Hyperkinetic Movement Disorders (18, Part 2) Flashcards
What are three hyperkinetic disorders that are common and we were taught about?
- Huntington’s disease
- Tourette’s syndrome
- Primary (idiopathic) dystonia
What characterizes hyperkinetic disorders?
Excessive, unwanted, or distorted movements
What type of inheritance pattern does Huntington’s have? What chromosome has the mutation (which arm)?
Autosomal dominant - short arm of chromosome 4
What type of mutation is responsible for the Huntingtin protein being defective?
Expanded trinucleotide CAG repeat –> altered Huntington protein and consequent neuronal damage
What is the typical age range of onset in Huntington’s? Life expectancy after onset?
35-45 typically
Life expectancy is 15-20 years after symptom onset
What is associated with a more rapid course of Huntington’s?
Younger age of onset - usually have larger number of repeats and this more severe pathological process
What symptom is the neurological hallmark of HD? Why is dysarthria a related symptom?
Chorea - rapid, random jerky movements that seem to flow from one movement to another
*dysarthria is related! because it is due to choreiform movements of the tongue and lips! which interfere with speech
As HD progresses, what replaces the chorea that is typically seen at the outset?
Replaced by dystonia (sustained, involuntary muscle contractions) and eventually rigid/akinetic Parkinsonism
With juvenile HD (onset in teenage years to due to lots of CAG repeats), what is the usual presenting symptom in contrast to normal HD?
Usually develop Parkinsonism right from the onset rather than chorea
What 4 behavioral changes might be seen as initial presenting features of Huntington’s?
- Impulsiveness
- Irritability
- Obsessive behavior
- Aggression
* depression also very common, some commit suicide
What kind of dementia is seen as a behavioral symptom in Huntington’s?
Subcortical dementia characterized by executive dysfunction–> impairment of planning, organizing, reasoning, judgment
What two oculomotor disturbances may be seen with Huntington’s?
- Difficulty iniatiating/slowed saccades
2. Gaze impersistence (cant maintain gaze)
What two structures in the brain show neuronal loss and gliosis (atrophy) in Huntington’s?
- Striatum (especially the caudate)
2. Cortex
What age range is typically seen for Tourette’s syndrome? Which sex is predominant?
2-15; does NOT present adulthood, in fact, usually symptoms diminish by then
* male predominance (3:1)
Is Tourette’s a genetic disease?
Almost certainly inherited, but genetic mutations have only been identified in a small fraction of patients
What is a hallmark of the motor, sensory, and vocal tics seen in Tourette’s?
The complement changes, so some dispappear and are replaced; also the frequency and severity of tics waxes and wanes over time
What 2 kinds of tics must be present as part of the formal diagnostic criteria for Tourette’s?
Multiple motor tics and at least one vocal tic (don’t have to be present concurrently)
What must be frequency of tics be according to the formal diagnostic criteria for Tourette’s?
Many times a day or intermittently over the course of a year, with no tic-free interval greater than 3 consecutive months
What age must onset occur before?
18
also the disorder must not be explainable by any other condition
What is echopraxia?
Involuntary repetition or imitation of another person’s movement
What is copropraxia?
Involuntary performance of obscene or forbidden gestures
What is echolalia?
Involuntary repetitions of vocalizations made by another person
What is palilalia?
Rapid repetition or echoing of one’s own words
What is coprolalia?
Involuntary swearing, or utterance of obscene, socially inappropriate or derogatory words
*actually quite rare in TS; only ~10%
What two behavioral conditions often occur with Tourette’s?
- ADHD (more commonly seen concurrently)
- Obsessive-Compulsive disorder
* compulsions usually about sex, counting, symmetry, and violence
What pathological abnormality is seen in Tourette’s?
None identified to date (maybe prefrontal cortex, unproven)
*also no identifiable neuron helical abnormalities
What is dystonia?
Sustained muscle contraction that produces sustained, sometimes repetitive twisting movements that result in abnormal postures
What is the difference between generalized and focal dystonia?
Generalized refers to involvement of muscles throughout the body; focal refers to an isolated muscle group or area of body
What is the inheritance pattern for Primary Generalized Dystonia? What ethnic group is it most common in?
Autosomal dominant - most common in Ashkenazi Jews
At what time of life to people usually present with primary generalized dystonia?
Childhood
Which gene on which chromosome is mutated in primary generalized dystonia?
DYT1 gene on chromosome 9
What protein is ultimately affected in primary generalized dystonia?
Torsion A (is due to a glutamate deletion)
The initial presentation of primary generalized dystonia is usually _____ and is an action dystonia, what does this mean?
Focal
Action dystonia - dystonia induced by movement
Which extremity is usually involved 1st in primary generalized dystonia?
Lower extremity –> ankle inversion, plantar flexion of the toes seen commonly
*over time will progressively spread to also involve axial musculature
What two postural abnormalities may develop that give a “dromedary” appearance to the gait?
- Flexion at the hips
2. Extension of the neck
What other two postural abnormalities may be seen in primary generalized dystonia?
- Exaggerated hip abduction
2. Knee hyperextension
What happens to cognition, strength, and sensory modalities in individuals with primary generalized dystonia?
They remain normal; dystonia (along with the gait/posture changes) usually remain the sole feature, except for a select few that develop a tremor
*no pathological or neurochemical changes have been identified
At what time in life does Primary Focal Dystonia usually appear? What genetic component does it have?
Usually in adulthood
*a few have a genetic basis identified, but tradionally assumed to be sporadic
Is primary focal or primary generalized dystonia more common?
Primary focal dystonia is more prevalent (30 vs. 3 /100,000)
Muscles in what region of the body are typically affected in primary focal dystonia?
Muscles above the waist
How does the degree of dystonia progress?
Usually progresses in severity over a number of years then becomes static (doesn’t improve but doesn’t get any worse either)
Some individuals have a task-specific dystonia, what does this mean?
The dystonia is only evident when a specific task is attempted, such as writing or playing a musical instrument
What is a peculiar characteristic in focal dystonia in terms of alleviating the dystonia?
Sometimes “sensory tricks” can alleviate - i.e. Alleviation of a cervical dystonia by touching the cheek on the side opposite to which the neck is turning
What is a dystonia that in involves specifically the muscles around the eyes, resulting in involuntary eye closure?
Blepharospasm (if severe may produce a functional blindness)
What is the dystonia called when it affects primarily the muscles around the mouth?
Oromandibular focal dystonia
-May result in either forced mouth opening or forced mouth closure
What is dystonia involving the laryngeal muscles called?
Laryngeal (spasmodic dysphonia)
What is another name for cervical dystonia?
Spasmodic torticollis
- no specific pathological or neurochemical abnormalities identified for any of the primary focal dystonias
Even though primary generalized dystonia is autosomal dominant, why are all people not affected?
It has a 30-40% penetrance rate = therefore, MOST individuals with the mutation may not ever develop the dystonia
