Movement disorders Flashcards
What is a movement disorder or dyskinesia?
Charachterised by the impairment of the planning, control or execution of movement.
Multiple manifestations
What brain structures are involved in co-ordinating movement and voluntary action?
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.
How can movement disorders be categorised? (2 main)
- akinetic / hypokinetic (i.e loss or decreased movement)
- hyperkinetic (i.e. increased movement)
What is the most common hypokinetic movement disorder?
Parkinsons disease
Hyperkinetic movement disorders have additoinal or excessive movement.
How can hyperkinetic movements be further categorised?
- Non -jerky (i.e tremor / dystonia)
- Jerky (i.e. chorea / tics / myoclonus
What are types of tremors and some causes ?
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.
What is chorea?
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.
What are some causes of Chorea?
Medications
* L-DOPA, neuroleptics
Inherited
* Huntingdon’s
* wilsons disease
Autoimmune
* SLE, antiphospholipid
Infections
* HIV, CJD
Structural
* vascular, demylination disorders, tumour
What is dystonia?
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
When can acute dystonia occur ?
Clue: think of psych patients
- 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
What are causes of secondary dystonia?
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
What is athetosis?
cause?
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
What is spasticity?
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
What is ataxia?
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
How would a pt with ataxia behave?
Pt:
poor coordination,
unsteady gait with a tendency to stumble,
difficulty with fine motor tasks,
impaired swallowing,
and abnormalities in eye movements.
How would a pt with spasticity present / look like?
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
How would a pt with chorea present / look like?
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.
What is Huntingdon’s chorea / disease ?
- Progressive and incurable neurodegenerative condition
- presents at age 40 ish progressed until dealth
- death often 12-20 years post initiation of symptoms
What are the clinical features of of Huntingdon’s?
- 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)
Explain the genetic component of Huntingdon’s chorea / disease
- 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
What is the pathophysiology of Huntingdons Chorea?
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.
When do symptomms typically develop in huntingdons?
After 35- 40 years
How is huntingdon’s chorea diagnosed?
Ethical issues?
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
What are the treatments for Huntingdon’s?
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
