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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
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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)
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 증가enhance 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.