| Popis: |
Up to the mid-1960s, beta-thalassemia was treated with blood transfusions as frequent as needed to keep symptoms under control and to prevent transfusional hemosiderosis. In the following years, high transfusion regimens and iron chelation therapy with desferrioxamine were used. Because of these different treatment modalities, skeletal findings in thalassemia have markedly changed. In the past, thalassemic patients treated with a low transfusion regimen and without chelation therapy developed osteopenia--with widened medullary spaces, cortical thinning and trabecular atrophy--secondary to chronic expansion of red marrow, due to increased erythropoietin response to chronic anemic hypoxia. Typical radiographic patterns in the skull included widened diploic space, atrophic-especially outer--tables and, in some patients, the "hair-on-end" pattern. As for the face, obliteration of the paranasal sinuses and the typical "rodent facies" were observed. In the ribs, bulbous expansion of the posterior and anterior segments and the "rib within a rib" patterns were observed. As for the spine, coarse trabecular arrangement was seen. The "cobweb" pattern was seen in the pelvis and finally the lack of the normal concave outline was observed in the long bones. In the patients treated with high transfusion regimens and iron chelation therapy over the last 30 years, both skull anomalies and disfigurement are less frequent. The skull is almost normal, with the exception of osteopenia and thickened diploic space in the frontal bone only; the paranasal sinuses are usually not obliterated. The hands and rib are normal, just like long bones, pelvis, scapulae and vertebral bodies. Nevertheless, in some adequately treated patients new skeletal features have been recently observed in the long bones, which are similar to those occurring in rickets and/or scurvy, and in the vertebral bodies, resembling platyspondylia. These abnormal features might be caused by several factors--i.e., marrow expansion, transfusion regimens, direct/indirect effects of desferrioxamine, iron load, endocrine abnormalities, deficiency of some minerals and finally dysvitaminoses. Nevertheless, osteopenia remains the main negative factor of thalassemia. |
