Ch. 44 Myofascial Pain Syndrome

1. Ch. 44 Myofascial Pain Syndrome R1 최 정 현

2. 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

3. MP • It is a treatable condition that responds to physical and injection techniques, if associated conditions and postural/ergonomic factors are also addressed. • most frequently found in head, neck, shoulders, extremities and low back • more prevalent In women • often associated with • chronic head and neck pain as seen with temporomandibular joint disorder • neck pain after whiplash injury • cervicogenic headache • tension-type headache

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

5. Diagnosis • carefull musculoskeletal examination seeks to identify postural, mechanical, orthopedic, or neurological abnormalities that may contribute to MP • Active TPs : suspected skeletal muscle  gentle palpation across and perpendicular to the muscle fibers. • TPs are detected by • identification of taut muscle bands and production of severe pain which is characteristic of the patient’s complaint. • Classic referred pain and involuntary muscle contraction or a jump sign may also be elicited • Referred pain may be an unreliable sign that is not usefull clinically • Pain relief may occur after muscle stretching or local injection

6. 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

7. Pathophysiology • etiology and mechanism not been established • peripheral nociception occurs along with central sensitization and an autonomic component • Simons et al. • primary abnormality is pathologic increase in acetylcholine release by abnormal motor endplates at rest in muscle TPs • more frequent endplate noise in myofascial TPs than adjacent muscle outside the TP

8. Pathophysiology • Needle examination recordings • TPs show low-voltage spontaneous activity and activity resembling endplate spikes • endplate noise is characteristic but not diagnostic of myofascial patient • 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

9. Pathophysiology • 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 • Endplate potential spike activity in TPs increased with experimental psychological stress

10. TREATMENT: MECHANlCAL • The goal of treatment • to 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 --> standard component of patient management

11. TREATMENT: MECHANlCAL • A Study of chronic oral and masticatory muscle pain • compared four single treatments: • relaxation • physial therapy • transcutaneous electrical nerve stimulation (TENS) • dental splinting  response was good, but similar • Acupuncture treatment at points (myofascial neck pain) • more effective than treatment with either nonsteroidal anti-inf1ammatory drugs (NSAIDs) or acupuncture at distant sites • value of massage therapy : not been demonstrated. • Ultrasound : not offer added benefit to combined exercise and massage

12. EXERClSE AND INJECTION THERAPY • Stretching exercises • cornerstone of all treatment approaches for MR • Slow, sustained muscle stretch • aims to restore normal muscle length and activity • combined with lightIy loaded daily physical activity until patients demonstrate improved pain and range of motion. • Topical cold appliation may be used to facilitate muscle stretch. •  initial goal도달 후 add a graded Stabilization and muscle Strengthening program to further improve functional status-An aerobic exercise component is included to maintain muscle and cardiovascular fitness

13. EXERClSE AND INJECTION THERAPY • Trigger point injections (TPIs) • best suited for initiation of treatment • In patients intolerant of physical therapy (PT) focused on a difficult area of persistent MP identified by the therapist. • The goaI of TPI • facilitate progress in PT • and ultimately to support patient success in program of home Stretching exercise < injected medications > • local anesthetics • steroids • botulinum toxin • no drug (dry needling)

14. Trigger point injections (TPIs) • Injection pain and postinjection soreness vary with the drugs employed but no difference in efficacy • Bupivacaine : increased injection pain and greater myotoxicity • Injection pain is diminished when lidocaine or mepivacaine are diluted with water to a concentration of 0.2% to 0.25% • sterile water alone : more painfull than similar injections of normal saline • intensity and duration of postinjection soreness : grater after dry needling • Cummings and white conclude • drug employed does not alter the outcome or offer any therapeutic benefit over dry needling • elicitation of a local twitch response during injection --> best indicator of a successfull procedure • Injection of botulinum toxin type A • increasingly popular • but very expensive treatment for TPs in MP • inhibits muscle contraction by inhibiting release of acetylcholine at the motor endplate --> sustained relaxation of muscles

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

16. CONCURRENT MANAGEMENT • 모든 방법이 실패하였을 때 physician은 other options을 고려해봐야함. • Search for a contributing psychological component • other undiagnosed pain generators • high levels of anxiety --> selected stress management techniques • other underlying pain sources • lumbar and gluteal MP : discogenic, ligamentous, facet joint, sacroiliac joint pathology • thoracic TP : pancreatic cancer

17. Ch. 45 Fibromyalgia

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

19. Associated symptoms • widespread pain at multiple tender points (at the muscle-tendon junction and in • muscles, bursae, and fat pads) • reduced pain threshold • fatigue • sleep disturbances • morning stiffness • depression • anxiety • psychological distress • subjective swelling • irritable bowel syndrome • headaches • paresthesias

20. prevalence : between 0.5% and 5% of the population • most fieqllently seen in women between the ages of 2O and 50 years • gender ratio is 10:1 favoring women • no association between FM prevalence and compensation

21. 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 (thumb pressure such that the nail bed starts to blanch) at these sites: • ·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.

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

23. 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

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

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

26. PATHOPHYSIOLOGY • 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

27. PATHOPHYSIOLOGY • often associated with diseases 1. autoimmune basis : rheumatoid arthritis, systemic lupus  possible immune system alteration시사 2. endocrine abnormality diminished responsiveness ofthe hypothalamic-pituitary system growth hormone deficient 3. underlying psychological disturbance 30% of FM patients -->clinical depression

28. PATHOPHYSIOLOGY • muscle pathology • most common findings : disuse or deconditioning 주로 central nervous system (CNS) pathophysiology임을 시사(rather than peripheral) • Abnormal central neurophysiology  most accepted pathologic mechanism in FM • pathological nociceptive processing within the CNS • substance P and nerve growth factor, neuropeptides의cerebrospinal fluid levels 증가: enhance nociceptive neurotransmission • Activation of N-methyl-D-aspartate (NMDA) receptors : important part in central senitization

29. 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

30. 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.

31. 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.

32. 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

33. PHARMACOLOGIC TREATHENT OF PAlN AND ASSOCIATED SYHPTOMS • nonsteroidal anti-inflammatory drugs(NSAIDs) or acetaminophen • addressing peripheral pain generators • 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) • less impressive analgesic effcts • helphll for emotional components and mood disorder • 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

34. 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 (started at 5 to 1O mg) TCA therapy at bedtime • 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

35. 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 • donazepam at bedtime이 효과적 • other dopamine agonists (pergolide, pramixepole, and tolixepole) and bedtime methadone역시 효과적 • Sleep apnea환자에서는 sedative피해야 • Fatigue • often resistant to drug therapy • SSRI와 5-HT3 antagonist(tropisetron)이 증상개선.