2: Movement Disorders - Huntington's Disease Flashcards
What age does huntington’s disease usually onset
40-years
What is the inheritance pattern of Huntington’s disease
Autosomal Dominant
What chromosome is impacted in Huntington’s
Chromosome 4
What genetic defect is present in Huntington’s disease
CAG trinucleotide repeat
What genetic phenomenon does Huntington’s disease present with
Anticipation
What is anticipation
CAG repeats increase with successive generations. Means disorder often onsets younger as generations progress
How does Huntington’s disease present in early stages
- Chorea
- Oculomotor disorders = hypsometric saccades, optokinetic nystagmus
- Hypereflexia
What are advanced features of huntington’s disease
- Bradykinesia
- Rigidity
- Akinetic mutism = unable to speak
- Motor impersistence = cannot sustain acts
what are cognitive changes associated with Huntington’s disease
- Change personality
- Dementia
- Depression
explain pathophysiology of huntington’s disease
Early stage: degeneration GABA neurons in indirect pathway causing increase in movement
Late stage: degeneration of GABAergic neutron in direct pathway - causes loss of movement
define spasticity
velocity-dependent increase in muscle tone that manifests with resistance to movement and involuntary muscle spasms and contractions
what causes spasticity
lesions in descending motor pathways:
- Stroke
- Cerebral Palsy
- MS
- Tumours
- ALS
- Hereditary spastic paraplegia
what is classic presentation of spasticity
- Flexed arms
- Extended legs
what type of rigidity is seen in spasticity
clasp-knife: initial rigidity when. limb is moved rapidly followed by sudden decrease in tone
what is spasticity
velocity dependent increase in muscle tone
