Parkinson's Disease Flashcards
What causes PD?
Degeneration of the dopamine-producing neurons found within the substantia nigra.
Name 2 genes associated with PD?
Parkin
Alpha-synuclein
Which part of the brain are the substantia nigra found in?
There are 2 of these, found either side of the midbrain.
What are the characteristic symptoms of PD?
Tremor (resting)
Rigidity
Akinesia
Postural instability
Remember TRAP!
What is the difference in the tremor experienced in cerebellar dysfunction compared with that of PD?
Tremor in PD is at rest, improves with movement.
Tremor in cerebellar dysfunction is an intention tremor (not present at rest).
What is meant by rigidity?
Increased muscle tone felt when trying to move limbs passively.
What test is used to check for rigidity?
Froment’s manoeuvre.
This initiates the ‘cogwheel’ sign.
What is akinesia?
Slowness/absence of voluntary muscle movement.
What is the typical gait observed in a PD patient?
Slow gait, with narrow, shuffling steps.
Hesitation initiating movement and a stooped posture.
Which test is used to analyse posture and gait in suspected PD?
Pull test.
Are most cases of PD idiopathic or genetic?
Idiopathic (95%).
What is thought to be a marker of neuronal ill-health?
Presence of Lewy bodies.
Is PD the most common neurodegenerative disease?
No, Alzheimer’s disease is - PD is second.
What investigation methods are used in the diagnosis of PD?
It is usually a clinical diagnosis, although a DaTSCAN can be helpful (this shows function, not structure).
Response to dopamine therapy will back-up diagnosis.
What is a major prevailing factor common in those with PD?
Old age.
What non-motor symptoms are linked to PD?
Late-onset hyposmia Depression/anxiety Constipation Bladder issues Pain Mild cognitive impairment
What are the 4 main types of drug used in PD?
Levodopa
COMT inhibitors
MAO-B inhibitors
Dopamine agonists
Which therapy is first-line in PD management?
Levodopa.
Why is levodopa an inactive form of dopamine?
To allow it to cross the blood-brain-barrier.
What is given alongside levodopa to produce active dopamine?
Carbidopa.
In those with levodopa-induced nausea and vomiting, what is given?
Domperidone.
What is the role of COMT inhibitors?
Blocks the enzymatic breakdown of levodopa prior to it crossing the blood brain barrier.
In PD, dopamine levels are decreased. What other neurotransmitter must be controlled in these patients to stop symptoms?
Acetylcholine.
What drugs are given to prevent tremor?
Anticholinergics.
Remember cause dryness.
Are treatment methods in PD preventative or do they aim to manage symptoms?
Symptomatic relief only - disease progression inevitable.
What are side-effects of dopamine agonists?
Impulsive behaviour
Sleepiness
Psychosis
What drugs can cause drug-induced PD?
Chlorpromazine
Metoclopramide
Methyldopa
Diltiazem
What are some long-term complications of dopamine therapy?
Motor fluctuations
Non-motor fluctuations
Dyskinesia
Drug-induced psychosis
When are MAO inhibitors used?
In moderate disease only.
How does substantia nigra degeneration present?
Loss of characteristic black appearance of the regions.
Is muscle weakness a feature of PD?
No.
This helps to set it apart from issues with the motor cortex and the corticospinal pathway.
Tremor is most commonly seen in which part of the body?
Upper limbs.
Is PD a condition characterised by symmetrical disease?
No, patients will have asymmetrical symptoms.
What % of PD patients develop Parkinson’s dementia?
Around 80%.
What is the difference between dementia with lewy bodies and Parkinson’s dementia?
Parkinson’s dementia will present after a year of PD - DwLB presents earlier.
Can PD be drug-induced?
Yes, following a few months of treatment withdrawal, symptoms will improve.
Which test is used to induce postural instability in an individual suspected to have PD?
The pull test.
Is PD usually symmetrical at point of onset?
No, it is common for PD to begin asymmetrically.
