Lecture one (Pain)-Exam 1 Flashcards
What is the definition of pain (both for american academy of pain medicine and margo mccaffery)?
- “An unpleasant sensation and emotional response to that sensation”-AAPM
- “Pain is whatever the person says it is, existing when and where the person says it does”-Margo
What is transduction?
Process that converts a pain stimulus to biologic signal
Transduction
- What are the different tissue injuries?
- What does these tissue injuries cause?
Tissue injury
* Mechanical – pinch, stab
* Thermal - burn
* Chemical – strong acid
Inflammatory response releases chemicals that stimulate sensory nerve fibers
* Prostaglandins
* Histamine
* Cytokines
* Bradykinins
What is transmission?
pain action potential from site of injury to cortex of brain
Ascending tract:
* Which horn?
* What happens in the ascending tract?
* Order neurons?
- Dorsal horn of spinal cord
- Stimulated sensory nerve fibers send impulse / action potential to the spinal cord
- 1st, 2nd, 3rd order neurons
What are the first order neuron?
Site of stimulus to dorsal horn of spinal cord
What is the second order neuron
Dorsal horn of spinal cord -> through brainstem -> to thalamus
* Crosses to opposite side of spinal cord
* Travels through spinothalamic tract (pain track)
Right hand injury=left side of brain is processing it
What is 3rd order neuron?
- Thalamus to cerebral cortex
- Region of cortex stimulated correlates to site of injury
- Opposite side stimulated
Impulse transmitted primarily by what two nerve fiber types?
- A-delta – thin, poorly myelinated, fast, sharp, stabbing, localized
- C – thin, unmyelinated, slow, dull, aching
What are the primary NTs of pain? What is it stimulated by?
Primary neurotransmitters of pain – stimulated by chemicals released during pain response
* Glutamate
* Substance P
Explain the whole process of transmission
What is perception?
Consciously perceiving pain and its characteristics
* Location
* Intensity
* Type
What does perception stimulate and result in?
- Stimulates emotional response
- Results in response
Where is perception processed in the brain?
Somatosensory cortex: different regions correspond to different parts of the body
What is modulation?
How the pain signal is altered by the descending pathway
Explain how pain signal is altered by the descending pathway?
- Descending modulatory fibers generally help to inhibit pain signals
- Noradrenaline/serotonin primary neurotransmitters
- Control (inhibit) communication between the 1st and 2nd order neuron
MODULATION
What are the effects of epinephrine and 5-HT?
Inhibit release of substance P and glutamate from presynaptic vesicles
Stimulate interneuron responsible for releasing endogenous opioids (enkephalin)
* Inhibits release of substance P and glutamate from presynaptic vesicles
* Inhibits postsynaptic neuron from depolarizing
What is nociceptive and neuropathic pain?
Nociceptive: caused by an injury to body tissues
* e.g., post-op, trauma, procedural pain
Neuropathic: caused by damage to or dysfunction of nerves
* e.g., neuropathies, post herpetic neuralgia, phantom limb pain
may be a combination
What is psychogenic pain?
psychologic factors such as headaches or abdominal pain caused by emotional, psychological, or behavioral factors
- What is break through pain?
- What are the three different types?
Break through – pain that occurs scheduled pain medications
* Spontaneous: no identifying factor -> give PRN medication
* Incident: after some stimulus -> give PRN medication
* End of dose: increase dose or frequency of scheduled medication
What are the two subtypes of nociceptive pain? What does this type of pain respond well to?
What are the two subtypes of neuropathic pain? What does this type of pain respond well to?
What is acute pain? (how long and associated with what)
- Of short duration; self-limited (< 3 months)
- Often associated with objective physical signs
Chronic pain:
* length?
* may begin as what?
* what is the cause?
* S/S?
- > 3 months
- May begin as acute pain but continues or recurs over a prolonged period
- Cause often unknown
- Does not look like in pain