T[2] relaxation time of the pituitary gland in patients with beta-thalassemia and its relation to iron overload and somatic and sexual development

ABSTRACT

Chelation therapy with deferoxamine mesylate [has revolutionized management of transfusion-dependent beta-thalassaemia, but monitoring of tissue iron deposition, particularly in the endocrine glands, is still largely empirical. Clinical, haematological, and endocrinal evaluation of 54 transfusion-dependent beta-thalassaemic patients and 25 age- and sex-matched controls was done, pituitary T2 relaxation time was studied in them by Magentic Resonance Imaging [MRI] to evaluate pituitary iron overload. Thalassaemic patients had significantly lower mean stature, growth velocity, and a more delayed pubertal stage. Sixty per cent of thalassaemic females had amenorrhoea, either 1 ry or 2ry. Serum insulin-like growth factor 1 [IGF-1] and lutenizing hormone [LH] were significantly lower in thalassaemic patients compared with controls. Serum growth hormone [and follicule stimulating hormone [GH] were also lower, but the difference was not statistically significant. Pituitary T2 relaxation rate was significantly higher in patients compared with controls. Serum ferritin in thalassaemic patients showed a statistically significant positive correlation with pituitary T2 relaxation time, and a statistically significant negative correlation with serum IGF-1. It was concluded that monthly follow up of haemoglobin level and serum ferritin are vital to guide a satisfactory transfusion/chelation regimen in thalassaemic patients. However, once a deviation arises in physical/sexual development, measurement of GH, IGFI, FSH, and LH is warranted. Patients with clinical and/or laboratory evidence of pituitary dysfunction will benefit from an MRI study to assess pituitary iron deposition and provide a better guide for the intensity of chelation therapy