Demyelinizing disorders

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 Demyelinizing disorders

A demyelinating disease is any disease of the nervous system in which the myelin sheath of neurons is damaged. This damage impairs the conduction of signals in the affected nerves. In turn, the reduction in conduction ability causes deficiency in sensation, movement, cognition, or other functions depending on which nerves are involved. Some demyelinating diseases are caused by genetics, some by infectious agents, some by autoimmune reactions, and some by unknown factors. Organophosphates, a class of chemicals which are the active ingredients in commercial insecticides such as sheep dip, weed-killers, and flea treatment preparations for pets, etc., will also demyelinate nerves. Neuroleptics can also cause demyelination
The spectrum of demyelinating diseases constitutes a group of clinical and imaging entities that present a basis autoimmune immunology where we most frequently found Acute Disseminated Encephalomyelitis (ADEM) in children, followed of Optic Neuritis (NO), Transverse Myelitis (MT), Optic Neuromyelitis (NMO), and Multiple Sclerosis (MS). Objective: Describe the clinical and epidemiological profile of demyelinating diseases in the pediatric age.

A pervasive theme among several articles is the identification of myelin-oligodendrocyte glycoprotein (MOG) antibodies in a variety of forms of demyelinating diseases in children. Although it is becoming clear that MOG antibodies are present in diverse pediatric demyelinating syndromes and appear to predict a non-MS outcome in children with acute demyelinating syndromes, there is still much to be clarified about the clinical significance including diagnostic and prognostic values of these antibodies.
The current knowledge of the demyelinating syndromes optic neuritis (ON), transverse myelitis (TM), and acute disseminated encephalomyelitis (ADEM) are summarized in “Acute disseminated encephalomyelitis: Updates on an inflammatory CNS syndrome,” “Pediatric transverse myelitis,” and “Pediatric optic neuritis.” A major advance is the use of optical coherence tomography in pediatric patients, which demonstrates pathology in non-ON eyes even in the early stages of the disease, signifying early silent tissue injury. ADEM is possibly not a single specific entity, but an inflammatory CNS syndrome with immune-mediated demyelination and strong predilection to young children. TM is a potentially devastating condition with significant cumulative demands on health and social care resources, and ongoing trials will hopefully inform on optimal treatment of TM. Recently, there has been increased recognition that neuromyelitis Optica spectrum disorders occur in children, as summarized in “Neuromyelitis Optica spectrum disorders in children and adolescents.” Further efforts are underway to evaluate the frequency and clinical associations of aquaporin-4 and MOG antibodies in this cohort. “Pediatric acquired CNS demyelinating syndromes: Features associated with multiple sclerosis” highlights clinical and MRI predictors of development of MS after an acute demyelinating syndrome. Common risk factors are age, female sex, presence of brain MRI lesions, and specific lesion features.
“Pediatric multiple sclerosis: Chronic inflammatory autoimmune disease in which, The myelin sheaths around the axons are damaged,leading to: demyelination, axonal loss, neurodegeneration, CNS atrophy, Occurrence in young adults -average age approx.30 years and the onset during childhood or adolescence is increasingly recognized

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