Medical Health Encyclopedia

Other conditions may also occur that are similar to fibromyalgia but do not rule out a diagnosis of fibromyalgia. They include:

• Irritable bowel syndrome
• Temporomandibular joint disorders (TMJ)
• Juvenile rheumatoid arthritis (JRA) -- usually diagnosis is clear cut, but the conditions may coexist. JRA should be considered in children with fibromyalgia if their condition worsens.
• Osteoarthritis -- a common form of arthritis than can coexist with fibromyalgia. The two conditions may be confused, particularly in elderly people. Osteoarthritis, however, causes joint pain, not widespread or generalized pain.

Osteoarthritis is a chronic disease of the joint cartilage and bone. It is often thought to result from "wear and tear" on a joint, although there are other causes such as congenital defects, trauma, and metabolic disorders. Joints appear larger, are stiff and painful, and usually feel worse the more they are used throughout the day.

• Chemicals and environmental toxins -- exposure to various chemicals and environmental toxins such as solvents, pesticides, or heavy metals (cadmium, mercury, or lead) can cause fatigue, chronic pain, and other symptoms of fibromyalgia.

Some tests may be positive for one or more of these diseases. However, if the results are ambiguous or weak or if they have been treated successfully, fibromyalgia should not be ruled out if the patient still also meets the criteria for it.

Conditions That Usually Rule Out Fibromyalgia

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Rheumatoid Arthritis and Other Autoimmune Diseases. Autoimmune diseases are conditions in which the person's immune system attacks the body's own tissues. Many autoimmune conditions resemble fibromyalgia. (Fibromyalgia, itself, may be an autoimmune disorder.) These diseases, like fibromyalgia, also occur more often in women than in men, and early symptoms are often muscle and joint pain and fatigue. The following are some autoimmune disorders that may be confused with fibromyalgia:

• Rheumatoid arthritis is most apt to mimic fibromyalgia, and the similarities present diagnostic problems in both young people and adults. Symptoms include morning stiffness, fatigue, and tender points. Pressing such points, however, does not produce the intense pain that occurs with fibromyalgia, and abnormal laboratory tests can usually differentiate this disorder from fibromyalgia. Juvenile rheumatoid arthritis may coexist with fibromyalgia.

Click the icon to see an image of rheumatoid arthritis.

• Hashimoto's thyroiditis, a form of hypothyroidism marked by low levels of thyroid hormone, can cause widespread muscle aches, depression, and fatigue if left untreated. This condition is usually easily identifiable with thyroid hormone tests.

Click the icon to see an image of Hashimoto's thyroiditis.

• Systemic lupus erythematosus resembles fibromyalgia, although most patients with lupus also have a rash. Lupus can be diagnosed with a blood test.

Click the icon to see an image of systemic lupus erythematosus.

• Multiple sclerosis has similar symptoms. There is no definitive test for diagnosing it. Magnetic resonance imaging scans, however, detect patches of injured tissue (lesions) in the brain that suggest MS.

Click the icon to see an image of multiple sclerosis.

• Sjogren's syndrome, a condition characterized by dry eyes and mouth, is sometimes mistaken for fibromyalgia.