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