Pain Flashcards
Describe the innervation of the heart?
The vagus provides afferent visceral supply to the inferior aspect of the heart therefore inferior MI’s present in a non-classical way: nausea, epigastric pain, and vomiting
The sympathetics from T1-4 supply the anterolateral and posterior aspect of the heart, pain is referred to the T1-4 dermatome which is on the precordium
What are some predictors for the development of chronic pain?
The severity of the pain Depression/Anxiety History of trauma Premorbid function Worker's Comp Educational level Genetics/FHx
Describe the pathophysiology of shingles pain?
Local infection in the dorsal root ganglion causes a ganglionitis
The virus then travels done the axon causing an axonitis and finally there is pain in the dermatome?
What are some rare complications of shingles?
Myotome involvement causing weakness
Systemic dissemination and encephalitis
What are the risk factors for the development of post-herpetic neuralgia?
Age
Severity
Use of antivirals
Efficacy of treatment
What class of medication is useful in the treatment of post herpetic neuralgia?
TCA anti-depressants
What is the tradename, mechanism of action and indication, and advantages of transdermal buprenorphine?
Norspan patches
Partial opioid agonist, mild to moderate pain
Tolerance doesn’t develop
Good for use in addicts as it well block the action of new opioids
What is the mechanism of action of morphine? Where does it act?
Antagonism of Mu, Kappa, and delta receptors
Increases downregulation from the brain
Inhibits sensitisation in the spinal cord
Local anti-inflammatory effect too
How do NSAIDs treat pain?
Local inhibition of prostaglandins prevent upregulation of pain
What is the mechanism of action of ketamine?
Antagonises NMDA receptors
Also interacts with muscarinic receptors, descending monoaminergic pain pathways, voltage-sensitive calcium channels and opioid receptors in brain and spinal cord
What is the mechanism of action of gabapentinoids? What are some common side effects?
Calcium channel blockers
Dizziness, sedation
What is the mechanism of action and advantages of transdermal fentanyl?
Potent Mu antagonist
Less constipation cf to morphine
Tolerance develops quickly
What is tapentadol?
A Na reuptake inhibition and weak opioid
What is tramadol?
A weak opioid, inhibits noradrenaline, and serotonin reuptake
Strong nausea and vomiting, serotonin syndrome
What is a useful approach to pain?
Who is the patient
What is their mechanism of pain
What is the impact of their pain
- Let this direct treatment
