Pain
an unpleasant sensory and emotional experience associated with actual or potential tissue damage
Origin of pain
The site where pain is felt, and not necessarily the source of pain.
Cutaneous/Superficial pain
- Arises in the skin or the subcutanoeus tissue
- may cause significant short-term pain
Deep somatic pain
comes from sources such as blood vessels, joints, tendons, muscles, and bone
Visceral pain
- Caused by the stimulation of deep internal pain receptors, most often in the abdominal cavity, cranium, or thorax
Radiating pain
pain felt at the site of tissue damage and in nearby areas
referred pain
pain that is felt in a location other than where the pain originates
phantom pain
pain or discomfort that is perceived to originate from an area that has been surgically removed
Psychogenic pain
pain that is believed to arise from the mind. The patient perceives the pain despite the fact that no physical cause can be identified.
Physical pain is either _____________ or _________________
nociceptive or neuropathic
Nociceptive pain
- Most common type of pain
- Occurs when pain receptors,
nociceptors
, respond to stimuli that are potentially damaging
Nociceptive pain may occur as a result of . . .
trauma, surgery, or inflammation
Neuropathic pain
abnormal processing of pain message; burning, shooting in nature
Acute pain may last up to. . .
6 months
Chronic pain duration
3 to 6 months or longer
Intractable pain
both chronic and highly resistant to relief
Pain quality descriptors
- sharp or dull, throbbing, stabbing, burning, ripping, searing, or tingling
Pain periodicity descriptors
episodic, intermittent, or constant
Pain intensity descriptors
it's described with a variety of terms, such as mild, distracting, moderate, severe, or intolerable
Transduction
nociceptors become activated by the perception of mechanical, thermal, and chemical stimuli
Mechanical stimuli
external forces that result in pressure or friction against the body
Thermal stimuli
result from exposure to extreme heat or cold
Chemical stimuli
- Can be internal or external.
- Examples: lemon juice on an open wound or pain experienced during an MI (chemical changes that result from tissue ischemia)
Transmission
The process where peripheral nerves carry the pain message to the dorsal horn of the spinal cord
two types of fibers that pain messages are conducted to the spinal cord
A-delta fibers & C fibers
A-delta fibers
transmit the initial sharp pain one might feel right away from a sudden injury
C fibers
transmit long, dull pain impulses that travel at a slow rate
Pain transmission involves the endogenous chemical called. . .
neurotransmitters
Pain perception
recognizing and defining pain in frontal cortex
pain threshold
the point at which a person feels pain
Pain tolerance
level of pain a person is willing to accept
Hyperalgesia
Extreme sensitivity to pain
pain modulation
Process that changes the perception of pain by either facilitating or inhibiting pain signals through the endogenous analgesia system and the gate-control mechanism
endogenous analgesia system
neurons in the brain stem activate descending nerve fibers that conduct impulses back to the spinal cord
gate control theory of pain
The belief that pain is perceived by the interplay between two different kinds of fibers--those that produce pain and those that inhibit pain
The most common emotion associated with pain
fear, frustration, anger, helplessness, and loneliness
Anxiety is most often associated with. . .
acute pain
Patients who have had effective pain relief in the past are usually. . .
less fearful and more confident they will achieve satisfactory pain relief
Pain occurs in more than half of what population?
geriatric
Some older adults may be unable to report pain because of. . .
cognitive impairment
Nonverbal discomfort cues in older adults
Grimacing, rapid blinking, withdrawal, labored breathing, altered gait, or decreased activity
Atypical ways that some older patients respond to pain
mental confusion or collapse
undertreated pain often leads to other problems that diminish quality of life, such as. . .
social isolation, depression, sleep disturbances, and mobility-related problems
Less obvious pain indicators in cognitively impaired patients:
- Facial expressions
- Vocalizations
- Changes in physical activity
- Changes in routine
- Mental status changes
- Physiological cues, including elevated B/P, respiration, and pulse
How does the body react to pain?
- The onset of pain activates the sympathetic nervous system
- If pain continues, the body adapts, and the parasympathetic nervous system takes over
Unrelieved pain effects on hormones of the endocrine system
- Excessive release of the hormones adrenocorticotropic hormone, cortisol, ADH, growth hormone, catecholamines, and glucagon
Unrelieved pains affect on insulin and testosterone levels
causes them to decrease
The inflammatory process, combined with endocrine and metabolic changes due to unrelieved pain, can result in. . .
weight loss, tachycardia, increased RR, and even death
Sympathetic responses tom acute pain
- Dilated blood vessels to the brain, increased alertness
- Dilated pupils
- Increased HR and force of contraction
- Increased RR
- Increased systolic B/P
- Rapid speech
- Pallor
Parasympathetic responses to deep or prolonged pain
- Changeable brain patterns
- Constricted pupils
- Decreased pulse rate
- Decreased systolic b/p, feeling faint, possible syncope
- Slow, monotonous speech
- Withdrawal
Unrelieved pain effects on the cardiovascular system
- Hypercoagulation
- increased HR, b/p, cardiac workload, and O2 demand
Unrelieved pain effects on the musculoskeletal system
- Impaired muscle function
- fatigue
- immobility
Unrelieved pain effects on respiratory system
- Splinting (shallow breathing to limit thoracic and abdominal movement)
Unrelieved pain effects on genitourinary system
- decreased urinary output
- urinary retention
- fluid overload
- hypokalemia
- HTN
- Increased CO
Unrelieved pain effects in GI system
- Intestinal secretions and muscle tone increase
- Gastric emptying and motility decrease
Three groups of analgesics
nonopioids, adjuvants, and opioids
What are nonopioid analgesics?
- Meds that relieve mild to moderate pain, and chronic and acute pain
- Many are available OTC
- Most also reduce inflammation and fever