Parkinson's disease Flashcards
What is PD?
A chronic, progressive neurodegenerative condition resulting from a loss of dopamine-containing cells of the substantial niagra.
What age group has highest PD incidence?
Incidence increases with age- highest in over 80s
What is the presentation triad seen in PD?
- Bradykinesia- slowness of movement
- Muscle rigidity
- Tremor
These 3 symptoms are known as parkinsonisms- they can be PD but can also be present in drug use, brain damage e.g. stroke
What are the non-motor PD symptoms?
Depression, anxiety
fatigue
cognitive impairement
sleep disturbance
constipation
hyposmia- dencreased sense of smell
excessive sweating
bladder problems
pain
hypotension
excess saliva or drooling
Which dopamine pathway is responsible for the motor symptoms?
Nigrostriatal
Which dopamine pathway is responsible for the behavioural symptoms?
mesolimbic and mesocorticol
Which dopamine pathway is responsible for the endocrine symptoms?
tuberohypophyseal
What are the motor symptoms of PD?
- Bradykinesia- slowness of voluntary movements.
Can include mask-like lack of facial expressions
Hypophonia- soft or monotone voice
Micrographia- small handwriting
difficulty in fine motor actions e.g. doing buttons
shuffling gait- smaller steps - Rigidity- increased muscle tension
mostly affects flexor muscles of trunk and limbs
stooping posture
increased falls, decreased balance
muscle pain - Tremor
not in all patients
presents at rest
1 or both hands
‘pill-rolling’- moving fingers in a circular motion
NOTE- lots of meds can cause a tremor so review to see if these can be adjusted e.g.
Anti-psychotics e.g. haloperidol
Beta-agonists e.g. salbutamol, salmeterol
Anti-emetics e.g. metoclopramide, prochlorperazine
What are the causes of PD?
Often unknown
- can be inherited genetics e.g. 𝛼-synuclein point ,station, PARKIN gene mutation, Lewy body formation
- main is increasing age
- environmental - prescription drugs e.g. APs, anti-emetics or recreational drugs.
- Physical e.g. cerebral ischaemia, viral encephalitis, brainstem injury, dementia pugilistic
What is encephalitis lethargy?
A viral illness that had an epidemic in the 1920s- gradually patients seized up and had drowsiness and rigidity- eventually became permanent
- levodopa provides short time relief
How is PD diagnosed?
- Often patient presents in primary care with gradual symptoms
- Refer to a specialist
- there is no conclusive diagnostic test- instead it is based on symptoms, medical history and neurological ecm
- MRIs may be used for differential diagnoses
- DATSCAN- measures density of nigrostriatal dopamine transporter sites (loss of dopaminergic neurones) - but even an abnormal DATSCAN cam exlusively confirm pd diagnosis
- improvements with PD meds confirm a diagnosis
What is the recommended first line treatment for motor symptoms?
Levodopa
What are the treatment guideline for motor symptoms?
1st line:
- Offer Levodopa in early PF where motor symptoms affect pt quality of life
- Consider dopamine agonists, levodopa, MAO-B inhibitors for early PD whose motor symptoms do not affect QOL.
Adjuvant therapies:
ensure 1st line is optimised
When: dyskinesias or motor fluctuations develop inc wear off episodes of meds, offer:
Choice of dopamine agonists, monoamine oxidase B inhibitors to COMT inhibitors as an adjuvant to levodopa
- if dyskinesia not adequately controlled, consider amantadine
What are acute side effects of levodopa?
Nausea
anorexia
hypotension
anxiety, depression, insomnia, nightmares, hallucinations
- on off phenomenon- increase in symptoms as dose wears off and may cause freezing
How is levodopa always given?
As a combination product with carbidopa and benserazide
As these decrease the peripheral metabolism of levodopa and decrease peripheral side effects- they do not cross the BBB
Carbidopa + levodopa = co-careldopa e.g. Sinemet
Benserazide + levodopa = co-beneldopa e.g. Madopar
What are examples of COMT inhibitors?
Entacaponr
Tolcapone- rarely used due to risk of liver toxicity
What are Stanek, Stavelo and Sastravi?
A co-careldopa + entacapone formulation
- these potentiate the effects of levodopa
- Helps counteract the fluctuations in plasma conc of levodopa
- entacapone isn’t useful alone
What are the side effects of entacapone?
Colours urine bright red/orange- need to counsel patient
Diarrhoea
May worsen Levodopa side effects e.g. nausea, psychological effects, dyskinesia
How is levodopa administered?
- in divided daily doses to reduce peaks and troughs- max of 800mg per day
- Often as a MR prep before bed