4.2.1 Pain II Flashcards
What are the characteristics of fast pain?
Free nerve endings - thermal and mechanical type
A delta fibers - thinly myelinated
Sharp pricking pain and are accurately located
What are the characteristics of slow pain?
Polymodial receptors
C fibers - unmyelinated and slow
Dull burning pain - poorly localized
What are the characteristics of sentization and what are some chemical mediators of it?
- Peripheral and central nervous system changes
- Decreased pain receptor thresholds resulting from changes in synaptic central circuits
- Histamine, PGE2
- ATP, ACH, Serotonin
- Bradykinin, Substance P
What are the characteristics of visceral pain?
This is similar to slow pain. There is a higher proportion of C fibers (2:1 in the skin; 10:1 in the gut). Pain is often referred to somatic structures.
What is referred pain and what is the mechanism?
Pain in deep structures is felt on the surface of the body
Mechanism - Convergence of cutaneous and visceral nociceptors onto same dorsal horn projection neurons OR branching pattern of sensory nerve.
What are the characteristics of “Reflex Sympathetic” Dystrophy?
Persistent hyperpathia associated with vasomotor changes after an injury
Usually after a period of immobilization
Extreme abnormal sensitization
Also known as complex regional pain syndrome
What are the characteristics associated with trigeminal neuralgia?
Abnormal conduction
Focal areas of demyelination with cross talk between bare axons.
Usually cryptogenic
What are the characteristics associated with Post Herpetic Neuralgia?
Persistent pain despite resolution of active infection
Associated with numbness
Presumed secondary to decreased modulation from deaffrentation; Loss of non-pain sensory inputs causes relative increase in pain : nopain ratio
What are some of the methods of central pain control?
Periaqueductal grey is rich in opiate receptors
Rostroventral medulla descending inhibitory neurons to the:
Dorsal horn - NE and serotonin which excite enkalphin-producing interneurons
What is decreased modulation?
Damage to descending inhibitory pathways
How would you treat pain associated with increased sensitization?
Efforts aimed to decrease sensitization
Early mobility
Capsacin
NSAIDs and steroids
How would you treat pain associated with abnormal pain conduction?
Efforts aimed at decreasing pain conduction
Nerve block - temporary or perm
Spinothalamic tractotomy
“Stabilize nerve” - anti seizure medication
How would you treat pain associated with decreased modulation?
Increase non-painful input
Mechanical stimulation
Posterior column stimulator
Stimulate periaqueductal grey
Medication - antidepressants and opiates
How would you treat pain associated with altered pain perception?
Focus on behavioral therapy
Relaxation therapy
Meds for anxiety
