Myofascial pain syndrome and its suggested role in the pathogenesis and treatment of fibromyalgia syndrome

Myofascial pain syndrome is a chronic muscle pain disorder in one or more muscles or groups of muscles accompanied by local and referred pain, decreased range of motion, weakness, and often autonomic phenomena. Patients are readily recognized by their history of muscle pain and the presence of myofascial trigger points, which are specific areas of hyperirritability in a muscle that cause local and referred pain on palpation. Failure to recognize MPS often leads to over-investigation, unnecessary medical intervention, and iatrogenic harm with serious cost implications. The purpose of this review is to present clinically relevant data regarding myofascial pain syndrome and to discuss its possible role in the pathophysiology and optimal treatment of fibromyalgia syndrome.     

Botulinum toxin for the treatment of musculoskeletal pain and spasm

The impressive pain relief experienced by sufferers of dystonia and spasticity from intramuscular injections of botulinum toxin suggested that patients with other chronic, musculoskeletal pain conditions also may benefit. However, there have been relatively few placebo-controlled studies of botulinum toxin in such non-neurologic conditions as myofascial pain syndrome, chronic neck and low back pain, and fibromyalgia; the results of these studies have not been impressive. One explanation for the lack of positive findings may be the lack of clinically evident muscle spasms (overactivity), despite the presence of muscle tenderness, tightness, or trigger points. Clinical observations of pain relief from injections of botulinum toxin for dystonia and spasticity and its apparent efficacy in treating migraine suggest an anti-nociceptive action independent of its neuromuscular junction-blocking action. Evidence from animal experiments supports this notion, and other data provide plausible physiologic mechanisms in the periphery and central nervous systems. These involve modulation of the activity of the neurotransmitters glutamate, substance P, calcitonin gene-related peptide, enkephalins, and others. However, even if botulinum toxin is firmly established as an analgesic, there is insufficient clinical evidence of its efficacy in treating non-neurologic, chronic, musculoskeletal pain conditions.     

Treatment of fibromyalgia, myofascial pain, and related disorders

Chronic muscle pain is a common complaint among patients who seek care for musculoskeletal disorders. A spectrum of clinical presentations exists, ranging from focal or regional complaints that usually represent myofascial pain syndromes to more wide spread pain that may meet criteria for a diagnosis of fibromyalgia. This article addresses the epidemiology, pathophysiology, and clinical management of myofascial pain syndrome and fibromyalgia. These conditions are challenging to treat and require physiatrists to be aware of the wide range of pharmacologic, rehabilitative,and psychosocial interventions that can be helpful.     

Tension myalgia as a diagnosis at the Mayo Clinic and its relationship to fibrositis, fibromyalgia, and myofascial pain syndrome

Tension myalgia is a diagnosis that has been in use at the Mayo Clinic for more than 40 years. The term describes a common muscle pain disorder that is conceptually similar to other muscle pain disorders such as fibrositis, fibromyalgia, and myofascial pain syndrome. This article outlines the history of these disorders and proposes "tension myalgia" as a term that unifies these separate diagnoses under one conceptual framework. Because the diagnostic criteria for tension myalgia have been vague, the Department of Physical Medicine and Rehabilitation at the Mayo Clinic has developed specific criteria for generalized, regional, and localized forms of this disorder. The recommended treatment approach includes reassurance, elimination of contributing factors, physical therapy to restore normal neuromuscular function, conditioning, and medications.     

Classification, epidemiology, and natural history of myofascial pain syndrome

Myofascial pain syndrome is a disease of muscle that produces local and referred pain. It is characterized by a motor abnormality (a taut or hard band within the muscle) and by sensory abnormalities (tenderness and referred pain). It is classified as a musculoskeletal pain syndrome that can be acute or chronic, regional or generalized. It can be a primary disorder causing local or regional pain syndromes, or a secondary disorder that occurs as a consequence of some other condition. When it becomes chronic, it tends to generalize, but it does not change to fibromyalgia. It is a treatable condition that can respond well to manual and injection techniques, but requires attention to postural, ergonomic, and structural factors, and toxic or metabolic factors that impair muscle function.     

