Pathophys 4.2

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1st order Neurons

from periphery to CNS
2nd order neurons

Spine to Thalamus
3rd order neurons

thalamus to cortex
General somatic afferent neurons
- throughout body
- pain
- touch
- temperature
special somatic afferent neurons
- muscles
- tendons
- joints
- position
- movement
General cisceral affernt neurons
- visceral structures
- fullness
- discomfort
Ascending neural pathways
- spinal column
- discriminative pathway
- anterolateral pathway
Discriminative Pathway

crosses at the base of the medulla
Anterolateral pathway
- crosses within the first few segments of entering the spinal cord
- transmission of crude sensory info
- no localization
- no intensity
- autonomic responses
Neospinothalmic tract

rapid transmission of sensory info to the thalamus
Paleospinothalamic tract
- slow conducting tracts
- transmission of signals that are not localized or discriminate
- projects into the intralaminar nuclei of the thalamus
- close connections with the limbic cortical systems
- associates emotions
List the chemical mediators involved in nociceptive pain impulses.
- Bradykinin
- histamine
- seratonin
- potassium
- ATP
- acetylcholine
- leukotrienes
- platelets
- prostaglandins
- glutamate
- norepinephrine
- substance p
A delta fibers
- Myelinated
- Fast
- Sharp discrimination
- mechanical or thermal stimuli
- discriminative pathway
- neospinalthalamic pathway
C Fibers
- unmylenated
- slow-wave pain
- chemicals
- persistent mechanical or thermal stimuli
- neurogenic inflamation role in cronic pain
- paleospinalthalamic pathway
Periaqueductal gray region
- pain modulator
- analgesic center
Nucleus raphe magnus
- pain modulator
- descending axon pathways from PAG
- inhibit pain transmission by dorsal horn
Pain modulating neurotransmitters
- serotonin in NRM
- norepinephrine in pons and medulla
- these break down in chronic pain
Endogenous opiod peptides
- enkephalins
- endorphines
- dynorphins
- stimulate opiod receptors in the CNS
Dynorphins
- found in primary afferent neurons
- function as neurotransmitters
- inhibit synaptic transmission of pain impulses
Epidemiology of pain
- #1 reason pt seek medical attention
- 50 million americans partially or totally debilitated
- 75 million in serious pain
- 9% of U.S. adults suffer from chronic pain
Etiology of pain
- Nociceptive pain - tissue injury
- neuropathic pain - injury to nerves
Acute Pain
- pain < 6 mo
- autonomic fight or flight responses
- anxiety
- may be nociceptive or neuropathic or both
chronic pain
- continuous or intermittent
- > 6 Mo
- no autonomic response
- increased irritability
- depression
- usually neuropathic but may also include nociceptive pain
Assesment of pain
- Range of motion
- muscle strenght test
- deep tendon reflex tests
- sensation tests
- History of pain
- quantify pain
Non-pharmacologic therapy
- surgery
- physical therapy
- heat
- braces
- TENS
Pharmacologic Treatment
- Analgesics
- Adjuvants
- -anticonvulsants
- -antidepressants
Allodynia

pain produced by stimuli that do not normally cause pain
Hyperpathia

an unpleasant and prolonged response to pain
Hyperesthesia

abnormal increase in sensitivity to sensation
Paresthesia

abnormal touch sensation souch as tingling in the absence of external stimuli

Author

Rx2013

36976

Card Set

Pathophys 4.2

Description

Pathophysiology of pain

Updated

2010-09-24T01:20:16Z

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