Rasmussen's Encephalitis
Rasmussen's Encephalitis, also Chronic Focal Encephalitis (CFE), is a rare, progressive neurological disorder, characterized by frequent and severe seizures, loss of motor skills and speech, hemiparesis (paralysis on one side of the body), encephalitis (inflammation of the brain), dementia, and mental deterioration. The disorder, which affects a single cerebral hemisphere, generally occurs in children under the age of 10.
What causes RE?
Nobody knows for sure. The pathology (indicators in the brain matter that is removed during a hemispherectomy or biopsy), when positive for RE, indicates there are antibodies in the blood similar to ones our immune systems develop in response to a virus or a cold. Research has discovered, however, that the antibodies that are possibly responsible for RE attack a type of glial cell found in the brain. This would indicate an autoimmune disease, such as Multiple Sclerosis – similar to an allergy, but the immune system is attacking a natural part of the body instead of an allergen. From medical experience, these types of antibodies are different from the type that indicate RE in a pathology report. So at this time, the cause of RE is undetermined and we have few clues to help find a way to discover it. What does seem certain, though, is that the “blood-brain barrier” must be breached/broken some way for the antibodies to be able to attack the brain glial cells. This can happen through a knock on the head or even through a seizure that occurs for an entirely different reason (a spiking fever, for instance).
What are the symptoms of RE?
- RE presents itself with multiple symptoms, not all of which show up in all patients. Every patient is different, although there are enough commonalities to diagnose the disease. The most obvious symptom, and by far the most universal, is seizures. The seizures also present themselves in different forms, from tonic-clonic – the type most commonly imagined by folks who have had no previous experience with seizures that involves the whole body shaking – to things that are easily mistaken for other problems (like vomiting). Yes, unexplained vomiting can be a form of seizure.
- RE is almost always confined to one side of the brain, so once the initial onslaught of seizures is over, patients usually experience just one-sided complex partial seizures involving only a part of the body on just one side – the opposite side of the brain hemisphere that is affected (since movement on each side of the body is controlled by the brain hemisphere opposite to it). So for example, if the diseased hemisphere is the right hemisphere, the left side of the body will be the side with the seizures.
- Epilepsia Partialis Continua often shows up. This is a form of seizure where one limb (arm/hand, leg/foot) or group of muscles (neck, face) twitches continually and rhythmically for relatively long periods of time. Episodes can last a matter of minutes to days, weeks, or even months.
- One-sided paralysis called hemiplegia, and one-sided weakness called hemiparesis, is a very common symptom, although it is important to realize that not all patients are subject to this, especially early in the progress of the disease. Again, this will also be seen on the side of the body opposite the side of the brain affected. Usually it is first noticed in a lack of use of the arm/hand, but then develops into a limp in the leg until finally the whole side will eventually be paralyzed, if the disease is left to run its course.
- Cognitive deterioration, especially in longer-term versions of the disease, causes the patient to lose learning ability.
- Speech ability, especially if the affected hemisphere is the left one, deteriorates.
Who is subject to RE?
RE is most commonly seen in children, especially between the ages of 2 and 12, although there are adult cases and cases where it has been diagnosed earlier than age 2.
How is RE diagnosed?
Some medical centers use a biopsy, usually in conjunction with some sort of scan or grid placement to try to figure out where the seizures are starting out in the brain.
- The presence of any or all of the symptoms listed above gives a good idea that a diagnosis of RE might be indicated.
- A Magnetic Resonance Imaging (MRI) scan of the brain shows spots of atrophy on the affected side.
- An Electro-Encephalograph (EEG) shows all seizures emanating (staring from) the same side of the brain.
Should we get a biopsy done?
Sometimes a biopsy is indicated. MRI’s and EEG’s can be difficult to read, and the visible symptoms of any given case can also be difficult to interpret, especially if it appears both sides are involved in the seizures. HOWEVER, biopsies often come back as inconclusive. A positive result can be taken to be reliable, but a negative result does not necessarily rule out the possibility that the patient has RE. There are a number of reasons for this, but for the patient and family, they should seriously consider this possibility and the risks of a biopsy, which is, after all, brain surgery, before they decide to go forward with one. Many of the larger centers in the U.S. and Canada diagnose the disease without a biopsy.
Why a hemispherectomy? Won’t a less drastic form of surgery work?
RE, at this time, is pretty much invisible in terms of mapping where it has gone in the brain. Similar to cancer in this way, there is no way to see for sure exactly how far the antibodies have attacked in the affected hemisphere and, because they are carried by the blood, they could be all over and just not have caused damage enough to cause a seizure. Many centers still favor a functional hemispherectomy, which leaves small portions of the hemisphere intact, but disconnected from the rest of the brain so there is no communication. There are cases where this approach has been successful, but families considering a hemispherectomy for RE should also be aware that quite often with a functional, seizures return and the patient and family are then faced with the choice of having to do another brain surgery to take out the rest of that hemisphere. Any surgery less than a hemispherectomy has not been successful against RE in the past, that is, it was not effective in stopping seizures or lessening them to a controllable level.
Are there other, non-surgical treatments?
- With varying degrees of success, several other treatments have been tried against RE depending on the patient. None of them has proven to be a permanent solution or “cure.”
- Intravenous Immuno-Globulin (IVIG) is one of the most common alternative treatments. This boosts the immune system temporarily and can provide some relief from seizures. Some patients get no relief from the seizures, however, and in all cases, eventually the treatment gets to the point where it is no longer doing any good.
- Steroids are sometimes used to help control seizures. Again, eventually the seizures return to their previous level and continue to progress.
- Plasmapheresis is a treatment where the blood is “cleansed” of the antibodies causing the problem and returned to the patient. It generally provides dramatic relief in the short-term, but gradually the treatments become less and less effective. It is also a rather long process.
- Chemo-like treatments are still experimental. One study showed promise, but eventually seizures returned. Another study is still ongoing.
- At least one adult case has had good results from a combination of treatments; for adults, hemispherectomy is not considered an option as adult brains cannot adjust as children's brains do and take over lost ability.
When should we have a hemispherectomy?
The major centers in the U.S. strike a balance between the age of the patient and their quality of life. The younger the patient is when the surgery is done, generally the better the recovery. However, if a patient still enjoys a reasonably good quality of life, it is probably better to wait until that changes. This is especially true if the affected hemisphere is the left side, where the language center of the brain is usually located. When one side of the brain is diseased, often the other side will start to take over functions for the diseased side even before it is removed. This is desirable for left-sided hemispherectomies, as it makes speech recovery afterward somewhat easier. The WADA test that some centers do before a hemispherectomy can help determine if that is occurring.
There are special issues with very young patients (under 4 or so), but most major centers with hemispherectomy experience are aware of these and take the proper precautions to mitigate the extra risk.
Are there different “strains” of RE?
Medically, nobody knows. However, there do seem to be at least two different versions – one slow and one quick. Some patients have had to go to surgery in a matter of months, or occasionally weeks, from onset of seizures, while others wait years before their quality of life is impacted severely enough that a decision to have a hemispherectomy becomes a consideration. A couple of patients have even survived to adulthood without surgery.
How rare is RE?
Unofficially, (I don’t think anyone’s done an official check) there are probably somewhere between 200 and 500 cases worldwide. It’s hard to measure, as RE tends to only be reported and diagnosed in developed countries. In the U.S and Canada, since 1958, there have probably been something like 200 cases diagnosed.