Pain and tension-type headache: a review of the possible pathophysiological mechanisms

Abstract Tension-type headache represents a considerable health problem and is one of the most costly diseases in the modern society. However, the knowledge about the pathophysiological mechanisms leading to this disorder is limited. The review presents a summary of available research and experimental data on the pathophysiological mechanisms and the recent pathophysiological models. Although the pain in tension-type headache clinically resembles pain from myofascial tissues, both peripheral and central mechanisms are believed to be involved. It is likely that myofascial nociception is important in episodic tension-type headache and that central mechanisms are involved in the pathophysiology of the chronic form. Neurophysiological investigations are introduced to be the most suitable to confirm an involvement of trigeminal pathways, to substantiate recent theories on sensitization phenomena, and to disclose the exact pain-control mechanisms. More studies are needed to elucidate the mechanisms leading to central sensitization and to develop new therapeutic strategies.     

Exercise in Muscle Pain Disorders

Muscle pain disorders range from local or regional (myofascial pain) to widespread (fibromyalgia). Many people with muscle pain have decreased fitness. Exercise intolerance is a common feature as well, and yet exercise plays an important role in the treatment of muscle pain disorders. Results of studies have shown repeatedly, via multiple modes and methods of delivery, that exercise is at least as effective as the best pharmacologic treatments. An understanding by clinicians and their patients of the unique benefits of a carefully crafted exercise program is one step in the successful management of these often frustrating muscle pain disorders.     

Botulinum toxin therapy for myofascial pain disorders

Myofascial pain disorder can originate from various muscles in the body. Numerous therapeutic approaches have been used to treat myofascial pain syndrome with varying success. Botulinum toxin neurolysis may become an important treatment regimen because it sustains relaxation of muscles. There is a growing body of clinical evidence for the efficacy of botulinum toxin in the treatment of painful myofascial conditions. The conditions that have been investigated include chronic low back pain, chronic cervical-associated headache, myofascial pain, myofascial pain syndrome and pain from chronic muscle spasm, and refractory myofascial pain. One of these studies was an open-label, exploratory pilot study into the cervicothoracic and lumbosacral regions using a novel injection technique.     

Hyperbaric oxygen therapy in chronic pain management

Chronic pain is one of the frequently encountered clinical problems that is difficult to cure. Hyperbaric oxygen (HBO) therapy has been reported in chronic pain syndromes with promising results. In this review, we focus on the effectiveness of HBO in fibromyalgia syndrome, complex regional pain syndrome, myofascial pain syndrome, migraine, and cluster headaches. HBO may be beneficial if appropriate patients are selected. HBO is a reliable method of treatment. However, physicians performing HBO must be aware of oxygen toxicity. Another problem regarding HBO is the scarcity of centers administering it. Further research is required focusing on the optimal treatment protocol, the cost/benefit ratio, and the safety of HBO in chronic pain management.     

Needle electromyographic evaluation of patients with myofascial or fibromyalgic pain

Several past studies have evaluated the electromyographic activity of myofascial trigger points with conflicting results. This study was performed to determine whether spontaneous activity or motor unit activity was present in patients with focal myofascial pain or fibromyalgia. Using routine needle electromyographic techniques, we sampled reproducibly tender focal areas (tender points), similar tender areas with pain referral (trigger points), associated muscle bands and adjacent uninvolved musculature. Twenty-five subjects (14 females, 11 males, mean +/- SD age 43 +/- 14 years) were studied; twenty-one subjects with focal myofascial pain and four with fibromyalgia. Spontaneous fibrillatory or positive sharp wave potentials were not found in any muscle in the 25 subjects. There was no evidence of focal motor unit activity in the tender points, trigger points or associated muscle bands in either group. Motor unit recruitment was similar in all areas sampled. We conclude that no electrodiagnostic evidence of ongoing denervation or focal muscle spasm is found in association with focal myofascial pain or fibromyalgia.     

Autonomic nervous system profile in fibromyalgia patients and its modulation by exercise: a mini review

This review imparts an impressionistic tone to our current understanding of autonomic nervous system abnormalities in fibromyalgia. In the wake of symptoms present in patients with fibromyalgia (FM), autonomic dysfunction seems plausible in fibromyalgia. A popular notion is that of a relentless sympathetic hyperactivity and hyporeactivity based on heart rate variability (HRV) analyses and responses to various physiological stimuli. However, some exactly opposite findings suggesting normal/hypersympathetic reactivity in patients with fibromyalgia do exist. This heterogeneous picture along with multiple comorbidities accounts for the quantitative and qualitative differences in the degree of dysautonomia present in patients with FM. We contend that HRV changes in fibromyalgia may not actually represent increased cardiac sympathetic tone. Normal muscle sympathetic nerve activity (MSNA) and normal autonomic reactivity tests in patients with fibromyalgia suggest defective vascular end organ in fibromyalgia. Previously, we proposed a model linking deconditioning with physical inactivity resulting from widespread pain in patients with fibromyalgia. Deconditioning also modulates the autonomic nervous system (high sympathetic tone and a low parasympathetic tone). A high peripheral sympathetic tone causes regional ischaemia, which in turn results in widespread pain. Thus, vascular dysregulation and hypoperfusion in patients with FM give rise to ischaemic pain leading to physical inactivity. Microvascular abnormalities are also found in patients with FM. Therapeutic interventions (e.g. exercise) that result in vasodilatation and favourable autonomic alterations have proven to be effective. In this review, we focus on the vascular end organ in patients with fibromyalgia in particular and its modulation by exercise in general.     

