Transient Thyroid Dysfunction Research Articles

Endocrinological Involvement in Children and Adolescents Affected by COVID-19: A Narrative Review.

Since the advent of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, an increased incidence of several endocrinological anomalies in acute-phase and/or long-term complications has been described. The aim of this review is to provide a broad overview of the available literature regarding changes in the worldwide epidemiology of endocrinological involvement in children since December 2019 and to report the evidence supporting its association with coronavirus disease 2019 (COVID-19). Although little is known regarding the involvement of endocrine organs during COVID-19 in children, the current evidence in adults and epidemiological studies on the pediatric population suggest the presence of a causal association between the virus and endocrinopathies. Untreated transient thyroid dysfunction, sick euthyroid syndrome, nonthyroidal illness syndrome, and hypothalamic-pituitary-adrenal (HPA) axis and central precocious puberty have been observed in children in acute infection and/or during multisystem inflammatory syndrome development. Furthermore, a higher frequency of ketoacidosis at onset in children with a new diagnosis of type 1 diabetes is reported in the literature. Although the direct association between COVID-19 and endocrinological involvement has not been confirmed yet, data on the development of different endocrinopathies in children, both during acute infection and as a result of its long-term complications, have been reported. This information is of primary importance to guide the management of patients with previous or current COVID-19.

Long-term outcome of thyroid abnormalities in patients with severe Covid-19.

We have previously observed thyroid dysfunction, i.e. atypical thyroiditis (painless thyrotoxicosis associated with non-thyroidal illness syndrome), in patients with severe acute respiratory syndrome coronavirus 2 disease (Covid-19). This study aimed to analyse the evolution of thyroid dysfunction over time. One hundred eighty-three consecutive patients hospitalised for severe Covid-19 without known thyroid history were studied at hospital admission (baseline). Survivors were offered 12-month longitudinal follow-up including assessment of thyroid function, autoantibodies and ultrasound scan (US). Patients showing US focal hypoechoic areas suggestive of thyroiditis (focal hypoechogenicity) also underwent thyroid 99mTc or 123I uptake scan. At baseline, after excluding from TSH analysis, 63 out of 183 (34%) Covid-19 patients commenced on steroids before hospitalisation, and 12 (10%) showed atypical thyroiditis. Follow-up of 75 patients showed normalisation of thyroid function and inflammatory markers and no increased prevalence of detectable thyroid autoantibodies. Baseline US (available in 65 patients) showed focal hypoechogenicity in 28% of patients, of whom 82% had reduced thyroid 99mTc/123I uptake. The presence of focal hypoechogenicity was associated with baseline low TSH (P = 0.034), high free-thyroxine (FT4) (P = 0.018) and high interleukin-6 (IL6) (P = 0.016). Focal hypoechogenicity persisted after 6 and 12 months in 87% and 50% patients, respectively, but reduced in size. After 9 months, thyroid 99mTc/123I uptake partially recovered from baseline (+28%) but was still reduced in 67% patients. Severe Covid-19 induces mild transient thyroid dysfunction correlating with disease severity. Focal hypoechogenicity, associated with baseline high FT4, IL6 and low TSH, does not seem to be related to thyroid autoimmunity and may persist after 1 year although decreasing in size. Long-term consequences seem unlikely.

The effect of COVID-19 on the presentation of thyroid disease in children.

Although studies suggest a potential link between COVID-19 and thyroid dysfunction in adults, there are insufficient data to confirm that association in children, and whether there is any effect on presentation to healthcare services. To identify whether presentations of thyroid dysfunction in children to a tertiary paediatric hospital changed as a result of the COVID-19 pandemic. A retrospective case note review was conducted of all children with abnormal thyroid function tests between 1st January 2016 and 31st December 2021 at a tertiary paediatric endocrine centre in the United Kingdom. Overall, 244 children whose first presentation was within the timeframe of interest were included in this study, with a median age (range) of 11.5 (6.1, 16.8) years. Of these, 43 (18%) were hyperthyroid and 201 (82%) were hypothyroid. The greatest number of thyroid presentations occurred in 2021 (n=60, 25% of total over time period) and the fewest in 2020 (n=10, 4% of total over time period). Prior to this, the median (range) number of presentations per year was 34 (28, 39). There were no statistically significant differences in biochemistry, antibody status or other clinical characteristics between those who presented with hyperthyroidism prior to the pandemic or after. In those with hypothyroidism, baseline biochemistry was similar between the 2 groups, but the presence of other autoimmune conditions was greater pre-pandemic (17.2% vs 15.0%, p=0.03). In addition, patients were more likely to have transient thyroid dysfunction, which did not require treatment post-pandemic (70.0% vs 49.6%, p=0.0086). Although overall rates of presentation with thyroid dysfunction have not altered since the first wave of the COVID-19 pandemic, presentations with transient thyroid dysfunction, not requiring ongoing treatment have increased. Further research regarding the relationship between COVID-19 and thyroid function in children and young people, is needed.

