Significance of Size of Lymph Node Metastasis on Postsurgical Stimulated Thyroglobulin Levels After Prophylactic Unilateral Central Neck Dissection in Papillary Thyroid Carcinoma

Background

The prognostic significance of size of central lymph node metastasis (CLNM) in papillary thyroid carcinoma (PTC) remains unknown. Because postsurgical detectable stimulated thyroglobulin (DsTg) after radioiodine ablation may imply persistent or recurrent disease, we evaluated the association between size of CLNM and rate of DsTg in patients with PTC who underwent unilateral prophylactic central neck dissection.

Methods

To be eligible for analysis, the prophylactic central neck dissection specimen with <3 central lymph nodes (CLNs) or size of CLNM ??1?cm as measured under the microscope was excluded. Of 132 specimens, 89 (67.4?%) were eligible. Forty patients (44.9?%) had no metastasis or pN0, 20 (22.5?%) had micrometastasis (<2?mm) or pN1mic and 29 (32.6?%) had macrometastasis (??2?mm) or pN1mac. Postablation sTg level was measured 9?months after surgery. A multivariable analysis was conducted to identify independent factors for postablation DsTg.

Results

Larger-sized CLNM correlated significantly with younger age (p?=?0.028), greater number of CLN retrieved (p?=?0.016), greater number of metastatic CLN excised (p?p?=?0.006) and postablation sTg level (p?=?0.012). In the multivariable analysis, after adjusting for tumor size and metastatic CLN ratio, size of CLNM was an independent predictor of postablation DsTg (odds ratio 1.56, 95?% confidence interval 1.09?C2.24, p?=?0.015). Relative to pN0, the odds ratios for postablation DsTg in pN1mic and pN1mac were 2.53 (95?% confidence interval 0.35?C19.00, p?=?0.351) and 5.81 (95?% confidence interval 1.22?C27.70, p?=?0.027), respectively.

Conclusions

Size of CLNM was an independent factor for DsTg 9?months after surgery. Patients with pN1mac were almost 6 times more likely to have postablation DsTg than those with pN0 or pN1mic.     

The use of aldosterone-renin ratio as a diagnostic test for primary hyperaldosteronism and its test characteristics under different conditions of blood sampling

Recent reviews recommended the use of the aldosterone/renin ratio (ARR) to screen for primary hyperaldosteronism. However, widely different cutoff levels have been proposed, and test characteristics of ARR under different conditions of sampling are not known. We conducted a retrospective review among 45 subjects with carefully validated diagnoses of primary hyperaldosteronism and 17 subjects with essential hypertension to study the utility of ARR. Sixty-two patients with 75 sets of plasma renin activity (PRA), aldosterone, and ARR values from a postural study and 48 sets of values from a saline suppression test were analyzed. Ninety-four percent of these subjects underwent investigations because of hypokalemic hypertension.ARR yielded larger areas under the curve in the receiver-operating-characteristics curve than PRA or aldosterone under all conditions of testing. Our results confirmed the superiority of ARR to either aldosterone or PRA alone as a diagnostic test for primary hyperaldosteronism.ARR cutoff levels were significantly affected by the condition of testing. Depending on posture and time of day, it varied from 13.1-35.0 ng/dl per ng/ml.h in our study population. When using ARR for screening primary hyperaldosteronism, posture and time of sampling should be standardized both within and between centers to minimize variability in cutoff levels.     

A review of oral food challenges in children presenting to a single tertiary centre with perceived or true food allergies

INTRODUCTION

The prevalence of perceived food allergies exceeds that of true food allergies. Unnecessary food avoidance may increase parental and patient anxiety, reduce quality of life and increase the risk of nutritional deficiency. An oral food challenge (OFC) can provide an objective measure regarding the presence or absence of food allergies in a child. This study reviews the indications for and outcomes of OFCs performed on children.

METHODS

A retrospective review was performed on all children who underwent OFCs at the Allergy Unit of the National University Hospital, Singapore, over a three-year period.

RESULTS

A total of 197 OFCs were performed among 58 patients (34 male, 24 female). Most of the tests were for allergies to tree nuts (n = 107). Among the OFCs, 43.1% were for foods that were avoided and never eaten due to perceived food allergies, 25.9% were for foods that had previously resulted in positive skin prick tests (SPTs) and/or immunoassay results, 16.2% were for foods thought to worsen eczema and 14.7% were for foods thought to have caused a previous reaction. Of all the OFCs, 5% were positive, although adverse reactions were mostly cutaneous. Challenge-positive patients had either positive SPTs (wheal > 3 mm) or raised serum immunoglobulin E levels to specific foods that they reacted to during the challenges. No episodes of anaphylaxis were reported after the challenge. Most of the patients were able to safely introduce the avoided foods into their diets.

CONCLUSION

OFCs provide an objective assessment for suspected food allergies.