The Journal of Emergency Medicine, Vol. -, No. -, pp. 1–7, 2015 Copyright Ó 2015 Elsevier Inc. Printed in the USA. All rights reserved 0736-4679/$ - see front matter
http://dx.doi.org/10.1016/j.jemermed.2015.04.027
Clinical Review MYOFASCIAL PAIN SYNDROMES IN THE EMERGENCY DEPARTMENT: WHAT ARE WE MISSING? Carlos J. Roldan, MD, FACEP, FAAEM* and Na Hu, PHD† *Department of Emergency Medicine, The University of Texas Health Science Center at Houston and †Department of Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas Reprint Address: Carlos J. Roldan, MD, FACEP, FAAEM, Department of Emergency Medicine, The University of Texas Health Science Center at Houston, 6431 Fannin Street, JJL 450G, Houston, TX
, Abstract—Background: Myofascial pain syndrome (MPS), pain originating in the myofascial tissue, is a widely recognized pathology characterized by the presence of referred pain (often distant from its origin and specific to each muscle) that can resemble other pathologies and by the presence of a trigger point, a localized hyperirritable band able to reproduce the pain and its associated symptoms. Patients with acute or chronic MPS are commonly seen in the emergency department (ED), usually complaining of pain of undetermined origin. Traditionally, the emergency physician (EP) is not trained to diagnose and treat MPS, and many patients with MPS have received less than optimal management of this condition in the ED. Many types of treatments are known to be effective against MPS. Among these, trigger point injection (TPI) is considered a practical and rapid approach that can be carried out in the ED by EPs. Objective: This article reviews the current diagnostic methods, treatment options, and procedures for MPS patients seen in the ED to enable EPs to diagnose and successfully treat this condition. Discussion: This article discusses the clinical characteristics, etiology, diagnosis, and treatment of MPS in the ED, including a description of performing TPI. Conclusions: MPS can mimic other clinical conditions commonly seen in the ED. MPS can be diagnosed on the basis of clinical findings; in many cases, no imaging or laboratory testing is needed. Therefore, MPS diagnosis and treatment can be successfully accomplished in the ED by EPs. Ó 2015 Elsevier Inc.
INTRODUCTION Myofascial pain syndrome (MPS), pain originating in the myofascial tissue, is a commonly recognized condition characterized by the presence of referred pain (often distant from its origin and specific to each muscle) (Table 1) and by the presence of a trigger point (Figure 1), a localized hyperirritable band able to reproduce the pain and its associated symptoms. Patients with acute or chronic MPS are commonly seen in the emergency department (ED), usually complaining of pain of undetermined origin (1). Myofascial pain is a common component of most chronic pain syndromes. In fact, myofascial pain is calculated to be present in 10% of the United States (US) population (2). According to the Centers for Disease Control and Prevention, second to arthritis of all etiologies, myofascial pain of the back is considered the top cause of disability among the working-age population (ages 20–64 years) in the United States (3). It is also known that, overall, pain accounts for up to 78% of visits to the ED; however, in the ED, the prevalence of pain secondary to MPS is unknown because MPS commonly goes undiagnosed in this setting (4). Even after many hours spent in the ED, patients with high-intensity pain are frequently discharged having received relatively little relief (5). Many patients with MPS seen in the ED receive less than optimal diagnosis and management of this
, Keywords—myofascial pain; trigger points; emergency medicine
RECEIVED: 15 November 2014; FINAL SUBMISSION RECEIVED: 24 March 2015; ACCEPTED: 16 April 2015 1
2
C. J. Roldan and N. Hu
Table 1. Referred Pain and Mimicking Pathology of Some Muscles Commonly Affected by Myofascial Pain Syndrome Muscle Trapezius Iliocostalis thoracis Iliocostalis lumborum Quadratus lumborum Gluteus medius Gluteus minimus Paraspinal
Muscle Location
Referred Pain
Mimicking Pathology
From occiput to thoracic spine and from the clavicle to the scapular spine Axial distribution parallel to thoracic spine; attaches to the lower six ribs
Head, neck, shoulder, and mid-back
Neck, spine, lung conditions (i.e., pneumothorax, meningitis, aortic dissection)
Anterior chest and upper abdomen; correlates with the level of muscle injury
Axial distribution parallel to lumbar spine; from lower six ribs to sacrum and ilium Lateral lower back; connects the hip and lower back vertebrae
Lower abdomen and pelvis
Lung, cardiac, vascular (i.e., pneumothorax, coronary artery syndromes) Upper abdominal visceral conditions (i.e., cholelithiasis and spleen disease) Visceral, vascular, and gastrointestinal conditions (i.e., diverticulitis, appendicitis)
Inferior-posterior to iliac crest
Lumbar area
Between posterolateral iliac spine and femoral head Adjacent to the spine
Buttock, lateral thigh, and posterior leg above ankle Posterior thoracic and lumbar area
Lower back, anterior aspect of lower abdomen and pelvis
condition. MPS has been largely neglected by the emergency medicine specialty, perhaps because MPS does not represent an immediate threat to life or limb. However, MPS does pose a substantial threat to the patient’s quality of life and might represent a portion of recurring visits to the ED. It is therefore crucial that all emergency physicians (EPs) learn to identify and, when possible, treat some of the most common MPS.
Lower visceral, gastrointestinal, and gynecological conditions (i.e., appendicitis, ovarian torsion, ectopic pregnancy) Renal and vascular conditions (i.e., urolithiasis, pyelonephritis, abdominal aortic aneurysm) Sciatica Vascular, thoracic, and retroperitoneal conditions (i.e., aortic dissection, aortic dissection)
Several issues have been identified that complicate the diagnosis and treatment of MPS in the ED. One issue, EPs’ general lack of familiarity with MPS presentation, diagnosis, and treatment, has been well documented (6). Briefly, the physicians in the Emergency Medicine specialty traditionally are not trained to diagnose and treat MPS. Therefore, the diagnostic presentation and therapeutic implications of MPS are frequently unknown
Figure 1. Referred pain and trigger point location of some common myofascial pain syndromes.