Follow-up study of preterm infants with thyroid dysfunction after medication.

To study the effect of levothyroxine sodium tablets on the growth and development and thyroid function in preterm infants with thyroid dysfunction. A retrospective analysis was performed for 82 preterm infants who were born in the Department of Obstetrics of the First People's Hospital of Yunnan Province, from January 1, 2013 to December 31, 2017, and these infants were hospitalized after birth in the Department of Neonatology of the hospital. They were regularly followed up to observe growth and development and thyroid function at the outpatient service of the Department of Neonatology. According to thyroid function test results, they were divided into an abnormal thyroid function group (observation group; n=31) and a normal thyroid function group (control group; n=51). The infants in the observation group were given oral administration of levothyroxine sodium tablets, while those in the control group were not given any treatment. The two groups were compared in terms of the physical and intelligence development and thyroid function of preterm infants with various gestational ages (28-<32 weeks, 32-<34 weeks, and 34-<37 weeks) after regular follow-up to the corrected age of 12 months. There were no significant differences in physical development indices (body length, body weight, and head circumference) between the observation and control groups at various gestational ages after follow-up to the corrected age of 12 months (P>0.05). There were no significant differences between the two groups in the scores of each functional area of the Gesell Developmental Scale among the preterm infants with a gestational age of 28-<32 weeks and 32-<34 weeks after follow-up to the corrected age of 12 months (P>0.05). For the preterm infants with a gestational age of 34-<37 weeks, compared with the control group, the observation group had a significantly lower score of gross motor ability at the age of 3 and 12 months, significantly lower scores of fine motor ability, language ability, and adaptation ability at the age of 12 months (P<0.05), and a significantly lower score of personal-social ability at the age of 3 months (P<0.05). However, the score of personal-social ability in the observation group was not significantly different from the control group at the age of 12 months (P>0.05). After 2-4 weeks of treatment with levothyroxine sodium tablets, the thyroid function of the 31 preterm infants with thyroid dysfunction returned to normal. Among the 31 infants, 21 (68%) achieved complete drug withdrawal, with normal results of neonatal screening (100%); 10 infants (32%) failed to achieve drug withdrawal, and only 2 (20%) out of the 10 infants had normal neonatal screening results (P<0.05). Early diagnosis and reasonable treatment can reduce the impact on growth and development in preterm infants with thyroid dysfunction. Most preterm infants tend to have transient thyroid dysfunction, while those with positive results of neonatal screening are more likely to develop permanent thyroid dysfunction.

The effect of acute and chronic iodine excess on thyroid profile and reproductive function of women using Lipiodol during hysterosalpingography and the potential impact on thyroid function of their offspring: The SELFI study protocol

