Sherpath Ch 44 Pain

Question 1

The International Association for the Study of Pain (IASP) defines pain as

Answer 1

“an unpleasant, subjective sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”

Question 2

Factors Influencing Perception of Pain

Answer 2

Both physical and emotional characteristics affect pain. These characteristics are influenced by the person’s cognitive, affective/behavioral, and sensory perceptions.

Question 2

Functions of pain include

Answer 2

-protection: Warning signal about an unmet need, or malfunction of the nervous system secondary to a disease process

-warning/symptoms of disease

-response to injury: Thermal injuries (sunburn), Mechanical injury (fracture),
Chemical injury (inhalation of toxic fumes), Ischemic injury (lack of oxygen to body tissues)

Question 3

Pattern Theory

Answer 3

-proposed the physiologic basis of pain and provided the foundation for the gate control theory of pain
-When injury occurs, sensations (stimulation of nerve endings) relay a unique pattern or sequence of signals to the brain.
-The brain deciphers the pattern and correlates it with the sensation.
-The pattern determines whether the brain interprets the stimuli as pain.

Question 4

Gate Control Theory of Pain

Answer 4

-this theory looked at pain via the mind-body perspective, explaining the influence of cognitive and emotional factors on pain perception.
-Tissue damage causes a stimulus to be sent to the brain.
-The stimulus first travels to three locations in the spinal cord.
-One of these locations, the dorsal horn of the spinal cord, provides a gating mechanism.
-The signals at this gate determine whether or not pain is felt. If the gate closes, the impulses are not transmitted to the brain and no pain is perceived. If the signals reach a specific level of intensity, the gate opens, allowing the signal to reach the brain and pain to be felt.
-State-of-mind and lifestyle choices can affect the intensity of the stimuli. For example, depression may cause the gate to remain open more often

Question 5

Neuromatrix Theory

Answer 5

-this theory proposed that the central nervous system, rather than injury at the periphery, is responsible for pain sensation.
-Pain is a complex issue that cannot be explained solely by physical factors.
-Perception of painful stimuli results from the neuromatrix, a unique genetically controlled network of neurons affected by an individual’s subjective physical, psychological, cognitive, and life experiences.
-Input from the periphery, such as tissue trauma, can initiate or affect but not create a neurosignature (the signal created by the neuromatrix).
-Specific neurosignatures elicit corresponding sensations, and alterations in signals yield memories of the experience, allowing the same sensation to be felt if the same circumstance occurs in the future.

Question 6

A nociceptor is a

Answer 6

peripheral nerve ending, or sensory neuron, that initiates the sensation of pain by sending “threat” stimuli to the spinal cord and brain and is sensitive to thermal, mechanical, and chemical stimuli

Question 6

Nociceptors are distributed throughout the body in

Answer 6

joints, muscles, skin, and viscera (internal organs), but density differs in each area

Question 7

Parietal Lobe

Answer 7

The sensory-discriminative aspect of the brain helps the person localize where on the body injury occurred.

Question 7

Nociception is the process by which

Answer 7

pain is conducted from the periphery to the central nervous system. The event begins with the conversion of the noxious stimuli (injury) to an electrical impulse, which is transmitted from one neuron (nerve) to the next with the help of neurotransmitters.

Question 8

Occipital Lobe

Answer 8

The cortical brain regions process the pain (cause of pain or reaction of pain) from the body and generate the actual experience of pain

Question 9

Cerebellum

Answer 9

The thalamus is a relay station that distributes sensory signals to several other regions of the brain.

Question 10

Brain Stem

Answer 10

Pain signals travel from the spinal cord to the brain, including the brainstem, thalamus, and cerebral cortex

Question 11

Temporal Lobe

Answer 11

The cognitive-evaluative aspect of the brain allows the person to plan ways of removing or getting away from the pain.

Question 12

Frontal Lobe

Answer 12

The affective-motivational aspect of the brain conveys the degree of unpleasantness of the pain experience.

