Rasmussen encephalitis represents a very rare form of noninfectious inflammation in the cerebral cortex. An autoimmunologic process of development is suspected. The disease usually occurs in children and is almost always fatal if untreated.
What is Rasmussen encephalitis?
Rasmussen encephalitis is named after Canadian neurologist Theodore Rasmussen. Rasmussen introduced surgical methods to cure epileptic diseases and, in this context, also dealt with the inflammatory disease of the cerebral cortex named after him. In English, Rasmussen’s encephalitis is also known as chronic focal encephalitis or CFE. This term refers to chronic focal encephalitis. According to it, the disease starts with a small focal inflammation in a certain limited, small area of the brain and from there it spreads more and more to the adjacent brain tissue. Usually, only one brain hemisphere is affected. In the vast majority of cases, the inflammation does not spread to the opposite hemisphere of the brain. The disease is always associated with an irreversible loss of nerve cells. It leaves scars and leads to death if left untreated. Even after treatment, affected individuals sometimes suffer from severe lifelong disabilities, depending on the extent of the inflammatory processes. In most cases, Rasmussen’s encephalitis occurs for the first time in children under the age of ten. In rare cases, however, the first symptoms of the disease are not found until adolescents reach puberty or even adults. Overall, the disease is very rare. For example, 50 new cases are registered in Germany every year. A prevalence of one to two persons per 1000,000 is assumed.
Causes
The cause of Rasmussen encephalitis is thought to be an autoimmunologic process. So-called CD8 T cells play a special role in this process. CD8 T cells are T cells with an additional CD8 receptor protein in the cell membrane. The CD8 receptor represents a so-called coreceptor of the T cell receptor. Through the CD8 receptors, cytotoxic T cells recognize foreign protein structures and stimulate an immune response, as a result of which the antigen-presenting cells are destroyed. It has now been recognized that CD8 T cells specifically select cells with certain antigen structures and destroy them. It has not yet been possible to determine which structures these are. It is not clear, for example, whether these structures are viral in nature or based on the body’s own proteins. In the case of Rasmussen’s encephalitis, the CD8 T cells attack and destroy nerve cells and astrocytes. The CD8 T cells proliferate very strongly and can still be detected in the blood for years. They enter the brain via the blood-brain barrier and attach themselves to nerve cells and astrocytes. There they specifically destroy cells with a certain antigen structure. Once cell destruction has begun, this process can no longer be stopped. The inflammation progresses and leads to the destruction of further areas of the affected brain hemisphere. So far, even immunosuppressants have only been able to attenuate the inflammation, but they have still been able to stop it.
Symptoms, complaints, and signs
Rasmussen encephalitis usually begins with focal epileptic seizures. In this case, the seizures are localized to one side of the body. Later, neurologic impairments progressively develop, including hemiplegia, visual disturbances, speech disorders, and mental retardation. The epileptic seizures may later become generalized (grand mal). In rare cases, both cerebral hemispheres are eventually affected, resulting in bilateral absence symptoms. If no treatment is given, the prognosis of the disease is very poor. Ultimately, it then always ends lethally. Treatment leads to better prognosis. However, depending on the extent of damage already done to the brain, severe physical and mental disabilities may sometimes remain.
Diagnosis and course of the disease
Imaging techniques such as MRI examination, EEG, and histologic examination of brain tissue may be used to diagnose Rasmussen encephalitis. EEG is concerned with localizing the area of the brain that triggers seizures. Histological examination of brain tissue is used for differential diagnosis to exclude infectious causes of encephalitis.
Complications
Severe complications invariably occur during the course of Rasmussen encephalitis. Neurologic impairments such as hemiplegia and mental retardation are typical of the disease. As the disease progresses, visual and speech impairments and epileptic seizures also increase. During severe seizures, patients often bite their lips and tongue bloody and suffer from severe twitching of the arms and legs. In most cases, patients also suffer psychologically from the symptoms – anxiety disorders, depression or inferiority complexes occur. If Rasmussen’s encephalitis is not treated, it is always fatal. Beforehand, severe brain damage usually sets in, which in the further course leads to deficits, pain and finally to coma. Various side effects and interactions can occur during treatment with immunosuppressants. Possible complaints include fluctuations in blood pressure, increased blood lipid levels and muscle weakness. In addition, late effects such as diabetes mellitus, osteoporosis and damage to the kidneys and liver can occur. In the long term, cardiovascular diseases and the development of tumors of the skin and lymph nodes may also occur. Similar risks are associated with concomitantly prescribed antiepileptic drugs and glucocorticoids. Brain surgery can cause severe complications.
