Parkinson's and Movement Disorders Flashcards
What is the most common movement disorder?
Parkinson’s disease
What is the age distribution of Parkinson’s disease?
Incidence rapidly increases over 60
Mean age of diagnosis = 70
What are the cardinal features of Parkinson’s disease?
Tremor
Bradykinesia
Rigidity
Postural instability
What is dyskinesia?
Reversible levodopa-induced motor complication Abnormal involuntary movements - Choreic - Dystonic - Ballistic - Myotonic
How is dyskinesia treated?
Adjusting levodopa dose
What is dystonia?
Involuntary muscle contraction involving abnormal movements and postures
More sustained abnormal posture than dyskinesia
Can be
- Under-treated Parkinson’s disease motor symptom
- Complication of levodopa treatment
What is the mechanism of action of levodopa?
Replacement of dopamine via prodrug
On which symptoms of Parkinson’s disease is levodopa most effective?
Hypokinetic motor symptoms
Also works on
- Tremor
- Rigidity
With which other drug is levodopa always combined, and why?
Combined with peripheral decarboxylase inhibitor to minimise peripheral conversion to dopamine
What are the gastrointestinal adverse effects of levodopa?
Nausea
Abdominal cramping diarrhoea
What are the neurological adverse effects of levodopa?
Somnolence
Dizziness
Headache
What are the psychiatric adverse effects of levodopa?
Confusion Hallucinations Delusions Agitation Psychosis
What are the cardiovascular adverse effects of levodopa?
Orthostatic hypotension
What are motor fluctuation, in terms of levodopa-related complications?
Wearing-off = end-of-dose effect
On-off syndrome = episodes of unpredictable “off” alternating with “on” +/- dyskinesia
Failure to turn “on” = due to excessively prolonged/severe “off” period
Acute akinesia = akinetic state last for days and not responding to antiparkinson medications = sudden exacerbation
What are other medications used in Parkinson’s disease?
COMT inhibitors MAO inhibitors Dopamine agonists Anticholinergics Amantadine
What are non-motor features of Parkinson’s disease?
Orthostatic hypotension
Urine frequency
Constipation
What are the psychological aspects of Parkinson’s disease?
Depression
Anxiety
Apathy and abulia
Sleep disturbance
What are the differential diagnoses of a tremor?
Parkinsonian Essential Enhanced physiological Drug induced Cerebellar Dystonia
What are the characteristics of an essential tremor?
Gradual onset Bilateral Resting tremor worse than kinetic Ethanol improves tremor FHx
What are the characteristics of a Parkinsonian tremor?
Asymmetrical
Onset latency = tremor starts later than posture
Pronation-supination tremor
Coarse tremor
What sort of balance is affected in Parkinson’s disease?
Medio-lateral balance more than antero-posterior
Why is an MRI done in Parkinson’s disease if it is a clinical diagnosis?
To look for structural problems
- Normal pressure hydrocephalus
- Subdural haematoma
- Stroke in basal ganglia
What things does bradykinesia cause in Parkinson’s disease?
Hypo-expressions Slower blinking > dry eyes Eating slower Drooling Gastroparesis > full early on Constipation
What is akinetic rigid syndrome in Parkinson’s disease?
Don’t have tremor, but
- Stiff
- Rigid
- More falls
What proportion of Parkinson’s patients have akinetic rigid syndrome, and what proportion are tremor dominant?
Akinetic rigid syndrome = 30%
Tremor dominant = 70%
What is the prognosis for patients with akinetic rigid syndrome, compared with those who are tremor dominant?
Faster progression
Worse response to medication
Poorer outcome
What is the abnormal protein in Parkinson’s disease?
Alpha synuclein
Which part of the brain is disproportionately affected in Parkinson’s disease?
Substantia nigra
What are the pre-motor features of Parkinson’s disease?
Anosmia Mood disturbance - apathy Impulsive behaviours Sleep disturbance - Insomnia - Nightmares - Myoclonic jerks - Cramps - Rigidity - Vivid dreams - REM behaviour disorder
What happens when Parkinson’s disease progresses to the cortex?
Parkinson’s disease dementia
How can bradykinesia be tested on examination?
Tapping fingers Opening and closing hands Toe tapping Heel tapping Have to make movements big and quick to demonstrate frequency and amplitude
Compare rigidity and spasticity
Rigidity = extrapyramidal Spasticity = pyramidal
Compare lead pipe rigidity to clasped knife rigidity
Lead pipe = resistance stays the same
Clasped knife = resistance decreases
What produces cogwheeling in Parkinson’s disease?
Tremor superimposed over rigidity
How is postural instability tested for on examination?
Retropulsion test > will fall like leaf/take >6 steps
What are the features of gait in Parkinson’s disease?
Difficulty standing up Slight flexion of knee, anterior flexion of trunk, anterior flexion of neck Gait initiation problem = difficulty taking 1st step Shortened stride length Reduced step height Reduced arm swing Narrow-based gait Festination Reappearance of tremor
How is mediolateral balance tested on examination?
Heel-to-toe walking
Stand on 1 leg while other leg’s knee held above waist height
What drugs can cause a drug-induced tremor?
Thyroxine Caffeine Anti-psychotics, especially typical Dopamine blocking agents; eg: metoclopramide Beta agonists; eg: salbutamol
