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Back to Table of Contents Part I: Principles of Pain Management

General Principles

• General Principles of Pain Assessment
• General Principles of Pain Management

Pain Pathophysiology

• Acute vs. Chronic Pain
• Nociceptive Pain
• Neuropathic Pain
• Additional Information about Pain Pathophysiology

Pharmacologic Approaches to Pain Management

General Principles

General Principles of Pain Assessment

• The process of pain management starts with adequate assessment of the pain

• The absence of appropriate assessment is the leading reason for poor pain management

• A comprehensive pain assessment addresses the pain's:

• Nature
• Cause
• Personal context:
• Psychological
• Social
• Spiritual
• Practical issues
• See Module 13: Cultural Issues, Module 14: Religion, Spirituality, and End of Life Care and Module 16: Social and Psychological Considerations


• Underlying pathophysiology

Pain assessment is discussed in detail in Module 3: Whole Patient Assessment

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General Principles of Pain Management

A comprehensive pain management strategy includes:

• Use of appropriate interventions

• Pharmacologic
• Nonpharmacologic

• Education of the patient, family, and all caregivers about the plan

• Ongoing assessment of treatment outcomes

• Regular review of the plan of care

• Use of other members of the interdisciplinary team, including:

• Nurses
• Social workers
• Pharmacists
• Chaplains
• Physiotherapists
• Occupational therapists
• Child life specialists

• Flexibility is essential—successful plans are tailored to the individual patient and family

• Willingness to ask for help from colleagues with more expertise when the plan is not effective at controlling the patient’s pain

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Pain Pathophysiology

Acute vs. Chronic Pain

Acute pain

• Is usually related to an easily identified event or condition
• Usually resolves within a period of days or weeks
• Is usually nociceptive

Chronic pain

• May or may not be related to an easily identified pathophysiologic phenomenon
• May be multifactorial
• May be present for an indeterminate period

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Nociceptive Pain

• Nociceptive pain is presumed to involve:

• Direct stimulation of intact mechanical, chemical, or thermal nociceptors
• Transmission of electrical signals along normally functioning nerves

• It can be subdivided into 2 subgroups:

1. Somatic pain
   • Involves skin, soft tissue, muscle, and bone
   • Due to stimulation of the somatic nervous system
   • Patients may describe this as sharp, aching, and/or throbbing pain that is easily localized
   
   
2. Visceral pain
   • Involves cardiac, lung, GI and GU tracts
   • Results from stimulation of the autonomic nervous system
   • Patients may find this pain difficult to describe or localize

• Nociceptive pain generally responds well to opioids and/or coanalgesics

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Neuropathic Pain

• Neuropathic pain is presumed to result from disordered function of the peripheral or central nervous system (CNS) due to any of many potential causes, including:

• Compression
• Transection
• Infiltration
• Ischemia
• Metabolic injury

• There are varied subtypes, including:

• Those sustained by peripheral processes (e.g., painful neuroma)
• Those sustained by CNS processes (e.g., phantom pain)
• Complex regional pain syndromes (previously referred to as causalgia or reflex sympathetic dystrophies)

• These pains can also be classified by syndrome (e.g., malignant plexopathy, painful polyneuropathy, phantom pain, postherpetic neuropathy, etc)

• Patients tend to describe neuropathic pain with words like burning, tingling, numbness, shooting, stabbing, or electric-like feelings

• The intensity of pain involved may exceed observable injury

• Although neuropathic pain may respond well to opioids, adjuvant analgesics (tricyclic antidepressants, anticonvulsants, antiarrhythmics, etc) are often required in combination with opioids to achieve adequate relief

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Additional Information about Pain Pathophysiology

• Acute and chronic pain may be conceptualized as either nociceptive or neuropathic in origin

• A broad description of the predominating pain pathophysiology can usually be inferred through:

• Patient description
• Physical findings
• Results of laboratory tests and imaging studies

• The International Association for the Study of Pain (IASP) has published precise definitions and made them available on their web site http://www.iasp-pain.org

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