A diffuse pain syndrome, fibromyalgia syndrome (FMS, previously called fibrositis) is one of the most common causes of chronic musculoskeletal pain; it’s observed in up to 15% of patients seen in a general rheumatology practice and 5% of general medicine clinic patients. Symptoms of FMS include diffuse musculoskeletal pain, daily fatigue, and sleep disturbances. Multiple tender points in specific areas on examination are the characteristic feature. Women are affected much more commonly than men, and although FMS can affect all age-groups, its peak incidence is between ages 20 and 60. It may occur as a primary disorder or in association with an underlying disease, such as systemic lupus erythematosus, rheumatoid arthritis, osteoarthritis, sleep apnea syndromes, and neck trauma.
The cause of FMS is unknown, but many theories exist regarding its pathophysiology. Although the pain is located primarily in muscle areas, no distinct abnormalities have been documented on microscopic evaluation of biopsies of tender points when compared to normal muscle. Other theories suggest decreased blood flow to muscle tissue (due to poor muscle aerobic conditioning versus other physiologic abnormalities); decreased blood flow in the thalamus and caudate nucleus, leading to a lowering of the pain threshold; endocrine dysfunction such as abnormal pituitary-adrenal axis responses; and abnormal levels of the neurotransmitter serotonin in brain centers, which affect pain and sleep. Abnormal functioning of other pain-processing pathways may also be involved. Considerable overlap of symptoms with other pain syndromes, such as chronic fatigue syndrome, raises the question of an association with an infection such as with parvovirus B19. Human immunodeficiency virus (HIV) infection and Lyme disease have also been associated with FMS.
It’s possible that the development of FMS is multifactorial and is influenced by stress (physical and mental), physical conditioning, and quality of sleep as well as by neuroendocrine, psychiatric and, possibly, hormonal factors (because of the female predominance).
Signs and symptoms
The primary symptom of FMS is diffuse, dull, aching pain that’s typically concentrated across the neck, shoulders, lower back, and proximal limbs. It can involve all four body quadrants— bilateral upper trunk and arms and bilateral lower trunk and legs. The pain is typically worse in the morning and sometimes accompanied by stiffness. It can vary from day to day and be exacerbated by stress, lack of sleep, weather changes, and inactivity.
The sleep disturbance associated with FMS may be another factor in symptom development. Many patients with this syndrome describe a habit of being a light sleeper and experiencing frequent arousal and fragmented sleep (possibly secondary to pain in those patients who have underlying illnesses, such as osteoarthritis and rheumatoid arthritis). Other patients may report feeling unrefreshed after a night’s sleep. Because of this nonrestorative sleep pattern, the patient can feel fatigued a half hour to several hours after awakening and remain so Continue reading »