Brain 6 Flashcards
Which factors contribute to the pathophysiology of Parkinson’s disease?
a. decreased dopamine in the basal ganglia
b. increased glutamate in the substantia nigra
c. decreased acetylcholine in basal ganglia
d. increased GABA in the thalamus
A. decreased dopamine in the basal ganglia
D. increased GABA in the thalamus
Parkinson’s disease is a
chronic neurodegenerative disorder of the basal ganglia
With Parkinson’s disease there is an imbalance between
dopamine (not enough) and acetylcholine (too much)
When given together ___ & ___ increase the concentration of dopamine in the basal ganglia
cabidopa & levodopa
Patients with Parkinson’s disease are at risk for
autonomic instability, orthostatic hypotension, dysrhythmias, and aspiration
_________ may be used to treat acute exacerbation of Parkinsonian symptoms
Anticholinergics
_____________________ can be used to treat the s/sx. of Parkinson’s disease.
A deep brain stimulator can be implanted
Procedure-related considerations for the insertion of a deep brain stimulator include
lack of airway access during the procedure and risk of venous air embolism
____________________ may exacerbate extrapyramidal s/sx and are contraindicated
Antidopaminergic drugs & phenothiazines
An example of a phenothiazine is
promethazine
Examples of antidopaminergic drugs include
metoclopramide
butyrophenones (haloperidol & droperidol)
Diagnosis of Parkinson’s disease requires 2 of the 4 cardinal signs:
- resting “pill-rolling” tremor
- skeletal muscle rigidity
- postural instability -loss of balance with an altered gait
- bradykinesia- very slow movement and reflexes
Risk factors for the development of Parkinson’s disease include
old age- greatest risk factor
exposure to manganese in welders as well as herbicides, pesticides, and possibly genetics
Levodopa is a precursor to
dopamine
Carbidopa is a
decarboxylase inhibitor
By preventing levodopa metabolism in the blood, more
levodopa can enter the CNS
In the circulation, levodopa is metabolized to
dopamine and DA in the blood does not penetrate the CNS
Cardiovascular effects of levodopa and carbidopa include
increased inotropy, tachycardia and orthostatic hypotension
Other side effects of levodopa & carbidopa include
dyskinesia, nausea and vomiting
Selegiline is a
MAO-B inhibitor
MAO-inhibitors restore
dopamine concentration by reducing dopamine metabolism in the CNS
Unlike non-selective MAOIs, selegiline does not increase the risk of
tyramine-induced hypertensive crisis
Other treatments for Parkinson’s disease include
dopamine agonists
anticholinergics
amantadine
hormonal replacement
catechol-o-methyltransferase inhibitors
Patients with Parkinson’s disease are at risk for
autonomic instability, orthostatic hypotension, dysrhythmias and aspiration
___________ has anticholinergic properties and is useful for sedation and reduction of tremors
diphenhydramine
Hypotension with patients with Parkinson’s should be treated with
intravascular volume expansion and direct acting agents such as phenylephrine
_______________ can cause an acute dystonic reaction due to the interruption of central dopaminergic neurotransmission.
Alfentanil
________ is controversial to give due to its effects on the SNS
Ketamine
It is important to monitor for __________ postoperatively for Parkinson’s patients.
postoperative ventilatory failure
Can you give neuromuscular blockers to Parkinson’s patients?
yes, no contraindications
Levodopa has a half-life of
6-2 hours; it must be given the morning of surgery to prevent worsening of symptoms such as rigidity which can impact ventilation
For longer surgeries for Parkinson’s patients,
levodopa should be administered via an orogastric tube
With deep brain stimulation surgery, seizures can be treated with
small dose of propofol, barbiturate or benzodiazepine
To minimize the risk of intracranial hemorrhage for deep brain stimulation surgery, SBP should not exceed
140 mmHg
The sitting position increases the risk of
VAE; a precordial doppler aids in diagnosis
If deep brain stimulation is planned, it may be helpful to withhold
levodopa; it causes symptoms to worsen which facilitates optimal electrode placement
Deep brain stimulation requires a ________
burr hole to insert electrodes into the subthalamic nucleus, globuc pallidus, and ventralis intermedius; this is done under stereotactic guidance
With deep brain stimulation, the patient’s head is placed in a
rigid frame. this can complicate airway management so avoid oversedation and respiratory depression
To determine optimal electrode placement, the patient must be
awake but can be lightly sedated with opioids or dexmedetomidine
Because of the crucial role of GABA in the thalamus,
GABA agonists such as propofol or benzodiazepines are avoided as they can interfere with electrophysiologic brain monitoring
