huntington's

Question 1

def of huntington’s

Answer 1

Autosomal dominant trinucleotide repeat disease (neurodegenerative) characterized by progressive chorea and dementia, typically commencing in middle age.

Question 2

aetiology of huntington’s

Answer 2

huntingtin gene on chromosome 4p and codes for protein huntingtin

in huntingtin gene - extended trinucleotide repeat expansion (CAG) = toxic gain in function

disease is inherited in an autosomal dominant pattern

anticipation - earlier age of onset in each generation

atrophy and neuronal loss of striatum and cortex

Question 3

epidemiology of huntington’s

Answer 3

Worldwide prevalence eight in 100 000.

30-50yrs

rare in E Asian populations - particularly Japan

Question 4

sx of huntington’s

Answer 4

FH of Huntington’s disease

insidious onset in middle-age of progressive fidgeting and clumsiness, irritability, depression

develop into invol jerky, dyskinetic movements, accompanied by grunting and dysarthria chorea, dementia +- fits and death within 15yrs

in late disease - rigid, akinetic and bed bound

Early cognitive, emotional and behavioural changes are dominated by lability, dysphoria, mental inflexibility, anxiety, leading on to dementia.

Inquire about drug history (especially cocaine, anti-psychotics).

Question 5

signs of huntingtons

Answer 5

chorea and dysarthria

slow voluntary saccades and supranuclear gaze restriction

other presentations: parkinsonism and dystonia - especially in juvenile-onset disease

mental state exam = cognitive and emotional deficits

Question 6

ix for huntington’s

Answer 6

genetic analysis

• diagnostic if >39 CAG repeats in HD gene
• Intermediate repeat lengths (27–39) exist with reduced penetrance.

brain MRI or CT - symmetrical atrophy of the striatum - particularly the caudate nuclei and butterfly dilation of the lateral ventricles

bloods

• necessary to exclude other pathology
• caeruloplasmin
• ANA blood film (acanthocytes)
• TFT
• ESR

Question 7

mx of huntingtons

Answer 7

1. conselling
2. OT PT, SALT
3. chorea - tetrabenazine or antipsychotics or benzodiazepines or amantadine
4. behaviour and moos instability - mood stabling anticonvulsants eg carbamazepine
5. consider antidepressants
6. dopamine agonists for bradykinesia `

Question 8

complications of huntingtons

Answer 8

wht loss
dysphagia
falls
suicide risk
incontinence