A Review of Duloxetine 60 mg Once‐Daily Dosing for the Management of Diabetic Peripheral Neuropathic Pain,Fibromyalgia, and Chronic Musculoskeletal Pain Due to Chronic Osteoarthritis Pain and Low Back Pain

Background: Duloxetine is a selective dual neuronal serotonin (5‐Hydroxytryptamine, 5‐HT) and norepinephrine reuptake inhibitor (SSNRI). It is indicated in the United States for treatment of major depressive disorder (MDD), generalized anxiety disorder (GAD), and several chronic pain conditions, including management of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain due to chronic osteoarthritis (OA) pain and chronic low back pain (LBP). Its use for antidepressant and anxiolytic actions has been extensively reviewed previously. We here review the evidence for the efficacy of 60 mg once‐daily dosing of duloxetine for chronic pain conditions. Method: The literature was searched for clinical trials in humans conducted in the past 10 years involving duloxetine. Results: There were 199 results in the initial search. Studies not in the English language were excluded. We then included only studies of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain (OA and LBP). Studies of painful symptoms reported in mental health studies were excluded. This resulted in 32 studies. Articles that did not include a 60 mg/day daily dose as a study arm were excluded. This resulted in 30 studies, broken down as follows: 12 for diabetic peripheral neuropathy, 9 for fibromyalgia, 6 for LBP, and 3 for OA pain. Conclusions: The studies reviewed report that duloxetine 60 mg once‐daily dosing is an effective option for the management of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain due to chronic OA pain and chronic LBP. As these pains are often comorbid with MDD or GAD, duloxetine might possess the pharmacologic properties to be a versatile agent able to address several symptoms in these patients. With adequate attention to FDA prescribing guidance regarding safety and drug–drug interactions, duloxetine 60 mg once‐daily dosing appears to be an effective option in the appropriate pain patient population.     

Memantine for the treatment of general neuropathic pain: a narrative review

Neuropathic pain (NP) is difficult to treat and is associated with a decline in quality of life. NP aetiologies are numerous and a number of pathologies display neuropathic characteristics. Of the various N‐methyl‐d ‐aspartate antagonists that are alternatives to be recommended in first‐line NP treatment, memantine has the safest side‐effect profile and has long been approved in Alzheimer's disease. The review covers memantine studies in postherpetic neuralgia, diabetic pain, postoperative pain, complex regional pain syndrome, chronic phantom limb pain, opioid‐refractory pain and fibromyalgia. Results were inconclusive because of studies with poor levels of evidence, paucity of trials and small samples. Two recent randomized trials, however, showed significant efficacy of memantine: one demonstrated prophylactic effects against postoperative neuralgia and pain‐associated psychological impairment; in the other, memantine improved pain and cognition in fibromyalgia. Both studies found no side effects or adverse events. Given the high rate of therapeutic failure in chronic states, often because of adverse events, the excellent benefit/risk ratio of memantine in these pilot studies encourages further exploration of this drug in NP prevention and in fibromyalgia in larger‐scale studies.     

Primary fibromyalgia syndrome and myofascial pain syndrome: clinical features and muscle pathology

Primary fibromyalgia syndrome (PFS) is a common form of nonarticular rheumatism with diffuse musculoskeletal aching and stiffness at multiple sites and tender points at characteristic locations. Nonmusculoskeletal "systemic" symptoms, eg, fatigue, poor sleep, irritable bowel symptoms, and chronic headaches, are also common. Although PFS is similar to myofascial pain syndrome (MPS) in that both conditions cause muscle pain and tenderness, important differences exist. Unlike PFS, muscle pain in MPS is usually local or regional, accompanied by trigger points. Unlike tender points, trigger points produce a referral pain pattern specific to each muscle. Moreover, "systemic" features of PFS are usually absent in MPS. Common and important pathologic changes in muscle in PFS are moth-eaten appearance of Type I fiber by histochemistry, and myofibrillar lysis with glycogen and mitochondria deposition by electron microscopy; inflammatory changes are absent by light microscopy. Recent investigations have shown that PFS is a characteristic clinical entity. Further controlled studies are, however, essential to establish the pathologic changes in tender muscles in PFS.     

