3. Taxonomy : Definitions of Pain Terms and Chronic Pain Syndromes
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Analgesia – absence of pain <- normally painful stimulus. Anesthesia – absence of all sensory modalities. Carpal tunnel syndrome – hand pain, usually occurring at night,
due to entrapment of the median nerve in the carpal tunnel (carpal bones and flexor retinaculum) First to third fingers tip : decreased sensation Positive Tinel’s sign, rarely thenar muscle atrophy
Central pain – regional pain caused by a primary lesion or dysfunction in the central nervous system Complex regional pain syndrome – regional painful conditions following injury,
distal abnormal finding - magnitude, duration +, impairment of motor function Previously called reflex sympathetic dystrophy
CRPS type I (RSD)
Develops after an initiating noxious stimuli Spontaneous pain or allodynia/hyperalgesia, not limited to the territory of a single peripheral nerve Edema, skin blood flow abnormality, abnormal sudomotor activity Excluded by the existence of conditions
CRPS type II (causalgia)
Develops after a nerve injury
Chronic pain – pain that persists beyond the course of an acute disease or reasonable time for an injury to heal
some investigator – pain duration > 6 month
Cubital tunnel syndrome – entrapment of the ulnar nerve (olecranon process and medial epicondyle of humerus)
ulnar nerve distribution : pain, numbness, paresthesia, weakness, atrophy, Tinel’s sign at the elbow
Deafferentiation pain – pain due to loss of sensory input into the central nervous system, occur with lesion of peripheral nerve or pathology of CNS Fibromyalgia – diffuse musculoskeletal aching and pain with multiple tender points
Occiput : suboccipital muscle insertion Low cervical : anterior aspect of the intertransverse process at C5-7 Trapezius : midpoint of the upper border Supraspinatus : origin above the scapula spine medial border Second rib : costochondral junction Lateral epicondyle : 2cm distal to epicondyle Gluteal : upper outer quadrant of buttock in anterior fold of muscle Greater trochanter : posterior trochanteric prominence Knee : medial fat pad
Hyperalgesia – increased response to a stimulus that is normally painful
Hyperesthesia – increased sensitivity to stimulation Hypoalgesia – diminished sensitivity to noxious stimulation Lateral epicondylitis (tennis elbow) – pain in the lateral epicondylar region due to strain or partial tear of extensor tendon of the wrist
Radiate to lateral forearm or upper arm During grasping and supination of wrist and repeated dorsiflextion Tenderness of wrist extensor tendon
Neuralgia – pain in the distribution of a nerve Neuritis – inflammation of a nerve Neurogenic pain, neuropathic pain – pain caused by primary lesion, dysfunction in the peripheral or central nervous system Central neuropathic pain – CNS lesion causing pain
Thalamic pain syndrome, poststroke pain, postspinal cord injury pain Postherpetic neuralgia, painful diabetic neuropathy, CRPS
Peripheral neuropathic pain
Neuropathy – disturbance of function or pathologic change in nerve, involve one nerve(mononeuropathy), several nerve(mononeuropathy multiplex), bilateral or symmetrical(polyneuropathy) Nociceptive pain – pain caused by activation of nociceptive afferent fiber Somatic pain – pain carried along sensory fiber, discrete and intense Visceral pain – pain carried by sympathetic fiber, diffuse and poorly localized Nociceptor – receptor preferentially sensitive to noxious stimulus Noxious stimulus – actually or potentially damaging to body tissue stimulus Pain – unpleasant sensory and emotional experience associated with actual or potential tissue damage
Pain of psychological origin:
Delusional or hallucinatory Hysterical, conversion, or hypochondriacal Depression
Peripheral neuropathy – burning, aching or lancinating limb pain due to disease of peripheral nerve Phantom pain – pain referred to surgically removed limb Piriformis syndrome – myofascial injury of piriformis muscle itself or dysfunction of sacroiliac joint Post-thoracotomy pain syndrome – pain along thoracotomy scar persisting at least two months after thoracotomy Radicular pain – pain perceived as arising in a limb or trunk wall caused by ectopic activation of nociceptive afferent fiber in a spinal nerve Radiculopathy – objective loss of sensory and motor function as a result of conduction block in axon of spinal nerve
Raynaud’s disease – burning pain associated with vasoconstriction of artery of extremity in response to cold or emotional stimuli Stump pain – pain at the site of an extremity amputation Stylohyoid process syndrome(Eagle’s syndrome) – pain following trauma in the region of calcified stylohyoid ligament Thoracic outlet syndrome – brachial plexus compression by hypertrophied muscle, congenital band, post-traumatic fibrosis, cervical rib -> neck, head, shoulder pain
4. Physical Examination of the Pain Patient
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Goal of physical examination – patient’s trust, gaining insight, identifying potential pain generator and other neurological derangement
Sensation and sensory examination
Physiological basis is differentiation of nerve fiber sensation Type of damaging stimuli
mechanical nociceptor <- pinch, pin-prick heat nociceptor <- temperature>45’C polymodal nociceptor <- mechanical, heat, chemical noxious stimuli : Adelta and C fiber transmission fast pain – well-localized myelinated A-delta fiber (sharp, shooting pain) slow pain – unmyelinated C fiber (poorly localized burning pain)
Based on Transmitting fiber
Hyperesthesia
