Acute disseminated encephalomyelitis is a disease in which inflammation occurs in the central nervous system (CNS). Acute disseminated encephalomyelitis most often follows a viral disease (such as smallpox or rubella) and usually affects children. The disease may have consequences in the form of various dysfunctions of the nervous system. What are the causes and symptoms of acute disseminated encephalomyelitis? What is the treatment?

Acute Disseminated Encephalomyelitis (ADEM) is a disease of the nervous system that causes inflammation and demyelination, i.e. damage the sheaths of nerve cells in various parts of the brain and spinal cord.

Acute disseminated encephalomyelitis is extremely rarely diagnosed and is much more common in children and adolescents than in adults. In the group of children under the age of 16, most, 72%, cases of the disease are diagnosed before the age of 10.

In addition, it is known that acute disseminated encephalomyelitis is very difficult to distinguish from multiple sclerosis (MS), especially since ADEM and MS can be consecutive.

Acute disseminated encephalomyelitis - causes

The causes of acute disseminated encephalomyelitis are unclear, and research has shown that it is usually not possible to identify the direct causative agent of the disease.

Half of the patients have previous non-specific infections of the upper respiratory tract.

However, it is supposed that ADEM may be related to:

  • viral diseases (measles, chickenpox, rubella, herpes, mumps, mononucleosis, cytomegaly, flu);
  • bacterial infections (group A and B streptococcus, tuberculosis, mycoplasma, brucellosis);
  • protective vaccinations (against: rabies, chicken pox, influenza, measles, hepatitis A, yellow fever);

Sometimes symptoms of the disease may appear after administration of anti-tetanus serum or after being bitten by insects.

Then the immune system responds, which is directed against the body's own, normal cells, i.e.the influence of a foreign antigen (e.g. virus, bacteria) produces antibodies that attack the components of myelin (the sheath surrounding nerve fibers), which leads to their damage and the development of ADEM.

Acute disseminated encephalomyelitis - symptoms

ADEM usually occurs several weeks (one to three) after having a viral or bacterial disease, vaccination, or ingestion of an immune serum or insect bite. Then suddenly they appear:

  • fever,
  • headaches,
  • vomiting,
  • meningeal irritation.

Then they are joined by: mood disorders, somnolence (which can lead to coma of varying severity), convulsions and focal neurological symptoms (paresis, speech disorders), as well as extrapyramidal syndromes - tremors, chorea, dystonia (occurrence of involuntary movements causing twisting and flexing various parts of the body).

Important

In most cases, the sick person recovers (only in 10-15% of cases it ends in death). Unfortunately, the disease usually has consequences in the form of focal neurological symptoms, e.g. epileptic seizures or behavioral disorders may persist.

Post-respiratory disseminated encephalomyelitis, which usually develops as early as 2-7 days after the onset of the skin rash, very rapidly, has been described separately. Then the number of neurological symptoms is very wide and includes brain and cerebellar syndromes (gait disturbances and ataxia ataxia; additionally, chanted speech, nystagmus are common), as well as spinal symptoms (paralysis of the lower limbs and dysfunction of the bladder and intestines) and neuritis visual. However, in this case, extra-pyramidal syndromes (tremor, chorea, dystonia or muscle stiffness) are less common. In this case, the mortality rate ranges from 10-20 percent.

With chickenpox, seizures appear - usually 2-8 days after the first symptoms of the disease. Then there are very extensive cerebral and spinal symptoms. There may be hemiparesis, choreo-athetotic syndromes, and cerebellar symptoms. Fortunately, the prognosis is better than for many other viral diseases leading to ADEM. Moreover, the disease does not have any serious consequences for the nervous system.

ADEM after rubella is rare, and symptoms appear early, sometimes as early as 3-4 days after the onset of the disease. In this case, cerebrospinal symptoms were also reported. The disease is generally successful, with little lasting effects.

Acute disseminated encephalomyelitis - diagnosis

The disease is difficult to diagnose andit mainly requires differentiation from multiple sclerosis. In this case, nuclear magnetic resonance imaging is used (it is the most helpful test). Acute disseminated encephalomyelitis is diagnosed on the basis of characteristic changes in the CNS. These changes may concern the gray matter of the cerebral hemispheres, but mainly the subcortical white matter, basal ganglia, diencephalon, brain stem, cerebellum and spinal cord.

Acute disseminated encephalomyelitis - treatment

The patient goes to the intensive care unit, where he is administered corticosteroids (usually leads to full recovery). In the most severe cases, plasmapheresis is used.

In addition, doctors try to hydrate the patient and fight complications such as bacterial infections of the respiratory and urinary tract. Anticonvulsants must be taken when seizures occur. If a significant increase in intracranial pressure is noted, anti-oedematous treatment is required.

Acute multiple encephalomyelitis and multiple sclerosis

Both ADEM and MS are diseases that lead to autoimmune demyelination of the brain, so there is still some debate as to whether they are different diseases. However, some specialists argue that they are two separate disease entities that are significantly different from each other. There is no genetic predisposition in ADEM. In addition, the disease course and imaging results for both conditions are different - in ADEM the lesions are more extensive (in MS they are delimited), and the gray matter is often involved. The lesions are much larger than those typically found in MS. In addition, the lesions affect several segments of the spine, which are characteristic of ADEM, and almost never occur in MS. Additionally, multiple sclerosis is usually a relapsing and remitting disease of young adults, while ADEM is usually a monophasic disease of children.

Bibliography:

1. Gołąbek V., Woźniakowska-Gęsicka T., Sokołowska D.,Acute disseminated encephalomyelitis in children as a consequence of sterile meningitis - two case reports , "Neurology and Neurosurgery Poland "2011, No. 22.Acute disseminated encephalomyelitis (ADEM) ," Practical Neurology "[access: 29.12.2014]. Available on the Internet: http://www.neurologia-praktyczna.pl/a1323/Ostre-rozsiane-zaprzał-mozgu-i-rdzia--ADEM-.html/m3053. Poser Ch., Brinar V.,Diffuse encephalomyelitis and multiple sclerosis; two different diseases - a critical look "Polish Neurological Review" 2008, vol. 4, no. 4

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Neurology