Late-onset spondyloarthropathy mimicking reflex sympathetic dystrophy syndrome

Abstract Atypical presentations are common when spondyloarthropathy develops in older patients. We report two cases initially mistaken for reflex sympathetic dystrophy syndrome (RSDS). Both the patients were men, aged 62 and 75 years, respectively, with marked painful edema of a foot. One patient reported a moderate-energy trauma as the triggering event. Severe diffuse demineralization was noted on radiographs and diffuse hyperactivity on bone scans starting at the early vascular phase. These findings suggestive of RSDS led to treatment with calcitonin, griseofulvin, and pamidronate, all of which were ineffective. Laboratory tests showed severe inflammation, promoting investigations for other conditions. Spondyloarthropathy was diagnosed based on oligoarthritis with sacroiliitis, presence of HLA B27, and a favorable response to non-steroidal antiinflammatory therapy. In older patients, edema of the foot with severe demineralization and the laboratory evidence of inflammation should suggest a spondyloarthropathy.