Myofascial Pain Syndrome, Fibromyalgia
In myofascial pain syndrome, the patient, who is generally 25 to 50 years of age, will be troubled by the gradual onset of localized or regional unilateral fibromuscular pain that at times can be immobilizing. There may be a history of acute strain, or a history of predisposing activities, such as holding a telephone receiver between the ear and shoulder to free the arms, prolonged bending, poor postural habits, repetitive motions, and heavy lifting using poor body mechanics. The areas most commonly affected are the axial muscles, used to maintain posture, which include the posterior muscles of the neck and scapula and the soft tissues lateral to the thoracic and lumbar spine.
Careful examination of the painful region will reveal one or more “trigger points,” which, when firmly pressed with an examining finger, will cause the patient to wince, cry out, or jump with pain. The underlying muscle may contain a small (2- to 5-mm) firm knot, nodule, or taut band of muscle fibers that produces the exquisitely tender trigger point and reproduces the pain of their chief complaint. Pain is often referred in a radicular pattern that may mimic the pain of cervical or lumbar disc herniation.
The patient with fibromyalgia, on the other hand, has widespread, bilateral symmetric musculoskeletal pain that is associated with multiple “tender points” on palpation and that do not cause any radiation of pain. This patient is often depressed or under emotional or physical stress and may have associated chronic fatigue with disturbed sleep, irritable bowel syndrome, cognitive difficulties, headache, morning stiffness, and sensations of numbness or swelling in the hands and feet. Other comorbid conditions might include irritable bladder symptoms, temporomandibular joint syndrome, myofascial pain syndrome, restless leg syndrome, and affective disorders. Cold or hot weather may be one of the precipitating causes of pain.
In both syndromes, most affected patients are women. Also, the pain is nonarticular, and there are no abnormal vital signs and no swelling, erythema, or heat over the painful areas.
What To Do:
Obtain a careful history and perform a general physical examination with special attention to the painful area. Myofascial pain is local or referred regional muscular pain of short (days) or prolonged (months) duration, often causing head, neck, shoulder, upper and lower back, buttock, and leg pain and associated with trigger points, as described earlier. The patient can usually point to the pain with one finger (Figure 123-1).
The pain of fibromyalgia is widespread (bilateral, above and below the waist), prolonged (>3 months), and associated with approximately 11 of 18 possible tender points (Figure 123-2). These tender points are predictable, and, unlike trigger points, they do not cause radiation of pain or have an underlying small tender muscular knot. The associated coexisting conditions mentioned earlier help to support this diagnosis.
Other conditions should be considered, such as medication-induced myalgias (e.g., statins, colchicines, corticosteroids, antimalarial drugs), connective tissue diseases (e.g., dermatomyositis, polymyalgia rheumatica, systemic lupus erythematosus, rheumatoid arthritis), hypothyroidism and other endocrine disorders, and cancer. In addition, evaluate for true radicular pain with a neurologic examination, and, if indicated, straight-leg raising.
With any suspicion that an underlying systemic illness exists, obtain appropriate radiographs and laboratory tests, such as an erythrocyte sedimentation rate, creatine phosphokinase (CPK) and thyroid-stimulating hormone. These and all other studies should be normal in both myofascial and fibromyalgia pain syndrome.
When a trigger point is found, have the patient maintain a comfortable, relaxed position. Map out its exact location (point of maximum tenderness) and place an “X” over the site with a marker or ballpoint pen. If the trigger point is diffuse, there is no need to outline its location.
When myofascial pain is suspected but trigger points are diffuse, unless contraindicated, prescribe a nonsteroidal anti-inflammatory drug (NSAID), such as naproxen sodium (Naprosyn), 250 mg, two tablets stat then one qid, or ibuprofen (Motrin), 800 mg stat then 600 mg qid × 5 days. A benzodiazepine such as lorazepam (Ativan), 1 mg qid, may also be helpful.
When a focal trigger point is present, suggest that the patient may get immediate relief with an injection. If the patient is willing, using proper aseptic technique and a 25- or 27-gauge, 1¼- to 1½-inch needle, inject through the mark you placed on the skin, directly into the painful site (Figures 123-3 to 123-13). Use 5 to 10 mL of 1% lidocaine (Xylocaine) or longer-acting 0.5% bupivacaine (Marcaine) with or without 20 to 40 mg of methylprednisolone (Depo-Medrol) or 2 to 5 mg of triamcinolone (Aristospan). Attempt aspiration to be sure you are not in a blood vessel or pleural cavity and then “fan” the needle in all directions while injecting the trigger point. Advise the patient before the procedure that there may be intensification of the pain before relief. Intensification of the pain with or without radiation, while injecting slowly, is a good indicator that the needle is in the precise trigger point location. Inject most of the anesthetic into this most painful site. In addition, massage the area after the injection is complete to ensure total coverage. Within a few minutes the patient will often get complete or near-complete pain relief, which helps to confirm the diagnosis of myofascial pain syndrome. Inform the patient that there will be approximately 1 day of muscular soreness after the anesthetic wears off. The beneficial effect of this injection may last for weeks or months. A supplementary 5-day course of NSAIDs is optional.
