Pain

Question 1

Factors affecting pain perception/input

Answer 1

• Mood: depressed, anxiety, catastrophizing
• Chemical/structural: atrophy (happens w/ chronic pain) and opiod/DA dysfunction
• Injury: peripheral and central sensitization
• Genetics
• Context: beliefs, culture, placebo, expectations
• Cognition: attention, distraction, hypervigilance
• Pain inhibitory center: periaqueductal gray sends messages to the thalamus that leads to profound analgesic affects

Question 2

Generation of pain

Answer 2

• Due to inflammatory events that lead to the formation of prostaglandins (COX2 pathway- inhibited by NSAIDs)
• Prostaglandins sensitize skin pain receptors and makes them more prone to firing
• Also regulates hypothalamic temperature control center

Question 3

Types of pain

Answer 3

• Can be chronic or acute, and nociceptive (inflammatory) or neuropathic
• Nociceptive: protective response of body to trauma or inflammation, pain is relieved when inflammation is gone, responds to NSAIDs
• Neuopathic: no protective purpose or biologic value, persists beyond healing, does not respond to NSAIDs

Question 4

Factors that chronic pain influences

Answer 4

• Non-opioid mediators
• Endogenous opioids (placebo works on same receptors)
• ANS
• Respiratory center

Question 5

Neuropathic pain

Answer 5

• Caused by a lesion or disease of the nervous system
• Central (stroke, MS, trauma, compression of SC, ect) or peripheral (diabetic, herpetic, etoh neuropathies, complex regional pain syndrome)
• Most common neuropathic pains are lower back pain and diabetic neuropathy

Question 6

Neuropathic pain Dx

Answer 6

• Dx: spontaneous pain that’s worse at night
• Exam: no sensory loss, may have allodynia (pain from cotton swab), hyperalgesia (exaggerated response to pain), or hyperpathia (summation of pain after repetitive stimulus)
• Sympathetically-driven pain: ANS is in overdrive
• Assess joints, fascia, tendons, psychology
• Lab tests: nerve conduction studies, skin biopsy, neuroimaging (fMRI and PET)

Question 7

Rx for nociceptive pain

Answer 7

• NSAIDs then opiates then sedatives/anesthetics

- Rx the injury

Question 8

Rx of neuropathic pain

Answer 8

• Rx the biological, social and psychological problems (biopsychosocial)
• Can use pharmacologic Rx (mostly anti epileptics, TCAs, and steroids) along w/ psychological and physical Rx
• TCAs block Na channels, do not use opiates as they can increase neuropathic pain
• Can also to stimulation on parts of the brain or SC
• Goals of Rx: improve pt understanding, level of function, promote self-management, and modify their perceived level of pain