Acute disseminated encephalomyelitis (ADEM) is an immune mediated disease of the brain. It usually occurs following a viral infection but may appear following vaccination, bacterial or parasitic infection, or even appear spontaneously. As it involves autoimmune demyelination, it is similar to multiple sclerosis, and is considered part of the Multiple sclerosis borderline diseases. 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%, full recovery is seen in 50 to 75% of cases, while up to 70 to 90% recover with some minor residual disability. The average time to recover 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, it is called recurrent disseminated encephalomyelitis or multiphasic disseminated encephalomyelitis(MDEM).
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 small pox 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,
Acute hemorrhagic leukoencephalitis 
Acute hemorrhagic leukoencephalitis (AHL, or AHLE), also known as acute necrotizing encephalopathy (ANE), acute hemorrhagic encephalomyelitis (AHEM), acute necrotizing hemorrhagic leukoencephalitis (ANHLE), Weston-Hurst syndrome, or Hurst's disease, is a hyperacute and frequently fatal form of ADEM. AHL is relatively rare (less than 100 cases have been reported in the medical literature as of 2006), it is seen in about 2% of ADEM cases, and is characterized by necrotizing vasculitis of venules and hemorrhage, and edema. Death is common in the first week and overall mortality is about 70%, but increasing evidence points to favorable outcomes after aggressive treatment with corticosteroids, immunoglobulins, cyclophosphamide, and plasma exchange. About 70% of survivors show residual neurological deficits, but some survivors have shown surprisingly little deficit considering the magnitude of the white matter affected. This disease has been occasionally associated with ulcerative colitis and Crohn's disease, malaria, septicemia associated with immune complex deposition, methanol poisoning, and other underlying conditions.
Experimental allergic encephalomyelitis 
Experimental allergic encephalomyelitis (EAE) is an animal model of CNS inflammation and demyelination frequently used to investigate potential MS treatments. An acute monophasic illness, EAE is far more similar to ADEM than MS.
See also 
- ^ Dale RC (April 2003). "Acute disseminated encephalomyelitis". Semin Pediatr Infect Dis 14 (2): 90–5. doi:10.1053/spid.2003.127225. PMID 12881796.
- ^ Garg RK (January 2003). "Acute disseminated encephalomyelitis". Postgrad Med J 79 (927): 11–7. doi:10.1136/pmj.79.927.11. PMC 1742586. PMID 12566545.
- ^ Jones CT (November 2003). "Childhood autoimmune neurologic diseases of the central nervous system". Neurol Clin 21 (4): 745–64. doi:10.1016/S0733-8619(03)00007-0. PMID 14743647.
- ^ Huynh W, Cordato DJ, Kehdi E, Masters LT, Dedousis C (Dec 2008). "Post-vaccination encephalomyelitis: literature review and illustrative case". J Clin Neurosci 15 (12): :1315–1322. doi:10.1016/j.jocn.2008.05.002. PMID 18976924.
- ^ Rust RS (June 2000). "Multiple sclerosis, acute disseminated encephalomyelitis, and related conditions". Semin Pediatr Neurol 7 (2): 66–90. doi:10.1053/pb.2000.6693. PMID 10914409.
- ^ Poser CM, Brinar VV (October 2007). "Disseminated encephalomyelitis and multiple sclerosis: two different diseases - a critical review". Acta Neurol. Scand. 116 (4): 201–6. doi:10.1111/j.1600-0404.2007.00902.x. PMID 17824894.
- ^ a b Leake JA, Albani S, Kao AS, et al. (August 2004). "Acute disseminated encephalomyelitis in childhood: epidemiologic, clinical and laboratory features". Pediatr. Infect. Dis. J. 23 (8): 756–64. doi:10.1097/01.inf.0000133048.75452.dd. PMID 15295226.
- ^ Hynson JL, Kornberg AJ, Coleman LT, Shield L, Harvey AS, Kean MJ (May 2001). "Clinical and neuroradiologic features of acute disseminated encephalomyelitis in children". Neurology 56 (10): 1308–12. doi:10.1212/WNL.56.10.1308. PMID 11376179.
- ^ Anlar B, Basaran C, Kose G, et al. (August 2003). "Acute disseminated encephalomyelitis in children: outcome and prognosis". Neuropediatrics 34 (4): 194–9. doi:10.1055/s-2003-42208. PMID 12973660.
- ^ Schwarz S, Mohr A, Knauth M, Wildemann B, Storch-Hagenlocher B (May 2001). "Acute disseminated encephalomyelitis: a follow-up study of 40 adult patients". Neurology 56 (10): 1313–8. doi:10.1212/WNL.56.10.1313. PMID 11376180.
- ^ Menge T, Kieseier BC, Nessler S, Hemmer B, Hartung HP, Stüve O (June 2007). "Acute disseminated encephalomyelitis: an acute hit against the brain". Curr. Opin. Neurol. 20 (3): 247–54. doi:10.1097/WCO.0b013e3280f31b45. PMID 17495616.
- ^ Wingerchuk DM (May 2003). "Postinfectious encephalomyelitis". Curr Neurol Neurosci Rep 3 (3): 256–64. doi:10.1007/s11910-003-0086-x. PMID 12691631.
