Huntington's Disease

Front 1

What is Huntington's?

Back 1

A genetic neurodegenerative disease causing involuntary 'jerky' movements known as chorea. It is a movement and psychiatric disorder.

Front 2

When does HD usually present?

Back 2

Middle age, usually between 35 - 44.

Front 3

What are the movement symptoms of HD?

Back 3

• Increased stiffness/worsening of overall motor function
• Physical instability
• Abnormal facial expressions
• Abnormal facial expressions
• Difficulty speaking/chewing/swallowing
• Sleep disturbance

Front 4

What are the psychiatric symptoms of HD?

Back 4

• Depression - 40% prevalence
  
• Anxiety - at least 40% prevalence
• Irritability - 50% prevalence
• Apathy - Almost 60% prevalence
• Obsessive/Compulsive - 30% prevalence
• Psychosis - 10% average prevalence

Front 5

What are the cognitive symptoms of HD?

Back 5

• Impaired executive functions
  
• Memory deficits
• Impaired cognitive flexiblity and abstract thinking
• Inhibition of appropriate actions
• Initiation of inappropriate actions
• Dementia

Front 6

Which symptoms are the first to be noticed?

Back 6

Physical

Front 7

What is the most common symptom in juvenile HD?

Back 7

Rigidity

Front 8

Which gene is implicated in HD?

Back 8

• Huntingtin (HTT)
  
• IT-15
  

Front 9

What is CAG?

Back 9

Trinucleotide repeat

Front 10

Where does the brain atrophy in HD?

Back 10

• Striatum
  
• Caudate
  
• Cortex
  

Front 11

How many repeats CAG repeats in a normal person?

Back 11

Under 26

Front 12

How many CAG repeats in a mutable normal person?

Back 12

27 - 35

Front 13

How many CAG repeats in a reduced penetrable person?

Back 13

36 - 39

Front 14

How many CAG repeats in the HD allele?

Back 14

Over 40

Front 15

How many CAG repeats in juvenile HD?

Back 15

Over 70

Front 16

What is the offspring risk in a normal person?

Back 16

None

Front 17

What is the offspring risk in a mutable normal person?

Back 17

Elevated but under 50%

Front 18

What is the offspring risk in a reduced penetrable person?

Back 18

50%

Front 19

What is the offspring risk in someone with the HD allele?

Back 19

50%

Front 20

What does CAG encode?

Back 20

Polyglutamine

Front 21

What is astrogliosis?

Back 21

Abnormal increase in astrocytes due to nearby destruction of neurons due to trauma, infection or neurodegeneration.

Front 22

What is the treatment for chorea?

Back 22

• Sulpiride - postsynaptic D2 blocker, 100-500mg. (SE: Rigidity)
  

• Olanzipine - Antipsychotic, also treats psychosis, up to 15mg, (SE: weight loss, increased irritability)
  

• Tetrabenazine - Presynaptic effect, only licenced drug, 12.5mg to 25mg (SE: depression and parkinsonism) - only used if sulpiride doesn't work.
  

• Haloperidol - Antipsychotic only used in emergency, up to 5mg
  

Front 23

What is the treatment course for irritability?

Back 23

• If triggered by particular carer, change it.
  

• Agitated depression? consider treatment with sedating antidepressants.
  

• Is it pain related eg teeth pain or problems emptying bladder? Put patient on buprenorphine patches in end stage.
  

• If none of the above consider lamotrigine up to 50mg, Olanzipine up to 15mg, escitalopram up to 20mg or propanadol.
  

Front 24

What is the treatment for depression?

Back 24

• Mirtazipine - Sedating, helps with night time sleep (SE: weight gain).
  

• SSRI - Stimulating, do not use in suicidal patients, reconsider diagnosis, change medications if they dont work or add another.
  

Front 25

What is the treatment for anxiety?

Back 25

• Is the problem mostly depression? Consider medication with sedating effects.
  

• Dependent on specific situations? Try modifying treatment.
  

• Out of the blue panic attacks? Consider a mood stabilizer eg Lamotrigine.
  

Front 26

What therapy/management can be put in place?

Back 26

• Speech and language therapy
  
• Occupational therapy
  
• Regular exercise