Wk 9 Parkinson's Disease

Question 1

Define Parkinson’s disease

Answer 1

• neurodegenerative brain disorder
• involves loss of dopaminergic neurons in the brain
• dopamine deficiency leads to loss of muscle control
• incurable and progressive, ↓ QOL

PD types:
Idiopathic Parkinsonism - most common
Vascular Parkinsonism - caused by multiple small strokes
Dementia with Lewy Bodies - leads to memory loss and fluctuation in thinking patterns
Drug-induced Parkinsonism - caused by meds, especially those affecting brain dopamine levels, ie antipsychotics, antiemetics, antidepressants

Question 2

What are the risk factors for Parkinson’s disease?

Answer 2

• Age & Gender: old, male
• Genetic predisposition: family history
• Medications:
  drugs/antipsychotics
  > typical antidepressant, haloperidol, droperidol, chlorpromazine
  > atypical antidepressant, olanzapine, risperidone, tramadol
• Exposure to toxin, ie agent orange, pesticides

Question 3

What are the clinical characteristics of Parkinson’s disease?

Answer 3

tremor - shaking, which usually starts on one side of the body
rigidity - limb stiffness
akinesia - difficulty in initiating movement
postural instability - problem with balance

Question 4

What are the non-pharmacological treatment approaches for Parkinson’s disease?

Answer 4

Non-pharmacological:

• PT education on medications to avoid (ie antipsychotics …)
• engage in physical activity/physiotherapy to ↑ body balance & motor function
• supportive care in the advanced stage when drugs are poorly tolerated

Question 5

What are the pharmacological treatment approaches for Parkinson’s disease?

Answer 5

Pharmacological:

• treatment goals are to provide symptomatic relief
• meds are used to ↑ dopamine, ↓ acetylcholine

Treatment choice:

• Patient’s age, (young, dopamine agonist, old - levodopa combinations)
• S/S, is QOL impacted?
• If the PT can tolerate side effects?
• How well the medication work overall

> Levodopa combinations or dopamine agonists are the 1st line choices for PD
> start with low dose and ↑ gradually
Levodopa combinations (for the old)
Drug class: central nervous system agents
MOA: replace the missing dopamine in the brain
AEs (lower incidence): N&O, postural hypotension, constipation, cardiac arrhythmias
CON: 
- some antipsychotics that may ↓ the effect of levodopa
- some dopamine agonists as the combination may ↑ the AEs of levodopa
- some BP control drugs (ACEI, A2RA, CCB, BB, Thiazide diuretics) as the combination may an additional drop in BP

Dopamine agonists (for the young)
(cabergoline, bromocriptine, pergolide)
MOA: mimic dopamine 
AEs (higher incidence): similar to levodopa, plus impulse control disorders, hypersexuality

MOA-B inhibitors (less effective)
(rasagiline, selegiline)
MOA: conserve dopamine by blocking the MOA-B enzyme
> less effective than levodopa
AEs: N/V, postural hypotension, headache, insomnia
CON: when used with levodopa, may ↑ AEs

Anticholinergic agents (worst)
MOA: to reduce excess cholinergic activity that accompanied dopamine deficiency in PD, not for older/motor symptoms
AEs: dry mouth, urinary retention, constipation, hallucinations

NP:

• first-line: levodopa combinations & dopamine agonists
• avoid use with antiemetics (ie metoclopramide), and antipsychotics (haloperidol, risperidone)
• if antipsychotic is needed, clozapine are less likely to worsen PD
• dopamine agonists are for younger PT
• start with a low dose and gradually adjust to control the symptoms
• need tampering stage before withdrawal

Question 6

What are the medications contraindicated to Parkinson’s meds?

Answer 6

• antiemetic drugs, ie metoclopramide

- antipsychotics, ie haloperidol, risperidone