Do I have lupus or fibromyalgia ?
by Robert Bennett MD

This is not an uncommon question that I frequently get asked. Unfortunately some fibromyalgia patients are erroneously diagnosed as having lupus, a potentially dangerous condition that affects about 2 in every 1000 people. Through your doctor and educational literature and support groups, you have learned lupus patients can have involvement of almost any system of the body including severe involvement of the kidneys, heart and brain. This is scary information; even though you know that only a minority of lupus patients have such a severe course.

The commonest problems encountered by most lupus patients are joint pains, muscles pains, fatigue and skin rashes. It is not unreasonable to assume an increased level of fatigue and increasing joint pain heralds a severe flare of your lupus that may even progress to life-threatening internal organ involvement. Such thoughts are anxiety-provoking and depressing; they can cause sleepless nights. Both you and your doctor may be convinced that your accelerating symptoms represent a lupus flare. You may be put on prednisone or the dose of your steroids may be increased. But before you and your doctor jump to conclusions, consider the possibility that you could also have fibromyalgia.

Fibromyalgia is a common condition of musculoskeletal pain, sleep disturbance and fatigue, that affects about 20 out of every 1000 persons. Recent studies have shown that approximately one-third of patients with lupus also have fibromyalgia. It is important to understand that the fibromyalgia in these patients develops after the lupus has become well established. It is extremely rare for a fibromyalgia patient to later develop lupus - I have only seen this in 2 patients in 30 years of practice as a Rheumatologist. Although fibromyalgia patients have widespread body pain which arises from their muscles, they often feel that the pain is originating in their joints. In addition to widespread pain, other common fibromyalgia symptoms include a decreased sense of energy, poor sleep and varying degrees of anxiety and depression (related to a changed physical status). To complicate matters further, other medical conditions are commonly associated with fibromyalgia. These include irritable bowel syndrome, tension headaches, migraine, irritable bladder syndrome, premenstrual tension syndrome, cold intolerance (including Raynaud’s phenomenon) and restless leg syndrome.

This combination of pain and multiple symptoms may lead physicians to pursue an extensive course of investigations, which are often frustratingly normal. In fact, there are no blood tests or x-rays which reliably diagnose fibromyalgia. In order to diagnose fibromyalgia, a physician must take a careful history and perform an examination which focuses on specific local areas of tenderness. These locations are called tender points. As many of the symptoms of fibromyalgia are similar to those experienced by lupus patients, there is a natural concern that the symptoms of a fibromyalgia flare could be the underlying lupus picking up steam. Ultimately, the treating physician has to make a call on these increased symptoms.

In general, lupus patients who are undergoing a flare have other findings; such as evidence of true arthritis (usually with joint swelling), skin rashes, sores in their mouth, fever, hair fall or evidence of specific organ disease such as pleurisy or microscopic amounts of blood and protein in the urine. Furthermore, in active lupus, blood tests such as the sedimentation rate often become elevated, the white count (particularly the lymphocyte subset) becomes depressed and there is often an increase in the level of anti-DNA antibodies.

None of these findings are a feature of fibromyalgia -- thus the distinction between a flare of fibromyalgia and a flare of lupus should not be too difficult if the problem is approached systematically. The American College of Rheumatology have developed criteria for diagnosing lupus - just as they have for diagnosing fibromyalgia. To have a definite diagnosis of lupus you must have 4 or more of the following features:

Positive anti-double stranded anti-DNA test, positive anti-Sm test, positive antiphospholipid antibody such as anticardiolipin, or false positive syphilis test (VDRL). It is important to realize that the symptoms of fibromyalgia do not respond to corticosteroids such as prednisone or even immunosuppressive agents, such as azathioprine, methotrexate or cyclophosphamide. These are powerful and important drugs in the treatment of lupus but are often associated with undesirable side effects. Thus, making a distinction between fibromyalgia symptomatology and lupus symptomatology is of great practical relevance in deciding what medications to use.

In my experience, most lupus patients are often shocked to hear that they also have fibromyalgia, and in many cases don’t like being given that diagnosis. They somehow think that fibromyalgia is not a real disease and detracts attention away from the realities of having lupus. I can understand these thoughts. However, knowing that some of your musculoskeletal pain is fibromyalgia-related and not lupus should also be good news -- as who wants to have lupus flare?

Lastly, there are some "lupus" patients who have only fibromyalgia, but on testing were found to have a weakly positive ANA. They were incorrectly diagnosed as having lupus on the basis of the blood test. There is an increasing recognition among lupus specialists that this false diagnosis scenario is not at all uncommon.