Thyroid nodules: diagnosis and management.

Thyroid nodules are common. Their importance lies in the need to assess thyroid function, degree of and future risk of mass effect, and exclude thyroid cancer, which occurs in 7-15% of thyroid nodules. There are four key components to thyroid nodule assessment: clinical history and examination, serum thyroid stimulating hormone (TSH) measurement, ultrasound and, if indicated, fine-needle aspiration (FNA). If the serum TSH is suppressed, a thyroid scan with 99Tc can distinguish between a solitary hot nodule, a toxic multinodular goitre or, less commonly, thyroiditis or Graves' disease within a coexisting nodular thyroid. Scintigraphically cold nodules are evaluated in the same way as in the setting of normal or elevated serum TSH levels. Thyroid ultrasonography should be performed only for palpable goitre and thyroid nodules and by specialists with expertise in thyroid sonography. Routine thyroid cancer screening is not recommended, except in high risk individuals, as the detection of early thyroid cancer has not been shown to improve survival. FNA may be performed for nodules ≥ 1.0 cm depending on clinical and sonographic risk factors for thyroid cancer. FNA specimens should be read by an experienced cytopathologist and be reported according to the Bethesda Classification System. Molecular analysis of indeterminate FNA samples has potential to better discriminate benign from malignant nodules and thus guide management. Surgery is indicated for FNA findings of malignancy or indeterminate cytology when there is a high risk clinical context. Surgery may also be indicated for suspicion of malignancy; larger nodules, especially with symptoms of mass effect; and in some patients with thyrotoxicosis.

Utility of Adrenal Vein Sampling With and Without Ultra-Low Dose ACTH Infusion in the Diagnostic Evaluation of Primary Aldosteronism.

BACKGROUND: Adrenal vein sampling (AVS), integral to identifying surgically remediable unilateral primary aldosteronism (PA), is technically challenging and subject to fluctuations in cortisol and aldosterone secretion. Intra-procedural adrenocorticotropic hormone (ACTH), conventionally administered as a 250-µg bolus and/or 50 µg per hour infusion, increases cortisol and aldosterone secretion and can improve AVS success, but may cause discordant lateralisation compared to unstimulated AVS. AIMS: To assess if AVS performed with ultra-low dose ACTH infusion causes discordant lateralisation. METHODS: Here, we describe our preliminary experience using an ultra-low dose ACTH infusion AVS protocol. We retrospectively reviewed the results of consecutive AVS procedures (n = 37) performed with and without ultra-low dose ACTH (1-µg bolus followed by 1.25 µg per hour infusion). RESULTS: Bilateral AV cannulation was successful in 70% of procedures pre-ACTH and 89% post-ACTH (p < 0.01). Sixty-nine percent of studies lateralised pre-ACTH and 55% post-ACTH, improving to 79% when both groups were combined. Lateralisation was discordant in 11 cases, including eight in which lateralisation was present only on basal sampling, and three in which lateralisation occurred only with ACTH stimulation. DISCUSSION: Overall, the decrease in lateralisation rates with ACTH was higher than previously reported for some protocols utilising conventional doses of ACTH. Our results suggest that AVS performed with ultra-low dose ACTH can cause discordant lateralisation similar to AVS performed with conventional doses of ACTH. CONCLUSION: Prospective studies directly comparing low and conventional dose ACTH AVS protocols and long-term patient outcomes are needed to help define the optimal ACTH dose for accurate PA subtyping.

Utility of semi-quantitative quick cortisol assay with low-dose adrenocorticotropic hormone infusion adrenal vein sampling.

BACKGROUND: Adrenal vein sampling (AVS) is integral to identifying surgically remediable unilateral primary aldosteronism (PA). However, right adrenal vein (AV) cannulation can be challenging, limiting its success. Intra-procedural cortisol assays can improve the reliability of AVS. The aim of this study was to validate the use of semi-quantitative cortisol estimates obtained utilizing a quick cortisol assay (QCA) during AVS procedures at our institution. METHODS: Retrospective review of results of AVS procedures before and after the introduction of the QCA. Twenty-three AVS procedures were performed with the provisional success determined by intra-procedural QCA. Successful AV cannulation was defined by an AV to peripheral vein cortisol ratio ≥ 4.0 (the selectivity index) from laboratory measurements. The control cohort consisted of 23 consecutive procedures prior to introduction of the QCA. RESULTS: QCA correctly predicted all AV cannulation attempts. Successful bilateral AV cannulation increased from 52% to 91% of procedures when performed with the QCA (P = 0.01) and adequate cannulation of the right AV increased from 61% to 91% (P = 0.03). There was no increase in procedural time, number of AV cannulation or sampling attempts. CONCLUSIONS: Point-of-care, semi-quantitative cortisol estimates can be performed accurately during AVS with QCA, facilitating improvements in AVS success rates without increasing procedural time.

