Fibrositis (Fibromyalgia)

Posted by Alex

Fibrositis (also called fibromyalgia) affects about 3–10% of the population, making it one of the most common rheumatic syndromes in general medicine. It shares many features with the chronic fatigue syndrome, namely, an increased frequency among women aged 20–50, absence of objective findings, and absence of diagnostic laboratory tests. While many of the clinical features of the two conditions overlap, musculoskeletal pain predominates in fibrositis whereas lassitude dominates the chronic fatigue syndrome.

The cause is unknown, but sleep disorders, depression, viral infections, and aberrant perception of normal stimuli have all been proposed. Fibrositis can be a complication of hypothyroidism, rheumatoid arthritis, or, in men, sleep apnea.

Clinical Findings

The patient complains of chronic aching pain and stiffness, frequently involving the entire body but with prominence of pain around the neck, shoulders, low back, and hips. Fatigue, sleep disorders, subjective numbness, chronic headaches, and irritable bowel symptoms are common. The patient feels incapable of performing normal activities, and even minor exertion aggravates pain and increases fatigue. Patients occasionally trace the onset of symptoms to an acute event or viral-like illness. Physical examination is normal except for “trigger points” of pain produced by palpation of various areas such as the trapezius, the medial fat pad of the knee, and the lateral epicondyle of the elbow.

Differential Diagnosis

Fibrositis is a diagnosis of exclusion. A detailed history and repeated physical examination can obviate the need for extensive laboratory testing. Rheumatoid arthritis and systemic lupus erythematosus virtually always present with objective physical findings or abnormalities on routine testing, including the erythrocyte sedimentation rate. Thyroid function tests are useful, since hypothyroidism can produce a secondary fibromyalgia syndrome. Polymyositis produces weakness rather than pain. The diagnosis of fibrositis probably should be made hesitantly in a patient over age 50 and should never be invoked to explain fever, weight loss, or any other objective signs. Polymyalgia rheumatica produces shoulder and girdle pain, is associated with anemia and an elevated sedimentation rate, and occurs after age 50.

Treatment

Patient education is of paramount importance. Patients can be comforted by the knowledge that they have a recognizable diagnosable syndrome that can be managed by means of specific though imperfect therapies and that the course is not progressive. Placebo-controlled trials have demonstrated modest efficacy of amitriptyline, fluoxetine, chlorpromazine, or cyclobenzaprine. Amitriptyline is initiated at a dosage of 10 mg at bedtime and gradually increased to 40–50 mg depending on its efficacy and toxicity. Exercise programs are also beneficial. NSAIDs are generally ineffective. Opioids and corticosteroids are ineffective and should never be used to treat fibrositis.

Prognosis

Most patients have chronic symptoms. With treatment, however, many do eventually resume increased activities. Progressive or objective findings do not develop.

10200:6:1 Carette S et al: Comparison of amitriptyline, cyclobenzaprine, and placebo in the treatment of fibromyalgia: A randomized, double-blind clinical trial. Arthritis Rheum 1994;37:32. (Both more effective than placebo, but only one-third significantly improved after 6 months of therapy.)

10200:6:2 Goldenberg D et al: A randomized double-blind crossover trial of fluoxetine and amitriptyline in the treatment of fibromyalgia. Arthritis Rheum 2006;39:1852. (Both work; the combination is better.)