diseases

Stage: Recruiting 

Contact: George E. Georges

Fred Hutch/University of Washington Cancer Consortium

Seattle, WA

This phase II trial studies the side effects and how well carmustine, etoposide, cytarabine, and melphalan together with antithymocyte globulin before a peripheral blood stem cell transplant works in treating patients with autoimmune neurologic disease that did not respond to previous therapy. In autoimmune neurological diseases, the patient’s own immune system ‘attacks’ the nervous system, which might include the brain/spinal cord and/or the peripheral nerves. Giving high-dose chemotherapy, including carmustine, etoposide, cytarabine, melphalan, and antithymocyte globulin, before a peripheral blood stem cell transplant weakens the immune system and may help stop the immune system from ‘attacking’ a patient’s nervous system. When the patient’s own (autologous) stem cells are infused, they help the bone marrow make red blood cells, white blood cells, and platelets to improve blood counts.


Title: Study on Patients With Rasmussen Encephalitis Treated With Adalimumab: Efficacy and Tolerance in the Short and Long Term

Stage: Recruiting 

Study director: Jean-Olivier Arnaud

Assistance Publique Hopitaux De Marseille

Marseille, France

Rasmussen Encephalitis (ER) is a particularly severe chronic inflammatory brain disorder resulting in the progressive destruction of a hemisphere. It is a rare disease, although no precise prevalence is available at present. It begins preferentially in children.

This inflammatory process is accompanied by a progressive loss of function of the affected hemisphere, associated with pharmaco-resistant partial epilepsy. The diagnosis is based on a bundle of clinical, radiological, and electroencephalographic arguments. CSF analysis directs diagnosis in 50% of cases.

No anti-epileptic treatment can stop seizures. Only hemispherotomy (surgical disconnection of a cerebral hemisphere) allows it, but it is associated with definitive motor and cognitive deficits.

Over the last 20 years, new therapeutic trials have focused on immuno-modulatory treatments targeted at the T-lymphocyte pathway, including tacrolimus. Although they seem to be more effective than immunoglobulins or corticosteroids, it remains transient. In addition, the number of published cases is low. In this context, starting in 2009, it has been proposed to use adalimumab (Ab anti TNF) based on a study of a case index and knowledge of the pathophysiology of Rasmussen Encephalitis. Unfortunately, to date, very few data provide precise information on the efficacy or tolerance of this product in the longer term. This information is essential to confirm the place of adalimumab in the therapeutic arsenal against Rasmussen encephalitis.

Thus, in the continuation of the work carried out previously (French study on the cases between 2009 and 2015), this research project aims to complete the follow-up of the patients who previously took part in in the first study and to establish the follow-up of the patients treated by adalimumab since then.

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