Parkinson's disease (N) Flashcards
Define Parkinson’s disease.
Degeneration of dopaminergic neurons in basal ganglia, from substantia nigra to striatum
What is the pathophysiology of Parkinson’s disease?
Degeneration of dopaminergic neurons from substantia nigra to striatum, due to mitochondrial DNA dysfunction
What demographics is Parkinson’s disease more common in? (2)
- M>F
- mean age of onset: 65y
What is parkinsonism (Parkinson’s disease)?
Triad of resting tremor, hypertonia and bradykinesia + additional clinical features
What are some different causes of parkinsonism?
- drug-induced (typically bilateral)
- Lewy-Body dementia
- progressive supranuclear palsy (Steel-Richardson)
- multisystem atrophy
What are some drug-induced causes of parkinsonism? (2)
- antipsychotics e.g. haloperidol
- metoclopramide
How do we manage tremor in drug-induced parkinsonism?
Procyclidine
What are the symptoms of Lewy-Body dementia (parkinsonism)? (3)
- memory loss
- visual hallucinations
- parkinsonism
What are the symptoms of progressive supranuclear palsy (Steel-Richardson)? (5)
- postural instability (falls)
- impaired vertical gaze AKA vertical gaze palsy (difficulty reading or descending stairs)
- cognitive impairment
- parkinsonism
- poor response to levodopa
What are the symptoms of multisystem atrophy (parkinsonism)?
Autonomic features like postural hypotension, incontinence and impotence
Poor response to levodopa
What conditions showing parkinsonism have poor response to levodopa?
Progressive supranuclear palsy (Steel-Richardson syndrome) & multisystem atrophy
What is sporadic/idiopathic Parkinson’s disease?
Most common, unknown aetiology, may be related to environmental toxins or oxidative stress
What can cause secondary Parkinson’s disease? (6)
- neuroleptic therapy (e.g. for schizophrenia)
- vascular insults (e.g. in basal ganglia)
- MPTP toxin from illicit drug contamination
- repeated head injury
- manganese or copper toxicity (Wilson’s disease)
- HIV
What are main clinical features of Parkinson’s disease? (4)
- bradykinesia - slowness of movements, shuffling gait, slow-turning
- resting tremor
- rigidity - lead pipe, cogwheel
- postural instability - imbalance or falling, festination and shuffling gait
Describe the resting tremor in Parkinson’s disease. (4)
- asymmetrical onset
- improves with voluntary movement
- typically ‘pill-rolling’ (thumb and index finger)
- 4-6Hz
Describe the rigidity seen in Parkinson’s disease.
- lead pipe rigidity of muscle tone
- superimposed tremor –> cogwheel rigidity
- rigidity enhanced by distraction
Describe gait in Parkinson’s disease. (5)
- shuffling
- stooped
- small-stepped
- reduced arm swing
- difficulty initiating walking
What are some other symptoms of Parkinson’s disease? (6)
- fatigue
- constipation
- depression
- anxiety
- insomnia
- hypomimia (reduced facial expressions)
Why can Parkinson’s disease lead to postural hypotension?
Due to autonomic failure
What are some risk factors for Parkinson’s disease? (5)
- increasing age
- Hx familial Parkinson’s disease in younger-onset disease
- mutation in gene encoding glucocerebrosidase
- MPTP exposure
- drug-induced (antipsychotics, metoclopramide)
How is a diagnosis of Parkinson’s disease primarily made?
Clinical diagnosis - Hx alongside presenting features
Revised Unified Parkinson’s Disease Rating Scale (MDS-UPDRS)
What are some investigations that can be done for Parkinson’s disease? (3)
- dopaminergic agent (levodopa) trial - improvement in Sx
- single photon emission computed tomography (SPECT)
- dopamine transporter scintigraphy - reduction in striatum and putamen
What are some differential diagnoses for Parkinson’s disease? (8)
- essential tremor (asymmetry, bradykinesia and rigidity uncommon)
- normal pressure hydrocephalus
- parkinsonism
- drug-induced parkinsonism
- Lewy-body dementia
- progressive supranuclear palsy (Steel-Richardson)
- multisystem atrophy
- Alzheimer’s disease with parkinsonism
What feature is not common in Parkinson’s disease?
Diplopia not common in Parkinson’s disease and may suggest an alternative cause of parkinsonism e.g. progressive supranuclear palsy
What is the first step to Parkinson’s disease treatment?
Urgent referral to neurology, medications can only be initiated by specialists
What is the general first line management for Parkinson’s disease?
Levodopa
What is first-line for Parkinson’s disease if motor symptoms affect QoL?
Levodopa (dopamine)
What is the first-line treatment for Parkinson’s disease if motor symptoms do NOT affect QoL? (3)
- dopamine agonist (non-ergot derived –> ropinerole, pramipexole, apomorphine), or
- levodopa, or
- monoamine oxidase B (MAO-B inhibitor) e.g. rasagiline
Why might dopamine agonists/MAO-B inhibitors be used for Parkinson’s disease when motor Sx are not significant?
Fewer motor complications
(But dopamine agonists have more specific adverse events)
How do we manage Parkinson’s disease if a patient already on optimal levodopa Rx has continued Sx/developed dyskinesia?
Addition of dopamine agonist, MAO-B inhibitor or catechol-O-methyl transferase (COMT) inhibitor as an adjunct
What is one of the first common side effects of levodopa? (Parkinson’s disease)
‘Wearing off phenomenon’ - Sx towards end of dose and prior to next dose, can be managed by increasing administration frequency
What may eventually happen with levodopa treatment?
On-off effect –> sometimes works, sometimes does not
How can we manage nausea (levodopa side effect) in Parkinson’s disease?
Domperidone
What are some side effects at peak levodopa dose (Parkinson’s disease)? (3)
- dystonia
- chorea
- athetosis (involuntary writhing)
What is a side effect of dopamine agonists (Parkinson’s disease)?
Impulse disorders e.g. pathological gambling
What does it mean that Parkinson’s disease medications are ‘critical medications’?
Should not be stopped even on acute admissions to hospital, and must be delivered on time to prevent symptom reoccurrence
What can acute withdrawal of levodopa cause?
Can precipitate neuroleptic malignant syndrome, treated with dopamine agonists (bromocriptine)
What supplement can we give for Parkinson’s disease?
Vitamin D
What supportive care is there for Parkinson’s disease? (3)
- exercise
- occupational therapy
- speech therapy
What drugs do we avoid in Parkinson’s disease?
Antipsychotics (e.g. haloperidol) - can worsen symptoms
What are some complications of Parkinson’s disease?
- dementia
- constipation
- depression
- anxiety
- psychosis
- dopamine agonists –> impulse control disorder
- levodopa-induced dyskinesias
Describe the prognosis of Parkinson’s disease.
Course is progressive, and no curative agents available
What is the difference between Parkinson’s disease dementia (PDD) and Lewy-body dementia?
Time of onset - overlapping Sx, PDD diagnosed if patient had Parkinson’s disease diagnosis for >1y –> different Rx (PDD = levodopa, DLB = rivastigmine with levodopa only if severe)
What is the triad of normal pressure hydrocephalus?
Wacky, wobbly, wet
- dementia
- gait ataxia/abnormality (similar to Parkinson’s disease)
- urinary incontinence
What is seen on neuroimaging in normal pressure hydrocephalus?
Ventriculomegaly in the absence of/out of proportion to sulcal enlargement