Selective intra-arterial calcium stimulation test for the localization of insulinomas: an Australian hospital experience.

BACKGROUND: Insulinomas are rare tumours of the pancreas and the most common cause of hypoglycaemia in non-diabetic adults. They can be cured by surgery but require precise localization. The aim of this study was to assess the utility of the selective intra-arterial calcium stimulation test (SIACST) in patients with an insulinoma to correctly localize the tumour. METHODS: Medical records of patients with a diagnosis of insulinoma or who underwent an SIACST were retrospectively reviewed. Localization of lesions by SIACST was compared to endoscopic ultrasound and radionuclide imaging studies and verified against findings at surgery. RESULTS: A total of 24 patients (mean age 58 years, 16 females, 20 with insulinoma) underwent SIACST. The SIACST correctly localized the insulinoma in 17 of 20 patients (85%). Localization rate for computed tomography was 55% and 75% for endoscopic ultrasound and glucagon-like peptide-1 receptor scan. CONCLUSION: SIACST provided incremental diagnostic information in patients with insulinoma who had equivocal non-invasive imaging preoperatively. This technique remains an essential diagnostic tool when a lesion is not localized by other methods.

Outcomes for minimally invasive parathyroidectomy: widening inclusion criteria based on preoperative imaging results.

BACKGROUND: Primary hyperparathyroidism is caused by a single adenoma in at least 80% of cases. Minimally invasive parathyroidectomy (MIP) has overtaken bilateral neck exploration as the gold standard for treatment in cases with adequate preoperative localization. There is evidence that, following careful review of preoperative imaging by the surgeon, increasing numbers of patients can successfully undergo MIP. METHODS: We conducted a retrospective review of 225 consecutive cases performed by a single surgeon. Outcomes for patients with disease reported as localized by radiologists and nuclear medicine physicians using sestamibi and ultrasound were compared with patients with negative or indeterminate localization studies, in which the surgeon reviewed the sestamibi, performed an ultrasound study and identified likely single adenomas and planned MIP. RESULTS: One hundred and sixty patients with radiologist-localized disease and an additional 29 patients with surgeon-localized disease underwent MIP. The surgeon-localized group had higher rates of conversion to bilateral neck exploration (21% compared with 4%, P = 0.004), but rates of failure to cure were comparable between the two groups (4.3% compared with 2.8%). CONCLUSION: Careful review of preoperative sestamibi and ultrasound studies by an experienced surgeon can increase the number of patients that can successfully undergo MIP for the treatment of primary hyperparathyroidism. Offering MIP to these patients does not result in increased rates of failure or recurrence.

Fine needle aspiration and intraparathyroid intact parathyroid hormone measurement for reoperative parathyroid surgery.

Some authors have praised the value of fine needle aspiration (FNA) with measurement of intraparathyroid intact parathyroid hormone (iPTH) for localization of the hypersecreting gland(s) in recurrent or persistent primary hyperparathyroidism (HPT). The aim of the present study was to determinate whether FNA for iPTH assay is an effective procedure to distinguish between normal and hypersecreting parathyroid glands. We performed a prospective study of 170 patients who underwent cervicotomy. They were divided into three groups: group A, 50 patients with thyroid diseases; group B, 100 patients with primary HPT; group C, 20 patients with secondary HPT. We performed intraoperative FNA for iPTH measurement from the thyroid, and from the normal and enlarged parathyroid glands, and we compared the different intraglandular iPTH assays. In group A, the intraparathyroid iPTH level was < 1000 pg/ml in 68% of the patients. In group B, in the pathological parathyroid gland iPTH was > 1000 in 88%; conversely, in the normal adjacent parathyroid glands it was < 1000 in 79%. In group C, intraparathyroid iPTH of enlarged glands was > 1000 in 80%. Intrathyroid iPTH was < 100 pg/ml in 96% for the three groups. We conclude that FNA for intraglandular iPTH measurement is an effective tool for distinguishing between normal and pathological parathyroid glands in the setting of primary HPT (p < 0.05), and between thyroid and parathyroid glands in groups A and B. But the procedure should be carried out in conjunction with the sestamibi scan and ultrasonography before surgical reintervention.