|
Acute disseminated encephalomyelitis (ADEM) (or acute demyelinating encephalomyelitis) is a rare autoimmune disease marked by a sudden, widespread attack of inflammation in the brain and spinal cord. ADEM also attacks the nerves of the central nervous system and damages their myelin insulation, which, as a result, destroys the white matter. It is often triggered after the patient has received a viral infection or vaccination. ADEM's symptoms resemble the symptoms of multiple sclerosis (MS), so the disease itself is sorted into the classification of the multiple sclerosis borderline diseases. However, ADEM has several features that distinguish it from MS.〔Lauren B. Krupp et al. Consensus definitions proposed for pediatric multiple sclerosis and related disorders, 2007 by AAN Enterprises, Inc. ()〕 Unlike MS, ADEM occurs usually in children and is marked with rapid fever, although adolescents and adults can get the disease too. ADEM consists of a single flare-up whereas MS is marked with several flare-ups over a long period of time. ADEM is also distinguished by a loss of consciousness, coma and death, which is very rare in MS, except in severe cases. The incidence rate is about 8 per 1,000,000 people per year. Although it occurs in all ages, most reported cases are in children and adolescents, with the average age around 5 to 8 years old. The mortality rate may be as high as 5%; however, full recovery is seen in 50 to 75% of cases with increase in survival rates up to 70 to 90% with figures including minor residual disability as well. The average time to recover from ADEM flare-ups is one to six months. ADEM produces multiple inflammatory lesions in the brain and spinal cord, particularly in the white matter. Usually these are found in the subcortical and central white matter and cortical gray-white junction of both cerebral hemispheres, cerebellum, brainstem, and spinal cord, but periventricular white matter and gray matter of the cortex, thalami and basal ganglia may also be involved. When the patient suffers more than one demyelinating episode of ADEM, the disease is then called recurrent disseminated encephalomyelitis or multiphasic disseminated encephalomyelitis(MDEM). Also a fulminant course in adults has been described〔Franziska Di Pauli et al. Fulminant demyelinating encephalomyelitis, Neurol Neuroimmunol Neuroinflamm December 2015 vol. 2 no. 6 e175, doi: http://dx.doi.org/10.1212/NXI.0000000000000175〕 ==Causes and antecedent history== Viral infections thought to induce ADEM include influenza virus, enterovirus, measles, mumps, rubella, varicella zoster, Epstein Barr virus, cytomegalovirus, herpes simplex virus, hepatitis A, and coxsackievirus; while the bacterial infections include Mycoplasma pneumoniae, Borrelia burgdorferi, Leptospira, and beta-hemolytic Streptococci. The only vaccine proven to induce ADEM is the Semple form of the rabies vaccine, but hepatitis B, pertussis, diphtheria, measles, mumps, rubella, pneumococcus, varicella, influenza, Japanese encephalitis, and polio vaccines have all been implicated. The majority of the studies that correlate vaccination with ADEM onset use small samples or case studies. Large scale epidemiological studies (e.g., of MMR vaccine or smallpox vaccine) do not show increased risk of ADEM following vaccination.〔 In rare cases, ADEM seems to follow from organ transplantation.〔 The risk of ADEM from measles vaccination is about 1 to 2 per million,〔 which is far lower than the risk of developing ADEM from an actual measles infection, which is about 1 per 1000 for measles (and 1 per 5000 for rubella).〔 Some vaccines, later shown to have been contaminated with host animal CNS tissue, have ADEM incident rates as high as 1 in 600.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「acute disseminated encephalomyelitis」の詳細全文を読む スポンサード リンク
|