Search

The incidence of aseptic necrosis of femoral head in homozygous beta-thalassaemia (Cooley's anaemia)--which is indeed significantly high--is not satisfactorily referred in late literature regarding haemolytic syndromes. Therefore, 4 cases of osteonecrosis of femoral head, recently recognized in a series of 280 patients affected by Cooley's anaemia (14.5 0/00) are presented, and a review of hypotheses about the pathogenesis of the lesions is considered. In Cooley's anaemia, the skeletal lesion (osteoporosis) must be believed as a propitious state, in which some other pathogenetic events (i.e. local ischemia, bony age, etc.) and microtraumas overlap. In any case, characteristic blood circulation of the femoral head is the "conditio sine qua non" in developing osteonecrosis.

Aseptic necrosis of the femoral head is described in 4 patients, selected from 280 patients with homozygous beta-thalassemia (Cooley anemia). The incidence of the complication appears to be very high (14.5%) in thalassemia, compared to the general population. The possible mechanism are discussed.

Since anaemia of varying degree is a quite common finding in heterozygous beta-thalassaemia, a research was done to see if beta-thalassaemia heterozygotes occupationally exposed to long-term continuous external radiation should be more susceptible to haematopoietic damage than non thalassaemic subjects. We examined peripheral haematological findings of 20 beta-thalassaemia heterozygotes previously exposed to a mean of 10.7 mSv, compared with 22 non thalassaemic subjects exposed to 6 mSv, and with 50 not exposed beta-thalassaemia heterozygotes. The obtained results suggest that whole-body external irradiation--with the mean doses reported--does not cause noteworthy changes in beta-thalassaemia heterozygotes.

Mean reticulocyte volume (MRV) and reticulocyte/nonreticulated erythrocyte (R/E) area ratio were determined by a planimetric method in normals and in heterozygous beta-thalassaemia subjects. The MRV in beta-thalassaemia group was significantly less, whereas no difference in the R/E area ratio was observed. These data suggest that in both groups the extent of splenic surface remodeling of the red cells should overlap, whereas the small reticulocyte size of beta-thalassaemia is determined by some alteration of bone marrow function. We suggest that a small MRV in beta-thalassaemia trait could also account for ineffective erythropoiesis, a major bone marrow feature of heterozygous beta-thalassaemia.

The skull in homozygous beta-thalassemia (Cooley's anemia) may present with several abnormalities, such as osteopenia, widening of the diploic space, and a "hair on end" appearance. In some cases it presents also a particular stratified aspect owing to a variable number of osseous lamellae, arranged so as to be parallel to the inner table. This "lamellated skull" was observed in 16 patients, selected from 150 patients with Cooley's anemia (10.6%). The possible mechanisms are discussed. The pluristratified lamellar osseous production could be brought about by repeated periosteal osteoblastic reaction to the sinusoidal neovascularization associated with marrow hyperplasia in poorly or not at all transfused patients.

Solitary or multiple circumscribed osteolytic areas are described in seven patients, selected from 250 patients with homozygous beta-thalassaemia (Cooley's anaemia). On X-ray examinations, these areas appear as purely osteolytic lesions with well-defined margins not associated with sclerosis. The possible mechanisms are discussed.

Iron status (expressed as serum ferritin and iron levels) has been compared in normal and in heterozygous beta-thalassemic subjects. A higher serum ferritin concentration has been found in beta-thalassemic males, showing, therefore, a shift towards super-normal values of the balance between tissue iron and serum ferritin levels. In beta-thalassemic subjects the serum ferritin levels have been found in the normal range and this seems to be correlated with an adequate and ready iron supply by protein transferrin to hyperplastic bone marrow. The higher urinary iron values in normal male subjects can be explained in this way: a large iron supply from the transferrin to the thalassemic erythroid cells limits the contribution from this protein to the urinary iron.