The term myalgia refers to muscle pain. The term myositis is not sufficiently precise for fibromyalgia, which lacks an inflammatory response, as myositis is due to inflammation of the muscle tissue. Fibromyalgia refers to pain in fibrous tissue, muscles, tendons, ligaments and other areas. Any fibromuscular tissue can be involved, with occiput, neck (cervical spasm), shoulder, thorax (pectoral pain), lower back (lumbago), and femur (thigh pain and quadriceps stiffness) being the most common. The lack of specific histologic changes and inflammatory cell response suggests that the old names of fibromyalgia “fibrositis” or “fibromyositis” are more appropriate. It is more common in women and can be caused or aggravated by excessive physical labor, stress, lack of sleep, trauma, dampness, cold, etc. It is also associated with a number of other diseases. Systemic diseases (usually rheumatic pains) can also occasionally trigger the disease. Viruses or other systemic infections (e.g., Lyme disease) can also trigger the disease in susceptible individuals. The disease may be generalized (sometimes secondary to other conditions) or limited (e.g., myofascial pain syndrome is often associated with strain or minor trauma). Primary fibromyalgia syndrome (PFS) is a generalized idiopathic disorder that occurs particularly in healthy young and middle-aged women with a tendency towards stress, depression, anxiety and a struggle type, but can also occur in children (especially girls) or older adults, often with mild osteoarthritic changes in the vertebrae. Men are particularly susceptible to specific occupational or recreational muscle strains resulting in limited fibromyalgia. A few cases may be associated with psychological and physiologic abnormalities. Symptoms can be exacerbated by environmental and emotional stress, or by the physician’s inability to relieve the patient’s concerns and simply dismissing them as “it’s all in your head”. Symptoms, signs and diagnosis In primary fibromyalgia syndrome, the onset of muscle stiffness and pain is gradual, diffuse and “achy” in nature. In the limited form, the onset is often sudden and acute. The pain is exacerbated by straining and over-exertion. There may be tenderness, often confined to a specific, small area, known as a “pressure point”. There may be localized muscle spasms, which are not always confirmed by electromyography. Inflammation is not a characteristic feature of the disease, it is a manifestation of a systemic primary disease. The diagnosis of primary fibromyalgia syndrome is made by recognizing the typical features of diffuse fibromyalgia with non-rheumatic symptoms (e.g., insomnia, anxiety, fatigue, intestinal allergies, etc.), ruling out other systemic diseases (e.g., systemic osteoarthritis, RA, polymyositis, rheumatoid polymyalgia, or other connective tissue disorders, etc.); and ruling out psychosomatic muscular pains and spasms, which is the most difficult. Fibromyalgia associated with the above diseases (coexisting or secondary) may have musculoskeletal signs and symptoms similar to those of primary fibromyalgia (with the exception of psychogenic rheumatism), which need to be differentiated to facilitate better treatment of the underlying disease as well as the fibromyalgia itself. In middle-aged female cases, underlying rheumatic diseases and hypothyroidism must be excluded. Non-specific and mild histopathologic changes in the muscle may be present, and these changes may also be seen in normal controls. Prognosis and treatment Mild fibromyalgia may resolve spontaneously with release of tension, but may recur or become chronic. Reassuring the patient and explaining that the disease is benign, stretching exercises, aerobic fitness, improved sleep, localized warm compresses, and gentle massage can help. Small doses of tricyclic antidepressants (e.g., amitriptyline 10 mg or the lowest tolerated dose) at bedtime can deepen sleep and modulate pain. Aspirin 650mg every 3-4 hours, or adequate doses of other non-steroidal anti-inflammatory drugs have been shown to be ineffective in clinical trials, but may be helpful in some people. Lidocaine 1% 1 ml or 2 ml may be injected alone into the area of tenderness or weakness, or in combination with 20-40 mg of hydrocortisone acetate suspension (see Soft Tissue Injections in the Treatment of Chronic Lower Back Pain). If somnolence occurs with a drug, it can be changed to another drug of the same type (in small doses). A morning dose of a 5-hydroxytryptamine-specific inhibitor (e.g., flupentixol HCl 10mg or 20mg) can reduce depression and improve symptoms. Care must be taken to avoid exacerbating sleep problems with medication, as this can lead to insomnia. Functional prognosis is good for those who use a combination of supportive therapies, although symptoms of varying degrees of severity may persist. Treatment of anxiety or depression requires a more aggressive and specific approach and patient support. In conclusion, optimal treatment should be individualized, comprehensive and adaptable, and require direct patient involvement.