The overdiagnosis of fibromyalgia syndrome

As fibromyalgia syndrome (FM) has gained greater acceptance and awareness in both the medical and the lay community, the possibility of overdiagnosis exists. Diffuse body pain in a woman is likely to suggest this diagnosis. We report the diagnosis of FM in 11 female patients whose primary cause for musculoskeletal symptoms was spondyloarthritis rather than only FM.

Of a total of 321 new rheumatology referrals in a 1-year period, 35 (11%) were diagnosed with FM. A further 11 (3%) were referred with either a previous diagnosis of FM or a presumed diagnosis of FM in whom the musculoskeletal syndrome could be attributed to previously unrecognized spondyloarthropathy.

The 11 female patients had mostly experienced musculoskeletal symptoms for prolonged periods of time ranging from 1 to 40 years. Symptoms included prominent spinal pain involving at least 2 locations in the spine (n = 10), night pain that disturbed sleep (n = 10), and prolonged morning stiffness (n = 9). A previous history of enthesopathy, or history in the patient or first-degree relative of one of the seronegative associated diseases, such as psoriasis or ulcerative colitis, occurred in nine patients. Most patients had already undergone extensive investigations by various specialists in musculoskeletal medicine, but spondyloarthritis had only infrequently been considered a diagnostic possibility.

Spondyloarthropathy in women may present subtly and have considerable overlap in symptomalogy with FM. A diagnosis of spondyloarthropathy should be considered in women with an ill-defined pain syndrome with prominent spinal pain and associated enthesopathy, or history or family history of seronegative-associated disease. It is possible that a primary diagnosis of FM is being made too freely, without consideration of other diagnoses, in the setting of ill-defined musculoskeletal pain.