Pain lecture Flashcards
Define acute pain
- well-defined source
- autonomic and reflex signs
- emotional distress abates when cause is eliminated
What is nociceptive pain?
- injury to muscles,bones,ligaments, skin
- can be nociceptive somatic OR
- nociceptive visceral (gut, uterus, stomach)
Define pain
subjective experience -
associated with tissue damage or described in such
Prevalence of chronic non cancer pain (CNCP)
10-17% prevalence
maybe up to 29%
- prevalence varies according to population
Define disease
- Disease - clinical entity associated with disturbed function or structure of body part
Define illness
1- symptom perception
2 - symptom interpretation
3 - symptom expression
4 - coping behaviors
How does the medical model of disease view illness?
- Physical pathology
- Proportional to symptoms and disability
- psychological elements are secondary
What determines the nature/extent of a painful experience?
- attention
- appraisal
- coping strategies
- social experiences
- cultural variations
What are pain behaviours?
- verbal (verbalization,moaning)
2. non-verbal (grimacing, limping, gesturing)
When does the vulnerability to chronic pain increase?
- Physical or sexual abuse
- Marital discord
- Family violence
- psychoemotional trauma
- family members with pain/disability
- exposure to psychosocial or personal stressors
Define chronic pain
- lasts >6 months
- beyond regular healing time
- autonomic and reflex changes diminish with time
- psychological responses augment
When is chronic pain a biomedical condition?
- persistent/recurrent pain of nociceptive/neuropathic origin
- Life goes on despite limitations
when is chronic pain a disorder or syndrome?
- persistent/recurrent ALL the time
- underlying pathology has healed
- sadness,hopelessness, social isolation….
What are some red flags for the development of chronic pain disorders?
- Intense prolonged pain
- spreading pains or new pains
- failure to respond to treatment
- PTSD, anxiety, seriously depressed after injury
- Mistaken/pessimistic beliefs
- workplace difficulties
- employer can’t provide modified work
What is neuropathic pain?
- primary injury or dysfunction of CNS or PNS
2. injures peripheral nerves, spinal cord, brain
How do we explain extraordinary trauma in cultures?
- Internal pain blockers (endorphins)
- Altered states of mind (hypnosis)
BOTH
What are alpha waves?
- Fast waves, occur at 8-13 cycles/sec
2. during regular, conscious activities
What are theta waves?
- slower waves, 4-7 cycles/sec
2. seen during light sleep, creative thought, detach from reality
which types of waves are seen in hook-hanging etc?
Theta waves
How does hypnosis suppress pain?
- Splitting consciousness
- activating spinal cord descending pathways (block pain signals)
- alters the meaning of pain - targets unpleasantness
How does hypnosis NOT work to suppress pain
By mobilizing the endogenous opioid system
what is a placebo?
- ineffective treatment believed to be effective
2. change in illness due to symbolic effect not pharm effect
What can placebo responses do?
- relieve pain
- Angina
- bronchospasm
- twisted posture or tremors or increase range of movement
what % of treatments have a placebo effect?
70%!
how is the placebo effect mediated?
partially by ENDORPHINS
How do nocebo responses occur?
Occur with negative suggestions but unknown mechanisms
what is fMRI based on?
Blood oxygenation level detection - due to different properties of deoxy and oxy hemoglobin
what are the two types of fMRI measures?
- evoked responses within a brain area
2. correlated activity between brain areas
What is seen in GM structures in chronic pain?
- cortical thinning of cingulate and insular cortex
2. discrepancy in thalamus, 1 somatosensory, prefrontal cortices
What is thought to signal emotional pain?
Mid and anterior Cingulate Cortex - ACC but it responds to situations that demand attention/emotionally charged
what is thought to be responsible for Subjective PAIN PERCEPTION?
Anterior portion of ACC and Posterior INSULA -
what do large areas in the ACC and INsula detect
Thermal stimuli
and non-painful tasks
Morphological brain changes have been seen in which conditions?
- Chronic back pain
- fibromyalgia
- CRPS
- Knee OA
- IBS
- temperomandibular disorder
- headaches/animal models of pain
what is thought to be behind mindfulness therapies?
- enhanced dorsal anterior insula activity
- mid cingulate cortex
- reduced baseline activity in other brain regions
What does CBT do?
Increases Gray Matter volume compared with controls but REDUCES gray matter in supplementary motor areas
Decreased pain catastrophizing is associated with
Increased gray matter in left dorsolateral cortex
what does yoga do?
Improve pain tolerance
Subjects who have had hypnosis have
Greater functional connectivity between left dorsolateral prefrontal cortex
Which brain structure is linked with an individual’s ability for endogenous pain control?
white matter integrity! - placebos
what are nondermatomal somatosensory deficits?
- prevalent problem in chronic pain
- may appear after insignificant trauma
- bad prognostic sign
- emotional charged conditions/personality organization
