Pain Physiology Flashcards
Physiologic Pain
normal response to a noxious stimuli producing protective behavioural responses to potential or actual tissue damage
Acute Pain
Sudden onset of pain, which may be severe but disappears when the stimulus is removed
Chronic pain
Pain that lasts several weeks to months and persists beyond the expected healing time
Somatic pain
originates from damage to bone, joint, muscle, or skin
well localized
Visceral pain
originates from internal organs - stretching or twisting of viscera, mesenteries, and ligaments
poorly localized
Neuropathic pain
originates from injury to the peripheral or central nervous system
Inflammatory pain
Originates from tissue damage
Referred pain
originates from one part of the body but perceived as occurring in another
Transduction
peripheral pain receptors activated by a stimulus
Transmission
signal communication via A-delta and C- nerve fibers to spinal cord
Modulation
nociceptive input modified at the spinal cord
Perception
Conscious recognition of pain at the cerebral cortex
What do the Mechanoreceptors respond to?
Stretching
compression
crushing
What do the Thermoreceptors respond to?
Heat
Cold
What do the Chemoreceptors respond to?
Neurotransmitters Prostaglandins autocoids cytokines leukotrienes nerve growth facotr
What are the two types of peripheral nerves?
A-delta fibers
C-fibers
A-delta fibers
Myelinated fast transmission
Acute, accurately localized, sharp, and rapid onset pain
C-fibers
Nonmyelinated, slow transmission
Chronic, diffuse, dull, burning, aching pain
What are the Facilitory/Excitatory substances?
Substance P
Glutamate
What receptor does Substance P act on?
NK1 receptor
What receptor does Glutamate act on?
AMPA
NMDA
Kainate
What is the inhibitory substance?
GABA
What tract transmits localized superficial pain?
Spinothalamic tract
What tract transmits deep and visceral pain?
Spinoreticular tract
How do you test the Spinoreticular tract?
hemostats across base of toenail
What mediates head pain?
Trigeminal nerve (CN V)
Allodynia
Pain evoked by a stimulus that does not normally cause pain
Hyperalgesia
An increased or exaggerated response to a stimulus that is normally painful
Peripheral sensitization
an increase in the activity, excitability, and responsiveness of peripheral nerve terminals leading to primary hyperalgesia
Windup
Summation of painful stimulation in the spinal cord, mediated by C-fibers. Contributes to control sensitization
Central sensitization
an increase in nerve excitability and responsiveness in the central nervous system, particularly the spinal cord, leading to primary and secondary hyperalgesia and allodynia
What does central sensitization result in?
Hyperalgesia
Allodynia
Spontaneous pain
Pain memory (phantom limb pain)
Analgesia
Loss of sensitivity to pain
Multimodal analgesia
The use of multiple drugs acting by different mechanisms to produce anlagesia
Preemptive analgesia
the administration of analgesic therapy before painful stimulation, used to Prevent Wind up
What is the clinical goal of analgesia?
reduce pain by interrupting nociception at one or multiple levels
