Huntington's Disease

Question 1

What is the etiology of Huntington’s disease?

Answer 1

-usually diagnosed in middle-aged adults
-juvenile or late-onset is possible
-usually people of western European decent
-genetic disorder

Question 2

What are the genetic causes?

Answer 2

-gene nutation on chromosome 4 that causes the DNA sequence on cytosine, adenine, and guanine (CAG) to repeat more than in normal DNA
-mutated protein in huntingtin
*mutations lead to a build of taxic fragments that lead to neuron death
*also damages the temporal and frontal loves of the cortex

Question 3

How does huntington’s disease effect the basal ganglia?

Answer 3

-initially, in the disease, there is a disinhibition of the indirect D2 pathway
*the result is that the thalamus is excited leading to the excess movement (chorea)
-late stages of the disease there is damage to the direct D1 pathway
*the thalamus is inhibited thus leading to a loss of movement or hypokinesia

Question 4

What are the signs and symptoms?

Answer 4

-personality changes, mood swings, depression
-forgetfulness and impaired judgement and memory
-unsteady gait and involuntary movements (chorea)
-slurred speech, difficulty swallowing, and significant weight loss

Question 5

What are the types?

Answer 5

-sporadic
-genetic
-juvenile onset
-late onset

Question 6

What is sporadic HD?

Answer 6

changed by a spontaneous mutation of the huntingtin protein

Question 7

What is genetic HD?

Answer 7

inherited mutation of the huntingtin gene

Question 8

What is juvenile onset HD?

Answer 8

-symptom onset before age 20
-has more rapid progression (usually 10 year life expectancy)
- more likely when the father has the HD gene

Question 9

What is late onset HD?

Answer 9

symptom onset after age 59

Question 10

Which type of HD is not inherited?

Answer 10

sporadic

Question 11

Which type of HD is inherited?

Answer 11

genetic

Question 12

What type of HD is the most common?

Answer 12

genetic

Question 13

What are the symptoms of juvenile onset HD?

Answer 13

-stiffness in legs (rigidity > chorea)
-clumsiness in arms and legs
-seizures
-other typical symptoms of HD

Question 14

What does the neurologic exam and medical history consist of when diagnosing HD?

Answer 14

-performed by a neurologist
-history goes extensively into family history
-the physical exam looks at reflexes, balance, tone, movement, gait, and mental status

Question 15

What imaging is used to diagnose HD?

Answer 15

-with disease progression, you would see shrinking in the brain with enlargement of ventricles
-this would show up on CT of the head and MRI
*early HD would have normal imaging

Question 16

What is the best diagnostic method for diagnosing HD?

Answer 16

genetic testing

Question 17

What would be a positive genetic test for HD?

Answer 17

36+ repeats of CAG on the huntingtin gene

Question 18

What would be a negative genetic test for HD?

Answer 18

26 or less repeats of CAG on the huntingtin gene

Question 19

What is the prognosis?

Answer 19

-fatal
*usually due to secondary complications like heart failure and pneumonia

Question 20

How long is the disease progression for HD?

Answer 20

10-25 years

Question 21

What is the medical treatment/management?

Answer 21

-no cure
-management of symptoms

Question 22

How would symptoms be managed?

Answer 22

-behavioral/psychological
*medication and a neurologist, neuropsychologist, or psychologist
-weight loss
*would need an SLP and nutritionist
-movement/balance/gait dysfunction
*we would treat this
-cognitive changes
*OT or SLP would treat this

Question 23

What are the characteristics of early stage HD?

Answer 23

-largely functional
-difficulty with coordination
-mild chorea
-difficulty with a higher level of problem-solving
-mild depression, irritability, and disinhibition

Question 24

What are the characteristics of middle stage HD?

Answer 24

-no longer able to go to work, drive, manage money, and do household chores
-need assistance with eating, dressing, and personal hygiene
-weight loss
-falls
-swallowing difficulty
-difficulty sequencing
-difficulty problem solving
-cannot prioritize tasks
-more chorea in this phase
-impulsivity
-suicidal behaviors
-paranoia/hallucinations

Question 25

What are the characteristics of late stage HD?

Answer 25

-require assistance with all ADLs
-usually non-verbal and bedridden
-either severe chorea or it has been replaced with more parkinsonian symptoms of severe rigidity and bradykinesia
-delirium
-global dementia

Question 26

What is the physical therapy exam/eval for HD?

Answer 26

-unified huntington’s disease rating scale (UHDRS)
-thorough neuro exam
*tone
*coordination
*strength
*balance
*cognition
*reflexes
*eye movement/function
* salient functional tasks
*fall risk
*ROM
*cranial nerves
*gait

Question 27

What interventions can be used for HD?

Answer 27

-based on deficits
-think of future needs
-caregiver education and training