Movement disorders

Question 1

What is a movement disorder or dyskinesia?

Answer 1

Charachterised by the impairment of the planning, control or execution of movement.

Multiple manifestations

Question 2

What brain structures are involved in co-ordinating movement and voluntary action?

Answer 2

The basal ganglia
* BG are symmetrial groups of grey matter or ‘nuclei’ deep in cerebral hemispheres and brainstem.
* made up of caudate nucleus, globus pallidus , putamen, substantia nigra and subthalamu
* direct and co-ordinate movement and voluntary action via 2 pathways - direct and indirect pathway.

Question 3

How can movement disorders be categorised? (2 main)

Answer 3

• akinetic / hypokinetic (i.e loss or decreased movement)
• hyperkinetic (i.e. increased movement)

Question 4

What is the most common hypokinetic movement disorder?

Answer 4

Parkinsons disease

Question 5

Hyperkinetic movement disorders have additoinal or excessive movement.

How can hyperkinetic movements be further categorised?

Answer 5

• Non -jerky (i.e tremor / dystonia)
• Jerky (i.e. chorea / tics / myoclonus

Question 6

What are types of tremors and some causes ?

Answer 6

Rest tremor
* abolished on movement
* cause: parkinsonism

Intention tremor
* irregular, large amplitude, worse at end of purposegul act i.e. finger pointing.
* cause: cerebellar damage (stroke, MS)

Postural tremor
* absent at rest, present if maintain posture
* causes: 1. benign essential tremor, 2. pyshiological tremor e.g. thyrotoxicosis, anxiety, b-agonsits.

Question 7

What is chorea?

Answer 7

Abnormal involuntary movement derived from Greek word for “dance”

nonrythmic, purposeless, abrupt, jerky movements that randomly move from one body part to the other.

Chorea can effect face, trunk and limbs or be generalsied. e.g facial grimacing, raising the shoulders, flexing/ extending the fingers.

Question 8

What are some causes of Chorea?

Answer 8

Medications
* L-DOPA, neuroleptics

Inherited
* Huntingdon’s
* wilsons disease

Autoimmune
* SLE, antiphospholipid

Infections
* HIV, CJD

Structural
* vascular, demylination disorders, tumour

Question 9

What is dystonia?

Answer 9

A hyperkinetic movement disorder - involuntary and repetitive contractions of opposing muscles causing twisting movements and abnormal postures.

Types:
* Generalised (whole body)
* Focal (1 part of body)
* Acute

Question 10

When can acute dystonia occur ?
Clue: think of psych patients

Answer 10

• Occurs when starting many drugs : e.g. neuroleptics (v. often in psych patients) and some anti emetics (metoclopramide, cyclizine)
• Oculogyric crisis - eyes drawn upwards and painful
• torticollis - head pulled back
• trismus - oromandibular spasm

Question 11

What are causes of secondary dystonia?

Answer 11

often side effects of meds that block dopamine e.g. neuroleptics can cause tardive dystonia (persists after you stopp drug)

Also can get in treatment of Parkinsons in “off state” when meds are wearing off

Question 12

What is athetosis?
cause?

Answer 12

symptom characterized by slow, involuntary, convoluted, writhing movements of the fingers, hands, toes, and feet and in some cases, arms, legs, neck and tongue.

Cause:
* cerebral palsy

Question 13

What is spasticity?

Answer 13

Loss of inhibition of motor neurons.

Abnormal increase in muscle tone or stiffness of muscle, which might interfere with movement, speech, or be associated with discomfort or pain

Question 14

What is ataxia?

Answer 14

incoordination of voluntary muscle movement - a neuro physical finding NOT a disease

Usually due to cerebellar dysfunction OR sensory (impaired vestibular or proprioceptive afferent) input to the cerebellum.

Ataxia can have:
- insidious onset e.g. spinocerebellar ataxias (genetic)

• acute onset e.g. cerebellar infarction, heamorrhage, infection
• subacute onset, e.g. infectious / immunologic disorder

Question 15

How would a pt with ataxia behave?