Myofascial Pain Syndromes
to and unrecognized by emergency practitioners. Another issue is that the referred pain associated with MPS complicates diagnosis because MPS can mimic other pathologies seen in the ED (Table 1). Using a traditional diagnostic approach, the anatomic location of the pain drives imaging and laboratory tests. However, the pattern of referred pain of each MPS compromises a specific body area and might mimic other conditions (i.e., pain originating on a quadratus lumborum muscle can resemble appendicitis and other lower abdominal pathologies) (Table 1, Figure 1). This situation can result in unnecessary work-ups, prolonged patient visits to the ED, and poor pain control. MPS can compromise any of the estimated 400 muscles of the human body. Pain related to MPS is characterized by a referred nondermatomal distributed pattern specific to each muscle, commonly known as ‘‘the muscle signature.’’ Compression of the trigger point (TP) present in the compromised muscle reproduces the pain and the associated symptoms. The TP is considered the diagnostic and therapeutic landmark of MPS. In many cases, chronic MPS can be associated with motor dysfunction and autonomic phenomena, which makes diagnosis even more challenging for practitioners who are not trained to diagnose MPS. Another complicating issue is that, traditionally, MPS is known to have very poor response to conventional opiate analgesics, which represent the most common therapeutic option used by EPs. In this review, we present an overview of the etiology, incidence, and prevalence, and clinical strategies to diagnose and treat MPS in the ED, with a focus on TP injections (TPIs). We also provide a rationale for the use of normal saline (NS) solution as the agent of preference in TPI, a low-cost, allergy-free, effective, and safe method that has been used in our ED for years to manage patients with MPS. ETIOLOGY Medical professionals have not yet reached a consensus about the etiology of MPS. Direct and indirect trauma and microtrauma of muscle fibers seem to be the most commonly agreed upon etiologies. Proposed predisposing and perpetuating factors include improper postural habits and skeletal asymmetry, repetitive localized muscle stress, nutritional deficiencies, sleep disorders, physical inactivity, muscle fatigue, aging, fractures, surgical incision healing sites, electrolyte imbalance, iron deficiency anemia, hypovitaminosis (of B-1, B-6, B-12, C), radiculopathy, visceral diseases, depression, hypothyroidism, hypoglycemia, hyperuricemia, and infectious and inflammatory conditions (7–9).
3
INCIDENCE AND PREVALENCE OF MPS MPS is one of the most common causes of chronic pain and one of the disorders most commonly encountered by physiatrists and other health professionals (10,11). In a series of 172 patients who presented to an urban university primary care practice, of the 54 patients who reported pain as one of the reasons for their visit, 16 (30%) were diagnosed with MPS (12). In another study conducted at a physical therapy clinic, among 26 subjects with patella-femoral pain, MPS of the gluteus medius and quadratus lumborum muscles was found in 97% (13). Again, the incidence of MPS in the ED is also presumed to be high, but is currently unknown. DIAGNOSIS OF MPS In clinical practice, a careful history and physical examination remain the cornerstones of effective diagnosis of MPS. Still, in some cases, diagnosis can be challenging and requires extended work-ups for exclusion. It is also crucial to have hands-on experience and training to be able to successfully diagnose and treat MPS (14). Most commonly, MPS affects the muscles that maintain body posture of the head, neck, shoulder, low back, and pelvic girdle. Patients in the ED are commonly seen with MPS of the trapezius, iliocostalis thoracis-lumborum, quadratus lumborum, gluteus medius, and gluteus minimus (Figure 1). In the presence of a myofascial injury, the main complaint is always pain, which is usually described as deep, dull, aching, or constricting in nature. The pain is located in the involved muscle and has a referred pattern that can present in a peripheral, central, or local fashion. The referred pain is reproducible by both direct palpation and TP stimulation. Interestingly, in many cases, patients perceive the referred pain to be of higher intensity than the pain in the originating muscle is. The distribution of the referred pain is specific and predictable for each muscle, a fact that assists in diagnosing MPS (Figure 1). A detailed map of the pain pattern has been identified and published for many muscles (15). Patients describe pain as worsening with any active or passive use of the muscle, including positional changes or localized pressure adopted in certain postures of sitting. The patients frequently use antalgic positions, which often lead to overuse of compensating muscles. The compensating muscles then become painful, thereby creating a self-perpetuating cycle. In addition to pain, motor dysfunction might manifest itself as weakness without atrophy, stiffness, and limited range of motion. As the pain evolves, ion chronicity, dysesthesia, paresthesia, and hyperalgesia might become evident. Unresolved MPS can also manifest itself as autonomic dysfunction, such as changes in skin temperature,
4
C. J. Roldan and N. Hu
sweating, piloerection, proprioceptive changes, and erythema of the overlying skin. In some muscles of the face and neck, MPS has been associated with coryza, lacrimation, salivation, and dizziness (16). MPS should be suspected in patients who have stable hemodynamic conditions in the presence of severe pain associated with a poor analgesic response to opiates, relatively negative findings of a review of body systems, and the absence of an alternative diagnosis. Patients with chronic MPS might have a history of previous negative work-ups and recurrent visits to the ED for unresolved pain, which is why they are frequently misclassified as having aberrant behavior or as being drug seekers. The presence of a TP, a localized, hyperirritable taut band of fibers in the belly of the compromised muscle, is a landmark characteristic of an MPS. When stimulated, the TP reproduces the pain and the associated autonomic and sensory phenomena if present. TPs are classified as active, which reproduce the symptoms of MPS; latent, which do not reproduce the referred pain but are still responsive to palpation; and satellite, which respond to stimulation of the active TP and disappear after the primary TP is deactivated. Latent TPs are known to restrict muscle movement and cause muscle weakness (17). When MPS is suspected, the body area compromised by pain should correlate with the referred pain pattern specific for the muscle that is affected (Figure 1). Subsequently identifying the TP is not only the diagnostic landmark, but also the target of the therapy. Identification of the TP relies on the physicians’ sense and feel, including visual and palpable observations of local twitch responses generated when firm pressure is applied, and on the patient’s response in terms of pain (7,8).
effects, the restrictions of a safe maximal dose, and the ceiling effect. Other therapies considered more effective than analgesics to treat MPS include a variety of invasive and noninvasive procedures (10,26). Noninvasive techniques for pain management include spray (freeze) and stretch, laser therapy, physical therapy, ultrasound-based interventions, electrical stimulation interventions, such as transcutaneous electrical stimulation, and magnetic stimulation. Invasive techniques include TPI, dry needling (repetitive insertion of the needle at the TP without injecting any agent), and acupuncture. A broad literature review published in 2011 summarized the wide variety of medications used in these modalities (27). The decision to use noninvasive or invasive methods depends on the severity of the disorder, training and skill of the physician, clinical setting, duration of pain, and comorbid disorders, as well as prior attempts to treat the pain (7,27). Studies comparing the effectiveness of the noninvasive and invasive therapies found that they produce similar clinical results in terms of decreased pain intensity and recovery of range of motion (11,26,28–30). The choice of therapy to treat MPS in the ED is directed by time constraints and by the limitation of resources available. Dry needling requires multiple injections that increase local pain, the chance of hematoma formation, and bacterial infection. In addition, results from a previous study comparing TPI with dry needling suggested that patients treated with dry needling had greater intensity and longer duration of post-injection soreness than did patients treated with TPI (30). Therefore, our modality of choice is TPI, a more practical and rapid approach to treat patients with MPS in the ED. In the following sections, we elaborate on the use of TPI to manage MPS patients seen in the ED.
