Parkinson's Flashcards
What is the definition of Parkinson’s disease
A progressive neurodegenerative disorder affecting dopaminergic neurones in the substantia nigra
What is the main triad of symptoms in Parkinson’s
Pill rolling tremor, rigidity and bradykinesia
What substance has been shown to cause severe Parkinsonism
MPTP
What is a pathological hallmark of Parkinson’s
Lewy bodies in the substantia nigra - composed of alpha-synuclein
What is the frequency of the resting tremor
4-6 Hz
What are the central side effects of levodopa
Abnormal involuntary movements (dyskinesias)
Confusion
Visual hallucinations (patients are aware that these are hallucinations unlike psychosis)
What are the systemic side effects of levodopa
Nausea and vomiting
Anorexia
Postural hypotension
Fluctuating response (on/off syndrome)
What are the causes of Parkinsonism
Neurodegenerative disorders - idiopathic Parkinson’s disease, Parkinson’s plus syndromes
Drug induced: Antipsychotics, lithium, metoclopramide
Arteriosclerosis: atherosclerotic pseudoparkinsonism (legs only, less tremor)
Toxins: CO poisoning, MPTP
Congenital: Wilson’s disease
Trauma: Dementia pugilistica
How do you treat drug-induced Parkinsonism
Add anti-muscarinic - procyclidine
What pathways are affected by Parkinson’s
Extrapyramidal pathways
What percentage of nigrostriatal dopaminergic neurones have to be lost for symptoms to appear
60-80%
Would you expect to see the signs of Parkinson’s bilaterally
The physical signs are asymmetrical
What is the sensation of a patient like in Parkinson’s
It is normal and unaffected
What is the power of a patient in Parkinson’s
It is normal and unaffected
What are the reflexes of a patient like in Parkinson’s
Normal
Which direction are the plantar responses in Parkinson’s
Downgoing
On examining the eyes of a Parkinson’s patient, what would you expect to find
Mild impairment of upgaze
Eyelids may be tremulous
Glabellar tap sign is elicited on repeated tapping (a primitive reflex)
What features of multiple system atrophy differentiate it from Parkinson’s
Autonomic failure
Cerebellar dysfunction
Pyramidal features
In combination with extrapyramidal features
On eye examination, how would you differentiate Parkinson’s from progressive supranuclear palsy
Failure of downgaze in progressive supranuclear palsy
Failure of voluntary gaze in progressive supranuclear palsy begins with loss of downgaze, then upgaze, then horizontal gaze
It is also associated with extrapyramidal dysfunction and dementia
How can you partially alleviate side effects of levodopa (on/off syndrome and dyskinesias)
Frequent small doses of medications
Controlled release preparations
Combine levodopa use with - MAO-B inhibitor, COMT inhibitor or direct dopamine agonist to reduce central breakdown of dopamine
Name a MAO-B inhibitor used in Parkinson’s
Selegiline
Name a COMT inhibitor used in Parkinson’s
Entacapone
Name some dopamine agonists used in Parkinson’s
Bromocriptine
Cabergoline
These drugs can also be used in early disease, potentially delaying the need for L-DOPA
Reduced use now due to side effects (valvular fibrosis defects)- non-ergolide versions preferred e.g. ropinerole
What are the treatments used in PD?
Dopaminergic drugs: L-dopa: Motor symptoms
Dopamine agonists
MAO-B inhibitors
Anticholinergics: Reduce tremor
COMT inhibitors: Reduces GI breakdown of L-dopa
Glutamate antagonists: Amantadine
Apomorphine: reduce off periods
What are the Parkinsons-plus syndromes?
Multi-system atrophy: Autonomic and cerebellar
Progressive supranuclear palsy: Eye movements
Corticobasilar degeneration: Unilateral parkinsonism with aphasia
Lewy Body Dementia: Visual hallucinations, fluctuating cognition
What disability scale is used to assess disability in PD?
UPDRS- Unified Parkinson’s Disease Rating Scale
How common are sleeping disorders in patients with Parkinson’s?
Affects around 90%.
Symptoms include: inability to turn, restless legs, insomnia, frequent waking.
Violent enactment of dreams (muscle atonia in REM sleep)
What symptoms of autonomic dysfunction might patients complain of?
Postural hypotension Constipation Hypersalivation and dribbling Urgency, frequency, nocturia ED Hyperhidrosis
What mnemonic can be used to remember the side effects of L-DOPA?
DOPAMINE: Dyskinesia On-off phenomena Psychosis ABP decrease (autonomic postural hypotension?) Mouth dryness Insomnia N/V Excessive daytime sleepiness
What is Parkinsonism?
A movement disorder characterised by bradykinesia and at least one of rest tremor, rigidity and postural instability
How common is dementia in PD?
15-30% of patients, usually in late disease.
Earlier cognitive symptoms are suggestive of LBD
What signs are suggestive of a Parkinsons-Plus syndrome?
Additional clinical features: pyramidal, cerebellar or ocular signs. Cognitive signs, early falls or postural instability.
Poor response to levodopa.
Symmetrical signs early in disease (PD is asymmetrical)
How do you diagnose PD?
Clinical diagnosis
Imaging- exclude other pathologies.CT/MRI to exclude vascular cause.
Dopamine transported SPECT scan (uses 18-fluorodopa): loss of nigrostriatal dopamine transporter binding, cant distinguish PD and PSPs.
What are the surgical options for PD management?
Eligible patients require a firm PD diagnosis and have responded well to dopaminergic therapy, be cognitively intact and predominantly motor-related disability:
Thalmotomy/subthalmotomy/pallidotomy: Destruction of parts of the brain overactive in PD.
Deep brain stimulation: Reversible.
Transplantation of dopamine producing cells: Currently in trials worldwide, ethical issues.
