Chronic Pain Flashcards
Pain definition
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
- chronic pain lasts >12 weeks, can evolve from acute pain or have no know cause
- fatigue - insomnia - depression - anxiety - decreased appetite
Pain job
- withdraws us from danger
- protective to help prevent further injury and allow for healing
- teaches us to avoid particular behaviors in the future
- stimulated by thermal, chemical, and mechanical peripheral nerve fibers (A-delta and C-fibers)
- acute pain generally resolves when stimulus is removed or damage is healed
Why is pain a problem
- Most common reason for MD visits
- disability is as likely in the chronic pain population as it is in those with kidney failure, ephysema or stroke
- this is the reality or 11 million US adults with high impact chronic pain
- 4.8 percent of US adult population
- there is no test or imagining that can confirm a diagnosis of chronic pain
Tissue of origin
Pain arises from:
- MSK system: follows strict pattern of s/six, usually sharp pain, aching
- Visceral: usually a diffuse aching with referred pain patterns
- does not decrease with position change - Neuropathic: more vague, described usually as burning or aching
- CPRS, neuralgia, allodynia, sciatica, etc
Clinica presentaitons of pain
The more closely related the s/sx and functional disability fit together, the more likely the pain is acute and amenable to intervention
- conversely, lack of consistency between s/sx and functional disability points to more chronic pain, which may require additional interventions
Acute pain presentation
Elected by acute inflammation and has biological significance to protect wounded tissue
- pain is a symptom
- onset is well defined and pathology is found
- signs of autonomic activity and increased anxiety
- normal response to inflammation and tissue injury
- has biological funciton
- responds to pain treatment and medications
- affects the individual
- fits the medical model
Chronic pain presentation
Is maladaptive, has no beneficial biological significance and is characterized by spontaneous pain (burning) as well as evoked pain
- pain is a disease
- onset is I’ll defined and pathology is not often found
- no or adapted ANS response
- response to change in the NS
- unknow biological function
- less responsive to treatment/meds
- can be associated with depression
- involves other people
- multi-factorial
Neuronal plasticity
- generally believed that it is the pain-coding pathways and circuits resulting in chronic pain
- peripheral sensitization in primary sensory neurons of dorsal root ganglia and trigeminal ganglia
- central sensitization of pain-processing neurons in the spinal cord and brain
- amplification of neural signaling within the CNS that elicits pain hypersensitivity
Allodynia
Pain in response to normally no painful stimuli
Hyperalgesia
Increased pain in response to normally painful stimuli
Functional MRI
Increased activity in specific parts of brain, people with chronic pain with matched non-chronic pain subjects
Conditioned pain modulation
Stimulation with noxious input, cold treatment, then same noxious input
Osteoarthritis
Increased sensitivity to pressure both at OA hip AND on other non-effected side (example of general pattern of pain rather than just local)
Physiological responses to CPS
- neural changes and adaptations within the PNS and CNS lowers the pain threshold
- with prolonged episodes of pain, non-pain receptors may start transmitting pain to CNS
Up regulation
A process that makes cells more responsive to stimuli like hormones by increasing the number of receptors on the surface of the cell
- involves ion channels K, Na, Ca
(Ex: insulin receptors after exercise, oxytocin receptors with late-term pregnancy, nerve hypersensitivity after injury)
Physiological responses to CPS cont
- hormonal chagnes, altered chemical release of neurotransmitters
- decreased endorphin levels
- decreased serotonin levels
- changes in HR, RR, BP due to autonomic nervous system “fight or flight” overactivation
- identification of the initial cause of pain is difficult if not impossible to define: multiple compensations across many body systems
- insomnia - decreased or increased appetite
Physiological effects 3
Usually associated with depression, anxiety, fear, and anger
- pt may become isolated or withdrawn and exhibit self limiting behaviors
- excessive drug use to control pain
- **red flag: pain symptoms are out of proportion to objective findings