MANAGEMENT OF MPS TPI Agents No standard treatment protocol for MPS is currently available. Studies have been conducted in an ED setting to compare the effectiveness of different kinds of analgesics and have found them to be inadequate (18–22). Pharmacologic therapy with nonsteroidal antiinflammatories and muscle relaxants has been used extensively, but has achieved suboptimal pain control. Several studies concluded that a large proportion of ketorolac- or ibuprofen-treated patients continued to have inadequate pain relief (23–25). Opiates are widely used for pain control in the ED. Despite its good analgesic profile, morphine, the opiate prototype, has shown no effectiveness in controlling pain evoked by repetitive stimulation or tonic muscle pain. This lack of a response to opiates is characteristic in patients with MPS. In addition to its inadequate pain control, analgesic treatment is also limited by adverse side
Previous studies suggest that TPI with NS solution has similar effects to those seen using TPI with active drugs (31,32). Various substances have been used for TPI. These substances include local anesthetics in combination with corticosteroids, which is the most common mix used in many centers. Other agents include local anesthetics alone (lidocaine, bupivacaine), botulinum toxin A, and sterile NS. In comparing the effectiveness of different therapeutic agents commonly used for TPI, it appears that relief of pain is mainly due to the needle effect rather than to which specific injected medications are used (31–38). In a doubleblinded study of 107 patients who had pain in the lateral aspect of the face and TPs in the masticatory muscles, local injection therapy using one of three solutions (1 mL 0.25% bupivacaine, 1% lidocaine, or 0.9% saline)
Myofascial Pain Syndromes
yielded no significant differences between the agents in pain relief achieved or in the overall assessment of the therapeutic effect (31). Similarly, in a prospective, randomized evaluation of TPI therapy for lower back pain, there was no significant difference in outcome between injections of lidocaine, lidocaine combined with a steroid, or dry needling at 2 weeks after treatment (37). In addition, we are currently conducting a randomized, double-blind trial using TPI to treat patients with MPS in the ED population (ClinicalTrials.gov HSC-MS-140072). Our preliminary data (n = 44 patients) have shown that TPI with NS as effective as conventional drugs are to treat MPS in the ED population (Roldan et al., unpublished data). The median pain level at 2 weeks post injection has decreased by at least 50%, regardless of the injected agent. When selecting what agent to use for TPI, NS solution has shown similar efficacy, lower cost, and absence of side effects or allergic reactions when compared with active drugs. The use of sterile water is extremely painful, and dry needling is associated with a higher risk of postinjection soreness, hematoma, and localized infection; both techniques are discouraged (7,39). Therefore, TPI with saline is a practical and effective treatment that should be considered by ED physicians when managing patients with MPS.
5
priate needle diameter is equally important; the needle needs to be wide enough to disrupt the TP without causing unnecessary additional discomfort to the patient (40). A 22- to 25-gauge, 1.5-inch needle is suitable for most muscles. Then, sterilize the surface of the underlying TP, grasp the segment of the muscle containing the TP between the index and the middle finger, and insert the needle at a 30-degree angle to the skin. Inject approximately 1 mL of the chosen agent directly into the TP as precisely as possible. After TPI Stretching of the affected muscle after TPI increases the long-term efficacy of the therapy and facilitates the recovery of the function of the muscle compromised. The physician should teach the patient active muscle stretching and encourage the patient to perform it on a regular basis as part of the rehabilitation plan. Strenuous use of the compromised muscle in the 72 h after TPI is discouraged (7). TPI provides pain control, the duration of which is unpredictable and might be affected by the existence of underlying pathology (e.g., inflammatory, infectious, and traumatic) and by the presence of perpetuating factors as listed previously. Follow-up in the ED is unlikely, and thus, referral to a pain specialist is the ideal plan for continuity of care.
TPI Precautions CONCLUSIONS Anticipating the occurrence of vasovagal events and some patients’ extreme fear of needles, patients receiving TPI therapy should ideally be in a recumbent position (17). As for the procedure itself, proper skin sterilization minimizes the risk of local infection. In addition, needles should never be inserted over areas that show signs of localized infection. The low-volume injection (1 mL) used for TP therapy presents a minimal risk of hematoma formation. Still, precaution is advised for patients with known bleeding or anticoagulation disorders; for these patients, the physician should avoid noncompressible areas and apply continued, localized pressure after the injection. TPI Technique The major impediment of successful TPI therapy is identifying the correct TP, largely because the same muscle can be affected by the presence of several active TPs. The active TP is usually identified as the most tender area able to reproduce the referred pain. This TP is chosen to receive the injection therapy. Depending on the thickness and location of the muscle receiving the injection, the physician should choose the appropriate needle length in order to reach and deactivate the TP (7). The appro-
Because MPS mimics other common pathologies, EPs are encouraged to learn more about this pathology. Inadequate diagnosis and treatment of MPS increases patient suffering. EP can accurately diagnose MPS in the ED, in many cases without imaging or laboratory testing. Furthermore, the treatment of MPS can be accomplished effectively in the ED. TPIs are an effective treatment to manage MPS. Using NS solution for TP therapy is safe, efficient, and inexpensive. Acknowledgments—The authors want to acknowledge Diane Hackett, Department of Scientific Publications at MD Anderson Cancer Center for her editing assistance. The authors also want to acknowledge those open-minded residents and faculty at The University of Texas-Houston Emergency Medicine residency program for their eagerness to learn what could be taboo to many others.
REFERENCES 1. Simons DG. Myofascial pain syndrome: one term but two concepts; a new understanding. J Musculoskeletal Pain 1995;3:7–13. 2. Wheeler AH. Myofascial pain disorders: theory to therapy. Drugs 2004;64:45–62.
