Rasmussen Encephalitis: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Rasmussen Encephalitis?
A pediatric neurologist, a doctor who treats brain and nerve problems in children, usually leads care for Rasmussen encephalitis. An epilepsy specialist and a neurosurgeon, a doctor who operates on the brain, are often involved too. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Rasmussen encephalitis?
Rasmussen encephalitis is a rare disorder of the central nervous system, which is the brain and spinal cord. It causes long-lasting inflammation, meaning swelling and irritation, that keeps getting worse in one half of the brain. It is also called Rasmussen syndrome.
The inflammation usually leads to frequent seizures that are hard to control. Over time, it also damages that half of the brain.
Symptoms
Most people first have focal seizures, which start in one part of the brain. These can turn into near-constant seizures called epilepsia partialis continua. This means fast, rhythmic jerking of a muscle. It is most often in the arms, legs, and face. The jerking happens on the side of the body opposite the inflamed side of the brain.
Other signs can include:
- Weakness or paralysis on one side of the body, called hemiparesis.
- Language problems, if the left side of the brain is affected.
- Developmental disabilities, if the seizures continue.
- Children who stop learning new skills or lose skills they already had.
- Shrinking of one side of the brain, called atrophy, along with growing confusion.
For many people, the disease is most severe in the first 8 to 12 months. After the peak of the inflammation, the disease appears to slow or stop. The person is then left with permanent problems with brain function.
Causes and who gets it
The exact cause is not known. Most researchers now suspect that it is an autoimmune disorder. In an autoimmune disorder, the body's natural defenses fight its own tissue by mistake. These defenses include antibodies and T-cells. Some researchers believe an unidentified infection may trigger the disease. Examples are influenza, measles, or cytomegalovirus.
It mostly affects children ten years of age and younger. It is unusual in children under two years of age. Teens and young adults are affected much less often.
How doctors diagnose it
Doctors start with a careful exam and a detailed health history. They also fully check the nervous system. Two tests are key. An EEG, or electroencephalogram, records the brain's electrical signals. An MRI uses a magnetic field and radio waves to make detailed pictures of the brain.
The diagnosis usually comes after at least two scans. They show the affected side of the brain shrinking over time. No lab test can confirm the disease for certain. Doctors also think about look-alike conditions, such as focal cortical dysplasia, which can cause similar muscle jerking.
Treatment
Treatment is mostly aimed at easing symptoms and supporting the person. Children may benefit from social support, physical therapy, and other medical, social, or vocational services.
Anti-seizure medicines may be prescribed, but they have not worked in most people. Doctors may also try medicines that act on the immune system, such as steroids, immunoglobulin, and tacrolimus. Immune medicines such as tacrolimus and immunoglobulin may slow the damage to the brain. But they usually do not improve the seizures or the shrinking. Steroids are often used first. Their side effects are significant. Another long-term medicine should follow.
Current guidelines suggest that brain surgery is the most recommended treatment for the seizures. The surgery is usually a cerebral hemispherectomy, an operation on the affected half of the brain. It can stop the seizures and halt the loss of skills. It also leaves lasting problems, such as weakness on one side of the body and loss of vision to one side. Language may also be affected. Timing is hard to decide. The family and an experienced specialist center should decide together.
When to see a doctor
Seizures and weakness on one side of the body are common signs of this disease.
Call 911 or go to the emergency room if the person has trouble breathing. Do the same if the person faints or cannot be woken up. Also go if there is a sudden change in mental state, such as confusion or unusual behavior.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either kind of doctor can listen to your concerns, order first tests, and refer you to a children's neurologist when seizures or weakness appear. They can also help keep track of medicines, therapy, and school needs over time.
Common questions
Does Rasmussen encephalitis keep getting worse?
Often it does, but mostly at first. In many people it is most severe during the first 8 to 12 months. After the peak of the inflammation, the disease appears to slow or stop. The person is then left with permanent problems with brain function.
Is surgery the main treatment for Rasmussen encephalitis?
Yes, surgery is the treatment most recommended for the seizures. It is usually a cerebral hemispherectomy, and it leaves lasting problems such as weakness on one side of the body. Medicines are usually less helpful for the seizures.
Who gets Rasmussen encephalitis?
Rasmussen encephalitis mostly affects children ten years of age and younger. It is unusual in children under two. Teens and young adults are affected much less often.
Sources
- NORD (National Organization for Rare Disorders) - Rasmussen Encephalitis
- National Library of Medicine (PMC) - Rasmussen Encephalitis: Clinical Features, Pathophysiology, and Management Strategies
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
