Physiology of Pain Flashcards
pain may enhace disability?
yes – with chronic pain
PAIN accronym
P - pattern - onset / duration
A - area localization - local refer, multiple?
I- intensity - level of pain / rating scale
N - nature - description of how pain feels to patient
nocicpetive pain
pain caused by activation of peripheral nerve fibers by harmful noxious stimuli
neuropathic pain
pain caused by damage to the nervous system 0 burning , tingling, or pins and needless dx of pain
Von Frey Dichotomy?
peripheral nervous system is “perception” component of pain
CNS : “reaction” component of pain
perception component of pain
the stimulation of specific nocicpetors located on free nerve endings (mechnical distortion, heat, or cold)
initiates an action potential - passes along the trigeminal nerve pathways to the nucleaus caudalis within the brain stem
action potentials travel along these primary nociceptor neurons transer the information through synapses to the SPINOTHALAMIC and TRIGEMINOTHALAMIC tracts that sen the information to more rostral areas of the brain
*nociceptor activation
transmission of AP
interpretation and initial interpretation
spinothalamic
pain temp and crude touch
posterior column
position . prorioception, vibration, pressure and fine tough
(dorsal column)
reactive component of pain
the higher brain centers provide the reactive component of noxious stimulaiton
- information is processed- rapidly - indicating the severity, duration, and location of stimulus
also elicits emotional reactions. autonomic responses, and escape behaviors
*emotional overtones, activation of autonomic nervous system, avoidance / escape responses
light myelinated a delta fibers
faster
intitate reflex responses (brainstems)
initiate escape responses (cerebral cortex)
pain interpreted as well localized, sharp or bright quality
pain, heat, cold
smaller unmyelinated C fibers
carried along more diffuse pathways
create what is referred to as secondary pain (diffuse, dull, aching, and or burning)
autonomic
mediators
prostaglandins - can cause free nerve endings to become more reactive to stimulation
severe pain may be attentuated as a result of the erlease of endogenous morphine- like substance - like endorphins and enkepalins – which can inhibit pain pathways via morphine receptors in the brain and spinal cord
wind up or central sensitization
greater or more prolonged pain if pain is not initially managed adequatily – due to plasticity in brain in its pain pathways
gate control theory
theory of pain modulation provides support for pain relief therapies action on different parts of the nervous system
spinal cord dorsal horn cells act as a gate - able to open or close to prevent nocioceptive impulses from reaching the brain
OPENING = influenced by a -delta and C fibers
CLOSING = influenced by a -alpha and a - beta fibers - along with other neuro structures
ABC’s of pain
perception of pain results from a complex interaction among the following:
AFFECTIVE - emotional factors that can effect the experience of pain
BEHAVIORAL = actions taken to express or control pain
COGNITIVE = the meaning, beleifs and attitude towards pain
treating acute dental pain with OMT patient
dental practioner should clarify preferred acute pain management strategies with patients OMT provider or primary pain specialist whenever possible
- prevent compications of combined opioid analgesic therapy
- prevent under tx of pain in the dental patient
pts with hx of opiod addiction fall into four categories
- opiod addict - revocery bases with no pharm
- tx with OMT
- naltrexone therapy
- opioids still using
dosing of the OMT therapy of methadone or buprenorphine?
do NOT adequately control acute pain
- sufficient evidence to suggest that patients receiving chronic opiod medications, in some cases, may have hyperalgesia
- pts receiving chronic opiods usually have some cross-tolerance to the sedative, euphoric, respiratory depressant, and analgesic effects of other opiods
what may be a greater stresser for pts with OMT relapse?
limited but information suggests that inadequate tx of acute pain, onset of physiologic withdrawl or anticipatory anxiety in OMT patients – greater stressor for relpase
how to manage OMT patient - basic
should be continued on OMT or be prescribes an equivalent opiod daily dosage regimn to prevent physiologic withdrawl and disruption o their opiod addiction recovery
event of respiratory depression without cardiac or hemodynamic compromise?
