Analysis of related factors of transient hypothyroidism in premature infants

Aim: In this paper, the related factors of transient hypothyroidism in premature infants were discussed, the incidence of THOP was observed, and the risk factors were analyzed to guide future work. Methods: From January 2017 to January 2018, 117 premature infants admitted to neonatology Department of the First Affiliated Hospital of Bengbu Medical College were selected and diagnosed with THOP in 48 cases, including 31 males and 17 females.< 1 500 g 17 cases, 1 500 ~ 2 500 g 70 cases, > 2 500 g 30 cases; Gestational age ≤32 weeks 30 cases, 33 ~ 34 weeks 37 cases, 35 ~ 36 weeks 50 cases. Results: The incidence of THOP in different gestational age groups was statistically significant (P < 0.05).The incidence of THOP in different weight groups was statistically significant(P < 0.05).The differences of asphyxia, RDS and gestational hypertension in premature infants were statistically significant (P < 0.05), while the differences of intracranial hemorrhage, polycythemia, sepsis and hypoglycemia were not statistically significant (P > 0.05). Conclusion: Gestational age ≤32 weeks and gestational hypertension were independent risk factors for THOP. Key words: transient hypothyroidism; correlative factors; premature infants

Long-Term Course of Hypothyroidism Detected through Neonatal TSH Screening in a Population-Based Cohort of Very Preterm Infants Born at Less than 32 Weeks of Gestation

After several decades of successful newborn screening (NBS) for congenital hypothyroidism, the optimal hypothyroidism NBS algorithm for very preterm infants is still controversial. Due to concerns about an elevated risk of a false-negative initial thyroid-stimulation hormone (TSH) screening, repeat NBS has been implemented for this group. While transient hypothyroidism is known to be more frequent among very preterm infants, the prevalence of permanent hypothyroidism is generally assumed to be the same as in more mature newborns. This study analyses screening and long-term follow-up data from the population-based cohort of 51 infants born from 1999–2017 at less than 32 weeks of gestation and diagnosed with hypothyroidism after NBS in the German Federal State of Bavaria (total number of infants screened 2,107,864). Severe permanent hypothyroidism was always detected at initial TSH screening unless there was a known confounding factor. Cases detected by repeat screening after a negative initial screen most frequently proved to be transient, less frequently mild permanent, or a definitive diagnosis was not possible because of inadequate re-evaluation of the thyroid axis. The prevalence of both permanent and transient hypothyroidism was elevated compared to a cohort of children from the same region born at a higher gestational age. The results seem to support the need for the repeated NBS of very preterm infants. However, as the recommendation to treat mild hypothyroidism is not based on high quality evidence, important issues for future research include treatment outcome studies or even a general review of whether this diagnosis meets the screening criteria. Meanwhile, involving a paediatric endocrinologist in treatment decisions is crucial for optimising the benefit of hypothyroidism screening for this particularly vulnerable group.

Assessment of Inter-Institutional Post-Operative Hypoparathyroidism Status Using A Common Data Model

Post-thyroidectomy hypoparathyroidism may result in various transient or permanent symptoms, ranging from tingling sensation to severe breathing difficulties. Its incidence varies among surgeons and institutions, making it difficult to determine its actual incidence and associated factors. This study attempted to estimate the incidence of post-operative hypoparathyroidism in patients at two tertiary institutions that share a common data model, the Observational Health Data Sciences and Informatics. Of the 4848 eligible patients at the two institutions who underwent thyroidectomy, 1370 (28.26%) experienced transient hypoparathyroidism and 251 (5.18%) experienced persistent hypoparathyroidism. Univariate logistic regression analysis predicted that, relative to total bilateral thyroidectomy, radical tumor resection was associated with a 48% greater likelihood of transient hypothyroidism and a 102% greater likelihood of persistent hypothyroidism. Moreover, multivariate logistic analysis found that radical tumor resection was associated with a 50% greater likelihood of transient hypothyroidism and a 97% greater likelihood of persistent hypothyroidism than total bilateral thyroidectomy. In addition to estimating the incidence of and risk factors for post-operative hypoparathyroidism at two institutions, these findings, by integrating and analyzing two databases, suggest that this analysis could be expanded to include other large databases that share the same Observational Health Data Sciences and Informatics protocol.

MON-082 The Neonatal Screen That Cried Wolff

Introduction: Hypothyroidism is one of the major causes of preventable mental retardation. Neonatal screening aids in the prompt diagnosis of newborns with congenital hypothyroidism. There are other clinical conditions that can alter thyroid function during the newborn period, including exposure of high iodine concentrations. Case Presentation: One day old female born at 37 3/7 weeks of gestational age by C-section with imperforated anus and congenital heart disease was transferred to our children’s hospital within the first day of life for a hybrid cardiac procedure of bilateral pulmonary artery banding and PDA stenting. She had an Illinois Neonatal screen done at 36 hours of life that was normal. Her cardiac surgery was performed at 10 days of life, where she was exposed to iodine products transdermally. At 14 days of age, she had a repeat Illinois Neonatal screen that was positive for congenital hypothyroidism with a TSH of 78 mIu/mL (normal &lt; 20 mIu/mL) and reflex total T4 of 5.4ug/dL (normal is &gt; 8ug/dL). No family history of thyroid disease; mother was healthy during pregnancy and was not on medications that could affect baby’s thyroid function. Subsequent serum laboratory testing confirmed a TSH of 74.3mIu/mL and Free T4 of 0.6ng/dL. Patient was diagnosed with Wolff-Chaikoff effect, which is the phenomenon of transient hypothyroidism caused by exposure to high doses of iodine (iodine containing contrast agents or topical antiseptics). Pediatric Endocrinology was consulted at 2 weeks of life and she was started on 25mcg of levothyroxine PO daily. Levothyroxine dose decreased at 16 month of age to 12.5mcg due to stable thyroid function tests. The patient was last seen at 30 months of age by Pediatric Endocrinology. She is still on the low dose of levothyroxine and her thyroid labs have been within normal limits for an infant. She will likely not require lifelong thyroid supplementation. Conclusion: Risk of hypothyroidism among neonates must be considered seriously after large iodine exposure and monitoring for transient hypothyroidism should be performed. It is thus recommended that attempts should be made to reduce the amount of iodine used during procedures and to carefully monitor thyroid function in all neonates exposed to an excess of iodine. Reference: Markou, K., et al. “Iodine-Induced Hypothyroidism.” Thyroid, vol. 11, no. 5, 2001, pp. 501–510., doi:10.1089/105072501300176462. Linder N, Sela B, German B, et al. Iodine and hypothyroidism in neonates with congenital heart disease. Archives of Disease in Childhood - Fetal and Neonatal Edition 1997;77:F239-F240. Kovacikova, Lubica, et al. “Thyroid Function and Ioduria in Infants after Cardiac Surgery: Comparison of Patients with Primary and Delayed Sternal Closure.” Pediatric Critical Care Medicine, vol. 6, no. 2, 1 Mar. 2005, pp. 154–159., doi:10.1097/01.pcc.0000154960.59452.06.

