Saturday, September 3, 2011

Acute disseminated encephalomyelitis (ADEM)

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Acute disseminated encephalomyelitis (ADEM) is an immune mediated disease involving the nervous system in which there is de-myelination of the nerves. It usually occurs after an infection of viral, bacterial or parasitic in origin or vaccination or sometimes spontaneously.

                                                            MRI differances in ADEM


The autoimmune response produce inflammatory lesions in the brain and spinal cord and is somewhat similar to multiple sclerosis. The areas involved are usually, in the white matter of the brain and spinal cord.


Incidence


Acute disseminated encephalomyelitis (ADEM) affects 8 per 1,000,000 people per year. Children and adolescents are more affected. There is a 5% mortality rate and in 50 to 75% cases there is complete recovery from the disease. Recovery is complete within 6 months of treatment.


Causes


Viral infections: enterovirus, measles, rubella, influenza virus, mumps, varicella zoster, cytomegalovirus, herpes simplex virus, coxsackievirus and hepatitis A

Bacterial infections: Mycoplasma pneumonia, leptospira, borrelia burgdorferi and beta haemolytic streptococci.

Vaccination: Semple form of rabies, Hepatitis B vaccine, Pertussis vaccine, diphtheria vaccine and rubella vaccine.

Other causes: Organ transplantation


Signs and symptoms


Usually Acute disseminated encephalomyelitis (ADEM) has an abrupt onset. After 1 to 3 weeks of infection the signs and symptoms begins which includes fever, head ache, seizure, drowsiness and coma. Symptoms usually worsens after two or three days and if untreated leads to hemoparesis and nerve damage which is irreversible.


Treatment


The first line treatment for Acute disseminated encephalomyelitis (ADEM) is aimed at reducing the inflammatory response of the patient. For this purpose high doses of corticosteroids like methylprednisolone or dexamethosone are used. After a 3 to 6 weeks of treatment with high dose corticosteroids the doses can gradually be decreased.

Intravenous immunoglobulin, mitoxantrone and cyclophosphamide are considered as alternatives in case the patient cannot be treated with corticosteroids or the treatment with corticosteroids show poor outcomes.

If both the above treatment modalities fails to control the disease, a combination of both that is corticosteroids with immunoglobulin is administered to control the immune reaction.


Prognosis


Complete recovery in 50% to 70% with adequate treatment and 70 to 90 per cent recovery with minor disorders. There is a 5 per cent mortality rate even with adequate treatment.

Complications


1. Motor deficiencies: about 8 to 30 per cent cases residual motor deficiencies are seen.
2. Neuro cognitive impairment
3. Acute disseminated encephalomyelitis (ADEM) with multiple sclerosis
4. Acute hemorrhagic leuko encephalitis.

1 comment:

  1. Very well written and informative article, thank you :-)

    TOSHIBA PVM-375AT

    ReplyDelete