Rasmussen's Syndrome and Rasmussen's Encephalitis

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If you or a loved one has been told that you have Rasmussen's syndrome or Rasmussen's encephalitis, you may have a sense of relief in knowing that you finally have a diagnosis that explains your symptoms. But you might also have great deal of concern about what to expect from this condition.

Rasmussen's syndrome or Rasmussen's encephalitis is not common, and it is estimated that there may be fewer than 2000 people living with this condition in the United States.

Despite the fact that it is rare, there is medical management for Rasmussen's syndrome and Rasmussen's encephalitis, although there is also a high chance that you will continue to experience some long-term effects even after you receive treatment and that you will need to maintain treatment for many years.

What Is Rasmussen's Syndrome and Rasmussen's Encephalitis?

Rasmussen's syndrome is the term used to describe the condition at any time during the course of the illness. It is believed that Rasmussen's syndrome may sometimes be caused by or preceded by a type of inflammation of the brain called Rasmussen's encephalitis.

Rasmussen's encephalitis itself is a condition in which the brain has a very strong immune reaction that causes severe disruption of brain function on one side. This can manifest as seizures, weakness, language problems or cognitive deficits (thinking and problem solving difficulties).

Typically, the active inflammation does not persist for the long term, but after the inflammation resolves, people often continue to experience symptoms. These symptoms may be called Rasmussen's syndrome rather than Rasmussen's encephalitis if there is not evidence of active inflammation in the brain.

Rasmussen's syndrome is a long lasting medical condition that persists for years, sometimes after the most intense stages of inflammation of Rasmussen’s encephalitis. Sometimes Rasmussen’s syndrome can occur even if it is unclear whether there ever was Rasmussen’s encephalitis preceding it.

Rasmussen’s syndrome, like Rasmussen’s encephalitis, is characterized by seizures that are difficult to control and that come from one side of the brain. Some people who have Rasmussen's syndrome also experience weakness on one side of the body, language problems, or trouble with cognitive skills.

This condition most commonly affects children between the ages of 2-12 years old, but can affect people at any age.

What Should I Expect?

Generally, the seizures caused by Rasmussen's encephalitis are difficult to control with medication, and often predominantly affect one side of the body. The seizures are usually associated with shaking and jerking of one side of the body, often with loss of consciousness or a decrease in consciousness.

If you have Rasmussen's encephalitis, you might not remember the seizures in detail, and you might feel exhausted afterwards. Weakness, language problems, and cognitive difficulties often start to occur months after the seizures begin, but these symptoms may occur sooner or not at all.

Diagnosis of Rasmussen’s Encephalitis

It may take a long time for you to be given a definitive diagnosis of Rasmussen's encephalitis. This is because there is not a simple test that can confirm this condition.

Rasmussen's encephalitis and Rasmussen's syndrome are diagnosed based on your doctor’s observations of your clinical symptoms over months (or even years) along with EEG testing and brain MRI testing.

An EEG is expected to show seizure activity on one side of the brain. But this EEG pattern is not unique to Rasmussen’s syndrome, and therefore an EEG is not a definitive test, but is used in correlation with your symptoms, your other tests, and your doctor’s observations of your condition.

A brain MRI is expected to show a significant difference between the two sides of the brain. Early in the course of the illness, one side of the brain may show an inflammatory pattern that appears like an infection. Later in the course of the illness, the brain MRI may show atrophy of the affected side, which is actually shrinking of the brain due to the prolonged damage from the inflammation. This brain MRI appearance is not unique to Rasmussen’s encephalitis or Rasmussen’s syndrome, and is considered along with the whole situation in order to reach a conclusion that you have Rasmussen’s syndrome or Rasmussen’s encephalitis.

Treatment and Management

If you have Rasmussen’s encephalitis, you will most likely receive anti-seizure medications to help control your seizures. Sometimes, steroids are used to decrease the inflammation in the brain. If your medical team has reason to believe that you have an infection in your brain (infectious encephalitis), then you may also receive medication to target the infection as well.

If you have seizures or weakness or any other neurological deficit, but no evidence of inflammation, then your treatment is largely going to be targeted to treating your seizures and your neurological deficit.

Sometimes, the epilepsy of Rasmussen’s syndrome is so severe that you may need to have epilepsy surgery. This surgery could involve removal of the affected region of your brain if the disease in a particular region of your brain is found to be causing much of the damage. Often, the surgical procedure produces effects such as partial or complete weakness of one side of the body. Surgical intervention for Rasmussen’s syndrome is very carefully deliberated, and it is only an option if it is expected to improve your overall quality of life.

What Causes Rasmussen’s Encephalitis and Rasmussen’s Syndrome?

Encephalitis is inflammation of the brain. It is unclear what the exact cause of Rasmussen’s encephalitis is. Currently, the medical community has considered two main possibilities:

  1. It may be caused by an infection that triggers a severe immune reaction.
  2. It may be caused by an autoimmune reaction (the body attacking itself).

Unfortunately, because the cause of Rasmussen’s encephalitis is not known, there is no known prevention for this rare disease.

A Word From Verywell

If you or your loved one has an uncommon medical condition such as Rasmussen’s encephalitis or Rasmussen’s syndrome, it can help to meet other people who are living with the same illness. You might be able to get advice and learn through shared experiences if you join a support group and speak to others who can provide guidance and tips as you navigate life with Rasmussen’s syndrome.

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