Pain Assessment
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
Patient-Related Barriers
to Pain Assessment
• Reluctance to report pain
• Reluctance to take opioid drugs
• Poor adherence
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
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
Comprehensive Pain Assessment
• History
• Physical examination
• Appropriate laboratory and
radiologic tests
Pain and Disability
Nociception
Disability
Pain
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. 1992;339:1026.
Pain History
• Temporal features—onset, duration, course,
pattern
• Intensity—average, least, worst, and current pain
• Location—focal, multifocal, generalized, referred,
superficial, deep
• Quality—aching, throbbing, stabbing, burning
• Exacerbating/alleviating factors—position,
activity, weight bearing, cutaneous stimulation
Pathophysiology
• Nociceptive pain • Commensurate with
identifiable tissue damage
• Neuropathic pain • May be abnormal, unfamiliar
pain, probably caused by
dysfunction in PNS or CNS
• Idiopathic pain • Pain, not attributable to
identifiable organic or
psychologic processes
• Psychogenic pain • Sustained by psychologic
factors
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
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
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
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
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
Pain Syndromes
• Acute pain • Recent onset, transient,
identifiable cause
• Chronic pain • Persistent or recurrent
pain, beyond usual course
of acute illness or injury
• Breakthrough pain • Transient pain, severe or
excruciating, over
baseline of moderate pain
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