Ch. 44 Myofascial Pain Syndrome

Ch. 44 Myofascial Pain Syndrome R1 유지웅

Myofascial pain (MP) • local and referred pain that arises from myofascial trigger points • Trigger points (TPs) • localized, very sensitive areas in skeletal muscle • contain palpable, taut bands • painfull to palpation, reproduce the patient’s pain, and are associated with referred pain

MP • It is a treatable condition : responds to physical and injection techniques • frequently found : head, neck, shoulders, extremities and low back • Women > Man • often associated with • chronic head and neck pain ( temporomandibular joint disorder) • cervicogenic headache • tension-type headache

TPs classified as active or latent • Active patients • with a regional pain complaint • Latent patient • asymptomatic patients by their local tenderness to palpation하며, • perhaps associated with diminished range of motion (but not associated with spontaneous pain)

Diagnosis • careful musculoskeletal examination seeks to identify postural, mechanical, orthopedic, or neurological abnormalities that may contribute to MP • TPs are detected by • identification of taut muscle bands and production of severe pain which is characteristic of the patient’s complaint. • Referred pain : not usefull clinically • Pain relief : after muscle stretching or local injection

Differential diagnosis • arthritis including facet syndrome • discogenic pain syndromes • radiculopathy • neuropathy • bursitis • tendonitis • referred visceral pain • infectious and autoimmune disorders • abnormal body mechanics • metabolic/endocrine disease including hypothyroidism • psychiatric disorders including depression • fibromyalgia

Pathophysiology(1) • etiology and mechanism :not been established • peripheral nociception occurs along with central sensitization and an autonomic component • Simons et al. primary abnormality : pathologic increase in acetylcholine release by abnormal motor endplates at rest in muscle TPs • Needle examination recordings • TPs : low-voltage의 spontaneous activity and activity resembling endplate spikes • endplate noise : characteristic but not diagnostic of myofascial patient

Pathophysiology(2) • Increased acetylcholine release --> sustained depolarization of the postjunctional membrane and sustained muscle contraction • Sustained maximal shortening of the sarcomere in the region of the motor endplate • Chronic sarcomere shortening --> localized alterations in energy consumption and perfusion --> ischemia --> increased resting tension in the taut muscle band • Muscle ischemia --> release of vasoactive substances that sensitize afferent nociceptors --> increased tenderness to palpation

Pathophysiology(3) • Chronic MP  central sensitization, refferred pain to adjacent spinal levels, and persistent pain at the spinal cord and brain levels • Psychological Stress and the sympathetic nervous system  perpetuate MP • TPs 에서 Endplate potential spike activity는 experimental psychological stress에의해증가

TREATMENT: MECHANlCAL(1) • The goal of treatment • educate and empower patients to understand and manage the symptoms of MP and to regain and maintain normal function with as much independence as possible • Correction of postural and ergonomic abnormalities

TREATMENT: MECHANlCAL(2) • A Study of chronic oral and masticatory muscle pain • compared four single treatments: • relaxation • physial therapy • TENS • dental splinting  response was good, but similar • Acupuncture treatment at points (myofascial neck pain) nonsteroidal anti-inf1ammatory drugs (NSAIDs) 나acupuncture at distant sites보다 더 효과적 • Ultrasound : not offer added benefit to combined exercise and massage

EXERClSE AND INJECTION THERAPY • Stretching exercises: • cornerstone of all treatment approaches for MR • Slow, sustained muscle stretch하여 normal muscle length and activity복구 (lightIy loading) • Topical cold appliation • initial goal도달 후 단계적 Stabilization 과 muscle Strengthening program 실행해 functional status향상 • (An aerobic exercise 도 포함하여 muscle 과 cardiovascular fitness향상케한다)

EXERClSE AND INJECTION THERAPY(2) • Trigger point injections (TPIs) • 초기 치료로 적당 • The goaI of TPI • facilitate progress in PT & 환자에게 home Stretching exercise가능케 함 < injected medications > • local anesthetics • steroids • botulinum toxin • no drug (dry needling)

