Protective mechansims Flashcards
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3 protective mechanisms
- Physical barriers
- Immune system
- Physiological responses
What are the physiological responses
Pain, nausea and vomiting
What is pain
“An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”.
How is pain classified
Chronicity - Acute or chronic
Pathophysiology (cause) - Nociceptive, neuropathic, neuroplastic
Happens TO you.
Acute pain
- Physiological & protective
- Occurs immediately after a stimulus is received & subsides once removed.
- Tissue damage relatively rapid resolution (days-weeks) and responds well to Rx.
- Severity can vary.
- Sympathetic hyperactivity when severe, e.g. tachycardia, hypertension, sweating,
Happens in you
Chronic pain
- Pathological & non-protective.
- Long history, well past initial stimulus, and poorly defined onset – may be internal/obscured.
- Variable severity and may cause significant psychiatric pathology.
- Resolution variable depending upon control and may not respond well to treatment - pain control rather than cure.
- Can result in allodynia, hyperalgesia, and opioid tolerance.
What is Nociceptive pain
Damage to Somatic or visceral tissue
Sharp, aching or throbbing
What is neuropathic pain
damage to central or peripheral nerves
Burning and sensitive to touch
Stroke, MS spinal chord c
Neuroplastic pain
Not pain from ongoing tissue damage but from how the brain and nervous system process pain signals
Abnormal increased sensitivity to pain
most common
3 types of Nociceptive pain
Radicular - nerve roots pinched
Somatic- pain receptors in muscles/bones/skin activated
Visceral - interal organs injured or inflamed
Outline the 4 parts of the pain pathway and how analgesic drugs work in each part.
2. Outline the mechanism of action of anti-inflammatory drugs.
Compare the 3 types of pain
see diagram
Pain pathways divied into 3 segments
- Afferent
- CNS
- Efferent
Name the 4 pain processes
- transduction
- transmission
- Perception
- Modulation
Where can nociceptive pain be blocked by analgesics?
At 1 or more points in the pain pathway
Outline the mechanism of action of anti-inflammatory drugs.
What can block transduction
Local anesthetics
NSAIDS
At site of injury or intravenously
Outline the mechanism of action of anti-inflammatory drugs.
What can block transmission
Local anesthetics
Along peripheral nerve, at nerve plexus, epidural or subarachnoid spaces
Outline the mechanism of action of anti-inflammatory drugs.
What can block perception
General anesthetics, opiods or alpha 2 agonists
Outline the mechanism of action of anti-inflammatory drugs.
What can block modulation
Local anesthetics, alpha2 adrengenic agonists and gabapentin
How are analgesics classified
Non-opioid – Paracetamol, NSAIDS (aspirin, ibuprofen, etc.) and local anaesthetics.(MILD PAIN)
Opioid – subdivided in to “weak opioids” (mild to moderate pain) & “strong opioids” (moderate to severe pain).
Adjuvant – drugs not designed as analgesics but have analgesic effects in certain clinical situations (steroids, antidepressants, anticonvulsants, etc.).
Outline the mechanism of action of anti-inflammatory drugs.
Examples of NSAIDS
Aspirin
Inbuprofen
Naproxen
Paracetamol
Outline the mechanism of action of anti-inflammatory drugs.
What do NSAIDS block
Enzyme called cyclo-oxygenase which is needed to produce prostaglandins
Outline the mechanism of action of anti-inflammatory drugs.
What does COX do
Produces prosoglandins which sensitize nociceptors, cause inflammation and fever and amplify pain signals
How do local anesthtics block pain
block sodium channels and reduce action potentials