Hyperalgesia – severe pain in response to mild noxious stimuli (eg. Pinprick) Allodynia – severe pain in response to non-noxious stimuli (eg. Light touch) , important indicator of neuropathic pain
C fiber : both pain and temperature (sharp edge of broken tongue blade and cold turning fork) A-delta fiber : pin-prick, light touch A-beta fiber : light touch, vibration, joint position (isolated decreased vibratory sense = early sign of large-fiber neuropathy, combined with position sense deficit = posterior column disease or peripheral nerve involvement) Pinpoint -> anatomical location of lesion (central, spinal nerve root, peripheral nerve lesion)
Motor examination
Inspection : hypertrophy, atrophy, fasciculation Palpation : myofascial trigger point Tone
hypotonia – decrease in normal expected muscular resistance to passive manipulation -> depression of alpha or gamma motor unit activity (extrapyramidal or cerebellar motor disorder, polyneuropathy, myopathy, spinal cord lesion) Hypertonia – divided into spasticity and rigidity
Spasticity : velocity-dependent increase in tone with joint movement (due to incresed excitation at spinal reflex arc level, loss of descending inhibitory control in reticulospinal or rubrospinal track) <- after brain and spinal cord injury, stroke, multiple sclerosis Rigidity : generalized increase in muscle tone (extrapyramidal disease, nigrostriatal system lesion
Isolated volutary muscle strength is graded from 0 to 5
Greater proximal muscle weakness indicate myopathy, greater distal muscle weakness indicate polyneuropathy, single innervation muscle weakness indicate peripheral nerve lesion
Reflexes and coordination
Most commonly tested reflexes
Deep tendon reflex grading system
Clonus : rhythmic, uniphasic muscle contraction in response to sudden sustained muscle stretch -> upper motor neuron disease Positive plantar or babinski’s reflex -> upper motor neuron disease Coordination and gait testing is sensitive indicator of cerebellar function and equilibrium
Cerebellar function : finger-nose-finger, heel-knee-shin test Equilibrium : normal gait, heel and toe walk, tendem gait test, Romberg’s test
Directed pain examination template
Descriptive template should include inspection, palpation, percussion, range of motion, motor examination, sensory examination, reflex, provocative test
General observation
Careful observation of patient’s mannerism, coordination, interpersonal interaction, gait -> insight into patient’s mental, emotional, physical status Nature of patient’s complaint during history -> physical exam can be efficiently directed toward affected region Global physical status by obtaining vital sign, vital sign are objective indication of general health status and provide baseline against to compare patient’s condition following any procedure
Mental examination
Level of consciousness, alertness, orientation to person place and time Vigilant for sign of undiagnosed depression frequently associated with chronic pain
Gait
Normal, antalgic, abnormal Antalgic gait : avoidance of bearing weight on an affected limb or joint secondary to pain Abnormal non-antalgic gait : balance, neurological, musculoskeletal disorder
Examination of the different regtions of the body FACE
Cranial nerve
CERVICAL AND THORACIC AREAS AND UPPER EXTREMITIES
Inspection : symmetry, muscle condition, scarring, head shoulder upper extremity position at rest Palpation : muscle spasm, myofascial trigger point, tender point, occipital nerve entrapment, gross sensory change, pulse symmetry Normal ROM : flexion 0-60’, extension 0-25’, lateral flexion 0-25’, lateral rotation 0-80’
Provocative tests
Distraction test : relieving compression caused by neural foramina stenosis / in contrast cervical compression test : exacerbation of symtom indicate foraminal stenosis Valsalva maneuver : compression of disc material or tumor->pain Drop arm test : not be able to retain arm in abducted position -> rotator cuff tear Tennis elbow test Yergason test Tinel’s sign Phalen’s sign
THORACIC REGION
Inspection : cutaneous landmarks, surgical scar, herpetic lesion, ecchymotic lesion Palpation : cutaneous sensory deficit, mass, bony integrity of thorax Deep palpation of abdominal wall – pulsatile mass : abdominal aortic aneurysm
LUMBOSACRAL REGION
Global inspection : gait, posture at rest -> asymmetry and degree of spinal curvature Infection, rash, cutaneous discoloration, subcutaneous mass, postsurgical scar – detailed inspection Palpation : bony landmark identification (sp, iliac crest) Common bony structure pain generator : facet joint, sacroiliac joint, coccyx Normal lumbar spine ROM : flexion 0-90’, extension 0-30’, lateral flexion 0-25’, lateral rotation 0-60’, Pain on flexion -> disc lesion, pain on extension -> facet arthropathy, muscular pain generator Provacative test
nerve root irritation : back flexion, straight leg raising Sacroiliac joing dysfunction : Faber patrick test, Gaenslen’s test, Yeoman’s test, posterior shear test Piriformis syndrome : Pace, Laseque, Freiberg sign Intrathecal lesion : Kernig test for meningeal irritation, valsalva, Milgram test Hoover test : malingering (paralysis of the legs)
Waddell’s sign : patient pain behavior, indication of nonorganic source for patient’s pain, five potential waddell’s sign and presence of three or more positive sign is a strong indication of a nonorganic source
Tenderness Simulation testing Distraction testing Regional disturbance Overreaction
CONCLUSION
Physical examination is secondary in importance only to pain history In order to gain a meaningful understanding of the patient’s symptom physical examination should be based on anatomical and physiological principle Diagnosis supported by physical examination finding and appropriate provacative test results