Secondary trigger points may develop in neighboring muscles as a result of stress and muscle spasm. It is common for patients to experience the pain of a secondary trigger point after a primary trigger point is eliminated. These trigger points can be treated in the same manner, either at the same visit or at an early follow-up visit if the symptoms persist.
Moist, hot compresses and massage may also be comforting to the patient after discharge.
Patients with the diffuse symptoms of fibromyalgia usually will not benefit from trigger point injection or NSAIDs. When other causes of such pain have been adequately ruled out, antidepressants, most commonly amitriptyline (Elavil), 10 to 50 mg qd, improve symptoms for up to several months. The muscle relaxant cyclobenzaprine (Flexeril), which is structurally similar to the tricyclic antidepressants, has also been found to be beneficial in doses of 15 to 45 mg/day divided tid. Tramadol (Ultram), 50 to 100 mg q4-6h (not to exceed 400 mg/day), is an analgesic that has also been found to benefit patients with fibromyalgia.
Aerobic exercise and warm compresses improve function and reduce pain in persons with fibromyalgia.
What Not To Do:
Do not order radiographs or laboratory tests for myofascial pain that is localized and relieved by trigger point injection.
Do not inject trigger points in the presence of systemic or local infection, in patients with bleeding disorders, in patients on anticoagulants, or in patients who appear to be or feel ill.
Do not prescribe narcotic analgesics or systemic steroids. They are no more effective than the abovementioned therapy and add side effects and the risk for dependence.
Do not prescribe NSAIDs to patients with fibromyalgia. They have been found to be no more effective than placebo in this group of patients.
Emergency physicians and other acute care clinicians often see patients with trigger points associated with simple self-limiting regional myofascial pain syndromes, which appear to arise from muscles, muscle–tendon junctions, or tendon–bone junctions. Myofascial disease can result in severe pain, but it is typically in a limited distribution, without the systemic feature of fatigue, and without the multiple somatic complaints of fibromyalgia. Trigger-point injection therapy, the treatment of choice for trigger points according to many, has gained widening acceptance in mainstream medicine. When symptoms recur or persist after this basic therapy or are accompanied by generalized complaints, acute care clinicians should refer these patients to a rheumatologist or primary care physician for follow-up and continued management.
When the quadratus lumborum muscle is involved (see Figure 123-13), there is often confusion whether or not the patient has a renal, abdominal, or pulmonary ailment. The reason for this is the muscle’s proximity to the flank and abdomen, as well as its attachment to the twelfth rib, which, when tender, can create pleuritic symptoms. A careful physical examination reproducing symptoms through palpation, active contraction, and passive stretching of this muscle can save this patient from a multitude of laboratory and radiograph studies.
Another affected muscle that often confuses and misleads clinicians is the piriformis (Figure 123-14). Piriformis syndrome is an uncommon and often undiagnosed cause of buttock and leg pain. It may be caused by anatomic abnormalities of the piriformis muscle and the sciatic nerve resulting in irritation of the sciatic nerve by the piriformis.
The typical patient with piriformis syndrome complains of buttock pain with or without radiation to the posterior thigh that sometimes extends below the knee to the calf, resembling typical sciatica and causes difficulty with walking. The cardinal characteristic of the syndrome is sitting intolerance secondary to intense buttock pain. Gluteal atrophy may occur.
Buttock tenderness in the region of the greater sciatic foramen is present in almost all patients, and buttock pain is elicited when the patient lifts and holds the knee several inches off the examination table. There may be moderate relief of pain by applying traction on the affected extremity with the patient in the supine position. A tender sausage-shaped mass may be palpated over the piriformis muscle.
A complete neurologic examination should be performed to test motor power, sensory function, and reflexes of the lower extremities to help rule out spinal causes of sciatic pain. One should also consider intrapelvic diseases, such as tumors and endometriosis, as a possible cause of sciatic pain.
Conservative treatment of piriformis syndrome consists of prescribing NSAIDs, analgesics, and muscle relaxants and providing physical therapy, which includes stretching the piriformis muscle with internal rotation and hip adduction and flexion.
More aggressive therapy includes local injection of anesthetic and corticosteroids that may reconfirm the diagnosis through therapeutic success (see Figure 123-14). This may be repeated twice with recurrent pain. If this fails, surgery can be considered.
The most likely cause of chronic diffuse myalgia is fibromyalgia. Among adults who seek medical attention for fibromyalgia, less than one third recover within 10 years of onset. Symptoms tend to remain stable or improve over time.
Although fibromyalgia was long believed to be primarily a muscle disease, research has not found any significant pathologic or biochemical abnormalities in muscle tissue. Many researchers now believe that the disease is caused by abnormalities in central nervous system function. This would suggest that the pain of fibromyalgia is in part because of a decrease in the threshold for pain perception and tolerance experienced by these patients. Fibromyalgia patients also appear to experience pain amplification because of abnormal sensory processing in the central nervous system.
The diagnosis of fibromyalgia is made by meeting the criteria of having widespread musculoskeletal pain for 3 months or longer and having 11 or more tender points among 18 potential sites defined by the American College of Rheumatology (see Figure 123-2). Some patients may not have an adequate number of tender points to make the diagnosis, but when typically associated symptoms are present, these patients should be treated for fibromyalgia.
Education, reassurance, psychological support, and reminders to exercise regularly are important in all follow-up visits.