Question 13

Four Steps of Nociception

Answer 13

transduction, transmission, perception, and modulation

Question 14

Transduction

Answer 14

-Injury occurs.
-Nociceptors identify pain stimuli and convert it to an electrical impulse.
-Injured tissues release neurotransmitters that are part of the inflammatory response.
-Neurotransmitters assist with transmission of pain signals across neurons.
-Inflammatory response is a significant cause of generalized pain.

Question 15

Transmission

Answer 15

-Pain signal is transmitted through the afferent nerve to the spinal cord and brain.

-Signals travel two pathways:
A-delta fibers: Larger fibers,
Rapid conduction, Pain translated as sharp, acute pain
C fibers: Smaller fibers, Slow conduction, Pain translated as diffuse, dull, and longer-lasting pain

-Both A-delta and C fibers carry pain impulses from the spinal cord to the cerebral cortex of the brain.

Question 16

Perception

Answer 16

-Brain translates afferent nerve signals as pain.
-Person perceives pain.
-Limbic system controls emotional reactions.
-Somatosensory cortex perceives location, intensity, and quality of pain:
-Pain threshold: lowest intensity at which the brain recognizes pain; varies per person
-Pain tolerance: intensity or duration of pain that a person can, or is willing to, endure; varies per person

Question 17

Modulation

Answer 17

-Once pain is recognized, the brain changes pain perception by sending inhibitory signals via the spinal cord.

-This signal results in the release of analgesic neurotransmitters called endogenous opioids:
-Enkephalins influence the emotional perception of pain.
-Beta-endorphins reduce pain via the central and peripheral nervous systems.
-Dynorphins modulate pain through stimulation or reduction, depending on which receptors are activated.

Question 18

Injury to tissues causes the release of

Answer 18

neurotransmitters, which send pain signals across adjacent neurons. Release of neurotransmitters is part of the inflammatory response, which is a significant cause of generalized pain

Question 19

There are three primary types of pain differentiated based on symptoms and pain mechanisms

Answer 19

nociceptive, neuropathic, and psychogenic

Question 20

Nociceptive pain occurs when

Answer 20

nociceptors encounter harmful stimuli such as trauma, inflammation, or tissue damage. It is the most common type of pain, generally felt as sharp, burning, aching, cramping, or stabbing sensations.

Question 21

Nociceptive pain originates

Answer 21

in visceral and somatic locations, and it may be referred or radiating

Question 22

visceral pain

Answer 22

-Originates from organs within the body
-Gradual in onset and tends to last longer than other types of pain
-Occurs from conditions such as chronic pancreatitis, inflammatory bowel disease, bladder distention, and cancer

Question 23

somatic pain

Answer 23

-Pain emanating from the skin, muscles, joints, and bones
-Occurs from conditions such as sunburn, lacerations, fractures, sprains, arthritis, and bone cancer

Question 24

referred pain

Answer 24

-Felt in a location of the body other than where it originated
-Originates in internal organs, but is often felt in other locations

Question 25

radiating pain

Answer 25

Extends from the source of pain (injury) to an adjacent area of the body

Question 26

The two less commonly occurring types of pain are

Answer 26

neuropathic and psychogenic pain. Neuropathic pain involves nerves, whereas psychogenic pain stems from psychological factors.

Question 27

Neuropathic pain

Answer 27

is often described as nerve injury or impairment. The pain can be continuous or episodic, and it often continues after the painful stimuli is removed. The condition is sometimes described as pathologic pain because the pain serves no purpose in relation to the body’s warning system or defenses. The pain is felt as sensations of numbness, tingling, burning, aching, crushing, stabbing, or shooting

Question 28

Psychogenic pain

Answer 28

has no physical source and is caused, increased, or prolonged by mental, emotional, or behavioral factors. Psychogenic pain often presents as headache, back pain, or stomach pain.

Hypersensitivity of the nervous system causes an individual to be more responsive than other people to any stimulus that registers as painful, even if not generally considered to be a painful stimulus. The triggers could be clothing fabric or a passing comment. Examples of factors that contribute to a hypersensitive nervous system are stress, anxiety, medication, lack of sleep, and poor nutrition.

Question 29

Breakthrough pain

Answer 29

can occur in patients with cancer or noncancer pain (acute or chronic), and it is associated with surgery, injury, or a fluctuation in pain from an existing condition.