Fibromyalgia: a rehabilitation approach. A review

Primary fibromyalgia syndrome, a myofascial disorder, is characterized by diffuse pain and tender points. Effective long term rehabilitation interventions for this disorder have not been demonstrated. The current rehabilitation interventions of fibromyalgia are evaluated and the psychologic consequences are summarized.     

New techniques for the quantification of fibromyalgia and myofascial pain

Myofascial pain and fibromyalgia share a number of common features: the patient is uncomfortable; abnormalities can be detected on physical examination; and there is a lack of an objective means to either quantify or visualize their core features. This has undoubtedly contributed to a slowed acceptance of their importance by the medical community. Fortunately, the situation is beginning to change. Although progress may be somewhat slower in fibromyalgia, in which attention appears to focus on pain sensitivity and functional brain imaging, a number of approaches now seem promising in their ability to quantify the physical and biochemical characteristics of the taut bands and trigger points of myofascial pain. This review focuses on myofascial pain with an emphasis on the growing capability of MRI, microanalytic techniques, and ultrasonography to assess, quantitate, and even visualize the characteristics of these stigmatic lesions.     

Myofascial trigger points in persistent posttraumatic shoulder pain

Persistent pain and disability after injuries to the shoulder sometimes create a difficult diagnostic and therapeutic problem. In many such cases, myofascial trigger points seem to cause symptoms. Three cases in which pain had persisted for eight to 33 months after injury illustrate the manifestations of posttraumatic myofascial trigger point disorders. Trigger points are located by finding discrete foci of tenderness in muscles. Trigger points may be palpably firmer than surrounding muscle, forming nodules; they may twitch in response to palpation and may refer pain to a specific area when stimulated. Failure to recognize the myofascial source of pain can lead to erroneous diagnoses of articular, neurologic, or emotional disorder. Current pathophysiologic theories about trigger points may explain the persistence and topographic spreading of pain after muscular injuries. Appropriate treatment of myofascial trigger points can relieve chronic pain and disability.     

Dry Needling for Management of Pain in the Upper Quarter and Craniofacial Region

Dry needling is a therapeutic intervention that has been growing in popularity. It is primarily used with patients that have pain of myofascial origin. This review provides background about dry needling, myofascial pain, and craniofacial pain. We summarize the evidence regarding the effectiveness of dry needling. For patients with upper quarter myofascial pain, a 2013 systematic review and meta-analysis of 12 randomized controlled studies reported that dry needling is effective in reducing pain (especially immediately after treatment) in patients with upper quarter pain. There have been fewer studies of patients with craniofacial pain and myofascial pain in other regions, but most of these studies report findings to suggest the dry needling may be helpful in reducing pain and improving other pain related variables such as the pain pressure threshold. More rigorous randomized controlled trials are clearly needed to more fully elucidate the effectiveness of dry needling.     

A Critical Appraisal of the Evidence for Botulinum Toxin Type A in the Treatment for Cervico‐Thoracic Myofascial Pain Syndrome

Myofascial pain syndrome (MPS) is a musculoskeletal condition characterized by regional pain and muscle tenderness associated with the presence of myofascial trigger points (MTrPs). The last decade has seen an exponential increase in the use of botulinum toxin (BTX) to treat MPS. To understand the medical evidence substantiating the role of therapeutic BTX injections and to provide useful information for the medical practitioner, we applied the principles of evidence‐based medicine to the treatment for cervico‐thoracic MPS. A search was conducted through MEDLINE (PubMed, OVID, MDConsult), EMBASE, SCOPUS and the Cochrane database for the period 1966 to 2012 using the following keywords: myofascial pain, muscle pain, botulinum toxin, trigger points, and injections. A total of 7 trials satisfied our inclusion criteria and were evaluated in this review. Although the majority of studies found negative results, our analysis identified Gobel et al.'s as the highest quality study among these prospectively randomized investigations. This was due to appropriate identification of diagnostic criteria, excellent study design and objective endpoints. The 6 other identified studies had significant failings due to deficiencies in 1 or more major criteria. We conclude that higher quality, rigorously standardized studies are needed to more appropriately investigate this promising treatment modality.