Trigger point injections (TPIs) • Injection pain 과 postinjection soreness 는 drugs마다 다르나 efficacy차이는 없음 • Bupivacaine : injection pain 과 greater myotoxicity 있음 • (lidocaine or mepivacaine are diluted with water to a concentration of 0.2% to 0.25%시 injection pain 감소) • injection pain : sterile water alone > normal saline • postinjection soreness강도및 기간 : dry needling시 더 큼 • injection시 local twitch response감소 -->successfull procedure의 best indicator • Injection of botulinum toxin type A • the motor endplate 에서 acetylcholine분비억제하여muscle contraction방해 sustained relaxation of muscles

PHARMACOLOGIC TREATMENT • NSAIDs • tramadol • antidepressants • alpha2-adrenergic agonist and muscle relaxant (tizanidine) : MP와 FM에서 analgesia 제공

CONCURRENT MANAGEMENT • 모든 방법이 실패하였을 때 physician은 other options을 고려해봐야함. contributing psychological component및undiagnosed pain generators찾음 • other underlying pain sources • lumbar and gluteal MP : discogenic, ligamentous, facet joint, sacroiliac joint pathology • thoracic TP등 에서 진단안된disease (pancreatic cancer)

Ch. 45 Fibromyalgia

Fibromyalgia (FM) • prevalent musculoskeletal pain disorder characerized by diffuse pain and abnormal soft tissue tenderness

Associated symptoms • widespread pain at multiple tender points • reduced pain threshold • fatigue • sleep disturbances • morning stiffness • depression • anxiety • psychological distress • subjective swelling • irritable bowel syndrome • headaches • paresthesias

prevalence : 0.5% ~ 5% • most fieqllently seen in women between the ages of 2O and 50 years • W:M = 10:1 (favoring women) • no association between FM prevalence and compensation

DlAGNOSIS • criteria : 1. Chronic widespread pain (CWP) at least 3 months' duration, present above and below the diaphragm on both sides of the body plus axial pain • 2. Painful tender points (TPs) in at least 11 out of 18 characteristic locations. • TPs are defined by mild or greater pain after palpation with an approximate force of 4 kg/cm2 (nail bed가 창백해지는 압력) • ·Bilateral occiput, at the suboccipital muscle insertion. • ·Bilateral low cervical, at anterior aspect of intertransverse • spaces between C5 and C7. • ·Bilateral trapezius, at midpoint of the upper border. • ·Bilateral supraspinatus, at its origin above scapular spine • near the border. • ·Bilateral second rib,just lateral to the costochondral junctions • on upper surface • ·Bilateral lateral epicondyle, 2 cm distal to the epicondyle • ·Bilateral gluteal, at the upper outer quadrant of the buttock. • ·Bilateral greater trochanter, posterior to the trochanter. • ·Bilateral knee, medial fat pad proximal to the joint line.

Two other important symptoms characteristic of FM • subjective swollen feeling without objective joint swelling • paresthesia without objective neurologic findings보임 이것은 reflect heightened sensory perception due to central sensitization

FM symptoms are often aggravated by • cold humid weather • interrupted sleep • repeated injury • mental stress • inactivity • FM symptoms tend to improve with • warm dry climate • rest • modest activity • good sleep • Relxation

associated with many similar conditions • irritable bowel syndrome (in 30% to 50%) • tension headaches • migraine • headaches • temporomandibular dysfunction • myofascial pain syndrome • chronic fatigue syndrome • restless legs syndrome(in one-third) • multiple chemical sensitivity • post-traumatic stress disorder

Several other diseases may be associated with and aggravate symptoms of FM: • systemic lupus • RA • Sjogren’s syndrome • OA • spinal stenosis • neuropathy • hypothyroidism • growth hormone deficiency(in about one-third of patients)

PATHOPHYSIOLOGY(1) • strong association between FM and sleep disturbance • Normal sleep • four nondream stage (non-REM sleep) • dream stage (REM sleep) • many FM patients : alpha-delta EEG panern not get into the restorative stages 3 and 4 of non-REM sleep • due to alpha wave (7.5 to 11 Hz) intrusion during delta wave (0.5 to 2 Hz) sleep • experimental induction of alpha-delta sleep in healthy individuals  induce symptoms suggestive of FM (muscle aching, stiffness, and tenderness) • Nonrestorative sleep  increased pain and fatigue • pharmamlogic correction of the sleep abnormality may improve both symptoms

PATHOPHYSIOLOGY(2) • often associated with diseases 1. autoimmune basis : rheumatoid arthritis, systemic lupus  possible immune system alteration시사 2. endocrine abnormality hypothalamic-pituitary system의 반응 저하 보임 growth hormone deficient (1/3) 3. underlying psychological disturbance 30% of FM patients : clinical depression

