CHRONIC PAINChapter 25

Chronic Pain

Pain is the most common reason why people visit health care providers and physical therapists

Chronic pain affects more people than diabetes, heart disease and cancer combined

Definitions of Pain

Pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage

More than merely firing of nociceptive neurons but also includes perception of pain, experience of suffering and pain behavior

Acute Pain Associated with tissue damage or threat of

such damage and typically resolves once the tissue heals or threat resolves

Associated with physiological signs of distress (sweating, pallor, nausea, heart rate changes)

May become persistent if cause of pain is unresolved

Chronic Pain Pain persisting more than 3 or 6 months

Long-lasting, persistent, and of sufficient duration and intensity to adversely affect a patient’s well-being, function and quality of life

Persists past the healing phase following an injury with impairment greater than anticipated based on physical findings of injury, and occurs in the absence of observed tissue injury or damage

Recurrent Pain

Includes episodes of acute pain or chronic pain in which symptoms are intermittent such as migraine headache.

Chronic Pain Syndrome When individuals have developed extensive

pain behaviors such as pre-occupation with pain, passive approach to health care, significant life disruption, feelings of isolation, demanding, angry, or doctor-shopping

considered a disease rather than a symptom

Models of Pain Biomedical: fix tissue damage > pain will resolve

non-organic pain/ psychogenic pain whose physiological source could not be found

Biopsychosocial model of pain Physical factors interact with personal and

environmental factors to affect body, function and structure, activity and participation in life activities

Pain Physiology

Pain Physiology

Gate Control Theory

Descending Inhibition

Peripheral sensitization

Afferent nociceptive input is increased through decreased threshold, increased responsiveness, and/or increased receptive field

d/t inflammation of peripheral tissues or neural connective tissues

Central sensitization

Wind-up repeated low-frequency nociceptor

stimulation results in progressively increased action potential in dorsal horn cells

Long term potentiation neural response is strengthened through

increased neurogenic inflammation

Classification of Pain Divided by body region Pathology: Phantom limb pain, MS or

malignant (cancer) Physiological process: nociceptive,

inflammatory, neurogenic, maladaptive Dimensions: (sensory-discriminative,

motivational-discriminative, cognitive-evaluated)/ (nociception, pain cognition, suffering and pain behavior)

Classification of Pain (Dimensions) Sensory-Discriminative

localization, intensity, duration and nature of pain (burning, sharp and so forth)

Motivational-affective dimension emotional response, physiological

manifestations Cognitive-affective

How pain is interpreted in context of past and present experience

Classification of Pain Nociceptive Pain

response to an immediate noxious stimulus (mechanical, thermal or chemical)

protective withdrawal response Inflammatory Pain

increase sensory sensitivity after tissue damage Maladaptive pain

abnormally functioning nervous system relaying pain signals unrelated or disproportional to tissue damage

Subjective and Objective Characteristics Associated with Different Types of Pain and Soft Tissue Sources

Type of Pain

Tissue Source Subjective Objective

Nociceptive: Cutaneous/ Superficial

Skin and Subcutaneous tissues (A fibers)

Well-localized, stabbing, burning, cutting

Clear, consistent proportional pain

Nociceptive: Deep Somatic

Bone, muscle, blood vessels, conncective tissue (C fibers)

Often referred to other locations, tearing, cramping, pressing, aching

Vague, sometimes referred pain reproduced through movement or mechanical testing of deeper tissues, trigger points

Nociceptive Visceral

Organs and linings of body cavity (C fibers)

Often referred to other locations; poorly localized, diffuse, deep cramping or splitting sharp, stabbing

Vague pain reproduction on movement or mechanical testing of visceral tissues

Subjective and Objective Characteristics Associated with Different Types of Pain and Soft Tissue Sources

Type of Pain

Tissue Source Subjective Objective

Peripheral Neurogenic

Nerve fibers Pain variously described as burning, shooting, sharp, aching, “electric like”

Pain symptoms provocation with movement or mechanical tests that move, load or compress neural tissues

Central Spinal Cord and Central Nervous system

Disproportionate, nonmechanical, unpredictable pattern of pain provication in response to multiple nonspecific aggravating or easing factors

Disproportionate, inconsistent, nonmechanical or nonanatomical pattern of pain provocation in response to movement or mechanical testing

Causes and Risk Factors for Pain Genetic Factors Women > Men Post-traumatic stress disorder Depression Comorbid conditions

Migraine Fibromyalgia CRPS Low Back Pain Irritable Bowel Syndrome

Lifestyle Factors

Smoking Alcohol Addiction Obesity/ Overweight Sleep disorders Vitamin D deficiency

