Lecture 7 - Demyelinating disorders

Question 1

Describe ADEM.

what is it; age of onset; preceding things; treatments; prevalence

Answer 1

ADEM = Acute Disseminated Encephalomyelitis

• Inflammatory demyelinating disease of the CNS (autoimmune, attacking White Matter and Myelin)
• Affects predominately children, adolescents, young adults; average age 5-8 years
• Often preceded by an infectious illness; also reports following immunisation, parasitic infection, spontaneous
• Treatment with high dose corticosteroids or intravenous immunoglobulin (IVIG) if resistant to steroids.
• Extremely rare, incidence 8 per 100, 000

Question 2

What percent of children diagnosed with ADEM will go on to be diagnosed with MS (multiple sclerosis)

Answer 2

-6-25% of children diagnosed with ADEM will go on to be diagnosed with multiple sclerosis (MS).

They are on the same continuum, ADEM is monophasic if more episodes will be diagnosed with MS.

Question 3

What are the clinically presenting features of ADEM?

Answer 3

common symptoms:

• nausea and vomiting
• headache
• confusion
• weakness
• ataxia
• sensory changes, including numbness or tingling
• optic neuritis, visual field deficits
• seizures (less commonly)

Children most often present to hospital with ataxia, followed by cranial nerve palsy and hemiparesis.

Duration often between 2-4 weeks, but there can be relapses (e.g., treatment failure), prognosis related to LOC.

Question 4

What are the neuroimaging findings in ADEM?

Answer 4

MRI:

• white matter involvement (bilateral, asymmetric, variable in size and no.) frontal/temporal/parietal etc
• grey matter can also be affected, particularly the basal ganglia, thalami, brainstem
• Lesions may also be restricted to the brainstem or cerebellum
• tumour like lesions occur

EEG:

• abnormal in most cases, diffuse slowing
• CSF usually increased white cells, protein

Question 5

What are the common cognitive and behavioural outcomes post ADEM?

Answer 5

• There has been been an assumption of normal cognitive and behavioural outcome
• However, diffuse damage to white matter early in life known to result in cognitive and behavioural deficits
• White matter an important substrate for attention, information processing and executive functioning-develops rapidly during early childhood, particularly around 5.
• Possible that children with ADEM suffer residual cognitive deficits associated with neurological insult evidence base not substantial yet.

RECENT STUDY:

• reduced overall functioning in the ADEM group compared to controls.
• Young onset group poorer overall cognitive functioning than older onset group, especially with respect to IQ and academic skills.
• Higher incidence of severe behavioural and emotional problems in young onset group
• Conclusion: neurologic symptoms in ADEM group had resolved but subtle long term problems exist.
• NC no difference between groups in terms of MRI abnormalities

LONG-TERM NEUROPSYCHOLOGICAL FOLLOW-UP IS IMPORTANT.