Parkinson's Flashcards
(39 cards)
What is the extrapyramidal system?
Part of the motor system network causing involuntary actions i.e. autonomic control of the muscles
What makes up the extrapyramidal system?
Basal ganglia: modulate fine motor planning and sequencing
Thalamus: processes information between basal ganglia and cerebral hemispheres
Brainstem nuclei: form the descending spinal pathways responsible for posture, muscle tone and reflexes
Which neurtransmitter is implicated in most movement disorders?
DA
Excess: Huntington’s
Deficiency: Parkinson’s
Examples of movement disorders
Parkinson’s
Huntington’s
MS
MND
SMA
Classic presentation of Parkinson’s
68 year old male with tremor in left hand
Slowing of movements and increasing stiffness in arms and legs
Unilateral tremor, worse at rest
Difficulty starting movements
Key differentials when presented with a patient who may have Parkinson’s
Drug-induced symptoms
Vascular parkinson’s
Parkinson’s plus syndrome
Epidemiology of Parkinson’s
20 in 100,000
Peak age 75yrs
Higher in non smokers
15% have FHx (park2 gene mutation associated with early onset)
Aetiology of Parksinon’s
Decrease in DA neurones in sub. nigra pars compacta (we also have a pars reticulata which contains GABAergic neurones)
- 15% have 1st degree FHx
- Loss of DA neurones is combined with accumulation of alpha synuclein in Lewy bodies which collect in neurones that remain - causing them to become defective
Decreased DA signalling leads to an increase of inhibitory output from the basal ganglia leading to hypokinesis
What are the clinical features of Parkinson’s?
Hyperkinetic motor features
Resting tremor (asymmetrical at start), restless legs syndrome (can precede diagnosis by many yrs), acting out dreams in sleep
Hypokinetic motor features
Bradykinesia/ akinesia, micrographia, rigidity, postural instability, difficulty with fine motor skills, loss of spontaneous blinking + serpentine stare 🐍
Bradykinesia
Shuffling gait, difficulty initiating movement, no arm swinging when walking, pausing at door frames
Non-motor features
Anosmia (90%), sleep disorders, dementia, depression, psychosis
Autoimmune features
Bladder and bowel dysfunction, dystonia, postural hypotension
Which symptoms of Parkinson’s often precede the others?
Restless legs and anosmia
Which system is associated with rigidity?
Rigidity = increased tone in all muscles, associated with the extrapyramidal system
What is spasticity?
Increased tone in the upper limb flexors and lower limb extensors associated with the pyramidal system/ UMN dysfunction
Investigations for Parkinson’s
Bedside: congitive test to exclude dementia, ask about sense of smell
Bloods: LFTs/ copper studies: exclude Wilson’s
Imaging: SPECT - shows dopamine levels in basal ganglia: people with PD and Parkinson’s + show symmetrical reduced uptake whereas drug-induced uptake is symmetrical and normal
MRI: can be used to identify specific patterns of gegeneration in Parkinsons + syndromes
Parkinson’s differentials
Resting tremor: different from cerebellar and essential tremor as these are both worse on movement - do cerebellar tests
Rigidity and not spasticity (rigidity = increased tone in both directions, not velocity dependent etc)
Drug induced: antipsychotics
What is the Glabellar tap?
Repetitively tap patients nose - after a while they should stop blinking but patients with Parkinson’s continue to blink
What has to be present for the diagnosis of Parkinson’s?
Bradykinesia
+ one of:
- Tremor
- Rigidity
- Postural instability
MRI findings in Parkinson’s plus
Midbrain atrophy: prpgressive supranuclear palsy
Parietal cortex atrophy: corticobasal degeneration
Pontocerebellar tract atrophy: multiple systems atrophy
Principles of management of Parkinson’s
Requires management of both hyperkinetic and hypokinetic symptoms, mood and sleep disturbance
Treatment started early because it has long term benefits
Medical management of Parkinson’s
Levodopa - dopamine precursor 1st line for those who have a reduced QoL due to motor symptoms
- Then add dopamine agonists or monoamine oxidase B inhibitors if needed
- Modafanil for daytime sleepiness
- Orthostatic HTN: review medication
- Psychosis: quetiapine (only treat if patient unable to cope)
Levodopa
Precursor of DA, given with carbidopa (dopa decarboxylase inhibitor) which prevents peripheral metabolism allowing it to cross BBB
Benefits: improves hypokineses
Downside: no effect on hyperkinesis and non-motor symptoms
Duration: works for 5-10yrs
Adverse effects: most remains peripheral so GI upset e.g. N&V, stiffness, dyskinesia, ‘on-off effect’ symptoms return before next dose given, psotural hypotension, hallucinations, excessive sleepiness, impaired impulse control, hypersexuality
Dopamine agonists
Example: ropinirole
DA agonists are 1st line in young patients
Not as efficacious as levodopa
Cause the same adverse effects as levodopa
Monoamine oxidase inhibitors
E.g. selegiline
Work by preventing breakdown and reuptake of DA, promoting its action for longer
Used to decrease the on-off effect and bridge between doses of levodopa/ DA agonists
Adverse effects: dyskinesia, insomnia
Management of non-motor symptoms of Parkinson’s
Fludrocortisone: orthostatic hypotension
Laxatives: bowel dysfunction
Anti-cholinergics: bladder dysfunction
Anti-depressants: mirtazapine
Dietician
Surgery in management of Parkinson’s
Deep brain stimulation: offer to those whose symptoms continue despite use of drugs
Levodopa carbidopa intestinal gel: given via percutaneous pump into jejunum