Psychosocial Factors Pain Beliefs and Coping Anxiety and Fear Avoidance Catastrophizing

pessimism, helplessness to control symptoms, magnification, and rumination (excessive focus on pain sensations)

Depression and Grieving Stress Non-organic Findings

Psychosocial Factors Non-organic Findings (Waddell signs)

Superficial or Nonanatomical tenderness Pain in response to simulation tests Inconsistent response to distraction Regional sensory and strength impairments Overreaction

Personality disorders Borderline, Histrionic, OCD = poorer prognosis,

Social Support

Examination of Pain

“Fifth Vital Sign” Psychosocial aspects of pain should be

examined Examined both at rest and movement

Examination of Pain

Standard Tools for Quantifying pain: Visual Analogue Scale (VAS) Numeric Rating Scale (NRS) Verbal Rating Scale (VRS) Faces Scale – children over 3 years old Body diagram: pain location, radiation and

character; more time consuming to administer

Visual Analog Scale

Numeric Rating Scale

FACES

Body diagram

Pain Questionnaires and Outcome Measures

McGill Pain Questionnaire (MPQ) / Short form MPQ examine sensory, affective, emotional, evaluative and

temporal aspects of pain Leads Assessment of Neuropathic Symptoms and

Signs (LANSS) distinguishes between neurogenic and nociceptive pain

Neuropathic Pain Scale disinguishes between neuropathic and non-neuropathic

pain

Pain Questionnaires and Outcome Measures

Brief Pain Inventory (BPI) initially designed for cancer-related pain rates pain interference with functional

activities such as walking, activity, normal work, relations with other people, mood, sleep and enjoyment of life

Tools for Specific Type of Pain

Western Ontario and McMaster University Osteoarthritis Index (WOMAC)

Oswestry Low Back Pain Disability Questionnaire for LBP

Revised Fibromyalgia Impact Questionnaire (FIQR)

Headache Impact Test Von Frey Filaments – pain treshold

Examination of Pain in Special Populations

Children FACES Pieces of Hurt Scale Crying, Requires increased oxygen administration,

Increased Vital Signs, Expression, Sleeplessness (CRIES) Pain scale: 0-6 months

Face, Legs, Activity, Cry, Consolability Scale (FLACC): for infants and Children 2 months to 7 years

COMFORT Pain Scale – Unconscious ventilated infants, children, adolescents

Pharmacological Management of Chronic Pain

Tx starts with acetaminophen and proceeds to NSAIDs

Adjuvant Medications medications whose primary indication is a

condition other than pain, but which have demonstrated benefit in pain management

Muscle Relaxants and Weak Opiates

Adjuvant Medications

Anti-depressants TCA SNRI

Anti-seizure Muscle Relaxant Sleep Medications

Serotonin Syndrome

Potentially dangerous consequence of polypharmacy

Symptoms: Agitation, Anxiety, Confusion, Hypomania,

Hyperthermia, Tachycardia, Diaphoresis, Flushing, Mydriasis, Hyperreflexia, Clonus, myoclonus, shivering, tremor, and hypertonia

PT Examination

Tests and Measurements Body Structure and Function Measure

Palpation for tenderness (tissue damage, muscle spasm, trigger points, hyperalgesia and allodyina)

Algometer: Measures palpation pressure Pressure Pain Treshold (PPT): point at which

pressure changes from comfortable pressure to slightly unpleasant pain

Trigger points: ropelike tautbands within a muscle fiber

Local twitch response, transient contraction, jump response

Examination of balance

Algometer

PT Examination

Activity and Participation Measures Revised Fibromyalgia Impact Questionnaire Oswestry Low Back Pain Disability

Questionnaire Patient Specific Functional Scale (PSFS) Activity Specific Balance Confidence Scale Physical activity measures:

30-second Sit to Stand Test Timed up and go test Short Physical Performance Battery Test

PT Management of Chronic Pain

Neuroblation

Implanted Spinal Analgesia

Implanted Spinal Cord Stimulation

Strong Opioids

Weak Opioids

Cognitive and Behavioral Therapies

Adjuvant Medications

PT and OT

OTC Medications

Independent ExerciseLeast Invasive

Most Invasive

Procedural Interventions

Therapeutic Exercise Graded Exercise: decreasing fear

avoidance No one type of exercise is superior to

others Individual patients may tolerate and

respond to some forms of exercise better than others

Manual Therapy Manipulation, Muscle Energy Techniques

Procedural Interventions

Neuromuscular Reeducation EMG Biofeedback Yoga, Tai-chi, Qigong

Assistive Device Physical and Electrotherapeutic

Modalities

Thank you for listening