Abstract Background: Hysterosalpingography (HSG) is a radiological procedure using iodinated contrast media to assess tubal patency in women with infertility. HSG using Lipiodol, an oil-soluble contrast medium (OSCM) has been shown to improve pregnancy rates, so its therapeutic use has increased. However, OSCM can cause marked and prolonged iodine excess, potentially impacting thyroid function. If pregnancy occurs, there is also concern regarding possible neonatal hypothyroidism resulting from maternal iodine excess. This study aims to improve knowledge on the safety profile of OSCM HSG in the context of iodine excess. Methods: This is a prospective longitudinal study of 200 consecutively consenting women undergoing an OSCM HSG in Auckland, New Zealand. After informed consent, participants will undergo baseline thyroid function tests and measurement of urine iodine-to-creatinine ratio (UI/Cr) and anti-thyroid antibodies. During the HSG, the volume of OSCM used will be recorded, and a delayed radiograph obtained to check for further spill of the contrast and for a semi-quantitative assessment of peritoneal retention of OSCM. Thyroid function tests, UI/Cr and reproductive hormones will be serially monitored over the next 6 months. If the woman conceives within the study period, the offspring's thyroid function will be tested at 7 days of age, in addition to the routine newborn screening. The primary outcome will be development of subclinical hypothyroidism (SCH) in these women. Secondary outcomes will include the incidence of elevated iodine levels in these women, and a transient or permanent thyroid dysfunction in the neonates conceived within the study period. In addition, mixed-model analyses will attempt to identify ‘high-risk’ groups for thyroid dysfunction. Discussion: This study will explore the acute and chronic effects of iodine excess on thyroid function in women who undergo an OSCM HSG and in their offspring conceived in the immediate cycles following HSG. Further, this study will provide information on the profile of thyroid function abnormalities following an OSCM HSG, and help guide the establishment of international protocols for thyroid monitoring and management in women undergoing this procedure. Trial registration: Trial acronym–SELFI (Safety and Efficacy of Lipiodol in Fertility Investigations) ACTRN: ACTRN12620000738921, retrospectively registered on 14/07/2020

Alemtuzumab-Induced Hypothyroidism Presenting in Pregnancy - the First 2 Reported Cases

Abstract Introduction: Alemtuzumab is a monoclonal antibody that improves outcomes in patients with relapsing-remitting multiple sclerosis. It binds to CD52 and causes a profound depletion of B and T lymphocytes. Autoreactive T cells often form as the immune system repopulates, causing autoimmune thyroid dysfunction in approximately 35% of patients. Alemtuzumab has been associated with new-onset hyperthyroidism during a subsequent pregnancy. Here, we present the first two cases of alemtuzumab-induced hypothyroidism diagnosed in pregnancy. Diagnosing and treating de novo thyroid dysfunction in pregnancy is essential for optimal fetal development and maternal wellbeing. Clinical Cases: Case A: A 28-year-old woman conceived 26 months after alemtuzumab therapy. Prior to pregnancy, routine TFTs showed euthyroidism. At 17 weeks’ gestation she presented with fatigue, and blood tests confirmed overt hypothyroidism (TSH &amp;gt;100mIU/L (&amp;lt;4IU/L), fT4 3.7pmol/L (9-15pmol/L)). TRABs were positive. She was treated with levothyroxine, and TFTs normalised by 38 weeks’ gestation. Serial fetal ultrasounds showed constant growth velocity and no fetal goitre or tachycardia. The baby was born at term with birthweight on the 30th centile. On day 5 postpartum, the baby had a normal TSH of 3.1mIU/l (0.27-4.20mIU/l) but elevated fT4 of 31.5pmol/L (12-22pmol/L), which fell spontaneously to 22.0pmol/L by day 11. Case B: A 37-year-old woman conceived 19 months after alemtuzumab therapy. Prior to pregnancy, routine TFTs had been within normal limits. However at 5 weeks’ gestation, blood tests showed overt hypothyroidism (TSH 47.9mIU/L (&amp;lt;4iU/L)), fT4 8.8pmol/l (10-16pmol/L)). Her only symptom was fatigue. TRABs were elevated. She was treated with levothyroxine, and TFTs normalised by 16 weeks’ gestation. Serial fetal ultrasound scans showed constant growth velocity and no fetal goitre or tachycardia. The baby was born at term with birthweight on the 25th centile. On day 1 postpartum, the baby had a normal fT4 (16.5pmol/l)but elevated TSH 13.02mIU/L, which normalised spontaneously by day 11 tp 1/64mIU/l. Conclusion: To optimise pregnancy outcomes, we recommend that women previously treated with alemtuzumab should be screened monthly for thyroid dysfunction during a subsequent pregnancy. The neonatal team should be alert to transient neonatal thyroid dysfunction, which, like spontaneous alloimmune neonatal thyroid disease, appears to settle spontaneously.

