Acute demyelinating encephalomyelitis (ADEM)Acute demyelinating encephalomyelitis (ADEM) is an inflammatory disease that affects the myelin sheaths of the nerves in the brain and spinal cord and occurs mainly in children.
What is acute demyelinating encephalomyelitis??
In the brain, spinal cord and nerves outside the central nervous system, the nerve fibers are surrounded by a protective sheath called the myelin sheath. In the rare disease ADEM, these same myelin sheaths in the brain become. Spinal cord damaged by inflammation.
Nerve cell with myelin sheath
Prior to acute demyelinating encephalomyelitis, affected individuals often had a viral illness, such as.B. pharyngitis. ADEM probably develops as a result of a transient autoimmune reaction, d. h. the body's defense system mistakenly attacks its own tie. The designation as "acute" and "disseminated" means that the disease usually occurs relatively quickly and can cause a variety of disease symptoms when it affects different parts of the nervous system.
ADEM affects children under 10 years of age in about 80% of cases, and rarely affects adults. In children, viral infections, which are thought to be the trigger, are particularly common. This also explains the increased occurrence in the winter months. In the U.S., it is estimated that there are approximately 3 new cases per 100.000 inhabitants under 10 years of age.
Since children today are vaccinated against the most serious viral diseases (z. B. measles, mumps, rubella), the number of virus-related diseases has fallen sharply. ADEM can also occur as a result of vaccination, but this is rare.
The risk of developing ADEM is influenced by hereditary factors, frequent viral infections, vaccination status, diet, and other less well-known factors.
Acute demyelinating encephalomyelitis is an inflammatory reaction that damages the myelin sheath surrounding nerve fibers (demyelinates). At first glance, the disease looks very similar to multiple sclerosis (MS), because here, too, antibodies of the body's immune system temporarily attack the myelin sheaths. However, while this occurs only temporarily in ADEM and usually heals without consequence after a single period of illness, MS often recurs in relapses over and over again, which over time can lead to significant damage to the nervous system.
The patient, usually a child, often had a preceding infectious disease. ADEM typically occurs one to 20 days after this infection, which is usually febrile. The onset of the disease is usually rapid and characterized by irritability, headache, fatigue, and mental changes (confusion, striking apathy, passivity). The onset of the disease is often accompanied by fever. There are almost always multiple neurological symptoms originating from different parts of the brain and spinal cord, such as decreased sensation in the arm with lack of bladder control. The patient's condition worsens for several days, in rare cases for up to six weeks.
In older children, ADEM may be difficult to distinguish from the first episode of multiple sclerosis (MS) in some cases. However, it is uncommon for MS to present with multiple neurological symptoms at its first onset. Similarly, neck stiffness, headaches, lightheadedness and cramps are uncommon in MS.
The diagnosis is made on the basis of the typical course of the disease and the findings of the medical examination, a nerve fluid examination and MRI. Even in the early stages, this MRI scan can show typical changes in 80 to 90 % of those affected.
Nerve fluid testing and MRI are also important to rule out other causes of symptoms.
The disease heals completely in most patients within 2-4 weeks even without treatment. Nevertheless, steroids (or cortisone preparations) are often given in high dosages for a short time in order to influence the course favorably. In the absence of response, intravenous immunoglobulins are occasionally used.
The prognosis of ADEM is very good. The majority of those affected show a complete recovery. The prognosis does not seem to depend on the severity of the disease, because complete recoveries have been observed even in children who were in a coma in the meantime. About one in three children with signs of nerve damage will have this damage for weeks or months. In most cases, however, these failures disappear within a year of the onset of the disease.
In a few sufferers, the disease causes permanent nerve damage, which can manifest itself in paralysis or epilepsy. In less than 2% of cases, the disease can be fatal.
Relapses occur in about 5% of those affected. Such relapses arouse the suspicion that MS could also be the cause. However, the risk of MS in children who had ADEM before puberty is hardly higher than that of other children. In children with several relapses before puberty or in older patients this risk increases accordingly.