Despite improved hematologic care, multiendocrine dysfunction is a common complication of homozygous transfusion-dependent beta-thalassemia. In this study our goal was to estimate the prevalence of thyroid dysfunction in a large homogenous group of thalassemic patients. Two hundred patients with beta-thalassemia major (100 males and 100 females; mean age, 23.2 +/- 6.7 years; age range 11-43 years), regularly transfused and desferioxamine chelated, were randomly selected from a pool of approximately 800 patients with beta-thalassemia followed in our department. Thyroid function and iron-load status were evaluated by measurements of free thyroxine (FT4), free triiodothyronine (FT3), thyrotropin (TSH), and serum ferritin levels. Of the subgroup of patients who proved to have normal thyroid hormone values, 26 (12 males, 14 females; mean age, 23.6 +/- 6.8 years; age range, 15-36 years) were randomly selected and underwent a standard TRH stimulation test. Thyroid dysfunction was defined as follows: overt hypothyroidism: low FT4 and/or FT3, increased TSH levels; subclinical hypothyroidism: normal FT4, FT3, increased TSH levels; exaggerated TSH response: normal FT4, FT3, normal basal TSH, deltaTSH > or = 21 microIU/mL (TSH levels measured prior and 30 minutes after intravenous TRH administration). Normal thyroid hormone values were found in 167 (83.5%) of the 200 patients studied. Eight (4%) of the remaining patients had overt hypothyroidisim, and 25 (12.5%) had subclinical hypothyroidism. Exaggerated TSH response to TRH was revealed in 7 of the 26 patients with normal hormone values tested (26.9%). Antithyroglobulin and anti-thyroid peroxidase (TPO) antibody titers were negative in 191 patients (95.5%). Mean ferritin levels in hypothyroid and euthyroid patients were 2707.66 +/- 1990.5 mg/L and 2902.9 +/- 1997.3 mg/L, respectively, (p = 0.61), indicating no correlation between ferritin levels and thyroid functional status. Mean ferritin levels in the patients who responded normally to TRH stimulation and in those who overresponded, were 2,586 +/- 1791 mg/L and 3,228 +/- 2473 mg/L, respectively (p = 0.46; NS). Thyroid failure is a rather rare endocrine complication in patients with beta-thalassemic from Greece. In our series, no case of central hypothyroidism was observed. No correlation was found between thyroid functional status and ferritin plasma levels. Approximately 1 of 5 beta-thalassemic patients with normal thyroid hormone values showed an exaggerated TSH response to TRH test. It is to be investigated how many of these patients will establish overt or subclinical hypothyroidism in the future.

Relief of symptoms can be achieved following surgery for growth hormone (GH)-secreting adenomas, as well as after pharmacological therapy with somatostatin analogs. Recently, long-acting somatostatin analog depot formulations, octreotide LAR and lanreotide SR have become available. Somatostatin analogs control GH/insulin-like growth factor (IGF)-1 excess, induce tumor shrinkage in a high proportion of patients, improve symptoms of acromegaly with relatively limited side effects and are successfully administered in patients not suitable for surgery. Furthermore, preoperative somatostatin analogs have been suggested to improve outcome for tumors with limited invasiveness, while surgical tumor debulking in cases that are, at least partially, somatostatin resistant, increases the achievement of normal IGF-1 levels by postoperative somatostatin analog treatment. Effective control of hypertension, as well as diabetes, is mandatory in order to reduce the increased vascular morbidity/mortality. Control of GH/IGF-1 excess generally improves glucose metabolism. Somatostatin analogs improve insulin sensitivity, exerting, however, a concomitant direct inhibitory effect on insulin secretion, with a net balance leaning towards a deterioration in glucose homeostasis. As a result, oral insulin secretagogues (and/or insulin) should probably be preferred to insulin sensitizers in acromegalic patients developing diabetes while on somatostatin analogs. Nevertheless, glucose tolerance remains normal in most of the nondiabetic acromegalic patients, while diabetic acromegalic patients on insulin are at risk for hypoglycemia during initiation of somatostatin analog therapy. Although successful management of acromegaly has been associated with improvement in morphological and functional parameters of cardiomyopathy, limited and conflicting information is available regarding the effect on blood pressure control. Contradictory results have also been reported regarding sleep hypopnea or apnea in treated acromegalic patients. As acromegalic skeletal abnormalities are rather irreversible, apneic episodes may persist after normalization of hormonal levels. Aggressive therapy, including surgery, pharmacological treatment and, in some cases, pituitary irradiation, aiming at normalization of IGF-1 levels, is required for arthropathy management. Some improvement in pain, crepitus and range of motion has been observed after treatment with somatostatin analogs. Information on the impact of disease control, either by surgery or somatostatin analog treatment, on gonadal function is limited. Finally, the link between the hormonal/biochemical and the psychiatric/psychological features of acromegaly, as well as a potential basis for positive effects of somatostatin analog therapy remain unclear.

GONADAL DYSFUNCTIONModern therapeutic approaches of β-thalassemia major-consisting of early and intensive blood transfusion protocols (in order to keep Hb level above 10 gr/dl) and regular iron chelation-have significantly increased the average lifespan and improved the quality of life of β-thalassemia (β-thal) patients. Consequently, issues such as normal sexual maturation, attainment of reproductive capacity, and creation of a family are now becoming of great importance for β-thal women.Multiple endocrine abnormalities develop during the course of β-thal major, attributable mainly to iron overload: growth retardation or failure, pubertal delay or failure, primary or secondary amenorrhea and infertility, diabetes mellitus, thyroid dysfunction, hypoparathyroidism, and metabolic bone disease. With the exception of growth retardation, hypothalamic-pituitary-gonadal (HPG) axis dysfunction represents the commonest disorder of the endocrine system.The etiology of the HPG axis altered functionality is multifactorial involving physical and psychological stress, concurrent infections, liver-spleen involvement, nutritional deviation, and damage of the gonadostat by chronic iron deposition. Studies of gonadotropin pulsatility (frequency and amplitude) reveals abnormalities even in cycling β-thal women. When, later on, secondary amenorrhea occurs, demonstration of a blunted gonadotropin response to single or multiple doses of GnRH stongly indicates pituitary gonadotrope failure. 1 Histological data are supportive of this notion. 2 The selective damage of gonadotrops among all pituitary cells is possibly explained by the expression of transferrin receptors in these cells. 3 Iron can also directly harm the ovaries, as is true for other endocrine targets, that is, thyroid and pancreas. The poor gonadal response to exogenous gonadotropin administration and the report of a pregnancy achieved with donor oocytes-after many unsuccessful IVF efforts-are consistent with the above. [4][5][6][7] The spectrum of clinical presentation of HPG axis dysfunction in β-thal patients includes pubertal failure or delay, failure of menstruation despite the spontaneous onset of puberty and development of secondary amenorrhea after a period of regular menstruation.a Address for correspondence: Phone and fax: 01-7786889. gtolis@atlas.uoa.gr

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