Frequency of thyroid dysfunction in pediatric patients with congenital heart disease exposed to iodinated contrast media- a long-term observational study.

Background The thyroid gland of patients with congenital heart disease may be exposed to large doses of iodine from various sources. We assessed the thyroid response after iodine exposure during conventional angiography in cardiac catheterization and angiographic computer tomography in childhood. Methods Retrospective mid- to long-term follow-up of 104 individuals (24% neonates, 51% infants, 25% children) with a median age and body weight of 104days [0-8 years] and 5.3kg [1.6-20]. Serum levels of thyroid-stimulating hormone, free triiodthyronine and free thyroxine were evaluated at baseline and after excess iodine. We also assessed risk factors that may affect thyroid dysfunction. Results Baseline thyroidal levels were within normal range in all patients. The mean cumulative iodinate contrast load was 6.6±1.6mL/kg. In fact, 75% had experienced more than one event involving iodine exposure, whose median frequency was three times per patient [1-12]. During the median three years follow-up period [0.5-10], the incidence of thyroid dysfunction was 15.4% (n=16). Those patients developed acquired hypothyroidism (transient n=14, long-lasting n=2 [both died]) with 10 of them requiring temporary replacement therapy for transient thyroid dysfunction, while four patients recovered spontaneously. 88 individuals (84.6%) remained euthyroid. Repeated cardiac interventions, use of drugs that interfere with the thyroid and treatment in the intensive care unit at the index date were strong predictors for acquired thyroid dysfunction. Conclusions The incidence of acquired hypothyroidism after iodine excess was 15.4%. However, most patients developed only transient hypothyroidism. Systemic iodine exposure seems to be clinically and metabolically well tolerated during long-term follow-up.

Thyroid dysfunction and cancer incidence: a systematic review and meta-analysis.

In this study, we aimed to evaluate site-specific cancer risks associated with hyperthyroidism or hypothyroidism. We performed a systematic review of observational studies reporting associations between hyperthyroidism or hypothyroidism and subsequent site-specific cancer incidence, in MEDLINE and the COCHRANE library (inception-28/01/2019) (PROSPERO: CRD42019125094). We excluded studies with thyroid dysfunction evaluated as a cancer biomarker or after prior cancer diagnosis and those considering transient thyroid dysfunction during pregnancy or severe illnesses. Risk of bias was assessed using a modified Newcastle-Ottawa scale. Risk estimates were pooled using random-effects models when ≥5 studies reported data for a specific cancer site. Twenty studies were included, of which 15 contributed to the meta-analysis. Compared to euthyroidism, hyperthyroidism was associated with higher risks of thyroid (pooled risk ratio: 4.49, 95%CI: 2.84-7.12), breast (pooled risk ratio: 1.20, 95%CI: 1.04-1.38), and prostate (pooled risk ratio: 1.35, 95%CI: 1.05-1.74), but not respiratory tract (pooled risk ratio: 1.06, 95%CI: 0.80-1.42) cancers. Hypothyroidism was associated with a higher risk of thyroid cancer within the first 10 years of follow-up only (pooled risk ratio: 3.31, 95%CI: 1.20-9.13). There was no or limited evidence of thyroid dysfunction-related risks of other cancer sites. In conclusion, thyroid dysfunction was associated with increased risks of thyroid, breast, and prostate cancers. However, it remains unclear whether these findings represent causal relationships because information on treatments and potential confounders was frequently lacking.

The Association between Low Vitamin D Status and Autoimmune Thyroid Disease in Korean Premenopausal Women: The 6th Korea National Health and Nutrition Examination Survey, 2013-2014.