6 3. Centers for Disease Control and Prevention. Prevalence of disabilities and associated health conditions among adults—United States, 2005. MMWR Morb Mortal Wkly Rep 2009;58:421–6. 4. Cordell WH, Keene KK, Giles BK, et al. The high prevalence of pain in emergency medical care. Am J Emerg Med 2002;20:165–9. 5. Todd KH, Ducharme J, Choiniere M, et al. Pain in the emergency department: results of the Pain and Emergency Medicine Initiative (PEMI) Multicenter Study. J Pain 2007;8:460–6. 6. Bennett R. Myofascial pain syndromes and their evaluation. Best Pract Res Clin Rheumatol 2007;21:427–45. 7. Simons D, Travell J, Simons L. Myofascial pain and dysfunction: the trigger point manual. Vol. 1. Upper half of body. 2nd edn. Baltimore: Williams & Wilkins; 1999:19–40. 8. Han SC, Harrison P. Myofascial pain syndrome and trigger-point management. Reg Anesth 1997;22:89–101. 9. Fricton JR, Kroening R, Haley D, et al. Myofascial pain syndrome of the head and neck: a review of clinical characteristics of 164 patients. Oral Surg Oral Med Oral Pathol 1985;60:615–23. 10. Lavelle ED, Lavelle W, Smith HS. Myofascial trigger points. Anesthesiol Clin 2007;25:841–51. 11. Unalan H, Majlesi J, Aydin FY, et al. Comparison of high-power pain threshold ultrasound therapy with local injection in the treatment of active myofascial trigger points of the upper trapezius muscle. Arch Phys Med Rehabil 2011;92:657–62. 12. Skootsky SA, Jaeger B, Oye RK. Prevalence of myofascial pain in general internal medicine practice. West J Med 1989;151:157–60. 13. Roach S, Sorenson E, Headley B, et al. Prevalence of myofascial trigger points in the hip in patella-femoral pain. Arch Phys Med Rehabil 2013;94:522–6. 14. Cummings M, Baldry P. Regional myofascial pain. Diagnosis and management. Best Pract Res Clin Rheumatol 2007;21:367–87. 15. Travell J, Rinzler S. Myofascial pain and dysfunction: the trigger point manual, Vol. 1–2. Baltimore: Williams & Wilkins; 1983:94–539. 16. Sola AE, Bonica JJ. Myofascial pain syndromes. In: Bonica JJ, ed. The management of pain. 2nd edn. Philadelphia: Lea & Febiger; 1990:352–67. 17. Ling FW, Slocumb JC. Use of trigger point injections in chronic pelvic pain. Obstet Gynecol Clin N Am 1993;20:809–15. 18. Miner JR, Moore J, Gray RO, et al. Oral versus intravenous opioid dosing for the initial treatment of acute musculoskeletal pain in the emergency department. Acad Emerg Med 2008;15:1234–40. 19. Garbez R, Puntillo K. Acute musculoskeletal pain in the emergency department: a review of the literature and implications for the advanced practice nurse. AACN Clin Issues 2005;16:310–9. 20. Lovell SJ, Taira T, Rodriguez E, et al. Comparison of valdecoxib and an oxycodone- acetaminophen combination for acute musculoskeletal pain in the emergency department: a randomized controlled trial. Acad Emerg Med 2004;11:1278–82. 21. Turturro MA, Paris PM, Larkin GL. Tramadol versus hydrocodoneacetaminophen in acute musculoskeletal pain: a randomized, double-blind clinical trial. Ann Emerg Med 1998;32:139–43. 22. Turturro MA, Paris PM, Yealy DM, et al. Hydrocodone versus codeine in acute musculoskeletal pain. Ann Emerg Med 1991;20: 1100–3.
C. J. Roldan and N. Hu 23. Turturro MA, Paris PM, Seaberg DC. Intramuscular ketorolac versus oral ibuprofen in acute musculoskeletal pain. Ann Emerg Med 1995;26:117–20. 24. Neighbor ML, Puntillo KA. Intramuscular ketorolac vs oral ibuprofen in emergency department patients with acute pain. Acad Emerg Med 1998;5:118–22. 25. Schwartz NA, Turturro MA, Istvan DJ, et al. Patients’ perceptions of route of nonsteroidal anti-inflammatory drug administration and its effect on analgesia. Acad Emerg Med 2000;7:857–61. 26. Esenyel M, Caglar N, Aldemir T. Treatment of myofascial pain. Am J Phys Med Rehabil 2000;79:48–52. 27. Annaswamy TM, De Luigi AJ, O’Neill BJ, et al. Emerging concepts in the treatment of myofascial pain: a review of medications, modalities, and needle-based interventions. PM R 2011; 3:940–61. 28. Uemoto L, Garcia MA, Gouvea CV, et al. Laser therapy and needling in myofascial trigger point deactivation. J Oral Sci 2013; 55:175–81. 29. Ga H, Choi JH, Park CH, et al. Acupuncture needling versus lidocaine injection of trigger points in myofascial pain syndrome in elderly patients—a randomized trial. Acupunct Med 2007;25: 130–6. 30. Hong CZ. Lidocaine injection versus dry needling to myofascial trigger point. The importance of the local twitch response. Am J Phys Med Rehabil 1994;73:256–63. 31. Tschopp KP, Gysin C. Local injection therapy in 107 patients with myofascial pain syndrome of the head and neck. ORL J Otorhinolaryngol Relat Spec 1996;58:306–10. 32. Frost FA, Jessen B, Siggaard-Andersen J. A control, double-blind comparison of Mepivacaine injection versus saline injection for myofascial pain. Lancet 1980;1:499–500. 33. Lewit K. The needle effect in the relief of myofascial pain. Pain 1979;6:83–90. 34. Ay S, Evcik D, Tur BS. Comparison of injection methods in myofascial pain syndrome: a randomized controlled trial. Clin Rheumatol 2010;29:19–23. 35. Ojala T, Arokoski JP, Partanen J. The effect of small doses of botulinum toxin a on neck-shoulder myofascial pain syndrome: a double-blind, randomized, and controlled crossover trial. Clin J Pain 2006;22:90–6. 36. Frost FA, Toft B, Aaboe T. Isotonic saline and methylprednisolone acetate in blockade treatment of myofascial pain. A clinical controlled study. Ugeskrift for Laeger 1984;146:652–4. 37. Garvey TA, Marks MR, Wiesel SW. A prospective, randomized, double-blind evaluation of trigger-point injection therapy for lowback pain. Spine 1989;14:962–4. 38. Cummings TM, White AR. Needling therapies in the management of myofascial trigger point pain: a systematic review. Arch Phys Med Rehabil 2001;82:986–92. 39. Wreje U, Brorsson B. A multicenter randomized controlled trial of injections of sterile water and saline for chronic myofascial pain syndromes. Pain 1995;61:441–4. 40. Alvarez DJ, Rockwell PG. Trigger points: diagnosis and management. Am Fam Physician 2002;65:653–60.
Myofascial Pain Syndromes
ARTICLE SUMMARY 1. Why is this topic important? Myofascial pain is the main cause of disability in the working-age population (ages 20–64 years). It is of crucial importance that all emergency physicians learn to identify and, when possible, treat some of the most common myofascial pain syndromes. 2. What does this clinical review attempt to show? Myofascial pain can be an isolated pathology, but is also a common component of most chronic pain syndromes. Nevertheless, the clinical presentation and therapeutic implications of myofascial pain syndromes are frequently unknown and unrecognized by emergency practitioners. 3. What are the key findings? Myofascial pain syndromes can mimic other common pathologies seen in the emergency department, and emergency physicians should be aware of the differential diagnoses. Once diagnosed, myofascial pain syndrome can be effectively treated by emergency physicians. Trigger point identification followed by trigger point injection is the most effective course of treatment. 4. How is patient care affected? Accuracy of the clinical diagnosis can lower the cost of treatment by avoiding unnecessary testing. Effective care in the emergency department, currently with trigger point injection therapy, could become the standard of care for this pathology.
