Nonopioid Analgesics and Adjuvants

1
Pain Assessment
2
Clinician-Related Barriers
to Pain Assessment

• Lack of pain training in medical school
• Insufficient knowledge
• Lack of pain-assessment skills
• Rigidity or timidity in prescribing practices
• Fear of regulatory oversight

3
Patient-Related Barriers
to Pain Assessment

• Reluctance to report pain
• Reluctance to take opioid drugs
• Poor adherence

4
System-Related Barriers
to Pain Assessment

• Low priority given to symptom control
• Unavailability of opioid analgesics
• Inaccessibility of specialized care
• Lack of insurance coverage for outpatient
  pain medication

5
Pain Assessment Goals

• Characterize the pain
• Identify pain syndrome
• Infer pathophysiology
• Evaluate physical and
  psychosocial comorbidities
• Assess degree and nature of disability
• Develop a therapeutic strategy

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Comprehensive Pain Assessment

• History
• Physical examination
• Appropriate laboratory and
  radiologic tests

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Pain and Disability

• Nociception
• Other physical symptoms
• Physical impairment
• Neuropathic Psychologic Social isolation
• mechanisms processes Family distress
• Sense of loss or inadequacy
• Adapted with permission from Portenoy RK. Lancet.
  19923391026.

Disability
Pain
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Pain History

• Temporal featuresonset, duration, course,
  pattern
• Intensityaverage, least, worst, and current pain
• Locationfocal, multifocal, generalized,
  referred, superficial, deep
• Qualityaching, throbbing, stabbing, burning
• Exacerbating/alleviating factorsposition,
  activity, weight bearing, cutaneous stimulation

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Pathophysiology

• Nociceptive pain
• Neuropathic pain
• Idiopathic pain
• Psychogenic pain

• Commensurate with identifiable tissue damage
• May be abnormal, unfamiliar pain, probably caused
  by dysfunction in PNS or CNS
• Pain, not attributable to identifiable organic or
  psychologic processes
• Sustained by psychologic factors

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Pain Assessment Tools

• Pain intensity scales
• Verbal rating
• Numeric scale
• Visual analogue scale
• Scales for children
• Multidimensional pain measures
• Brief Pain Inventory
• McGill Pain Questionnaire

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Nociceptive Pain

• Presumably related to ongoing activation of
  primary afferent neurons in response to noxious
  stimuli
• Pain is consistent with the degree of tissue
  injury
• Subtypes
• Somatic well localized, described as sharp,
  aching, throbbing
• Visceral more diffuse, described as gnawing or
  cramping

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Neuropathic Pain

• Pain believed to be sustained by aberrant
  somatosensory processing in the peripheral
  or central nervous system
• Subtypes
• Central generator
• Deafferentation pain (central pain, phantom pain)
• Sympathetically-maintained pain (CRPS)
• Peripheral generator
• Originate in the nerve root, plexus, or nerve
• Polyneuropathies, mononeuropathies

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Idiopathic Pain

• Pain in the absence of an identifiable
  physical or psychologic cause
• Pain is perceived to be excessive for the
  extent of organic pathology

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Psychogenic Pain

• Pain sustained by psychologic factors
• More precisely characterized in psychiatric
  terminology
• Patients have affective and behavioral
  disturbances
• Patients with organic component often have
  concurrent psychologic contributions and
  comorbidities
• Chronic pain syndrome sometimes used to depict
  this phenomenon

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Pain Syndromes

• Acute pain
• Chronic pain
• Breakthrough pain

• Recent onset, transient, identifiable cause
• Persistent or recurrent pain, beyond usual course
  of acute illness or injury
• Transient pain, severe or excruciating, over
  baseline of moderate pain

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Identify Pain Syndromes

• Syndrome identification can direct assessment and
  predict treatment efficacy
• Cancer pain syndromes
• Bone pain
• Pathologic fracture
• Cord compression
• Bowel obstruction
• Noncancer-related pain syndromes
• Atypical facial pain
• Failed low-back syndrome
• Chronic tension headache
• Chronic pelvic pain of unknown etiology