Neurology - Dyskinesias

Question 1

Dyskinesia

Answer 1

= Abnormal involuntary movement

Caused by extrapyramidal or cerebellar lesions

Question 2

Tremor

Answer 2

= Regular, rhythmic oscillation

NB Asterexis is not the same, it is rhythmic myoclonus

Question 3

Types of tremor

Answer 3

“RAPID”

• Resting (e.g. PD)
• Action/ Postural
• Intention (e.g. cerebellar)
• Dystonic

Question 4

What are the features of resting tremor?

Answer 4

4-6Hz pill rolling
Abolished on voluntary movement/ action
Increases with distraction - e.g. counting backwards

Cause - PD (basal ganglia abnormalities manifest at rest)

Question 5

Features of an action/ postural tremor

Answer 5

6-12Hz
Absent at rest
Worse with outstretched hands or movement
Equally bad at all stages of movement

Question 6

What are the causes of an action/ postural tremor?

Answer 6

“BEATS”

• Benign essential tremor
• Endocrine - thyrotoxicosis, decr. glucose, phaeo
• Alcohol withdrawel
• Toxins - beta agonists, theophyline, valproate
• Sympathetic - physiological tremor may be enhanced e.g. anxiety

Question 7

Features of an intention tremor

Answer 7

Irregular, large amplitude
Worse at the end of movement - e.g. past pointing

Cause - cerebellar damage

Question 8

Important features of benign essential tremor

Answer 8

Autosomal dominant 
Occurs with action and worse with anxiety, emotion etc
Arms, neck and voice
Doesn't occur during sleep 
Better with alcohol

Question 9

What is myoclonus?

Answer 9

= Sudden involuntary jerks

Question 10

Causes of myoclonus

Answer 10

Epilepsy (i.e. juvenile myoclonic epilepsy, infantile spasms)
Neurodegenerative diseases
CJD - important one to remember!

Question 11

Chorea

Answer 11

= Irregular random movements that have a flowing/ purposeful quality
Any part of the body can be affected

Question 12

Causes of chorea

Answer 12

Hereditary (e.g. Huntington's) 
Post infectious (Sydenhams chorea is associated with rheumatic fever)
Polycythaemia rubra vera
SLE
Wilson's disease

Question 13

What are tics?

Answer 13

Type of dyskinesia
= Rapid, compulsive, repetitive stereotyped movement s
Also referred to as “habit spasms”
Associated with involuntary utterances in Tourette’s syndrome

Question 14

Hemiballismus

Answer 14

= Violent, jerky movements typically restricted to one side of the body
Caused by damage to the contralateral sub thalamic nucleus (often elderly diabetics)
Resolves spontaneously

Question 15

Athetosis

Answer 15

= Slow, within movements often seen with congenital brain damage in cerebral palsy

Question 16

What is the difference between physiological and pathological tremor?

Answer 16

Physiological tremor - appears when maintaining a fixed posture, fine character

Pathological tremor - occurs at rest or movement (action), slow rate and course character

Question 17

How should a tremor be examined?

Answer 17

Observe the tremor at rest (e.g. PD)
Observe on maintaining posture (e.g. physiological or postural)
Observe on movement and at the end of movement - finger nose pointing (e.g. cerebellar)

Question 18

What is dystonia?

Answer 18

= Prolonged muscle contracture causing unusual joint posture or repetitive movements

Question 19

How are dystonia’s classified?

Answer 19

By distribution:

• Generalised
• Focal - limited to one area of the body

By aetiology:

• Primary - often genetic involvement
• Secondary - e.g. drugs, metabolic disorders etc

Question 20

Idiopathic generalised dystonia

Answer 20

Autosomal dominant
Childhood onset
Begins in one leg then spreads to that side of the body over 5-10 years

Question 21

Idiopathic focal dystonia

Answer 21

Most common form of dystonia 
Affects one part of the body
Worsened by stress
Types:
- Spasmodic torticolis (cervical dystonia)
- Writers cramp
- Oromandibular dystonia

Question 22

Negative features of extrapyramidal disease

Answer 22

Hypokinetic features of extrapyramidal disease

1. ) Bradykinesia - loss or slowness of voluntary movement
2. ) Postural disturbance - flexion of limbs and trunk is associated with a failure to make quick postural “righting” adjustments to correct balance

Question 23

Positive features of extrapyramidal disease

Answer 23

Hyperkinetic features of extrapyramidal disease

1. ) Abnormal involuntary movements - “Dyskinesia”
2. ) Rigidity

Question 24

What is the definition of rigidity?

Answer 24

Velocity independent increase in tone
Affects flexor and extensor muscle groups equally
Also called “Lead pipe rigidity” - indicates extrapyramidal disease

Question 25

Cog wheel rigidity

Answer 25

Tremor superimposed on rigidity

Question 26

Tardive dyskinesia

Answer 26

= Delayed onset (“tardive”) following chronic exposure to Da agonists (e.g. antipsychotics, anti-emetics, L-DOPA)

Da receptors become super-sensitive

Question 27

How is tardive dyskinesia treated?

Answer 27

1) Using new atypical antipsychotics

2) Early recognition and drug withdrawal

Question 28

Wilson’s disease

Answer 28

(Hepatolenticular degeneration)

Autosomal recessive disorder - build up of copper in the lentiform nucleus (= globus pallidus + putamen)

Question 29

What is the underlying biochemical defect in Wilson’s disease?

Answer 29

Deficiency of alpha 2 globulin - Ceruloplasmin - normally binds 98% of plasma copper and transfers to a copper enzyme

Increase in loosely bound copper/ albumin and organ deposition (esp liver and brain)

Question 30

Acute form of Wilson’s disease

Answer 30

There are 2 clinical forms of Wilson's disease
Acute:
1) Bradykinesia 
2) Behavioural change
3) Involuntary movements 
4) Liver involvement common 

HIGH mortality rate if untreated (death in approx 2 years)

Question 31

Chronic form of Wilson’s disease

Answer 31

Proximal “wing beating” tremor
Dysarthria, dystonia, and rigidity
Psychosis and behavioural disorders
Liver involvement is less severe

Question 32

How are neurotransmitter substances altered in extrapyramidal disease?

Answer 32

Dopamine - inhibitory
ACh - excitatory

Extrapyramidal disease involves imbalance of these 2 neurotransmitters:

• Dopamine deficiency or ACh excess - akinetic rigid syndrome
• Dopamine excess or ACh deficiency - involuntary movements (i.e. dyskinesia)