Joint Hypermobility Misdiagnosed as Fibromyalgia?
The precise pathogenic basis of primary fibromyalgia (FM) is poorly understood, although many mechanisms have been proposed, including abnormal pain perception, sleep disorders, aberrant circulating levels of central neurochemical substances, and skeletal muscle abnormalities.
The suggestion that FM may be related to joint hypermobility (JH), defined as abnormally increased mobility of small and large joints (beyond normal limits of physiological movement), led to this investigation involving 178 participants.
The patient group comprised 88 subjects presenting with widespread pain, and the control group included 90 healthy subjects. Diagnosis of fibromyalgia was made based upon meeting the 1990 American College of Rheumatology (ACR) criteria for FM - typical widespread musculoskeletal pain and tenderness in 11 or more of 18 specific point sites. Diagnosis of joint hypermobility was made according to the Beighton modification of Carter and Wilkinson criteria for hypermobility (scores greater than or equal to 4).
Fifty-six patients and six controls met ACR diagnostic criteria for FM, and JH was noted in 8% of patients and 6% of controls. Interestingly, joint hypermobility was recognized in 10 of 32 patients who had not "exactly" met the ACR criteria for fibromyalgia, a finding the authors suggest may result in misdiagnosis: "Both syndromes can be responsible for widespread and migratory arthralgia without arthritis/synovitis, and this must be considered..."
Karaaslan Y, Haznedaroglu S, Ozturk M. Joint hypermobility and primary fibromyalgia: a clinical enigma. Journal of Rheumatology