PATHOPHYSIOLOGY(3) 4.muscle pathology • most common findings : disuse or deconditioning 주로 central nervous system (CNS) pathophysiology임을 시사(rather than peripheral) 5.Abnormal central neurophysiology  most accepted pathologic mechanism in FM 6.pathological nociceptive processing within the CNS • substance P 와 nerve growth factor, neuropeptides의CSFlevels 증가enhance nociceptive neurotransmission 7.Activation of NMDA(N-methyl-D-aspartate) receptors : important part in central senitization ex) NMDA receptors 길항인 Ketamine,Dextrometrophan :pain소실

MANAGEMENT • goals of patient management • accurate diagnosis • patient education and empowerment • symptom control for pain, fatigue, and sleep • management of associated psychological, endocrine, and autonomic disorders • Treatment of any peripheral pain generators • improved physical conditioning and function

patient education • by Bennett • Key components • . validate the patient’s symptoms and explain nature of FM syndrome • ·Emphasize nondestructive and treatable nature of FM symptoms • ·Set realistic goals: improving function without complete symptom eradication. • ·Discuss all treatment options and enlist patient in selection of plan • ·Stress importance of gentle, life-long aerobic exercise and pacing activity. • ·Educate patient on principles of sleep hygiene. • ·Teach coping skills: meditation and relaxation techniques. • ·Improve patient assertiveness and active role in FM management plan • ·Refer patients to educational resources, including on-line selfhelp material.

NONPHARMACOLOGIC PATlENT MANAGEMENT • Cognitive-behavioral Strategies • teach patients how their thoughts and behaviors influence symptoms • how they an potentially control their symptoms  significant changes in tender points, pain scores, coping scores, or pain behaviors.

EXERClSE THERAPY • FM patients : good candidate for rehabilitative physical therapy • too rigorous program may be deleterious  carefully planned individual exercise program is required • aerobic exercise produces significant benefits • improvements in pain scores and tender points • Strength training may also have had benefits on some FM symptoms

PHARMACOLOGIC TREATHENT OF PAlN AND ASSOCIATED SYHPTOMS • nonsteroidal anti-inflammatory drugs(NSAIDs) or acetaminophen • tricyclic antidepressants (TCAs) • most common drug tratment for FM • improve sleep, fatigue, pain, and well-being in that order • but not improve tender points • selective serotonin reuptake inhibitors (SSRIs) • analgesic effcts 떨어짐 • emotional components and mood disorder에 도움 • combination of fluoxetine and amitriptyline --> superior to either agent alone • serotonin-epinephrine dual reuptake inhibitors (SNRIs) • quite similar to TCAs • but other receptor • improve on side-effect profile and increase patient tolerance when compared to TCA

PHARMACOLOGIC TREATHENT OF PAlN AND ASSOCIATED SYHPTOMS • Venalafaxin • 5-HT system at low doses • NE effects apparent at higher doses • tizanidine • alpha2-adrenergic agonist and muscle relaxant with antinociceptive and antispasmodic actions • effectively for FM-related pain and for sleep disturbance • Low-dose TCA therapy at bedtime (started at 5 to 1O mg) • most common sleep therapy for FM patient with sleep disturbance • Cyclobenzaprine • TCA-analogue muscle relaxant • effects on sleep and evening fatigue • For patients intolerant of TCAs • short-acting imidazopyridine hypnotics(zolpidem and zaleplon) • unlike benzodiazepines, not interfere with stage 3 and stage 4 sleep, or with memory

PHARMACOLOGIC TREATHENT OF PAlN AND ASSOCIATED SYHPTOMS • most common sleep disorder in FM patients --> restless leg syndrome • characterigd by crawling sensations ofthe legs and an uncontrollable urge to stretch • L-dopa/carbidopa at dinner • 취침시 donazepam이 효과적 • other dopamine agonists (pergolide, pramixepole, and tolixepole) 와 bedtime methadone역시 효과적 • Sleep apnea환자에서는 sedative피해야 • Fatigue • often resistant to drug therapy • SSRI와 5-HT3 antagonist(tropisetron)이 증상개선.

Ch. 44 Myofascial Pain Syndrome