7
http://dx.doi.org/10.1016/j.jemermed.2015.04.027
Clinical Review MYOFASCIAL PAIN SYNDROMES IN THE EMERGENCY DEPARTMENT: WHAT ARE WE MISSING? Carlos J. Roldan, MD, FACEP, FAAEM* and Na Hu, PHD† *Department of Emergency Medicine, The University of Texas Health Science Center at Houston and †Department of Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas Reprint Address: Carlos J. Roldan, MD, FACEP, FAAEM, Department of Emergency Medicine, The University of Texas Health Science Center at Houston, 6431 Fannin Street, JJL 450G, Houston, TX
, Abstract—Background: Myofascial pain syndrome (MPS), pain originating in the myofascial tissue, is a widely recognized pathology characterized by the presence of referred pain (often distant from its origin and specific to each muscle) that can resemble other pathologies and by the presence of a trigger point, a localized hyperirritable band able to reproduce the pain and its associated symptoms. Patients with acute or chronic MPS are commonly seen in the emergency department (ED), usually complaining of pain of undetermined origin. Traditionally, the emergency physician (EP) is not trained to diagnose and treat MPS, and many patients with MPS have received less than optimal management of this condition in the ED. Many types of treatments are known to be effective against MPS. Among these, trigger point injection (TPI) is considered a practical and rapid approach that can be carried out in the ED by EPs. Objective: This article reviews the current diagnostic methods, treatment options, and procedures for MPS patients seen in the ED to enable EPs to diagnose and successfully treat this condition. Discussion: This article discusses the clinical characteristics, etiology, diagnosis, and treatment of MPS in the ED, including a description of performing TPI. Conclusions: MPS can mimic other clinical conditions commonly seen in the ED. MPS can be diagnosed on the basis of clinical findings; in many cases, no imaging or laboratory testing is needed. Therefore, MPS diagnosis and treatment can be successfully accomplished in the ED by EPs. Ó 2015 Elsevier Inc.
INTRODUCTION Myofascial pain syndrome (MPS), pain originating in the myofascial tissue, is a commonly recognized condition characterized by the presence of referred pain (often distant from its origin and specific to each muscle) (Table 1) and by the presence of a trigger point (Figure 1), a localized hyperirritable band able to reproduce the pain and its associated symptoms. Patients with acute or chronic MPS are commonly seen in the emergency department (ED), usually complaining of pain of undetermined origin (1). Myofascial pain is a common component of most chronic pain syndromes. In fact, myofascial pain is calculated to be present in 10% of the United States (US) population (2). According to the Centers for Disease Control and Prevention, second to arthritis of all etiologies, myofascial pain of the back is considered the top cause of disability among the working-age population (ages 20–64 years) in the United States (3). It is also known that, overall, pain accounts for up to 78% of visits to the ED; however, in the ED, the prevalence of pain secondary to MPS is unknown because MPS commonly goes undiagnosed in this setting (4). Even after many hours spent in the ED, patients with high-intensity pain are frequently discharged having received relatively little relief (5). Many patients with MPS seen in the ED receive less than optimal diagnosis and management of this
, Keywords—myofascial pain; trigger points; emergency medicine
RECEIVED: 15 November 2014; FINAL SUBMISSION RECEIVED: 24 March 2015; ACCEPTED: 16 April 2015 1
2
C. J. Roldan and N. Hu
Table 1. Referred Pain and Mimicking Pathology of Some Muscles Commonly Affected by Myofascial Pain Syndrome Muscle Trapezius Iliocostalis thoracis Iliocostalis lumborum Quadratus lumborum Gluteus medius Gluteus minimus Paraspinal
Muscle Location
Referred Pain
Mimicking Pathology
From occiput to thoracic spine and from the clavicle to the scapular spine Axial distribution parallel to thoracic spine; attaches to the lower six ribs
Head, neck, shoulder, and mid-back
Neck, spine, lung conditions (i.e., pneumothorax, meningitis, aortic dissection)
Anterior chest and upper abdomen; correlates with the level of muscle injury
Axial distribution parallel to lumbar spine; from lower six ribs to sacrum and ilium Lateral lower back; connects the hip and lower back vertebrae
Lower abdomen and pelvis
Lung, cardiac, vascular (i.e., pneumothorax, coronary artery syndromes) Upper abdominal visceral conditions (i.e., cholelithiasis and spleen disease) Visceral, vascular, and gastrointestinal conditions (i.e., diverticulitis, appendicitis)
Inferior-posterior to iliac crest
Lumbar area
Between posterolateral iliac spine and femoral head Adjacent to the spine
Buttock, lateral thigh, and posterior leg above ankle Posterior thoracic and lumbar area
Lower back, anterior aspect of lower abdomen and pelvis
condition. MPS has been largely neglected by the emergency medicine specialty, perhaps because MPS does not represent an immediate threat to life or limb. However, MPS does pose a substantial threat to the patient’s quality of life and might represent a portion of recurring visits to the ED. It is therefore crucial that all emergency physicians (EPs) learn to identify and, when possible, treat some of the most common MPS.
Lower visceral, gastrointestinal, and gynecological conditions (i.e., appendicitis, ovarian torsion, ectopic pregnancy) Renal and vascular conditions (i.e., urolithiasis, pyelonephritis, abdominal aortic aneurysm) Sciatica Vascular, thoracic, and retroperitoneal conditions (i.e., aortic dissection, aortic dissection)
Several issues have been identified that complicate the diagnosis and treatment of MPS in the ED. One issue, EPs’ general lack of familiarity with MPS presentation, diagnosis, and treatment, has been well documented (6). Briefly, the physicians in the Emergency Medicine specialty traditionally are not trained to diagnose and treat MPS. Therefore, the diagnostic presentation and therapeutic implications of MPS are frequently unknown
Figure 1. Referred pain and trigger point location of some common myofascial pain syndromes.
