Reflex sympathetic dystrophy syndrome: an unusual mode of presentation of osteomalacia

We report 2 patients with reflex sympathetic dystrophy syndrome (RSDS) associated with renal tubular osteomalacia. In both patients, RSDS was the presenting manifestation. Treatment of the underlying condition with calcitriol resulted in healing in both patients. These cases prompted us to undertake a retrospective study of 24 consecutive patients with osteomalacia (6 of renal tubular origin, 18 related to vitamin D deficiency), and of 259 consecutive patients with RSDS. Among those with osteomalacia, radiologic lesions strongly suggestive of RSDS were found in 5 patients (21%), 4 of whom had renal tubular defects, and only 1 had vitamin D deficiency. In the group with RSDS, 1 patient (0.4%) was found to have osteomalacia of renal tubular origin. Thus, radiologic findings suggestive of RSDS are frequent in patients with osteomalacia, especially that of renal tubular origin. On rare occasions, the full-blown clinical picture of RSDS may obscure the diagnosis of osteomalacia.