BackgroundThis study aimed to analyze the association of low vitamin D status with thyroid autoimmunity and dysfunction in the Korean population according to sex and menopausal status in women.MethodsThis study was based on the data acquired from the 6th Korea National Health and Nutrition Examination Survey. We enrolled 4,356 subjects who had data of thyroid function, antithyroid peroxidase antibody (TPOAb), and serum 25-hydroxyvitamin D (25[OH]D) levels. We excluded subjects who were pregnant and who had a history of thyroid disease or thyroid cancer, and those with transient thyroid dysfunction who tested negative for TPOAb (TPOAb[-]).ResultsTPOAb positivity (TPOAb[+]) with thyroid dysfunction (subclinical and overt hypothyroidism) was more prevalent in the vitamin D deficient group than in the vitamin D insufficient and sufficient groups including premenopausal (P=0.046) and postmenopausal women (P=0.032), although no significant differences were observed in men. The mean serum 25(OH)D level was significantly lower in the TPOAb(+) with thyroid dysfunction group than in the TPOAb(+) with euthyroidism and TPOAb(-) groups of premenopausal women (P=0.001), although no significant differences were observed in men and postmenopausal women. Multivariate binary logistic regression analysis, adjusted for age, body mass index, and current smoking status, showed that vitamin D insufficiency and deficiency were significantly associated with TPOAb(+) with thyroid dysfunction in premenopausal women (P<0.001), although no significant associations were observed in men and postmenopausal women.ConclusionLow vitamin D status was significantly associated with thyroid autoimmunity and dysfunction in the Korean population, especially in premenopausal women.

SAT-588 Unique Presentation of Postpartum Thyroiditis with Features of Graves' Disease

Introduction - Postpartum thyroiditis (PPT) is a rare medical condition occurring after pregnancy. Postpartum thyroiditis is a syndrome of transient or permanent thyroid dysfunction occurring in the first year after delivery. It can present as clinical thyrotoxicosis, followed by hypothyroidism and subsequent recovery of thyroid function or it may present as an isolated thyrotoxicosis or hypothyroidism. An estimated 20-40% of women develop permanent hypothyroidism; usually during the 3 to 10 year interval following an episode of PPT. PPT is the most common thyroid disease in the postpartum period with an incidence between 5-9%. The condition is most common in patients with positive thyroid antibodies (TPO), type 1 diabetes or prior history of PPT. We present a unique case of postpartum thyroiditis with postpartum hyperthyroidism, with markers of Graves’ disease, in a patient with a maternal history of Graves’ disease. Case description - An 18 year old female, without prior medical history, presented with thyrotoxicosis following delivery of her first child. Initially, she responded to therapy with propranolol; however, when her thyroid function became increasingly symptomatic, therapy was augmented with methimazole. Methimazole was selected because of the corresponding clinical features of Graves’ disease coupled with a positive thyroid stimulating immunoglobulin (TSI = 431) and family history of Graves’ disease. Thyroid scan and uptake showed homogenous thyroid without discrete nodule with normal thyroid uptake. Unfortunately, methimazole precipitated urticaria and pruritus, without any liver abnormalities, necessitating its’ discontinuance. Propranolol monotherapy subsequently provided effective symptomatic relief. The patient’s thyroid levels eventually peaked following delivery (fT4 -4.32) before trending downward (fT4 = 1.79), paralleling the resolution of her symptomatic biochemical thyrotoxicosis and resolution of her goiter. Conclusion - Literature review revealed lack of similar case report. Our patient benefitted from symptomatic therapy with propranolol. Women with preexisting thyroid disorders are at high risk for developing postpartum thyroiditis and should be closely monitored for one year post-partum. We hypothesize that our patient most likely had preexisting Grave’s disease that was exacerbated after her delivery. Reference - Pearce EN. Thyroid disorders during pregnancy and postpartum. Best Pract Res Clin Obstet Gynaecol. 2015;29(5); 700-706.

