Clinical Movement Disorders 1: Hyperkinetic Disorders

Question 1

What is a ballism and why does it generally occur?

Answer 1

Sudden flinging movements of an entire limb, usually due to a lesion in the subthalamic nucleus

Usually unilateral (hemiballismus)

Question 2

What is chorea vs athetosis?

Answer 2

Chorea - “dance” - sudden, brisk, usually distal movements (i.e. dancing)

Athetosis - Typically more proximal, snake-like, writhing movements. Slower than choreiform movements.

Question 3

What causes Huntington disease? Include inheritance and chromosome.

Answer 3

Autostomal dominant trinucleotide repeat disorder of chromosome 4 “Huntin 4 food”. CAG repeat disorder >30 will express disease.

Caudate loses
Ach
GABA

(Striatal neurons are GABAnergic and cholinergic)

Question 4

Give four examples of dysimmune chorea.

Answer 4

1. Sydenham’s chorea -post-strept
2. anti-NMDA receptor encephalitis - usually presents with chorea
3. Chorea gravidarum - occurring in pregnancy
4. Lupus - due to anticardiolipin Abs

Question 5

Give an example of toxic chorea.

Answer 5

Over-medicated Parkinson’s disease - “peak dose dyskinesia”

or:

CO poisoning - very rate

Question 6

What is the definition of dystonia and what can change it? Where does it occur most frequently?

Answer 6

Continuous or near-continuous involuntary contraction of muscles with abnormal posture, which is often stimulus-modulated (changes with touch or action, present more in certain actions)

• Most frequently cervical

Question 7

What does it mean for dystonia to be focal, segmental, or generalized?

Answer 7

Focal - Affecting a limb or part of a limb
Segmental - Affecting multiple muscles innervated by same spinal cord segments
Generalized - affecting whole body, or a hemidystonia

Question 8

What is the most common cause of genetic dystonia?

Answer 8

Wilson’s disease - copper in the basal ganglia

Question 9

What is torticollis, blepharospasm, and Writer’s cramp and what causes them? What type of dystonia is the third?

Answer 9

Torticollis - cervical dystonia
Blepharospasm - spasm of orbicularis oculi muscle, making it difficult to see
Writer’s cramp - motor program problem -> task-specific dystonia

Question 10

Give three examples of toxic dystonia.

Answer 10

1. Acute dystonia to neuroleptics
2. Tardive dyskinesia - chronic D2 blockade
3. Tetanus - loss of GABA and glycine from Renshaw cells in spinal cord

Question 11

Where are the three characterizing features of a tremor?

Answer 11

1. Rhythm - fast vs slow (they are always regular)
2. Morphology - flexion vs extension, pillrolling, etc
3. Circumstance when tremor is greatest - resting, postural, or action

Question 12

What type of tremor is essential tremor, and what is the frequency? Is it unilateral or bilateral?

Answer 12

High-frequency tremor (8-12 Hz), postural tremor (worsens with sustained posture)

Onset is BILATERAL, although it may be asymmetric

Question 13

How is essential tremor inherited?

Answer 13

Familial -> autosomal dominant

Question 14

How is essential tremor treated?

Answer 14

Drugs: Nonselective beta blockers + primidone

Self-medication: Transient suppression by alcohol

Thalamic deep brain stimulation if severe and refractory

Question 15

What causes Wilson’s disease and what three tests are used to definitely test for it with high sensitivity?

Answer 15

Autosomal recessive loss of copper-transporting ATPase on chromosome 13

1. Serum ceruloplasmin - decreased in most
2. 24-hour urine copper - increased in most
3. Slit-lamp exam - Check for Kayser-Fleischer rings - present in 90% with neurologic presentation

Question 16

What are the features of a tic?

Answer 16

Stereotypic, reptitive, may be volitionally suppresses, have premontory urges

Generally more complex han myoclonus

Simple tic: simple movement
complex: gestures which may appear purposeful

Question 17

What two psychiatric conditions is Tourette syndrome associated with it, and what is the diagnostic criteria?

Answer 17

Associated with OCD and ADHD

Multiple motor and 1+ vocal tics persisting for >1 year

Question 18

What are the features of myoclonus?

Answer 18

Sudden, focal, localized muscle contraction

It is recurring but not regular, and may be generalized or segmental

(i.e. hiccups or jerks)

Question 19

Where do myoclonus jerks originate from and what are they frequently seen in?

Answer 19

Originate from any part of CNS (cortex, brainstem, spinal cord)

Frequently seen in metabolic abnormalities -> renal or liver failure

Question 20

What is asterixis? When does it often happen?

Answer 20

“negative myoclonus” - Intermittent lapses in postural tone -> not truely rhythmic

Flapping of hands when trying to hold extension is an example
-> Happens often in Wilson’s disease (along with dystonia) and hepatic encephalopathy

Question 21

Is ataxia a motor deficit? Common features?

Answer 21

Yes -> deficit of motor function due to sensory or cerebellar lesion
Common features:
-dyscoordination
-dysmetria (overshoot/undershoot)
-dysdiadochokinesis

Question 22

What is the most common hereditary ataxia in the Western world? What causes it?

Answer 22

Friedreich’s ataxia

• Trinucleotide repeat “GAA”
• Frataxin gene - iron binding protein in mitochondria causing free radical damage - chromosome 9

-> damage to multiple spinal cord tracts, ataxia with hypertrophic cardiomyopathy

Question 23

What are some other autosomal recessive / nutritionally related ataxia other than Friedreich’s?

Answer 23

1. Ataxia-telangectasia (DNA repair problem)
2. Ataxia with vitamin E deficiency - spinocerebellar degeneration
3. Abetalipoproteinemia - Vitamin E deficiency
4. Refsum disease - accumulation of branched fatty acids from lack of peroxisome genesis

Question 24

What are the autosomal dominant ataxias of concern?

Answer 24

Mostly spinocerebellar ataxias (SCAs) for which you should do a gene panel for

Question 25

What is a fibrillation / fasciculation and why isn’t this considered a movement disorder?

Answer 25

Twitching involving a motor unit, not whole muscle

-> movement disorders involve whole muscles or muscle groups