1 Pain. 2 Types of Pain Acute Pain Acute Pain –Complex combination of sensory, perceptual, & emotional experiences as a result of a noxious stimulus –Mediated.

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Pain

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Types of Pain

Acute Pain– Complex combination of sensory, perceptual, &

emotional experiences as a result of a noxious stimulus

– Mediated by rapidly conducting nerve pathways & associated with increased muscle tone, heart rate, & blood pressure (sympathetic nervous system response)

– Intensity depends of the degree of injury– Serves as a protective function– Tx – reduce inflammation & modify

transmission of pain

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Types of Pain Chronic Pain

– Starts as acute pain but persists ≥ 3 – 6 months

– Continues even after noxious stimulus is absent (unlike chronic inflammation)

– Associated with physical (strength, endurance), psychological, & social dysfunction

– Source maybe increased sympathetic response (increased sensitivity of nociceptors) or financial gain

– Tx – decrease risk of chronic pain by using physical agents &/or meds to tx acute pain

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Types of Pain

Chronic pain

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Types of Pain Referred Pain

– Felt at one area distant from the source Ex – spinal nerve root impingement, angina

– Pain may be referred from a nerve to innervation site or from different areas of the same dermatome

– Clinicians should not “chase” pain– Rule-out proximal sources of pain– Determine the structure(s) that are responsible

for the pain Rotator cuff injuries can refer pain to the

lateral & upper arm Kidney pathologies can refer pain to the low

back

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Mechanisms of Pain Reception and Transmission Specificity Theory

– Type of pain depends on the stimulation of specific nerve endings

Pattern Theory– Type of pain depends on intensity or

frequency of stimulation of receptors that also respond to touch, pressure, or temperature

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Mechanisms of Pain Reception and Transmission

Pain Receptors– Nociceptors can be

activated by thermal, mechanical, or chemical stimuli

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Mechanisms of Pain Reception and Transmission

Peripheral Nerve Pathways– C fibers (80%) –

cause sensation of dull, throbbing, aching, or burning pain

– A-delta fibers (20%) – cause sharp, stabbing, pricking pain

– Both types of fibers may or may not be stimulated

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Mechanisms of Pain Reception and Transmission Pain-spasm cycle

– Muscle guarding

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Whiplash injury– Muscle guarding– “Protective

guarding”

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Pain Modulation and Control

Gate Control Theory– Proposed by

Melzack & Wall (1965)

– Degree of pain is determined by the balance of excitatory and inhibitory inputs to the spinal cord

– Increased activity of the non-nociceptive fibers causes inhibition of nociceptive fibers

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Pain Modulation and Control

Gate Control Theory– Physical agents and interventions “close

the gate” for pain by activating nonnociceptive nerves

– Ex’s – traction, compression, & massage

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Pain Modulation and Control

The Endogenous Opioid System– Pain can be modulated by endogenous

opioids– Opioids bind to opioids receptors in the

nervous system which inhibits pain– Electrical stimulation has been shown to

release endogenous opioids

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Measuring Pain Visual Analog &

Numeric Scales– VAS – draw a line on

the scale to indicate the present level of pain

– Numeric scale – rate pain from 0-10/10 or 1 to 100

– Face Scale - Used for individuals who have difficulty understanding the VAS and numeric scales

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Measuring Pain

Comparison with a Predefined Stimulus– May allow greater intrasubject &

intersubject reliability– The subject compares the present pain

to a predefined stimulus Tourniquet pain, electrical pain, thermal

pain, or pressure pain You can imagine the limitations to this form

of assessment!!!

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Measuring Pain

Semantic Differential Scales– Consists of word

lists and categories that represent various aspects of pain

– McGill pain questionnaire

– Attempts to quantify pain

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Measuring Pain

Other Measures– Daily activity/pain

logs– Body diagrams– Open-ended,

structured interviews

– Pain response to examination tests/measures

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Pain Management Approaches

Pharmacological Approaches– Systemic Analgesics– Non-steroidal anti-inflammatory drugs

(NSAIDS)– Acetaminophen– Opiates– Antidepressants– Spinal Analgesia– Local Injection

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Pain Management Approaches

Physical Agents– Cryotherapy – reduce local metabolism

& slow production of histamine, bradykinin, & prostaglandins

– Cryotherapy, thermotherapy, & traction stimulate non-nociceptive nerve fibers

– Physical agents have some advantages over medications Ex – less side-effects and can be readily

used by the patient (ice pack or hot pack)

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Pain Management Approaches

Multidisciplinary Pain Treatment Programs– Teams consist of the patient, families,

PTs, MDs, RNs, psychologists, etc– Management techniques include:

medications, physical agents, therapeutic exercise, &/or psychological intervention Pain Clinics