Parkinsonism Flashcards
What is the main cause of Parkinsonism?
Idiopathic Parkinson’s Disease
Describe the pathology of IPD
Loss of dopaminergic neurones in the basal ganglia - most notably the substantia nigra (inadequate dopamine transmission). Surviving neurons contain aggregations of a protein called Lewy bodies.
In some cases Lewy bodies seen throughout brain - in such cases there is often co-existing dementia.
IPD is a slowly progressive disorder, without remission. True or false?
True
What is the mean age of onset of IPD?
45-60
Symptoms of Parkinson’s are seen once levels of dopamine are what percentage below normal levels?
20-40%
Parkinsonism is often described as a triad of…
Tremor
Rigidity
Bradykinesia
Signs are initially worse on one side. True or false?
True - neurodegenerative disorders are not symmetrical
May progress to be bilateral
Describe the tremor seen in IPD
Resting tremor - disappears with deliberate activity
Pill rolling - rolling of thumb over fingers
4-6 Hz
Describe the bradykinesia seen in IPD
Slow movements
Slow to initiate
Decrease in amplitude with repetition
Fine motor movements particularly affected
Describe the rigidity seen in IPD
Increased resistance to passive movement - sometimes called lead pipe rigidity
Rigidity equal in extensors and flexors
Can be called cogwheel rigidity - temporarily gives way at certain points
What signs are associated with the patient’s gait?
Slow Shuffling steps Pitched forward Reduced arm swing Narrow based Turning on block Freezing at obstacles
What non motor symptoms are seen in IPD?
Autonomic dysfunction - postural hypotension, constipation, urinary frequency/ urgency, dribbling of saliva
Sleep disturbance - REM sleep disorder
Depression
Dementia
Hallucinations are common- combination of the disease and drugs used to treat it (often not unpleasant)
Speech - slow and monotonous (may be lost in late stages)
What is typically seen in a patient’s hand writing?
Typically smaller and more spidery
Do patients experience changes in sense of smell?
Yes - anosmia
How is IPD diagnosed?
Clinically - signs and symptoms
To diagnose Parkinsonism what 2 elements are necessary?
Bradykinesia
Rigidity
(Tremor may be predominant in some people, but absent in others)
What does a significant improvement with treatment suggest?
The cause is IPD rather than other causes of parkinsonism
What is the main treatment used?
Levodopa - a dopamine precursor.
Dopamine cannot cross the BBB, so a precursor is given
What is L-dopa given with?
A dopa-decarboxylase inhibitor e.g carbidopa
- prevents too much conversion to dopamine in the peripheries and allows increased amounts of levodopa to cross BBB
How long does it take for the benefits of L-dopa to be seen?
2-3 weeks
What are the side effects of levodopa?
Dyskinesia Painful dystonia - increased tone Psychosis Compulsive behaviours - gambling, sexual Nausea and GI upset On- off effect at end of the dose
Why should levodopa be started late?
Efficacy reduces with time, requiring larger and more frequent dosing, which increases side effects.
Also response fluctuations occur with prolonged use - unpredictable freezing and pronounced end of dose reduced response
Why should levodopa not be stopped suddenly?
Risk of acute akinesia and neuroleptic malignant syndrome
Why are dopamine agonists useful?
They can delay starting levodopa and allow lower doses of levodopa once PD progresses.
What are some examples of dopamine agonists?
Ropinirole
Pramipexole