Pain pathway

Question 1

Pain

Answer 1

• emphasizes the complex nature of pain as a physical, emotional, and psychological condition
• does NOT correlate with tissue damage

Question 2

Nociception

Answer 2

• the experience of pain with a series of complex neurophysiologic processes
• Medications target causes of pain by actions on transduction, transmission, interpretation and modulation in both PNS and CNS

Question 3

Hyperalgesia

Answer 3

increased pain sensations to normally painful stimuli

Question 4

Allodynia

Answer 4

Perception of pain sensations in response to normally non-painful stimuli

Question 5

Chronic pain affects ____% of adult population

Answer 5

40%

Question 6

The order of pain perception

Answer 6

Transduction > transmission > modulation > perception

Question 7

Transduction

Answer 7

Nerve/electrical impulses/signals start at the nerve endings

Question 8

Transmission

Answer 8

Travel of nerve/electrical impulses to the nerve body connecting to the dorsal horn of the spinal cord

Question 9

What is modulation and where does it occur?

Answer 9

Dorsal horn

Process of altering (inhibiting/excitatory) pain transmission mechanisms at the dorsal horn to the PNS and CNS

Question 10

Perception occurs where

Answer 10

Thalamus acts as central relay station for incoming pain signals and the primary somatosensory cortex serving for discrimination of specific sensory stimuli

Question 11

Which drugs affect transduction

Answer 11

• Local anesthetics
• NSAIDs

Question 12

Which drugs affect transmission

Answer 12

• local anesthetics

Question 13

Which drugs affect modulation

Answer 13

• local anesthetics
• opioids
• ketamine
• a2 agonists (clonidine, precedex)

Question 14

Which drugs affect perception

Answer 14

• opioids
• a2 agonists (clonidine, precedex)
• general anesthetics

Question 15

What are the 2 types of afferent nerve fibers, and what do they sense

Answer 15

• Unmyelinated (C-fibers): burning pain from heat and pressure from sustained pressure
• Myelinated A-fiber:
• Type I fibers ( Aβ & Aδ fibers):
  heat, mechanical, chemical
• Type II fibers (Aδ fibers): heat

Question 16

Which chemical mediators cause pain

Answer 16

• peptides
• Eicosanoids
• Lipids
• neutrophins
• cytokines
• chemokines
• extracellular proteases and protons

Question 17

Which chemical mediators of pain are peptides?

Answer 17

Substance P, Calcitonin, Bradykinin (1st released), CGRP

Question 18

Which chemical mediators of pain are lipids?

Answer 18

Prostaglandins, Thromboxanes, Leukotrienes, Endocannabinoids

Question 19

What is the difference between primary and secondary hyperalgesia?

Answer 19

Primary= at the original site of injury from heat and mechanical injury; decreased pain threshold, increase response to suprathreshold stimuli, spontaneous pain, expansion of receptive field

Secondary= uninjured skin surrounding the injury (only from mechanical stimuli); sensitization of central neuronal circuits.

Question 20

Which part of the spinal cord serves as the relay center

Answer 20

dorsal horn

Question 21

Which dorsal horn lamina are C fibers present

Answer 21

1 (marginal layer) and 2 (substantia gelatinosa)

Question 22

Which dorsal horn lamina do opioids primarily act on

Answer 22

lamina 2 (substantia gelatinosa)

Question 23

Which lamina are A fibers present?

Answer 23

1, 3, 4, 7

Question 24

Which lamina is substance P found

Answer 24

3 and 4

Question 25

In gate theory if the gate is open: pain is projected to __________ brain regions

Answer 25

supraspinal

Question 26

If the gate is closed: pain is _____________________

Answer 26

not felt with simultaneous inhibitory impulses A-Beta fibers deliver information about pressure and touch (rubbing)

Question 27

If the gate is open, which fibers are active

Answer 27

A-delta and C fibers

Question 28

What purpose does the limbic cortex and thalamus play in pain physiology

Answer 28

Perception of motivational-affective pain components

Question 29

Which area of the CNS depress or facilitate the integration of pain info in the spinal dorsal horn?

