Gastric bypass surgery in morbid obesity: Influence on thyroid function tests and insulin resistance status.

Background: There are inconsistent results about the effect of gastric bypass surgery on thyroid function tests in morbidly obese subjects. The aim of this study was to investigate the changes in thyroid function tests and insulin resistance status in euthyroid morbidly obese subjects before and three months after gastric bypass surgery (GBS). Methods: Twenty-nine subjects with morbid obesity (BMI≥40) were enrolled in this before-after study. Patients with known thyroid disorders or a history of thyroid ablative therapy, users of drugs that affect thyroid function, or fasting blood sugar and insulin were excluded. TSH, Free T4, total T3, fasting blood sugar and insulin level, and BMI were measured before and 3 months after GBS. Statistical analysis was performed with appropriate tests and p<0.05 was considered significant. Results: Body mass index (BMI), insulin sensitivity index (HOMA-IR), and total T3 significantly decreased after bypass surgery (all with p<0.001) but no significant changes were seen in TSH (P=0.203) and FreeT4 (P=0.33). There was a significant negative correlation between changes in HOMA-IR and changes in FreeT4 (P=0.038, r= -0.38). There was no statistically significant correlation between the percentage of excess BMI loss (%EBMIL) and changes in T3 (P=0.66), Free T4 (P=0.92), TSH (P= 0.27), and HOMA-IR (P=0.17). Conclusion: Although significant changes can occur in BMI, insulin sensitivity index, fasting blood sugar, and T3 in short-time follow-up after bariatric surgery, significant TSH and FreeT4 changes may need longer follow-ups.

Preoperative Vitamin.D Status and Post-Total Thyroidectomy Hypocalcemia.

Introduction: Hypocalcemia is a common complication of total thyroidectomy (TT). This study was designed to investigate the effect of preoperative vitamin.D (Vit.D) status on the occurrence of post-total thyroidectomy hypocalcemia. Materials and Methods: Patients who underwent TT without parathyroidectomy were divided into three groups based on their preoperative Serum Vit.D levels (<20 ng/ml, 20-30 ng/ml, and ≥30 ng/ml were considered deficient, insufficient, and normal Vit.D levels, respectively). Serum levels of calcium and phosphorus were measured before and 24 hours after surgery in all patients. The patients were examined for clinical symptoms and signs of hypocalcemia postoperatively. In cases with positive clinical symptoms and signs of hypocalcemia and/or calcium levels <8 mg/dl, PTH level was measured before starting calcium infusion, while serum calcium and phosphorus levels were also measured 24 hours later. Results: Among 100 patients enrolled in this study, 81% were females. The mean age was 36.60±8.32 years. Before surgery, the mean Vit.D level was 26.9±16.89 ng/ml, while 47% of cases had normal Vit.D level, 32% had insufficient vitamin levels, and 21% had Vit.D deficiency. Twenty-four hours after surgery, the calcium (P=0.356) and phosphorus (P=0.743) levels were not significantly different between the three Vit.D groups. A comparison of postoperative PTH levels between the three Vit.D groups showed no significant difference (P=0.596). Conclusions: Based on our findings, preoperative serum Vit.D levels did not affect postoperative serum calcium levels.

Feasibility and safety of minimally invasive radioguided parathyroidectomy using very low intraoperative dose of Tc-99m MIBI.

BACKGROUND: Surgical resection of the abnormal parathyroid glands is the only curative treatment for primary hyperparathyroidism (PHPT). Radioguided parathyroidectomy with technetium-99m (TC-99m) sestamibi has been successfully used in patients with PHPT. This study was designed to evaluate the results of a series of patients with PHPT who underwent minimally invasive radioguided parathyroidectomy (MIRP) using very low dose (1 mCi) of TC-99m sestamibi (MIBI) without application of intraoperative parathyroid hormone (PTH) assay or frozen section analysis. METHODS: Eighty-seven patients with PHPT were prospectively studied from November 2012 to January 2015. Following neck ultrasound (US) and MIBI scan concordant for single gland disease, patients underwent MIRP using a handheld gamma probe. The technique involved injecting of 1 mCi MIBI in the operative room before the beginning of the intervention. All patients were followed up for a minimum of 6 months postoperatively. RESULTS: MIRP was successfully performed in 86 out of 87 patients (98.85%). The Gamma probe was particularly useful in detection of ectopic parathyroid adenomas in upper mediastinum. Mean operative time was 23.95 ± 7.982 min and mean hospital stay was 1.44 ± 0.604 days. No major surgical complications were recorded. CONCLUSIONS: The MIRP technique using very low dose (1 mCi) of Tc-99m MIBI without intraoperative PTH assay and frozen section analysis resulted in excellent cure rate for PHPT. This technique involves a radiation exposure to patients and surgical staffs 20 times lower than conventional MIRP using 20 mCi Tc-99m MIBI. Besides, patients with PHPT due to ectopic parathyroid adenoma may especially benefit from MIRP.

Vascular pattern and spectral parameters of power Doppler ultrasound as predictors of malignancy risk in thyroid nodules.

INTRODUCTION: Determination whether spectral Doppler ultrasound parameters, including resistance index (RI) and pulsatility index (PI), or vascular pattern can be used to distinguish malignant from benign thyroid nodules. MATERIALS AND METHODS: We prospectively examined 85 thyroid nodules in patients undergoing surgery. The flow pattern seen via power Doppler examination was ranked for each nodule on a scale of 0 to 4 as follows: absent, perinodular alone, mixed with perinodular prominency, mixed with intranodular prominency, and exclusively intranodular, respectively. For each nodule, the RI and PI values were recorded as the average of the recordings obtained. Pathological examination were used as a proof of final diagnosis to categorize all nodules as benign or malignant. RESULTS: The malignant nodules had a mean RI of 0.72 +/- 0.13. These values were significantly higher than those associated with benign nodules (0.60 +/- 0.08) (P = .000). Malignant nodules had a mean PI of 1.15 +/- 0.33 that were also significantly different from those associated with benign nodules (0.91 +/- 0.19) (P = .000). Shifting to intranodular vascularization had a significant correlation with malignancy (P = .001). CONCLUSION: Spectral parameter and vascular pattern are useful to distinguish malignant from benign thyroid nodules, especially for those with suspicious or undetermined fine-needle aspiration biopsy.