Myofascial Pain Syndromes
to and unrecognized by emergency practitioners. Another issue is that the referred pain associated with MPS complicates diagnosis because MPS can mimic other pathologies seen in the ED (Table 1). Using a traditional diagnostic approach, the anatomic location of the pain drives imaging and laboratory tests. However, the pattern of referred pain of each MPS compromises a specific body area and might mimic other conditions (i.e., pain originating on a quadratus lumborum muscle can resemble appendicitis and other lower abdominal pathologies) (Table 1, Figure 1). This situation can result in unnecessary work-ups, prolonged patient visits to the ED, and poor pain control. MPS can compromise any of the estimated 400 muscles of the human body. Pain related to MPS is characterized by a referred nondermatomal distributed pattern specific to each muscle, commonly known as ‘‘the muscle signature.’’ Compression of the trigger point (TP) present in the compromised muscle reproduces the pain and the associated symptoms. The TP is considered the diagnostic and therapeutic landmark of MPS. In many cases, chronic MPS can be associated with motor dysfunction and autonomic phenomena, which makes diagnosis even more challenging for practitioners who are not trained to diagnose MPS. Another complicating issue is that, traditionally, MPS is known to have very poor response to conventional opiate analgesics, which represent the most common therapeutic option used by EPs. In this review, we present an overview of the etiology, incidence, and prevalence, and clinical strategies to diagnose and treat MPS in the ED, with a focus on TP injections (TPIs). We also provide a rationale for the use of normal saline (NS) solution as the agent of preference in TPI, a low-cost, allergy-free, effective, and safe method that has been used in our ED for years to manage patients with MPS. ETIOLOGY Medical professionals have not yet reached a consensus about the etiology of MPS. Direct and indirect trauma and microtrauma of muscle fibers seem to be the most commonly agreed upon etiologies. Proposed predisposing and perpetuating factors include improper postural habits and skeletal asymmetry, repetitive localized muscle stress, nutritional deficiencies, sleep disorders, physical inactivity, muscle fatigue, aging, fractures, surgical incision healing sites, electrolyte imbalance, iron deficiency anemia, hypovitaminosis (of B-1, B-6, B-12, C), radiculopathy, visceral diseases, depression, hypothyroidism, hypoglycemia, hyperuricemia, and infectious and inflammatory conditions (7–9).
3
INCIDENCE AND PREVALENCE OF MPS MPS is one of the most common causes of chronic pain and one of the disorders most commonly encountered by physiatrists and other health professionals (10,11). In a series of 172 patients who presented to an urban university primary care practice, of the 54 patients who reported pain as one of the reasons for their visit, 16 (30%) were diagnosed with MPS (12). In another study conducted at a physical therapy clinic, among 26 subjects with patella-femoral pain, MPS of the gluteus medius and quadratus lumborum muscles was found in 97% (13). Again, the incidence of MPS in the ED is also presumed to be high, but is currently unknown. DIAGNOSIS OF MPS In clinical practice, a careful history and physical examination remain the cornerstones of effective diagnosis of MPS. Still, in some cases, diagnosis can be challenging and requires extended work-ups for exclusion. It is also crucial to have hands-on experience and training to be able to successfully diagnose and treat MPS (14). Most commonly, MPS affects the muscles that maintain body posture of the head, neck, shoulder, low back, and pelvic girdle. Patients in the ED are commonly seen with MPS of the trapezius, iliocostalis thoracis-lumborum, quadratus lumborum, gluteus medius, and gluteus minimus (Figure 1). In the presence of a myofascial injury, the main complaint is always pain, which is usually described as deep, dull, aching, or constricting in nature. The pain is located in the involved muscle and has a referred pattern that can present in a peripheral, central, or local fashion. The referred pain is reproducible by both direct palpation and TP stimulation. Interestingly, in many cases, patients perceive the referred pain to be of higher intensity than the pain in the originating muscle is. The distribution of the referred pain is specific and predictable for each muscle, a fact that assists in diagnosing MPS (Figure 1). A detailed map of the pain pattern has been identified and published for many muscles (15). Patients describe pain as worsening with any active or passive use of the muscle, including positional changes or localized pressure adopted in certain postures of sitting. The patients frequently use antalgic positions, which often lead to overuse of compensating muscles. The compensating muscles then become painful, thereby creating a self-perpetuating cycle. In addition to pain, motor dysfunction might manifest itself as weakness without atrophy, stiffness, and limited range of motion. As the pain evolves, ion chronicity, dysesthesia, paresthesia, and hyperalgesia might become evident. Unresolved MPS can also manifest itself as autonomic dysfunction, such as changes in skin temperature,
4
C. J. Roldan and N. Hu
sweating, piloerection, proprioceptive changes, and erythema of the overlying skin. In some muscles of the face and neck, MPS has been associated with coryza, lacrimation, salivation, and dizziness (16). MPS should be suspected in patients who have stable hemodynamic conditions in the presence of severe pain associated with a poor analgesic response to opiates, relatively negative findings of a review of body systems, and the absence of an alternative diagnosis. Patients with chronic MPS might have a history of previous negative work-ups and recurrent visits to the ED for unresolved pain, which is why they are frequently misclassified as having aberrant behavior or as being drug seekers. The presence of a TP, a localized, hyperirritable taut band of fibers in the belly of the compromised muscle, is a landmark characteristic of an MPS. When stimulated, the TP reproduces the pain and the associated autonomic and sensory phenomena if present. TPs are classified as active, which reproduce the symptoms of MPS; latent, which do not reproduce the referred pain but are still responsive to palpation; and satellite, which respond to stimulation of the active TP and disappear after the primary TP is deactivated. Latent TPs are known to restrict muscle movement and cause muscle weakness (17). When MPS is suspected, the body area compromised by pain should correlate with the referred pain pattern specific for the muscle that is affected (Figure 1). Subsequently identifying the TP is not only the diagnostic landmark, but also the target of the therapy. Identification of the TP relies on the physicians’ sense and feel, including visual and palpable observations of local twitch responses generated when firm pressure is applied, and on the patient’s response in terms of pain (7,8).
effects, the restrictions of a safe maximal dose, and the ceiling effect. Other therapies considered more effective than analgesics to treat MPS include a variety of invasive and noninvasive procedures (10,26). Noninvasive techniques for pain management include spray (freeze) and stretch, laser therapy, physical therapy, ultrasound-based interventions, electrical stimulation interventions, such as transcutaneous electrical stimulation, and magnetic stimulation. Invasive techniques include TPI, dry needling (repetitive insertion of the needle at the TP without injecting any agent), and acupuncture. A broad literature review published in 2011 summarized the wide variety of medications used in these modalities (27). The decision to use noninvasive or invasive methods depends on the severity of the disorder, training and skill of the physician, clinical setting, duration of pain, and comorbid disorders, as well as prior attempts to treat the pain (7,27). Studies comparing the effectiveness of the noninvasive and invasive therapies found that they produce similar clinical results in terms of decreased pain intensity and recovery of range of motion (11,26,28–30). The choice of therapy to treat MPS in the ED is directed by time constraints and by the limitation of resources available. Dry needling requires multiple injections that increase local pain, the chance of hematoma formation, and bacterial infection. In addition, results from a previous study comparing TPI with dry needling suggested that patients treated with dry needling had greater intensity and longer duration of post-injection soreness than did patients treated with TPI (30). Therefore, our modality of choice is TPI, a more practical and rapid approach to treat patients with MPS in the ED. In the following sections, we elaborate on the use of TPI to manage MPS patients seen in the ED.
