Limb deformity and metaphyseal abnormalities in thalassaemia major

Regular bone survey radiographs have allowed identification of limb deformity and metaphyseal changes in several patients with thalassaemia major treated at the Adelaide Children's Hospital. Following the progression of limb deformity in five of these patients who were receiving human growth hormone therapy, the records of 25 thalassaemia patients were reviewed. Six patients had evidence of limb deformity, four of whom also had metaphyseal changes. Three additional patients had metaphyseal changes alone. Patients with either type of skeletal change shared similar characteristics, including younger age, earlier commencement of desferrioxamine therapy, better compliance and, in general, lower levels of ferritin. Females predominated in both groups. The frequency of sensorineural hearing loss was similar in affected and nonaffected groups and biochemical parameters, especially plasma calcium, phosphate, alkaline phosphatase, and zinc, which were normal in all patients. The cause of these skeletal changes is not clear; however, several potential factors need to be considered. Among these are focal marrow expansion in the metaphyseal region due to incomplete suppression of erythropoiesis and possible effects of desferrioxamine, including direct interference with bone growth, altered response of bone to inflammation or infection, and altered bone metabolism related to chelation of trace metals. While we can only speculate on aetiological factors, it is clear that human growth hormone therapy has resulted in exaggeration of deformity due to an increased rate of bone growth or decreased rate of mineralization of physeal cartilage. We believe that bone survey radiographs are useful in early identification of skeletal changes.(ABSTRACT TRUNCATED AT 250 WORDS)