Pain Flashcards
Pain pathways - fast, localized pain
lateral pain system
transmitted over thinly myelnated A delta fibers
processed in spinal cord dorsal horn lamina (I and V)
crosses to excite lateral neospinothalamic tract
terminates in brainstem reticular formation and thalamus with projections to cortex
Functions for localization, discrimination of pain
Pain pathways - slow pain
divergent pathways
transmitted over small diameter, unmyelinated C fibers
processed in spinal cord lamina (I and III-V)
cross to excite anterior paleospinothalamic tract
terminates in brainstem reticular formation
excites RAS
terminates in thalamus with projections to cortex
Functions for diffuse arousal (protective reactions), affective and motivational aspects of pain
Pain pathways - intrinsic inhibitory mechanisms - gate control theory
transmission of sensation at spinal cord level is controlled by balance btw large fibers (A alpha and A beta) and small fibers (A delta and C)
Activity of large fibers at level of first synapse can block activity of small fibers and pain transmission (counterirritant theory)
Pain pathways - intrinsic inhibitory mechanisms - descending analgesic systems
endogenous opiates produced throughout CNS can depress pain transmission at various sites through mechanisms of presynaptic inhibition
Acute pain
pain provoked by noxious stimulation
associated with underlying pathology
signs include sharp pain and sympathetic changes
Chronic pain
pain that persists beyond the usual course of healing
sx present for over 6 months fo rwhich an underlying pathology is no longer identifiable or may never have been present
Classification of pain - nociceptive pain =
response to an immediate noxious stimulus (mechanical, thermal, or chemical) signaling impending tissue damage
inflammatory pain occurs after tissue damage and inc sensitivity to pain
Classification of pain - neurogenic pain =
pain as a result of lesions in some parts of the nervous system
usually accompanied by some degree of sensory defici t
Classification of pain - neurogenic pain - central neurogenic pain =
arises from injury or disease affecting CNS
pain is often burning, aching, or prickling
hyperanalgesia and allodynia
Seen with central poststroke pain, TBI, fibromyalgia
Classification of pain - neurogenic pain - peripheral neurogenic pain
arises from mechanical or chemical damage to peripheral nerves
may include symptoms of paresthesia, dysesthesia, and pain
Classifications of pain - neurogenic pain - peripheral neurogenic pain - complex regional pain syndrome
A complex disorder or group of disorders that develop as a consequence of trauma affecting body parts and disuse
Characterized by reflex neurogenic inflammation affecting SNS and pain disproportionate to injury
Classifications of pain - neurogenic pain - peripheral neurogenic pain - complex regional pain syndrome - acute or early stage
diffuse, severe burning or aching pain
increases with emotional stress
allodynia (pain with light touch)
hyperpathia (inc sensitivity to normal stimuli)
vasomotor instability (dusky mottling, cool skin, swelling, edema)
Classifications of pain - neurogenic pain - peripheral neurogenic pain - complex regional pain syndrome - dystrophic or middle stage
skin changes with thin, pale, cyanotic skin cessation of hair or nail growth hyperhidrosis muscle atrophy OP
Classifications of pain - neurogenic pain - peripheral neurogenic pain - complex regional pain syndrome - atrophic or late stage
decreased hypersensitivity normal blood flow and temp smooth, glossy skin severe mm atrophy pericapsular fibrosis diffuse OP development of claw hand may occur
Classification of pain - disorders of peripheral roots and nerves
Includes neuralgia - pain along branches of a nerve
Includes radiculagia - neuralgia of nerve roots