Etiological Evaluation of Congenital Hypothyroidism Cases

INTRODUCTION: The aim of this study was to determine, (i) the cause of congenital hypothyroidism (permanent or transient), (ii) the etiological cause of persistent congenital hypothyroidism and (iii) to investigate the role of clinical and laboratory data in predicting persistent and transient congenital hypothyroidism. METHODS: Patients with congenital hypothyroidism who were started L-thyroxine treatment and discontinued at the age of 3 years were included in the study. The data of the cases were obtained retrospectively from the hospital records. Serum thyroid hormones were measured of the cases 4 weeks after discontinuation of treatment at the age of 3 years. Patients with TSH> 10 mIU/mL were accepted as permanent hypothyroidism and those with normal TSH value for 6 months were accepted as transient hypothyroidism. RESULTS: A total of 63 patients were included in the study. Permanent congenital hypothyroidism was detected in 16 (25%: 9 females, and 7 males) and transient congenital hypothyroidism in 47 (75%: 22 females, and 25 males) cases. There was no difference between the permanent and transient groups in terms of gender, gestational week, birth weight, age at diagnosis, physical examination findings at the time of diagnosis, serum fT4, TSH levels, and initial L-thyroxine doses. While thyroid ultrasonography was normal in all patients in the transient hypothyroidism group, dysgenesis was detected in 9 (56%), and dyshormonogenesis in 1 (6%) patient. The mean thyroxin dose in permanent congenital hypothyroidism group was significantly higher than the transient group at the time of treatment cessation (2.8±0.9 and 1.2±0.5 mcg/kg/day, p<0.001, respectively). L-thyroxin dose of >2.1 mcg/kg/d was 81% sensitive and 90% specific for predicting permanent congenital hypothyroidism (p<0.001). DISCUSSION AND CONCLUSION: It has been shown that the most common etiologic cause of congenital hypothyroidism is transient hypothyroidism. Thyroxine dose at the time of treatment cessation was found to be the most important determinant in the differentiation of permanent and transient congenital hypothyroidism.

Transient neonatal hypothyroidism secondary to postnatal maternal exposure to contrast medium

We report a preterm breastfed infant who developed a transient hypothyroidism after his lactating mother had a CT scan with iodinated contrast medium, despite the advised 24 hours’ pause in breast feeding. The aetiological assessment did not show any other cause for this hypothyroidism. Transient neonatal hypothyroidism after the use of topical iodine is well known, but it has not been described as a complication of intravenous contrast medium administration to a lactating mother. This case highlights the possibility of transient neonatal hypothyroidism secondary to contrast medium exposure to a lactating mother. When imaging is needed in the lactating mother, a longer break in breast feeding might be needed to prevent transient hypothyroidism in the preterm infant.

Screening for congenital hypothyroidism: results of screening 5600 Ardabil province infants

<p class="abstract"><strong>Background:</strong> Congenital hypothyroidism (CH) is a condition of thyroid hormone deficiency which varies more by geographic areas and affecting 1 in 3000 to 4000 of newborns. The aim of this study was to investigate the screening of CH results in in Ardabil Province, Iran.</p><p class="abstract"><strong>Methods:</strong> This descriptive study was conducted on 158624 neonates during 2007 to 2013 which were screened for CH by measuring serum TSH obtained by heel prick. Of all neonates 5600 neonates who had a TSH ≥5 mU/L were recalled for measurement of serum T4 and thyroid stimulating hormone (TSH) in venous samples. Collected data analyzed by statistical methods in SPSS.16. </p><p class="abstract"><strong>Results:</strong> The incidence of congenital hypothyroidism was found to be 1:916 with a female to male ratio of 0.76:1. In 220 patients with CH, 40 patients were diagnosed with permanent CH (18.2%) and 140 with transient hypothyroidism (81.8%). The frequency of transient hypothyroidism was 4.5 times more than permanent hypothyroidism and was significant. In newborns with permanent hypothyroidism the average of TSH levels in the first and second times was 37.15 and 31.56 μIU/ml, respectively.</p><p><strong>Conclusions:</strong> Results showed that the prevalence of CH in Ardabil province was significantly high and comparing the results of this study with other studies in other countries suggests the proper efficacy of congenital hypothyroidism screening in Ardabil's health system. Also we should be attention to other environmental factors especially during pregnancy which affect the performance of the mother’s thyroid. </p>