Answer 15

Pt:
poor coordination,
unsteady gait with a tendency to stumble,
difficulty with fine motor tasks,
impaired swallowing,
and abnormalities in eye movements.

Question 16

How would a pt with spasticity present / look like?

Answer 16

Pt= variable combination of paralysis, increased tendon reflex activity (hyperreflexia with brisk reflexes and a positive Babinski sign) and hypertonia (as opposed to rigidity seen as a characteristic feature of parkinsonism).

Clonus (most commonly present in the ankle) may be present and presents as involuntary, rhythmic, muscular contractions and relaxations

Question 17

How would a pt with chorea present / look like?

Answer 17

Brief, abrupt, irregular, unpredictable, non-stereotyped movements.

Mild: may appear purposeful. Pt =fidgety and clumsy.

Chorea affects many body parts, e.g. speech, swallowing, posture and gait, and disappears in sleep.

Question 18

What is Huntingdon’s chorea / disease ?

Answer 18

• Progressive and incurable neurodegenerative condition
• presents at age 40 ish progressed until dealth
• death often 12-20 years post initiation of symptoms

Question 19

What are the clinical features of of Huntingdon’s?

Answer 19

• Progressive personality beahvioural changes
• Generalised chorea
• Eventually dementia

Towards end of disease:
* chorea diminishes and parkinsonism and dystonia dominate the clincial picture

(low mood, memory problems, choreiform movements)

Question 20

Explain the genetic component of Huntingdon’s chorea / disease

Answer 20

• Autosomal dominant
• trinucleotide repeat disorder: repeat expansion of CAG.
• Genetic mutation in the HTT gene on chromosome 4
• Genetric anticipation - each generation the CAG repeats in greater length - manifests as an earlier age of onset

Question 21

What is the pathophysiology of Huntingdons Chorea?

Answer 21

degeneration of cholingeric and GABAergic neurones in the striatum of the basal ganglia
* initially neuronal loss in caudate nuclues and putamen as well as other areas e..g cerebral cortex.

Question 22

When do symptomms typically develop in huntingdons?

Answer 22

After 35- 40 years

Question 23

How is huntingdon’s chorea diagnosed?
Ethical issues?

Answer 23

Specialist genetic centre to find faulty gene

Ethics:
* counsel before testing to understand implications of positive or negatice result on relatives e.g. asymptomatic carriers
* many relatives chose to not test pre symptoms

Question 24

What are the treatments for Huntingdon’s?

Answer 24

No options for stopping / slowing disease

Speech + language therapy if difficulties

Genetic counselling

quality of life - OT. physio etc

Depression - antidepressants

MEDS to suppress disordered movements e.g. Antipsychotics / benzodiazepams

Question 25

How to distinguish between sensory and cerebellar ataxia?

Answer 25

Sensory or vestibular component to ataxia = increased gait disturbance when visual cues are removed (walking with eyes closed or in the dark)

Cerebellar component to ataxia = gait ataxia remains the same regardless of visual cues

Question 26

What neurodegenerative diseases have symptoms that include dystonia?

Answer 26

Parkinsons
Wilsons disease
multiple system atrophy
Huntingdons disease

Question 27

What is a tic?
example?

Answer 27

• Brief, repeated, stereotyoed movements with patients may suppress for a while
• common in children

Example:
* Tourrette’s syndrome - also see motor and vocal tics

Question 28

How to treat a tic?

Answer 28

• Psychological supoprt
• Clonazepam if severe

Question 29

What is myoclonus? What are some causes?

Answer 29

What
* sudden involuntary focal or general jerks arising from cord, brainstem, or cerebral cortex.

Causes:
* seen in metabolic problmes
* neurodegenerative diseases
* CJD
* myoclonic epilepsy
* Asterixis (metabolic flap) liver or kidney failure