When should you see a doctor?
Patients who have already been diagnosed with Rasmussen encephalitis should seek medical attention. Unless there is a diagnosis, some clues exist on the basis of which a visit to the doctor is advisable. If an affected person has convulsions, it is advisable to see a doctor or a neurologist straight away. He or she can first clarify the cause of the seizure and secondly prescribe appropriate medication to alleviate the general susceptibility to seizures on the one hand and an on-demand medication to provide relief in the event of acute seizures on the other. Apart from the most obvious sign, however, it is also advisable to pay attention to changes in everyday life and, if necessary, to take these as an occasion for a visit to the doctor. For example, a reduction in vision or slurred, halting speech may already be signs of Rasmussen’s encephalitis. An accumulation of cognitive difficulties is also a warning signal that should be clarified by a doctor. Once the disease has been diagnosed, the doctor should be visited regularly so that the medication can be adjusted. Blood tests and, if necessary, EEG’s are necessary for optimal medication adjustment.
Treatment and therapy
To date, there is no clear treatment recommendation for Rasmussen encephalitis. Treatment is often very difficult, especially since the disease progresses inexorably. Attempts are made to stop the encephalitis with a combination therapy of immunosuppressants. Combinations of immunoglobulins, high-dose glucocorticoids and tacrolimus, among others, are administered for this purpose. The inflammation can probably be attenuated, but the disease still progresses. Treatment of the epileptic seizures is also very difficult. Initially, it is a symptomatic treatment that has no effect on the course of Rasmussen’s encephalitis. However, it has also been noted that even the antiepileptic drugs used so far have brought little progress in the control of epilepsy. Real curative success, however, is opened up by surgical therapy. This involves removing the affected section of the cerebral hemisphere. In severe generalized cases, however, the entire affected hemisphere of the brain must be removed to prevent the disease from spreading to the entire brain. Without surgery, the prognosis of the disease is always poor. After surgery, the course of Rasmussen’s encephalitis can be stopped. Whether and what disabilities remain depends on how far the disease had already progressed and how the child’s brain is able to compensate for severe damage again through regeneration. Medical research is focused on finding effective drugs that can stop the progression of the disease even without surgical intervention.
Prevention
There is currently no recommendation for prophylaxis of Rasmussen encephalitis. To date, the cause of the disease has not been fully elucidated.
Follow-up
Rasmussen’s encephalitis causes disturbances in motor function and paralysis.In severe cases, secondary damage remains in the affected area of the brain; if left untreated, the disease leads to death. For this reason, follow-up care is necessary. A recurrence of the symptoms must be avoided in the long term. During follow-up, the patient’s condition is monitored, and the duration depends on the extent of the disease. A neurologist performs the aftercare during regular examinations. The effect of the administered drugs is determined, side effects must be detected and averted in time. In the case of severe disease progression, brain surgery is necessary. During aftercare, the healing process is monitored by a doctor, and after discharge, the specialist continues the checks. The goal is successful elimination of encephalitis without late consequences. If the inflammation has already caused physical or mental limitations, the patient receives support in everyday life. These measures are also part of aftercare. The affected person learns how to deal appropriately with the new situation. In addition to the specialist, it is advisable to visit an appropriate counseling center. Severe disabilities require professional help from trained personnel. During aftercare, the patient receives professional care.
What you can do yourself
There is limited support available for the treatment of Rasmussen syndrome. Sufferers must learn a healthy way to cope with the disease, which can be done through literature and documentation, as well as by visiting a specialist center for neurological disorders. Participation in self-help groups and conversation with other sufferers are important measures to facilitate coping with the disease. Drug treatment may be supported by various general measures such as exercise or a change in diet. Natural remedies can also bring relief. However, the use of alternative medicine should be discussed with the doctor beforehand to rule out complications. Sufferers are best advised to visit an alternative practitioner or a well-stocked drugstore to find the appropriate medicines for their symptoms. Antiepileptic treatment is primarily to be supported by attentive observation of the sufferer, because then prompt action can be taken in the event of a seizure. In the long term, Rasmussen’s encephalitis patients must be treated as inpatients. Self-help measures are no longer effective in the later stages of the disease. However, family members and friends provide important support for those affected.
