Parkinson's disease Flashcards
What is Parkinson’s disease?
Parkinson’s disease is a progressive neurodegenerative condition caused by degeneration of dopaminergic neurons in the substantia nigra.
What are the classical features of Parkinson’s disease?
The classical triad of features includes bradykinesia, tremor, and rigidity.
How are the symptoms of Parkinson’s disease characterized?
The symptoms are characteristically asymmetrical.
What is the epidemiology of Parkinson’s disease?
It is around twice as common in men, with a mean age of diagnosis of 65 years.
What is bradykinesia?
Bradykinesia refers to poverty of movement, sometimes called hypokinesia, characterized by short, shuffling steps with reduced arm swinging and difficulty in initiating movement.
What is the nature of tremor in Parkinson’s disease?
Tremor is most marked at rest, typically ‘pill-rolling’ in the thumb and index finger, and is worse when stressed or tired but improves with voluntary movement.
What are the types of rigidity associated with Parkinson’s disease?
Rigidity can be described as lead pipe or cogwheel, the latter due to superimposed tremor.
What are other characteristic features of Parkinson’s disease?
Other features include mask-like facies, flexed posture, micrographia, drooling of saliva, and psychiatric features such as depression.
What psychiatric features are associated with Parkinson’s disease?
Depression is the most common feature, affecting about 40%, with possible dementia, psychosis, and sleep disturbances.
What are some additional features of Parkinson’s disease?
Impaired olfaction, REM sleep behaviour disorder, fatigue, and autonomic dysfunction such as postural hypotension.
How does drug-induced parkinsonism differ from Parkinson’s disease?
Motor symptoms are generally of rapid onset and bilateral, with rigidity and rest tremor being uncommon.
How is Parkinson’s disease diagnosed?
Diagnosis is usually clinical, but if differentiating between essential tremor and Parkinson’s disease is difficult, NICE recommends considering 123I-FP-CIT single photon emission computed tomography (SPECT).
A Lewy body (stained brown) in a brain cell of the substantia nigra in Parkinson’s disease. The brown colour is positive immunohistochemistry staining for
alpha-synuclein
Normal substantia nigra vs PD
PD drugs MOA
PD drugs - effect on motor symptoms, activities of daily living, off time, adverse events, hallucinations
PD drugs - effect on motor symptoms, activities of daily living, off time, adverse events, hallucinations
Who should diagnose and manage Parkinson’s disease?
Parkinson’s disease should only be diagnosed and managed by a specialist with expertise in movement disorders.
What are the first-line treatments for Parkinson’s disease based on quality of life?
If motor symptoms affect quality of life: levodopa. If not: dopamine agonist (non-ergot derived), levodopa, or MAO-B inhibitor.
What are the effects of levodopa compared to dopamine agonists and MAO-B inhibitors?
Levodopa provides more improvement in motor symptoms and activities of daily living but has more motor complications. Dopamine agonists and MAO-B inhibitors offer less improvement in these areas.
What should be added if a patient continues to have symptoms despite optimal levodopa treatment?
NICE recommends adding a dopamine agonist, MAO-B inhibitor, or COMT inhibitor as an adjunct.
What are the risks associated with acute akinesia or neuroleptic malignant syndrome?
These risks arise if medication is not taken or absorbed, such as during gastroenteritis.
What are the common issues with dopaminergic therapy?
Impulse control disorders can occur, especially with dopamine agonist therapy, and in patients with a history of impulsive behaviors or alcohol consumption.
What should be done if excessive daytime sleepiness develops?
Patients should not drive, and medication should be adjusted to control symptoms. Modafinil can be considered if alternative strategies fail.
What medication can be considered for orthostatic hypotension?
Midodrine can be considered if symptoms persist after a medication review.
What is the common combination for levodopa treatment?
Levodopa is nearly always combined with a decarboxylase inhibitor (e.g., carbidopa or benserazide) to prevent peripheral metabolism.
What are the common adverse effects of levodopa?
Common adverse effects include dry mouth, anorexia, palpitations, postural hypotension, and psychosis.
What is the ‘on-off’ phenomenon in levodopa treatment?
It refers to large variations in motor performance, with normal function during the ‘on’ period and weakness during the ‘off’ period.
What are dopamine receptor agonists and their risks?
Examples include bromocriptine, ropinirole, and cabergoline. They can cause impulse control disorders and are more likely to cause hallucinations in older patients.
What do MAO-B inhibitors do?
They inhibit the breakdown of dopamine secreted by dopaminergic neurons.
What is the mechanism of action for Amantadine?
Its mechanism is not fully understood but likely increases dopamine release and inhibits its uptake at dopaminergic synapses.
What are COMT inhibitors used for?
They are used as an adjunct to levodopa therapy in patients with established Parkinson’s disease.
What are antimuscarinics used for?
They block cholinergic receptors and are now used more for drug-induced parkinsonism rather than idiopathic Parkinson’s disease.
