Lecture 7: Chronic Pain Flashcards
Define pain.
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.
What is the MC reason that people seek medical care?
Pain
What do most opioid OD deaths come from?
Heroin and fentanyl
What is nonmaleficence?
Not doing harm.
Slightly different from doing good. (Beneficence)
How long does acute pain usually last?
Momentarily to 6 months.
At what point is pain considered chronic?
3 months on average.
ASIPP defines it as 6 months.
What is the purpose of chronic pain?
No purpose :(
What kind of chronic pain is adaptable?
Constant chronic pain.
What happens to gray matter in patients with chronic pain?
Decreases.
When is chronic pain mostly treatable?
Within 2 years
What are the 3 NTs that excite pain?
- Substance P
- CGRP (calcitonin gene related peptide)
- Glutamate
What is a nocireceptor?
A receptor that can differentiate between what is painful and not.
Describe an A-beta fiber.
- Thick, myelinated, low threshold mechanoreceptors.
- Associated with light touch, pressure, and hair movement.
Describe an A-delta fiber.
- Thin, myelinated, high and low mechanical + thermal.
- First, Sharp intense pain
d= damn that hurts
Describe a C fiber.
- Unmyelinated, free nerve endings.
- High threshold to all stimuli.
- Majority of afferent fibers
- Prolonged, burning sensation after the A-stimulus
C = continuous
Where are the veins and arteries contained with the spinal cord?
Epidural space
Describe the pathway of pain beginning with peripheral sensory receptors.
- Peripheral sensory receptor
- Dorsal root ganglia
- Dorsal root
- Synapse in dorsal horn/column
- Connect with secondary order neurons
- Goes other contralateral and ascend (lateral spinothalamic)
- Other: ascend ipsilateral, descends, then goes to reflex arc.
What is the anterolateral system?
Describe white matter in the spinal cord.
- Myelinated
- Longitudinal
- Up down
- Signal conduction
High speed internet
Describe gray matter.
- Segmented
- Side to side
- Signal processing
- Also makes up nerve roots
Processors
When do spinal nerves not match the # of vertebrae?
Cervical; you have 8 Cervical spinal nerves and 7 cervical vertebrae.
What are the 3 types of pain and what is the MC?
- Nociceptive (MC)
- Neuropathic
- Psychogenic
What is Nociceptive pain?
- Activation of A delta and C fibers.
- Sensing dangerous/noxious things
What falls under nociceptive pain disorders?
- Arthritis
- Gout
- Cancer
- Facet joint arthropathy
What is neuropathic pain?
- Abnormal processing in the PNS or CNS.
- Burning, stabbing, or electrical sensations.
- NMDA/glutamate governs it.
Methadone works on neuropathic pain bc it works on NMDA.
What is allodynia?
Things that don’t cause pain cause pain
I.E. a bedsheet hurting you
What is dysthesia?
Abnormal pain “like fire”
What is hyperalgesia?
Hypersensitivity to a stimulus that normally isn’t very painful.
Pinprick feeling like a bullet
What are trophic changes?
Change of skin/nail due to injury
What is type I complex regional pain syndrome? Type II?
- Idiopathic or reflex sympathetic dystrophy.
- Causalgia/normal CRPS
What kind of pain is opiate sensitive?
Nociceptive pain
What kind of pain does not worsen with position?
Neuropathic.
What is psychogenic pain typically associated with?
Depression
What questionnaire is used to evaluate the effect of pain on someone’s quality of life?
Oswestry disability index
What is a pain agreement?
A non-legally binding document to help with patient compliance.
However, if YOU follow it, it may help with making a case.
What are the aspects of a pain agreement?
- One prescriber for meds
- Agree to UDS and any testing
- lost/stolen meds WILL NOT be replaced
- One pharmacy only
- Unfilled and unused meds must be brought back
- Insist on f/u for any med changes
What is the scale used to estimate pain?
Wong-baker FACES scale
What questionnaire can be used in place of the pain scale to monitor improvement?
Brief pain impact questionnaire
What are the common spinal physical exam tests?
- Straight leg raises for herniated discs
- Crossed leg raises for herniated discs
- Patrick’s/FABER = hip joint pathology
- Zygomatic joint loading = contralateral pain
- Foot-drop or toe drag = L5 root compression, sciatica, cauda equina syndrome
- Piriformis test = Lat Decubitus with hip flex produces pain
- Spurling’s
- Axial compression = disc joint disease
What are Waddell’s signs?
Nonsensical/anatomical pain from normal tests.
Producing weird pain different from expected pain.
waddells is weird
What is a fake Hoover’s test?
Good leg isn’t fighting you when they lift their weak one.
What is a fake UE arm test?
Give-way weakness appears in “bad” arm, but if both are tested, both give-way.
What is spinal cord stimulation mainly used to treat?
Lower back pain
What peripheral nerves can be stimulated?
- Ilioinguinal
- Somatic peripheral
- Occipital
- Cranial Nerves
What kind of stimulation type varies its waveforms and can cover a large range of pathology?
Burst stimulation
What part of the spinal cord is the target for stimulators?
Dorsal root ganglion
What does true CRPS look like?
- Hyperalgesia
- Swollen, smooth, glossy appearance
- Injury precipitated it
- Long-lasting
What is the mild procedure?
Minimally invasive lumbar decompression procedure
When are intrathecal pain meds given?
Last resort
What are the common intrathecal meds?
- Morphine
- Baclofen
- Hydromorphone
- Fentanyl
- Sufetanil
- Clonidine
- Bupivacaine
- Prialt (sea snails)
- Octreotide
How do we begin opioid dosing?
IR dosing with 50-90 MME.
Morphine equivalents