- ^ Poser CM (May 2008). "Multiple sclerosis and recurrent disseminated encephalomyelitis are different diseases". Arch. Neurol. 65 (5): 674; author reply 674–5. doi:10.1001/archneur.65.5.674-a. PMID 18474749.
- ^ Dale RC, de Sousa C, Chong WK, Cox TC, Harding B, Neville BG (December 2000). "Acute disseminated encephalomyelitis, multiphasic disseminated encephalomyelitis and multiple sclerosis in children". Brain 123 (12): 2407–22. doi:10.1093/brain/123.12.2407. PMID 11099444.
- ^ a b Tenembaum S, Chitnis T, Ness J, Hahn JS (April 2007). "Acute disseminated encephalomyelitis". Neurology 68 (16 Suppl 2): S23–36. doi:10.1212/01.wnl.0000259404.51352.7f. PMID 17438235.
- ^ Hemachudha T, Griffin DE, Giffels JJ, Johnson RT, Moser AB, Phanuphak P (February 1987). "Myelin basic protein as an encephalitogen in encephalomyelitis and polyneuritis following rabies vaccination". N. Engl. J. Med. 316 (7): 369–74. doi:10.1056/NEJM198702123160703. PMID 2433582.
- ^ Hemachudha T, Griffin DE, Johnson RT, Giffels JJ (January 1988). "Immunologic studies of patients with chronic encephalitis induced by post-exposure Semple rabies vaccine". Neurology 38 (1): 42–4. doi:10.1212/WNL.38.1.42. PMID 2447520.
- ^ a b Murthy JM (September 2002). "Acute disseminated encephalomyelitis". Neurol India 50 (3): 238–43. PMID 12391446.
- ^ a b c Tenembaum S, Chamoles N, Fejerman N (October 2002). "Acute disseminated encephalomyelitis: a long-term follow-up study of 84 pediatric patients". Neurology 59 (8): 1224–31. doi:10.1212/WNL.59.8.1224. PMID 12391351.
- ^ Fenichel GM (August 1982). "Neurological complications of immunization". Ann. Neurol. 12 (2): 119–28. doi:10.1002/ana.410120202. PMID 6751212.
- ^ Takahashi H, Pool V, Tsai1 TF, Chen RT (July 2000). "Adverse events after Japanese encephalitis vaccination: review of post-marketing surveillance data from Japan and the United States. The VAERS Working Group". Vaccine 18 (26): 2963–9. doi:10.1016/S0264-410X(00)00111-0. PMID 10825597.
- ^ Tourbah A, Gout O, Liblau R, et al. (July 1999). "Encephalitis after hepatitis B vaccination: recurrent disseminated encephalitis or MS?". Neurology 53 (2): 396–401. doi:10.1212/WNL.53.2.396. PMID 10430433.
- ^ Karaali-Savrun F, Altintaş A, Saip S, Siva A (November 2001). "Hepatitis B vaccine related-myelitis?". Eur. J. Neurol. 8 (6): 711–5. doi:10.1046/j.1468-1331.2001.00290.x. PMID 11784358.
- ^ Sejvar JJ, Labutta RJ, Chapman LE, Grabenstein JD, Iskander J, Lane JM (December 2005). "Neurologic adverse events associated with smallpox vaccination in the United States, 2002-2004". JAMA 294 (21): 2744–50. doi:10.1001/jama.294.21.2744. PMID 16333010.
- ^ Ozawa H, Noma S, Yoshida Y, Sekine H, Hashimoto T (August 2000). "Acute disseminated encephalomyelitis associated with poliomyelitis vaccine". Pediatr. Neurol. 23 (2): 177–9. doi:10.1016/S0887-8994(00)00167-3. PMID 11020647.
- ^ a b Davies NW, Sharief MK, Howard RS (July 2006). "Infection-associated encephalopathies: their investigation, diagnosis, and treatment". J. Neurol. 253 (7): 833–45. doi:10.1007/s00415-006-0092-4. PMID 16715200.
- ^ a b Stone MJ, Hawkins CP (2007). "A medical overview of encephalitis". Neuropsychol Rehabil 17 (4–5): 429–49. doi:10.1080/09602010601069430. PMID 17676529.
- ^ a b Archer H, Wall R (February 2003). "Acute haemorrhagic leukoencephalopathy: two case reports and review of the literature". J. Infect. 46 (2): 133–7. doi:10.1053/jinf.2002.1096. PMID 12634076.
- ^ Venugopal V, Haider M (2013) First case report of acute hemorrhagic leukoencephalitis following Plasmodium vivax infection. Indian J Med Microbiol 31(1):79-81. doi: 10.4103/0255-0857.108736.
- ^ Rivers TM, Schwentker FF (1935). "Encephalomyelitis accompanied by myelin destruction experimentally produced in monkeys". J. Exp. Med. 61 (5): 689–701. doi:10.1084/jem.61.5.689. PMC 2133246. PMID 19870385.
- ^ Sriram S, Steiner I (December 2005). "Experimental allergic encephalomyelitis: a misleading model of multiple sclerosis". Ann. Neurol. 58 (6): 939–45. doi:10.1002/ana.20743. PMID 16315280.
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