Pain
Pain is: A. a subjective experience that is difficult to measure objectively. B. associated with changes in vital signs reflecting its intensity. C. experienced in the same way by all individuals. D. always the result of tissue damage that activates nociceptors.
A
Transmission of pain signals occurs through: A. afferent sensory nerves. B. the pituitary gland. C. the release of neurotransmitters. D. the hypothalamus
A
How can pain be classified?
According to duration, source, location, or referral pattern
Describe process of nociception
Activity is transmitted to the spinal cord by two types of neurons; large, myelinated A delta fibers (fast pathway) which transmit sharp, localized sensations, and small, unmyelinated C fibers (slow pathway) which transmit dull, aching, poorly localized sensations.
What is pain a symptom of and of not?
An underlying problem rather than a primary disorder
The findings of increased blood pressure, pulse, and respiration in a patient are characteristic of pain that is: A. Chronic B. Acute C. Referred D. Psychogenic
B
Clinical manifestations of Acute pain
BP changes, increased heart rate, diaphoresis, peripheral vasoconstriction, pupillary dilation, hyperventilation, nausea (decreased intestinal motility), anxiety, increased muscle tension, increased blood glucose level
Physiologic Responses to pain
Blood shifts from superficial vessels to muscle, heart , lungs, brain Bronchioles dilated to increase oxygenation Decreased gastric secretions Decreased gastric motility Increase circulating blood sugar Hypomotility of the bladder and ureters
Slow pain sensation is transmitted primarily by: a. group I-a afferents. b. a motor neurons. c. unmyelinated C fibers. d. A-d fibers
C
What is pain?
Complex physiologic and perceptual phenomenon. Unpleasant sensory and emotional experience associated with actual or potential tissue damage. Subjective feeling---pain is what ever the experiencing person says it is. Components of pain are affective, behavioral, beliefs and attitudes, sensory, and physiologic. Unrelieved pain has harmful effects that slow healing. Pain tolerance is the degree of pain an individual can withstand. Pain threshold is the point of pain recognition.
Transduction
Conversion of a stimulus to an action potential at the site of tissue injury. Chemical substances are released with cellular damage i.e. histamine, serotonin, and prostaglandins. Chemicals sensitize the primary afferent nociceptors that carry painful stimuli. Some analgesics work by interfering in the production of these chemicals i.e. NSAIDS
Pain Tolerance
Duration of time or the intensity of pain that a person will endure before initiating pain responses Varies greatly among people and in the same person over time
Signs & symptoms of pain
Increased heart rate Increased blood pressure Increased respiratory rate Dilated pupils Pallor and perspiration Nausea and vomiting Urine retention
Modulation
Inhibition of nociception. Efferent fibers descending from the brain stem modulate or alter pain. Opioids such as endorphins (endogenous pain relief) are thought to be mediators of presynaptic inhibition- before brain starts stopping everything, endorphins work. Many analgesics modulate pain by mimicking endogenous neuromodulators.
What does pain affect?
Our ability to function/ move
What is often referred to as the 5th vital sign?
Pain
What is the single most common medical complaint?
Pain
Perceptual Dominance
Pain at one location may cause an increase in the threshold in another location -An individual with many painful sites may report only the most painful -After the dominant pain is diminished, the individual may then identify other painful areas
What two major subtypes can pain be categorized?
Physiologic pain (normal) and pathologic pain
Pain Threshold
Point at which a stimulus is perceived as pain Does not vary significantly among people or in the same person over time Intense pain at one location may cause an increase in the threshold in another location *Subjective
What is the relationship with age and pain?
Prevalence of pain increases with age; there also may be an increase/decrease in pain threshold
What factors will influence the experience of pain?
Previous experience and how we remember them. Ability to understand the pain and its consequences. Culture---threshold, perception. Tolerance. Feelings of control over the pain. Meaning of the situation. Attention, anxiety, and distraction
Perception
Result of neural processing of pain sensations in the brain---involves several brain structures. Includes an awareness and interpretation of the meaning of the sensation. Pain perception can be described in terms of pain threshold and pain tolerance.
Stimuli that Activate Nociceptors (list & how)
Skin---pricking, cutting, burning, freezing GI Tract---inflamed mucosa, distention, spasm Skeletal muscle---ischemia, necrosis, hemorrhage, contraction, injuries of connective tissue Joints---synovial inflammation Arteries---inflammation, piercing Head---traction, inflammation, displacement of structures Heart---ischemia, inflammation
Nociception
Special receptors that respond only to noxious stimuli and generate nerve impulses which the brain interprets as pain. The physiological mechanisms involved in the pain phenomenon. It is the process of how pain is recognized consciously
Transmission
The neuronal action potential is transmitted to and through the CNS so it can be perceived (A delta and C fibers). The impulse goes to the brain, processed in the dorsal horn, and is the transmitted to the brain.
How is pain tolerance generally increased?
by alcohol consumption, persistent use of pain medication, hypnosis, warmth, distracting activities, and strong beliefs or faith
What is the purpose of pain?
To learn that something is harmful. Pain occurs before injury occurs---to prevent damage. Pain sets limits on activity which forces inactivity which is required for healing
What is pain tolerance influenced by?
cultural perceptions, expectations, role behaviors, and physical and mental health
Clinical manifestations of chronic pain
depression, normal vital signs, difficulty sleeping and eating, localization is imprecise, exhaustion, irritability, and lack of energy
Chronic pain
exists when pain lasts more than expected healing time usually greater than six months Cause may be unknown Insidious Prolonged/usually more than 3/6 months Painful areas not well differentiated Response patterns vary (psychogenic/behavior changes) Few overt signs Intensity varies Suffering increases over time Complete relief not possible---does not respond to usual therapy
Referred pain
is perceived in an area other than the actual source of the injury (the area of referred pain is supplied by the same spinal segment as the actual site)
ischemia
lack of blood flow
Hypoxia
lack of oxygen
Radiculopathy
nerve pain that travels from center down *common with people who have back pain
Neuropathy
nerve pain, numbness, more related to peripheral causes *shingles (sores along dermatome on one side that wraps around)
What is pain tolerance decreased with?
repeated pain, fatigue, anger, boredom, apprehension, and sleep deprivation
Ischemic pain
results from sudden loss of blood flow to the tissues
Neuropathic pain
results from tissue damage in which the nerves become damaged or dysfunctional---most often chronic
Acute pain
results from tissue injury and resolves in less than six months Protective mechanism---alerts the person to a condition that is immediately harmful to the body. Usually sudden Transient Painful areas well defined Typical response pattern Self-limiting or readily corrected Suffering decrease over time Leads to actions to relieve pain Prognosis is complete relief
Cancer-related pain
subcategory of chronic pain but may be associated with acute episodes
necrosis
tissue cell death
What are the four stages of nociception?
transduction, transmission, perception, and modulation