Rasmussen Syndrome

Also known as Rasmussen’s encephalitis, Rasmussen syndrome is a very rare form of chronic brain inflammation. It is most common in children between ages 5 and 7 but can occur in younger or older children, too. Rasmussen syndrome typically affects one side of the brain and can trigger seizures as well as weakness, changes in language, and difficulty thinking.

Seizures are usually the first symptoms of Rasmussen syndrome. These seizures tend to be focal seizures, which can cause abnormal muscle movements, vision changes, and behavioral changes. They can become more frequent — and even continuous — over time. 

Note: If you believe your child is having a seizure, please seek immediate medical attention.

Other symptoms of Rasmussen syndrome may include:

• Progressive weakness on one side of the body, which may lead to partial paralysis
• Progressive loss of speech and language skills
• Problems with thinking and memory

The exact cause of Rasmussen syndrome is still unclear, but experts believe that it may be a type of inflammatory or autoimmune condition. It’s also possible that Rasmussen syndrome occurs in response to infection by an unknown virus or that some patients have a genetic predisposition to it.

Your child’s doctor will perform a physical and neurological exam and ask about their medical history and symptoms. They may also recommend other tests to help diagnose Rasmussen syndrome, such as:

• Blood tests
• MRI scan
• Electroencephalogram (EEG)
• Spinal tap
• Neuropsychological testing

The goal of treatment for Rasmussen syndrome is to help relieve brain inflammation and address symptoms. Depending on your child’s individual situation, their doctor may recommend:

• Medication. Rasmussen syndrome usually doesn’t respond well to traditional anti-seizure medications. Doctors may prescribe medications to help suppress the immune system, such as steroids and intravenous immunoglobulin, in some cases.
• Surgery. A type of brain surgery called hemispherotomy may help treat some children with Rasmussen syndrome. This procedure surgically disconnects the affected side of the brain from the unaffected side. The goal is to help decrease further damage and prevent seizures. Your child’s doctor will help you weigh the benefits and risks of a hemispherotomy.

At Boston Children’s Hospital, we care for children with Rasmussen syndrome in our Neuroimmunology Center and our Epilepsy Center. Our team takes a multidisciplinary approach, working with other specialists throughout Boston Children’s who have expertise in caring for children with Rasmussen syndrome, including neurologists, neurosurgeons, neuropsychologists, neuroradiologists, pathologists, occupational therapists, speech therapists, physical therapists, education specialists, and others. Together, we will create a treatment plan that puts your family in the center and aims to get your child back to optimal function and health as soon as possible.