MANAGEMENT OF MPS TPI Agents No standard treatment protocol for MPS is currently available. Studies have been conducted in an ED setting to compare the effectiveness of different kinds of analgesics and have found them to be inadequate (18–22). Pharmacologic therapy with nonsteroidal antiinflammatories and muscle relaxants has been used extensively, but has achieved suboptimal pain control. Several studies concluded that a large proportion of ketorolac- or ibuprofen-treated patients continued to have inadequate pain relief (23–25). Opiates are widely used for pain control in the ED. Despite its good analgesic profile, morphine, the opiate prototype, has shown no effectiveness in controlling pain evoked by repetitive stimulation or tonic muscle pain. This lack of a response to opiates is characteristic in patients with MPS. In addition to its inadequate pain control, analgesic treatment is also limited by adverse side
Previous studies suggest that TPI with NS solution has similar effects to those seen using TPI with active drugs (31,32). Various substances have been used for TPI. These substances include local anesthetics in combination with corticosteroids, which is the most common mix used in many centers. Other agents include local anesthetics alone (lidocaine, bupivacaine), botulinum toxin A, and sterile NS. In comparing the effectiveness of different therapeutic agents commonly used for TPI, it appears that relief of pain is mainly due to the needle effect rather than to which specific injected medications are used (31–38). In a doubleblinded study of 107 patients who had pain in the lateral aspect of the face and TPs in the masticatory muscles, local injection therapy using one of three solutions (1 mL 0.25% bupivacaine, 1% lidocaine, or 0.9% saline)
Myofascial Pain Syndromes
yielded no significant differences between the agents in pain relief achieved or in the overall assessment of the therapeutic effect (31). Similarly, in a prospective, randomized evaluation of TPI therapy for lower back pain, there was no significant difference in outcome between injections of lidocaine, lidocaine combined with a steroid, or dry needling at 2 weeks after treatment (37). In addition, we are currently conducting a randomized, double-blind trial using TPI to treat patients with MPS in the ED population (ClinicalTrials.gov HSC-MS-140072). Our preliminary data (n = 44 patients) have shown that TPI with NS as effective as conventional drugs are to treat MPS in the ED population (Roldan et al., unpublished data). The median pain level at 2 weeks post injection has decreased by at least 50%, regardless of the injected agent. When selecting what agent to use for TPI, NS solution has shown similar efficacy, lower cost, and absence of side effects or allergic reactions when compared with active drugs. The use of sterile water is extremely painful, and dry needling is associated with a higher risk of postinjection soreness, hematoma, and localized infection; both techniques are discouraged (7,39). Therefore, TPI with saline is a practical and effective treatment that should be considered by ED physicians when managing patients with MPS.
5
priate needle diameter is equally important; the needle needs to be wide enough to disrupt the TP without causing unnecessary additional discomfort to the patient (40). A 22- to 25-gauge, 1.5-inch needle is suitable for most muscles. Then, sterilize the surface of the underlying TP, grasp the segment of the muscle containing the TP between the index and the middle finger, and insert the needle at a 30-degree angle to the skin. Inject approximately 1 mL of the chosen agent directly into the TP as precisely as possible. After TPI Stretching of the affected muscle after TPI increases the long-term efficacy of the therapy and facilitates the recovery of the function of the muscle compromised. The physician should teach the patient active muscle stretching and encourage the patient to perform it on a regular basis as part of the rehabilitation plan. Strenuous use of the compromised muscle in the 72 h after TPI is discouraged (7). TPI provides pain control, the duration of which is unpredictable and might be affected by the existence of underlying pathology (e.g., inflammatory, infectious, and traumatic) and by the presence of perpetuating factors as listed previously. Follow-up in the ED is unlikely, and thus, referral to a pain specialist is the ideal plan for continuity of care.
TPI Precautions CONCLUSIONS Anticipating the occurrence of vasovagal events and some patients’ extreme fear of needles, patients receiving TPI therapy should ideally be in a recumbent position (17). As for the procedure itself, proper skin sterilization minimizes the risk of local infection. In addition, needles should never be inserted over areas that show signs of localized infection. The low-volume injection (1 mL) used for TP therapy presents a minimal risk of hematoma formation. Still, precaution is advised for patients with known bleeding or anticoagulation disorders; for these patients, the physician should avoid noncompressible areas and apply continued, localized pressure after the injection. TPI Technique The major impediment of successful TPI therapy is identifying the correct TP, largely because the same muscle can be affected by the presence of several active TPs. The active TP is usually identified as the most tender area able to reproduce the referred pain. This TP is chosen to receive the injection therapy. Depending on the thickness and location of the muscle receiving the injection, the physician should choose the appropriate needle length in order to reach and deactivate the TP (7). The appro-
Because MPS mimics other common pathologies, EPs are encouraged to learn more about this pathology. Inadequate diagnosis and treatment of MPS increases patient suffering. EP can accurately diagnose MPS in the ED, in many cases without imaging or laboratory testing. Furthermore, the treatment of MPS can be accomplished effectively in the ED. TPIs are an effective treatment to manage MPS. Using NS solution for TP therapy is safe, efficient, and inexpensive. Acknowledgments—The authors want to acknowledge Diane Hackett, Department of Scientific Publications at MD Anderson Cancer Center for her editing assistance. The authors also want to acknowledge those open-minded residents and faculty at The University of Texas-Houston Emergency Medicine residency program for their eagerness to learn what could be taboo to many others.
REFERENCES 1. Simons DG. Myofascial pain syndrome: one term but two concepts; a new understanding. J Musculoskeletal Pain 1995;3:7–13. 2. Wheeler AH. Myofascial pain disorders: theory to therapy. Drugs 2004;64:45–62.
