Semra Ayturk

Metabolic syndrome and its components are associated with increased thyroid volume and nodule prevalence in a mild-to-moderate iodine-deficient area

OBJECTIVE Metabolic syndrome (MetS) is a cluster of metabolic abnormalities with insulin resistance (IR) as a major component. It has been recently questioned whether MetS and its related components are associated with functional and morphological alterations of the thyroid gland. The aim of our study is to examine thyroid volume and nodule prevalence in a case-control study of patients with MetS in a mild-to-moderate iodine-deficient area. DESIGN Two hundred and seventy-eight patients with MetS were randomly matched for age, gender, and smoking habits with 261 subjects without MetS. Serum TSH, free tri-iodothyronine and thyroxine, and the level of IR, which was estimated by the homeostasis model assessment for IR, as well as other MetS parameters were evaluated. Thyroid ultrasonography was performed in all subjects. All subjects with thyroid nodules >1 cm were offered to undergo thyroid fine needle aspiration biopsy. RESULTS TSH was significantly positively correlated with the presence of MetS diagnosis. There was no association between free thyroid hormone levels and MetS and its related components. Mean thyroid volume was significantly higher in patients with MetS than in controls (17.5 + or - 5.5 vs 12.2 + or - 4.2 ml, P<0.0001). Also the percentage of patients with thyroid nodules was significantly higher in patients with MetS (50.4 vs 14.6%, P<0.0001). Subjects were also divided into two groups according to the presence of IR. The group of subjects with IR had increased thyroid volume and nodule formation. The odds ratio for the development of thyroid nodule in the presence of IR was 3.2. TSH as well as all MetS components were found to be independent predictors for thyroid volume increase. IR but not TSH was found to be correlated with thyroid nodule formation. Thyroid cancer was diagnosed in 3 out of 38 patients with MetS who agreed to have a biopsy (7.9%). None of the subjects in the control group was diagnosed to have thyroid cancer. CONCLUSIONS The results suggest that patients with MetS have significantly increased thyroid volume and nodule prevalence. Multivariate regression analysis model demonstrated that the presence of IR contributed substantially to this increased risk. Our data provide the first evidence that IR is an independent risk factor for nodule formation in an iodine-deficient environment.

Impaired glucose metabolism is a risk factor for increased thyroid volume and nodule prevalence in a mild-to-moderate iodine deficient area

OBJECTIVE Insulin resistance (IR) is a key factor involved in the pathogenesis of impaired glucose metabolism. IR is associated with increased thyroid volume and nodule prevalence in patients with metabolic syndrome. Data on the association of thyroid morphology and abnormal glucose metabolism are limited. This prospective study was carried out to evaluate thyroid volume and nodule prevalence in patients with pre-diabetes and type 2 diabetes mellitus (DM) in a mild-to-moderate iodine deficient area. MATERIALS AND METHODS Data were gathered on all newly diagnosed patients with pre-diabetes and type 2 diabetes mellitus between May 2008 and February 2010. 156 patients with pre-diabetes and 123 patients with type 2 DM were randomly matched for age, gender, and smoking habits with 114 subjects with normal glucose metabolism. Serum thyroid-stimulating hormone (TSH) and thyroid ultrasonography was performed in all participants. RESULTS Mean TSH level in the diabetes group (1.9±0.9 mIU/L) was higher than in the control group (1.4±0.8 mIU/L) and the pre-diabetes group (1.5±0.8 mIU/L) (P<0.0001 for both). Mean thyroid volume was higher in the pre-diabetes (18.2±9.2mL) and diabetes (20.0±8.2mL) groups than in controls (11.4±3.8mL) (P<0.0001 for both). Percentage of patients with thyroid nodules was also higher in the pre-diabetes (51.3%) and diabetes groups (61.8%) than in controls (23.7%) (P<0.0001 for both). CONCLUSIONS The results suggest that patients with impaired glucose metabolism have significantly increased thyroid volume and nodule prevalence.

Evaluation of brain natriuretic peptide levels in hyperthyroidism and hypothyroidism.

BACKGROUND Brain natriuretic peptide (BNP) is secreted from the ventricular myocardium in response to volume expansion and pressure overload. Serum BNP levels are also affected by thyroid function status, which was mostly related to a direct stimulatory effect of thyroid hormones on the secretion of BNP. Although the diagnostic value of BNP in heart failure is undisputed, its value in the presence of the thyroid dysfunction has been recently questioned. The aim of this study was to evaluate the influence of thyroid dysfunction on BNP levels. METHODS Evaluation of 18 overt and 47 subclinical hyperthyroid patients together with 39 subclinical and 13 overt hypothyroid patients was carried out in a cross-sectional study. Thirty-three age-, sex- and body mass index (BMI)-matched control subjects were also included. RESULTS BNP levels were more than five times higher in hyperthyroid than euthyroid control subjects (P < 0.001). BNP levels were also higher in subclinical hyperthyroidism than euthyroid control subjects (P = 0.09). Correlation analysis revealed that free T4 and free T3 concentrations were associated with high serum BNP levels. The BNP level in patients with subclinical or overt hypothyroidism was similar to that of the controls. CONCLUSION The current study provides additional insight into the diagnostic value of BNP in the presence of coexistent thyroid dysfunction and demonstrates important independent effects of thyroid hormones upon BNP plasma concentrations.

