Pain & Temperature - CH. 15 Flashcards
Nociceptive pain
Physiologic response to heat, cold, vibration, stretch, or chemicals released from damaged cells that may cause tissue damage.
Somatic nociceptive pain
Aching, throbbing, or dull pain arising from the skin, muscles, and joints that is usually discrete and intense
Visceral nociceptive pain
Squeezing, cramping, dull, and deep pain originating in a bodily organ. Often poorly localized to the affected organ and commonly associated with referred pain
Neuropathic pain
Increased sensitivity to painful stimuli and results from abnormal processing of pain information in the peripheral or central nervous system. It is generally the result of trauma or disease of nerves and is most often chronic. Does NOT active nociceptive receptors and does not follow a typical transmission pattern of impulse conduction
Causes of neuropathic pain
Pressure on nerve
Physical injury to neuron
Chemical injury to neuron
Infection of neuron
Ischemia
Inflammation
Neuritis
Inflammation of a nerve
Neuralgia
Pain that follows the distribution of a nerve
Radiculopathy
Pain or the loss of sensory and/or motor function as a result of impaired conduction in a spinal nerve or its roots
Neuropathy
A disease or disorder of the PNS and/or CNS
Peripheral neuropathy
Constant or intermittent burning, aching, or lancinating limb pain due to lesions or dysfunction of peripheral nerves
Central neuropathy
Caused by lesion in CNS. Cord trauma, phantom limb
Acute pain
Associated with acute tissue damage/trauma, inflammation, a surgical procedure, or a brief disease process. May be somatic (superficial), visceral (internal), or referred (present in an area distant from its origin). Can last from hours to weeks
Protective mechanism of acute pain
Alerts an individual to a condition or experience that is immediately harmful to the body. Duration and intensity of pain diminish as tissue healing occurs
Manifestations of acute pain
Fear & anxiety
Tachycardia, hypertension, fever, diaphoresis, dilated pupils, outward pain behaviors, elevated blood sugar levels, decreased gastric acid secretion and intestinal motility, and a general decrease in blood flow
Chronic pain
Pain lasting well beyond the expected normal healing and may be intermittent or persistent. Chronic pain is a situation; state of existence and is often associated with chronic diseases. Usually defined as lasting at least 3-6 months or longer than expected for healing to take place.
Chronic recurrent pain
Repeated and intense episodes of pain separated by pain-free periods
ex. migraine
Chronic intractable benign pain
Continuous pain with varying levels of intensity
Chronic progressive pain
Continuous pain that increases in intensity
ex. cancer pain
Pain physiology
Involves transduction, transmission, modulation, and perception of the pain.
3 responsible portions of nervous system: afferent, CNS, efferent pathways
Transduction
Conversion of a noxious thermal, mechanical, or chemical stimulus into a nerve impulse
Specialized sensory (afferent) neurons
Responsible for the detection of a noxious thermal, mechanical, or chemical stimuli
Nociceptor
Free nerve endings in skin, muscle, joint, arteries, and the viscera that respond to chemical, mechanical, and thermal stimuli. Responsible for the transduction of a noxious stimulus into a nerve impulse
Afferent system
Responsible for transmission of a noxious stimulus to the spinothalamic tract in the CNS.
Ad Fibers
Large myelinated fibers that have a low stimulation threshold and a fast conduction velocity
Type 1 - Ad fibers
High-threshold mechanical nociceptors that respond to both chemical and mechanical stimuli
High threshold for thermal but will respond to lower temps with continued stimuli or in presence of tissue injury
Response for first or fast pain of a mechanical stimulus
Fast pain starts abruptly and ends when the stimulus is removed
Type 2 - Ad fibers
Low-heat threshold and high mechanical threshold
Responsible for the conduction of fast pain in response to a noxious heat stimulus
Fibers release glutamate in the cord.
Unmyelinated C fibers
Smallest of all peripheral nerve fibers and transmit slow-wave pain with slower onset and longer duration
Chemical - unmyelinated C fibers
Tissue trauma, ischemia, inflammation releases chemicals
H+, K+, prostaglandins, leukotrienes, bradykinin, acetylcholine & serotonin
Prostaglandin & chronic pain
Prostaglandins enhance sensitivity of pain endings but do NOT directly stimulate them
What do C fibers release
Glutamate and substance P in the cord
Substance P
Belongs to the peptide class of neurotransmitters, thus its name
Primary function appears to be signaling messages from nociceptors to the dorsal horn of the spinal cord.
Opiates, 5HT agonists, and NE agonists exert analgesic effect by acting on substance P nerve terminals to limit release of this pain-inducing peptide.
