title: [Partial decalcifying algodystrophy].
abstract: Partial decalcifying algodystrophy (PDA) appears in two forms: one, a radial form, affects, following a certain metameric topography, one or two radiuses of the hand or of the foot (two cases reported); the other, a zonal form, is more peculiar: only part of a condyle or of the femoral head, are demineralized for two to three months. The authors report 7 cases of this misleading zonal form, 2 of them after histological verification. The image leads to various diagnostic errors: osteitis or infectious osteo-arthritis, acute inflammation close to the bone, and especially malignant processes. However, zonal PDA has its own characteristics: demineralization, that becomes clear only during the second month, and quickly extends over a rather long sub chondral bone surface. Tomography is very useful: it demonstrates better the severe sub chondral osteoporosis and the retention of the bone sole, which becomes detached from the bone. Scintigraphy shows the massive localized or panregional hyperfixation and sometimes other infraradiological sites (hips, knee or ankle). Zonal osteoporosis remains partial and misleading for only 2 or 3 months, after which it becomes a classical panregional form. The rate of development is that of DA. Painful impotence quickly increases, with cure in 6 months.
mesh_terms: D000328:Adult; D000368:Aged; D001862:Bone Resorption / Q000209:etiology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000000981:diagnostic imaging / Q000209:etiology*; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000209:etiology*; D011859:Radiography; D012019:Reflex Sympathetic Dystrophy / Q000150:complications* / Q000000981:diagnostic imaging
vernacular_title: L'algodystrophie décalcifiante partielle.