Chapter 14 - Huntington's Disease

Question 1

Epidemiology

Answer 1

• avg age of onset ranges from 35-44 y.o.
• duration of disease is about 19 years, so avg age of death is 51-57 y.o.

Question 2

Juvenile HD

Answer 2

• onset occurs before 20 y.o.
• subtle changes/difficulty in handwriting and movement such as slowness, rigidity, tremor and rapid muscular twitching

Question 3

What triad of symptoms of HD characterized by?

Answer 3

1. chorea
2. behavioral and emotional alterations
3. cognitive decline (dementia)

Question 4

Chorea

Answer 4

• excessive, involuntary, abrupt and irregularly timed movements
• increases in severity during first phase (10 years), and then is replaced by Parkinsonian temors

Question 5

What motor symptoms dominate the final stages (last 10 years) of HD?

Answer 5

• bradykinesia and rigidity
• dystonia (slow, abnormal twisting movements w/ increased muscle tone)

Question 6

Ocular disturbances of HD

Answer 6

• eye movements slow down
• can’t suppress looking @ novel stimuli
• can’t suppress blinking
• occurs late in the disease

Question 7

Cognitive symptoms of HD

Answer 7

• impairment of intellectual functioning
• memory disturbances
• STM deficits
• diminished verbal fluency (difficulty w/ COWA)

Question 8

Psychiatric symptoms of HD

Answer 8

• severe anxiety
• depression
• mania
• pts are more susceptible to suicidal ideations

Question 9

What occurs in the advanced stages of HD?

Answer 9

• loss of independence due to restrictions in function
• speech is dysarthric
• weight loss
• swallowing becomes difficult

Question 10

Neuropathology of HD

Answer 10

• neuron loss in the caudate nucleus (communicates less w/ the frontal lobe, causing executive functioning impairment) and basal ganglia
• enlargement of ventricles
• astrogliosis (to clean up dead neurons)

Question 11

Cause of neuropathology

Answer 11

• excitotoxicity due to excess glutamate
• oxidative stress (free radicals)
• impaired energy metabolism (mitochondral dysfunction)
• apoptosis

Question 12

Hereditary factor of HD

Answer 12

• autosomal dominant disorder, causes a CAG repeat of the protein huntingtin

Question 13

How is HD diagnosed?

Answer 13

• CT or MRI of the bicaudate diameter is a reliable marker (shrinks due to enlargement of ventricles)
• genetic testing for CAG repeats

Question 14

Tx of HD

Answer 14

• benzodiazepines to treat severe chorea
• neuroleptics to treat psychosis
• L-dopa for parkinsonian symptoms
• SSRIs for psychiatric symptoms
• antipsychotics

Question 15

Syndham’s Chorea

Answer 15

• caused by Strep infiltrating the brain and affecting the basal ganglia
• common in children
• not permanent, does not lead to adult form

Question 16

Gilles de la Tourette’s Syndrome

Answer 16

• motor tics involving many muscle groups
• can be tx w/ antipsychotics

Question 17

Wilson’s Disease

Answer 17

• genetic disorder in which the pt cannot expel copper
• builds up in the basal ganglia, causing Parkinsonian symptoms and liver disease

Question 18

Amyotrophic Lateral Sclerosis (ALS)

Answer 18

• loss of upper and lower motor neurons results in a loss of motor function
• some pts develop dementia