Serum Adiponectin Level as a Predictor of Subclinical Cushing’s Syndrome in Patients with Adrenal Incidentaloma

Subclinical Cushings syndrome (SCS) is a condition of slight but chronic cortisol excess in patients with adrenal incidentaloma (AI) without typical signs and symptoms of Cushings syndrome. Adiponectin has potent roles in modulating energy balance and metabolic homeostasis and acts in opposition to glucocorticoids. This study aimed to evaluate adiponectin level in SCS and nonfunctional AI (NAI) patients and its relation with metabolic parameters. Patients with AI (n = 40) and metabolically healthy controls (n = 30) were included. In AI patients and controls, detailed medical history assessment, physical examinations, anthropometric measurements, and laboratory measurements were performed. Age, body mass index, waist circumference, and lipid profiles were significantly higher and waist-to-hip ratio and adiponectin level were significantly lower in the AI patients than in the controls. The midnight cortisol and urinary free cortisol levels were significantly higher in the SCS patients (n = 8) than in the NAI patients (n = 32). Adiponectin level of the SCS group was significantly lower than those of the NAI and control groups. The sensitivity and specificity for an adiponectin level of ≤13.00 ng/mL in predicting the presence of SCS were 87.5% and 77.4%, respectively. In conclusion, adiponectin is valuable in predicting the presence of SCS in AI patients.

Unresectable huge sternal and mediastinal metastasis of follicular thyroid carcinoma; radiotherapy as first-line and palliative therapy.

Distant metastases as initial manifestation of follicular thyroid carcinoma is rare. We report a case of an unusual initial presentation of follicular thyroid carcinoma on follow-up. A 52- year-old woman presented with a 12-month history of progressively enlarging mass in the anterior chest wall. The mass was fixed to the chest wall, measuring 12 x 10 cm in diameter. Computed tomography demonstrated a lobulated soft-tissue mass (17 x 11 x 6 cm) destructing sternum and extending into the anterior mediastinum. There was no lung metastasis. Invasion of tumor to the ascending aorta, superior vena cava, and right atrium could not be excluded. Multiple lymph nodes were observed in the supraclavicular regions. Ultrasonography of the thyroid gland showed 46 x 37 mm nodule in the left lobe with milimetric gross calcifications and cystic-necrotic areas. Hyperthyroidism was detected. Biopsy from this nodule and the sternal mass revealed typical histology of follicular carcinoma. She was considered inoperable. Since there was huge tumor burden and iodinated contrast exposure for several times during evaluation, we decided to treat the patient with external beam radiotherapy (EBRT) rather than radioiodine as first-line therapy. After a course of conventional radiation with 50 Gy in 25 fractions over 4 weeks, encompassing the thyroid bed and the gross disease, tumor regressed remarkably in 6 months. In conclusion, when surgical resection is not possible, EBRT may be used for palliative purpose to obtain local control for extensive disease as first-line therapy. The indications of EBRT for differentiated thyroid cancer still remain poorly defined.

Effects of raloxifene on platelet functions in patients with postmenopausal osteoporosis

Many studies have addressed the effects of estrogenic compounds on platelet function. Raloxifene is a selective estrogen receptor modulator (SERM), which is currently used for the treatment of postmenopausal osteoporosis. At present, there are no clinical data about the effects of raloxifene on platelet function. The purpose of this study was to determine if raloxifene at therapeutic doses affects platelet function in patients with postmenopausal osteoporosis. The effects of raloxifene on platelet function were investigated using a commercial platelet function analyzer (PFA-100) with collagen epinephrine and collagen adenosine 5′-diphosphate (ADP) cartridges. We studied platelet function of 30 patients with postmenopausal osteoporosis before and 15 days after initiation of raloxifene 60 mg/daily. Closure times did not differ significantly between samples obtained before (117.8 ± 20.5 s) and after raloxifene therapy (106.5 ± 25.4 s) in collagen/epinephrine cartridges (P > 0.05). There was also no statistically significant difference in mean closure times with collagen/ADP cartridges at baseline (86.2 ± 18.5 s) and after raloxifene therapy (84.4 ± 13.8 s) (P > 0.05). Platelet counts (278.3 ± 72.9 vs. 262.4 ± 56.7 109/L, P > 0.05) and mean platelet volumes (8.9 ± 1 vs. 9.1 ± 1 fL, P > 0.05) were not different before and after raloxifene therapy. Although estrogen related compounds do affect platelet function, there is suggestive data in our study that raloxifene in therapeutic dose exhibit no effect on platelet function in patients with postmenopausal osteoporosis.