Endocrine Abstracts

Objective: Beta thalassemia is associated with a number of endocrinopathies. Iron overload is thought to be at the root of thalassemia-related endocrinopathies, including hypothyroidism; however, morphologic changes that could be attributable to iron deposition in the thyroid gland have been under investigated. This study aims to evaluate thyroid gland volumes and stiffness in thalassemia patients using shear-wave ultrasound elastography (SWE), and to analyze if there is any relationship between thyroid stiffness and thyroid functions.

Methods: A total of 43 thalassemia patients were examined. Three patients were excluded because thyroid volume measurements were missing, and five were excluded because they were on levothyroxine treatment. The final analysis included thirty-five patients (19 male, 16 female). Regarding the significant difference between left and right thyroid lobe volumes, SWE measurements were corrected according to ipsilateral thyroid volume (cSWE=SWE:ipsilateral thyroid volume).

Results: The median age at the time of study enrollment was 33 years (range: 19-46). Most patients had thalassemia major (29, 83%), whereas the remaining six had thalassemia intermedia. Twenty-six (74%) of the patients had at least one thalassemia-related endocrinopathy. All patients were euthyroid except the two with subclinical hypothyroidism, and all were negative for thyroid autoantibodies. None of the patients were receiving levothyroxine. The median serum TSH, fT4, and fT3 levels and serum ferritin values were presented in the Table. Mean volumes for the right and left thyroid lobes were 3.24±1.49 cm³ and 4.19±1.85 cm³, respectively. Mean SWE measurements in the right and left thyroid lobes were 10.25±4.51 kPa and 10.32±4.62 kPa, respectively. Thyroid volume was negatively associated with serum TSH (P = 0.03, r =-0.37 for left lobe, P = 0.017, , r =-0.40 for right lobe). cSWE was also negatively correlated with serum TSH (P = 0.03, r =0.37 for left lobe, P = 0.01, r =0.43 for right lobe). In addition, cSWE showed negative significant correlations with patients’ height (P = 0.006, r =-0.46 for left lobe, P = 0.002, r =-0.53 for right lobe), and positive correlations with age (P < 0.001, r =0.56 for left lobe, P = 0.01, r =0.44 for right lobe). No correlations were found between cSWE and ferritin, cardiac or hepatic magnetic resonance T2 star values.

Conclusions: SWE has been successful in making the differential diagnosis of thyroid nodules and diffuse thyroid diseases. To date, no studies have investigated thyroid gland stiffness and its relationship with thyroid function tests in thalassemia patients. Our findings indicate that thyroid gland volume decreases and thyroid stiffness increases in thalassemia patients as they age, in correlation with an increase in TSH.