6 3. Centers for Disease Control and Prevention. Prevalence of disabilities and associated health conditions among adults—United States, 2005. MMWR Morb Mortal Wkly Rep 2009;58:421–6. 4. Cordell WH, Keene KK, Giles BK, et al. The high prevalence of pain in emergency medical care. Am J Emerg Med 2002;20:165–9. 5. Todd KH, Ducharme J, Choiniere M, et al. Pain in the emergency department: results of the Pain and Emergency Medicine Initiative (PEMI) Multicenter Study. J Pain 2007;8:460–6. 6. Bennett R. Myofascial pain syndromes and their evaluation. Best Pract Res Clin Rheumatol 2007;21:427–45. 7. Simons D, Travell J, Simons L. Myofascial pain and dysfunction: the trigger point manual. Vol. 1. Upper half of body. 2nd edn. Baltimore: Williams & Wilkins; 1999:19–40. 8. Han SC, Harrison P. Myofascial pain syndrome and trigger-point management. Reg Anesth 1997;22:89–101. 9. Fricton JR, Kroening R, Haley D, et al. Myofascial pain syndrome of the head and neck: a review of clinical characteristics of 164 patients. Oral Surg Oral Med Oral Pathol 1985;60:615–23. 10. Lavelle ED, Lavelle W, Smith HS. Myofascial trigger points. Anesthesiol Clin 2007;25:841–51. 11. Unalan H, Majlesi J, Aydin FY, et al. Comparison of high-power pain threshold ultrasound therapy with local injection in the treatment of active myofascial trigger points of the upper trapezius muscle. Arch Phys Med Rehabil 2011;92:657–62. 12. Skootsky SA, Jaeger B, Oye RK. Prevalence of myofascial pain in general internal medicine practice. West J Med 1989;151:157–60. 13. Roach S, Sorenson E, Headley B, et al. Prevalence of myofascial trigger points in the hip in patella-femoral pain. Arch Phys Med Rehabil 2013;94:522–6. 14. Cummings M, Baldry P. Regional myofascial pain. Diagnosis and management. Best Pract Res Clin Rheumatol 2007;21:367–87. 15. Travell J, Rinzler S. Myofascial pain and dysfunction: the trigger point manual, Vol. 1–2. Baltimore: Williams & Wilkins; 1983:94–539. 16. Sola AE, Bonica JJ. Myofascial pain syndromes. In: Bonica JJ, ed. The management of pain. 2nd edn. Philadelphia: Lea & Febiger; 1990:352–67. 17. Ling FW, Slocumb JC. Use of trigger point injections in chronic pelvic pain. Obstet Gynecol Clin N Am 1993;20:809–15. 18. Miner JR, Moore J, Gray RO, et al. Oral versus intravenous opioid dosing for the initial treatment of acute musculoskeletal pain in the emergency department. Acad Emerg Med 2008;15:1234–40. 19. Garbez R, Puntillo K. Acute musculoskeletal pain in the emergency department: a review of the literature and implications for the advanced practice nurse. AACN Clin Issues 2005;16:310–9. 20. Lovell SJ, Taira T, Rodriguez E, et al. Comparison of valdecoxib and an oxycodone- acetaminophen combination for acute musculoskeletal pain in the emergency department: a randomized controlled trial. Acad Emerg Med 2004;11:1278–82. 21. Turturro MA, Paris PM, Larkin GL. Tramadol versus hydrocodoneacetaminophen in acute musculoskeletal pain: a randomized, double-blind clinical trial. Ann Emerg Med 1998;32:139–43. 22. Turturro MA, Paris PM, Yealy DM, et al. Hydrocodone versus codeine in acute musculoskeletal pain. Ann Emerg Med 1991;20: 1100–3.
C. J. Roldan and N. Hu 23. Turturro MA, Paris PM, Seaberg DC. Intramuscular ketorolac versus oral ibuprofen in acute musculoskeletal pain. Ann Emerg Med 1995;26:117–20. 24. Neighbor ML, Puntillo KA. Intramuscular ketorolac vs oral ibuprofen in emergency department patients with acute pain. Acad Emerg Med 1998;5:118–22. 25. Schwartz NA, Turturro MA, Istvan DJ, et al. Patients’ perceptions of route of nonsteroidal anti-inflammatory drug administration and its effect on analgesia. Acad Emerg Med 2000;7:857–61. 26. Esenyel M, Caglar N, Aldemir T. Treatment of myofascial pain. Am J Phys Med Rehabil 2000;79:48–52. 27. Annaswamy TM, De Luigi AJ, O’Neill BJ, et al. Emerging concepts in the treatment of myofascial pain: a review of medications, modalities, and needle-based interventions. PM R 2011; 3:940–61. 28. Uemoto L, Garcia MA, Gouvea CV, et al. Laser therapy and needling in myofascial trigger point deactivation. J Oral Sci 2013; 55:175–81. 29. Ga H, Choi JH, Park CH, et al. Acupuncture needling versus lidocaine injection of trigger points in myofascial pain syndrome in elderly patients—a randomized trial. Acupunct Med 2007;25: 130–6. 30. Hong CZ. Lidocaine injection versus dry needling to myofascial trigger point. The importance of the local twitch response. Am J Phys Med Rehabil 1994;73:256–63. 31. Tschopp KP, Gysin C. Local injection therapy in 107 patients with myofascial pain syndrome of the head and neck. ORL J Otorhinolaryngol Relat Spec 1996;58:306–10. 32. Frost FA, Jessen B, Siggaard-Andersen J. A control, double-blind comparison of Mepivacaine injection versus saline injection for myofascial pain. Lancet 1980;1:499–500. 33. Lewit K. The needle effect in the relief of myofascial pain. Pain 1979;6:83–90. 34. Ay S, Evcik D, Tur BS. Comparison of injection methods in myofascial pain syndrome: a randomized controlled trial. Clin Rheumatol 2010;29:19–23. 35. Ojala T, Arokoski JP, Partanen J. The effect of small doses of botulinum toxin a on neck-shoulder myofascial pain syndrome: a double-blind, randomized, and controlled crossover trial. Clin J Pain 2006;22:90–6. 36. Frost FA, Toft B, Aaboe T. Isotonic saline and methylprednisolone acetate in blockade treatment of myofascial pain. A clinical controlled study. Ugeskrift for Laeger 1984;146:652–4. 37. Garvey TA, Marks MR, Wiesel SW. A prospective, randomized, double-blind evaluation of trigger-point injection therapy for lowback pain. Spine 1989;14:962–4. 38. Cummings TM, White AR. Needling therapies in the management of myofascial trigger point pain: a systematic review. Arch Phys Med Rehabil 2001;82:986–92. 39. Wreje U, Brorsson B. A multicenter randomized controlled trial of injections of sterile water and saline for chronic myofascial pain syndromes. Pain 1995;61:441–4. 40. Alvarez DJ, Rockwell PG. Trigger points: diagnosis and management. Am Fam Physician 2002;65:653–60.
Myofascial Pain Syndromes
ARTICLE SUMMARY 1. Why is this topic important? Myofascial pain is the main cause of disability in the working-age population (ages 20–64 years). It is of crucial importance that all emergency physicians learn to identify and, when possible, treat some of the most common myofascial pain syndromes. 2. What does this clinical review attempt to show? Myofascial pain can be an isolated pathology, but is also a common component of most chronic pain syndromes. Nevertheless, the clinical presentation and therapeutic implications of myofascial pain syndromes are frequently unknown and unrecognized by emergency practitioners. 3. What are the key findings? Myofascial pain syndromes can mimic other common pathologies seen in the emergency department, and emergency physicians should be aware of the differential diagnoses. Once diagnosed, myofascial pain syndrome can be effectively treated by emergency physicians. Trigger point identification followed by trigger point injection is the most effective course of treatment. 4. How is patient care affected? Accuracy of the clinical diagnosis can lower the cost of treatment by avoiding unnecessary testing. Effective care in the emergency department, currently with trigger point injection therapy, could become the standard of care for this pathology.
7
