![]() In a small proportion (reported figures range from 10-20% 12) the course is more fulminant, frequently resulting in death. Treatment typically consists of methylprednisolone, with immunoglobulin and cyclophosphamide reserved for patients refractory to steroids 4.Ĭomplete recovery within one month is the most common outcome (50-60%), with sequelae (most commonly seizures) seen in a significant proportion of cases (20-30%). Magnetization transfer may help distinguish acute disseminated encephalomyelitis from multiple sclerosis, in that normal-appearing brain (on T2-weighted images) has normal magnetization transfer ratio and normal diffusivity, whereas in multiple sclerosis both measurements are significantly decreased 3. cerebral abscess), nor does it demonstrate absent signal on DWI as one would expect from a cyst this is due to increase in extracellular water in the region of demyelination T1 C+ (Gd): punctate, ring or arc enhancement ( open ring sign) is often demonstrated along the leading edge of inflammation absence of enhancement does not exclude the diagnosisĭWI: there can be peripherally restricted diffusion the center of the lesion, although high on T2 and low on T1, does not have increased restriction on DWI (cf. T2: regions of high signal, with surrounding edema typically situated in subcortical locations the thalami and brainstem can also be involved MRI is far more sensitive than CT and demonstrates lesions characteristic of demyelination: The lesions are usually indistinct regions of low density within the white matter and may demonstrate ring enhancement. The most accepted criteria for differentiation in children are the Callen MS-ADEM criteria 13,14. The spinal cord may show confluent intramedullary lesions with variable enhancement, but these are only seen in approximately one-third of cases 12.ĭespite the clinical and radiological differences mentioned above, it is frequently difficult to differentiate between acute disseminated encephalomyelitis and MS at first presentation. In addition to lesions involving grey matter, antibodies to basal ganglia can also develop, especially in the setting of post-streptococcal pharyngitis, resulting in more diffuse involvement 11,12. Involvement of cerebral cortex, subcortical grey matter - especially the thalami - and the brainstem is not very common, but if present are helpful in distinguishing from multiple sclerosis 4,12. Lesions are usually bilateral but asymmetrical. Compared to multiple sclerosis, involvement of the callososeptal interface is unusual. MarkersĬerebrospinal fluid may show an increase in myelin basic proteinĪppearances vary from small punctate lesions to tumefactive regions, which have less mass effect than one would expect for their size, distributed in the supratentorial or infratentorial white matter. However, multiple sclerosis typically presents confluent sheets of macrophage infiltration mixed with reactive astrocytes in completely demyelinated regions 9. The pathological hallmark is perivenular inflammation with limited ‘‘sleeves of demyelination", which is also a feature of multiple sclerosis. In approximately half of all confirmed cases, anti-MOG (myelin oligodendrocyte glycoprotein) immunoglobulin G antibodies can be identified (see MOGAD) 12,15. PathologyĪcute disseminated encephalomyelitis is thought to occur from a cross-reactivity in immunity to viral antigens, triggering a subsequent autoimmune attack on the CNS. Unlike multiple sclerosis, symptoms are more systemic rather than focal and include fever, headache, decreased level of consciousness varying from lethargy to coma, seizure, and multifocal neurologic symptoms such as hemiparesis, cranial nerve palsies, and movement disorders behavioral changes like depression, delusions, and psychosis may dominate the symptoms 3. ![]() In 10% of cases, relapse within the first three months is encountered 12. Clinical presentationĪcute disseminated encephalomyelitis is usually a monophasic illness, although, within the episode, individual lesions may be of varying stages of evolution, with different lesions maturing over a number of weeks 4. multiple sclerosis or neuromyelitis optica), acute disseminated encephalomyelitis has no female predilection if anything, there is slight male predominance 12. Unlike many other demyelinating diseases (e.g. Less than 5% of all acute disseminated encephalomyelitis cases follow an immunisation 8. Winter and spring seasonal peaks in the presentation have been observed in some studies, supporting the infectious etiology hypothesis 9. However, cases have been reported in all ages 12. Typically, acute disseminated encephalomyelitis presents in children or adolescents (usually younger than 15 years of age).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |