Pain Flashcards
Merskey def.
Pain is the “prima facie” (predominant) evidence of a disease
def: pain is a sensory and emotional experience which is associated with an actual or potential tissue damage or can be described in terms of such a damage
Sternbach def.
Pain is an abstract concept which refers:
- to the personal feeling of being damaged
- to a harmful stimulus associated with an actual or potential injury
- to a response pattern which intends to protect the organism against a damage
Csuhai def.
Pain is a tomato-psychic phenomenon; signaling that structural or functional integrity of the organism had become disturbed
The teachers own def. :)
Pain is an important signal of a disturbance of the homeostasis, i.e. of the structural or functional integrity of the organism; an unpleasant sensory and emotional experience and a consequent abstract conception, which refers to the personal appreciation of an actual or potential tissue damage or can be described by such terms, and which may induce protective response patterns of the organism
Nociception
picking up and conveying stimuli potentially leading to pain; in itself does not necessarily means pain!!
Nociceptors
receptors specialized to pick up damaging stimuli
affective-motivational (Aspects of pain)
experienced feelings associated with a desire to escape from the damage or expectations to avoid damages
Cognitive-evaluative (Aspects of pain)
evaluation of what actually happens or may happen in association with the experience, based on and modified by earlier experiences etc.
Threshold
the least stimulus that we feel as painful
- surprisinlgy constant
- depends on the quality of the stimulus
- cannot be modified on a cognitive way
Is stable and individual
Tolerance
the strongest painful stimulus that one still can bear
- changeable
- state dependent
- can be cognitively modified
may vary according to external and internal circumstances and states.
3 steps of the pain of an injury
Direct effect of the damaging stimulis
Secondary effect initiated by chemicals released from the nerve endings or broken cells on the site of the injury
Teritiary effects; consequences of increased blood flow, autonomic nervous activity on site of injury. Typical signs are edema, red color, warmth, and pain.
Characteristic pain-behaviors
- arousal
- orientation
- attention
- muscle reactions
- defense position
- visceral changes
- conscious experiences
sensitisation
increase of peripheral or central sensitivity
hypersensitivity
excess sensitivity of the peripheral fibers
primary hyperalgesia
strong reactions to moderate pain stimuli
secondary hyperalgesia
strong reactions induced by stimuli around the affected area
allodynia
pain reactions induced by non-painful stimuli
acute pain
max 6 weeks
chornic pain
min 6 months
Pain behavior
• changes of the activity level (decrease, restlessness),
• posture changes (protecting the painful parts, curling up,
humping, withdrawal),
• motor pattern alterations (falling, rolling, hobbling, dragging),
• Anorexia and anodipsia, loosing weight,
• grooming (decreased grooming, piloerection, scratching or
biting an area, self mutilation),
• facial expression (dim eyes, loose ears, spontaneous snarling, mimics),
• vocalization (strong sounds, especially when touched or moving),
• emotional reactions (aggression, withdrawal, protection of body parts).
Acute pain (physiological reactions)
- heart rate increase
- cardiac output increase
- blood pressure raises
- pupils dilate
- hyperventilation
- escape behavior
in general: excitation, anxiety state
Chornic pain (physiological reactions)
- sleep disturbances
- irritability
- anorexia
- obstipation
- psychomotor retardation
- low pain tolerance
- social withdrawal
- abnormal sickness behavior
in general: depressive state
Measuring pain
Need to define pain-threshold and tolerance-threshold
Acute pain-tests
- motor reflect methods
- non-learnt behavioral methods
Long-term and chronic pain-test
- inflammatory processes
- neuropathy tests
- learning tests
Specific nociceptive neurons (dorsal horn neurons)
react only to noxious stimuli. They are less sensitive to intensity difference but are responsible for recognizing the physical characteristics and localization of the stimuli - sustaining neurons
Wide dynamic range neurons (dorsal horn neurons)
React to mechanical, thermal and chemical stimuli.
They are primary sensitive to the stimulus intensity. They receptive field is wide and changes depending on the intensitity - adapting neurons.
Non-nociceptive neurons (dorsal horn neurons)
sensitive to non-damaging stimuli, may be responsible for the indirect inhibition of pain.
Ascending pathways
A primitive system, running through the medial brain-stem; the pain there is ill-localized, burning, dull and slow
Brain “centers” of the brain
processing is divided in both the sensory and the limbic cortex.
- thalamus
- midbrain
- hypothalamus
Descending pain systems
at least two systems:
- a narcotic, and
- a non-narcotic
Important startingpoint: periadequductal gray
Descartes (pain theories)
Direct and straight pain-pathway: carries the information about the tissue damage through intermediary stations to the centrals sensory processing center, where the pain sensation is formed (this was called the carterisan theatre)
behavioral (pain theories)
operant learning (with social reinforcement)
- responding pain
- observation, imitation
Cognitive (pain theories)
Meaning of the pain (personality, coping, attribution, expectation, beliefs etc…)
Psychophysiological (pain theories)
effect of mental events (thoughts, memories, emotions, etc.) that increase the motor/autonomic tone mediated by arousal and lead to pain sensation)
Psychological component of pain
- tissue damage is neither necessary nor suffixion for the pain. a necessary condition is consciousness, but we don’t know what is sufficient!
Merskey
Psychogenic pain
Pain, which has no or not sufficient physiological cause
- hallucinations
- myscle tension
- conversion hysterics and hypochondrias
Social pain
Unpleasant(distressing)experience(feeling), which stems from the feeling of being actually or potentially separated (in psychological sense) from a significant other or from a social group. Includes the feeling of distance from an attached caregiver but also similar feelings of adults.
- only in mammals
- main center is the anterior cingulum
Central drugs for pain
opiates
Components of pain
sensory, emotional, and cognitive