patients should receive respiratory support as opposed to reversal treatemnt with naloxone due to the liklihood of inducing fulminant opiod withdrawl
buprenorphine managemnt
may benefit by dividing the total daily dose of buprenorphine into 3-4 doses throughout day to prvide a better analgesic coverage
in addition to daily dose - think about sublingual low dose (2mg) at 4-6 hr intervals may help with acute managment
acute pain managment in patients receiving naltrexone therapy
receieving daily naltrexone therapy should have their nelrexone discontinued ideally 72 HOURS BEFORE NAY PLANNED SURGICAL OR INTERVENTIONAL PROCEDURES where opioids may be encessary for managment of moderate to severe acute pain
patients receiving depot naltrexone
clinical dilemma
- high dose of opioids are required ot overcome the i-receptor blockade by naltrexone
- patients need continous respiratory monitoring for respiratory depression and oversedation at an appropriate tx facility due to inceased doses of opioids to achieve adequate analgesia
ASK in alcohol and drug screening 1 and 2?
if response is more than ___ or more times, _____ use for severity using ____
- do you sometimes drink beer, wine, or other?
- if yes – how many times in the past year have you had 5 or more (men under 65)/ 4 or more (women and men 65+) drinks in a day? - how many times in the past year have you used an illegal dru or used a prescription medication for non-medical reasons?
- if yes -w hich drugs?
if response is more than ___ or more times, _____ use for severity using ____
more than ONE
ASSESS use for severity using CAGE. CAGE-AID, then ADVISE the patient
ASSESS: CAGE
- have you ever felt you should CUT DOEN on your drinking or drug abuse?
- have people ANNOYED you by criticizing your drinking or drug use?
- have you ever felt bad or GUILTY about your drinking or drug use?
- have you ever had a drink or used drugs first thing in the morning (EYE OPENER) to steady your erves or get rid of a hangover?
psoitive to CAGE?
2+
advise?
provide personalized feedback and state concern
- ask permission to give feedback
- discuss your screening and assessment findings
- link unhealthy substance use to any known or potential risks / consequences
- ask for patietns reaction to feedback
Make a nonjudgmental yet explicit recommendation for change in behavior
- cut back to lower risk amounts
- further assessment and discussion wit their PCP
- positive CAGE
-
screen, then …..
intervene: advise, assess, assist, and arrange
collateral opiod risk mitigation
store mediation safely
discuss proper disposal of unused medication
have poison control phone number available
educate family members about the use of opiod use
at risk patients for overdose
combination of opioids opioid dose previous overdose social isolation substance use disorder abstinence chronic medical and or mental illness
naloxone
strong affanity to opioid receptor - blocks or reverses the effects of opiods
can be given IM, SC, IV : .4 to 2 mg - may repeat every 2-3 minutes
- takes into effect in 2-3 minutes
lasts for 30-90 minutes – so could relapse if taking longer acting opioid - infom patient not to take opioid after administration even if having withdrawl
shelf life 12-24 months
signs of opioid overdose
pinpoint pupils
slowed or stopped breathing
unconscioussness/ non-responsiveness
additional symptoms may include
- limp body
- pale face
- clammy skin
- purple or blue color of lips and fingernaisl
- vomitting
tx in opioid overdose
911/ naloxone / cpr
nasal narcan spray?
4 mg - intranasal into one nostril (onl holds singly dose )
can be repeated every 2-3 mins
place into alternate nostril
issues in treating pain in SUD patients
- when these individuals experience pain - less likely to recieve adequate pain mangement that the general population
- inadequate pain relief is a significant ris k factor for relapse
- distinguish b/w patients who are seeking pain releief and those seeking drugs for euphoric effects and identifying tolerance and physiologic dependence is critical to effective care and pain control
comorbid psychiatric and medical illness may complicate effective pain managemnt