Answer 29

Periaqueductal gray (PAG) and Rostral ventromedial medulla (RVM) system

Question 30

Neuromodulators of pain include

Answer 30

- substance P - glutamate - CGRP - NMDA - AMPA - BDNF - Cytokines

Question 31

Tissue injury releases which neuromodulators

Answer 31

Substance P and glutamate

Question 32

Which neuromodulators in spinal area are excitatory impulses

Answer 32

- glutamate - calcitonin - Neuropeptide Y - Aspartate - Substance P

Question 33

Which neuromodulators in spinal area are inhibitory impulses

Answer 33

- GABA - glycine - enkephalins - norepinephrine - dopamine

Question 34

Ascending pathways of nociceptive information

Answer 34

- Spinothalamic - pain, temp, itch (I, VII, VIII) all afferent fibers - Spinomedullary - Spinobulbar - behavior toward pain (I, V, VII) - Spinohypothalamic - autonomic, neuroendocrine, emotional aspects (I, V, VII, X)

Question 35

Supraspinal modulation of pain occurs

Answer 35

- Forebrain SI and SII - location and intensity - Anterior cingulate cortex (ACC) - emotional and motivational aspects - Insular cortex (IC) - emotional and motivational aspects - Prefrontal cortex - Thalamus - Cerebellum

Question 36

Descending inhibitory tracts originate in

Answer 36

Periaqueductal gray (PAG), travels through rostral ventromedial medulla (RVM), dorsolateral funiculus, synapse in dorsal horn

Question 37

Which neurotransmitters are in the descending inhibitory tracts

Answer 37

endorphins, enkephalins, serotonin

Question 38

How do descending inhibitory tracts inhibit pain?

Answer 38

Hyperpolarize A-delta and C fibers, - decreases release of substance P - opening of K+ channels and inhibition of Ca2+ channels

Question 39

Pain that persists after tissue has healed is called

Answer 39

Neuropathic -> allodynia and hyperalgesia

Question 40

Treatment of neuropathic pain includes

Answer 40

symptomatic (opioids, gabapentin, amitryptiline, cannabis)

Question 41

Pain that is diffuse and poorly localized (referred to somatic sites: muscle and skin)

Answer 41

Visceral

Question 42

Visceral pain is caused by

Answer 42

ischemia, stretching of ligamentous attachments, spasms, distention

Question 43

Pain perception in neonate occurs at ___ weeks

Answer 43

23 weeks

Question 44

Neonates have a ____ threshold for pain and ______ pain responses

Answer 44

lower, exaggerated

Question 45

What are complex regional pain syndromes

Answer 45

- A variety of painful conditions FOLLOWING INJURY in a region with impairment of sensory, motor, and autonomic systems - Spontaneous pain, allodynia, hyperalgesia, edema, autonomic abnormalities, active and passive movement disorders, and trophic changes of skin and SQ tissues

Question 46

CV responses to pain include

Answer 46

- HTN - Tachycardia - myocardial irritability - inc SVR In compromised LV can cause dec. CO and ischemia

Question 47

Pulmonary responses to pain include

Answer 47

- Increased total body O2 consumption - Increased CO2 production - Increased Vm and work of breathing - Splinting - Decreased movement of chest wall -> atelectasis and shunting - Impaired coughing

Question 48

GI/GU responses to pain include

Answer 48

- N/V - enhanced sympathetic tone = inc. sphincter tone and dec. motility (ileus and urinary retention) - Hypersecretion of acid = stress ulceration and aspiration - Abd. distention

Question 49

Endocrine response to pain include

Answer 49

- Increased catabolic hormones = catecholamines, cortisol, glucagon - Decreased anabolic hormones = insulin, testosterone effects: negative nitrogen balance, carbohydrate intolerance, increased renin, aldosterone and angiotensin

Question 50

Hematologic response to pain include

Answer 50

Stress related - platelet adhesiveness - reduced fibrinolysis - hypercoagulability

Question 51

Immune responses to pain include

Answer 51

Stress related leukocytosis, depressed reticuloendothelial system -> increased infection