Determining the Beighton score (
Figure 3) is essential for making the diagnosis. The first step is to calculate the Beighton score, which is a measure of generalized joint laxity.
1 Physicians calculate this score by doing five simple maneuvers (
Figure 4) that can be completed in 45 to 60 seconds. A Beighton score of 4 or more points is considered indicative of generalized joint laxity. Most patients with BJHS have symmetric joint laxity. The Brighton criteria were developed to establish diagnostic criteria for BJHS. Using these criteria helps physicians to distinguish BJHS from other connective tissue disorders.
1,4,14
Diagnosis of BJHS is one of exclusion. For patients with painful or swollen joints, it is important to rule out inflammatory, infectious, and autoimmune causes. Workup may include a complete blood cell count, erythrocyte sedimentation rate, rheumatoid factor, antinuclear antibody test, serum complement (C3, C4, CH50) levels, and serum immunoglobulin (IgG, IgM, IgA) levels. Any of these test results that are not within the normal reference range suggest an alternate diagnosis. Sometimes, patients with BJHS have an effusion, but the joint aspirate shows a noninflammatory pattern from meniscal and cartilage irritation.
Benign joint hypermobility syndrome needs to be distinguished from other disorders that share many common features, such as Marfan syndrome, EDS, and osteogenesis imperfecta. Generalized hypermobility is a common feature in all these hereditary connective tissue disorders and many features overlap, but often distinguishing features are present that enable differentiating these disorders.