Fetal atrial flutter and supraventricular tachycardia

Supraventricular tachycardia(SVT) and atrial flutter(AF) are life-threatening fetal conditions. Prenatal diagnosis of fetal arrhythmia is possible. In M-mode atrias and ventricles should be “cut” on the same image, heart rate of atrias and ventricles are counted. In AF there is usually 2:1 conduction. Type of SVT relied on time intervals. Flow in the vein and artery should be recorded simultaneously using pulsed Doppler. “A” wave in the vein corresponded with atrial contraction, the onset of the artery corresponded with ventricle contraction. Time between the onset of a wave to the onset of arterial flow is atrio-ventricular(AV-time). Period from arterial onset to the a-wave onset is ventriculoatrial(VA-time). Hydrops is diagnosed if there is fluid accumulation in the pericardial, pleural, abdominal cavity, or subcutaneous oedema. Between 1995 – 2001 five fetuses with AF(3 paroxysmal) and 12 with SVT(5 paroxysmal) were diagnosed. All were treated with different combination of drugs. Digoxin was always the first choice, sotalol, flecanide or amiodaron (in 1 fetus) were used additionally. Results were not satisfactory. Since 2002 precise diagnosis based on AV-time and VA-time intervals was introduced. We conducted prospective trial in which digoxin was the first drug in fetuses with short VA-time and no hydrops, amiodaron in cases with long VA-time and all with hydrops. Between 2002-2017, 27 fetuses with AF and 125 with SVT were diagnosed. Digoxin in monotherapy was successful in 59% of cases, amiodaron in 87%, overall successful rate was 94%. 33 fetuses (28%) were hydropic, in two therapy was unsuccessful. Long VA-time was in 66 fetuses, short VA-time in 34 fetuses. AF was diagnosed in 27 fetuses, one with HLHS, two were hydropic. One was without treatment. Digoxin was administered in 9 cases, amiodaron in 12 or combination (5 cases) with an overall successful rate 54%. Blood flow in umbilical vessels, middle cerebral artery and ductus venosus was checked. Fetal condition was defined using cardio-vascular profile score (CVPS). At diagnosis CVPS was between 4-7 in majority of cases and it improved up to 9-10 after successful treatment. In all fetuses UV and DV Doppler were abnormal due to fetal heart failure, not to fetal hypoxia. Umbilical artery Doppler was normal in all what indicated good placental function. There were 4 neonates with transient thyroid dysfunction, other amiodaron side effects were not observed. Nausea, vomiting and ECG changes were observed in women who received digoxin. SVT and AF can be successfully diagnosed and treated in fetuses.

Clinical course of infants with congenital heart disease who developed thyroid dysfunction within 100 days.

PurposeWe investigated the clinical course of infants with congenital heart disease (CHD) who experienced thyroid dysfunction within 100 days of birth.MethodsWe performed retrospective medical reviews of 54 CHD patients (24 male patients) who underwent a thyroid function test (TFT) between January 2007 and July 2016. Data were collected on birth history, diagnosis of CHD, underlying chromosomal or genetic abnormalities, medication history, surgery, ventilator care, and exposure to iodine contrast media (ICM). Results of neonatal screening tests (NSTs) and TFTs were reviewed.ResultsA total of 36 patients (29 transient, 7 permanent) showed thyroid dysfunction. Among the seven patients with permanent hypothyroidism, three had an underlying syndrome, three showed abnormal NST results, and one was admitted to the intensive care unit for macroglossia and feeding cyanosis. We found that infants with transient thyroid dysfunction had a lower birth weight and were more commonly exposed to thyroid disrupting medication and/or ICM. However, these risk factors were not significant. A total of 8 patients with a history of ICM exposure showed thyroid dysfunction. Excluding 3 patients with elevated thyroid stimulating hormone before ICM exposure, 5 patients recovered from transient thyroid dysfunction.ConclusionsWe observed thyroid dysfunction in two-thirds of CHD infants (53.7% transient, 13.0% permanent) who had risk factors and received TFT screening within 100 days, despite normal NSTs. Further studies with larger sample sizes are required to revise the criteria for TFT screening in CHD infants.

Permanent and Transient Congenital Hypothyroidism in Hamadan West Province of Iran.

BackgroundPrimary congenital hypothyroidism (CH) is the most common treatable cause of mental retardation and can be classified into permanent and transient types. The purpose of this study was to determine the prevalence of permanent and transient congenital hypothyroidism (CH) in Hamadan, West province of Iran.MethodsThe study population included all cases with primary congenital hypothyroidism, which were confirmed by thyroid function tests (TSH levels ≥ 10 mIU/L). All these patients had been followed up at the outpatient pediatric endocrine clinic of Besat hospital (Hamadan, Iran) for a period of time between May 2006 and March 2013. Biochemical findings at diagnosis and detailed medical records were collected. Patients were considered as permanent hypothyroidism if their TSH level was 10 (mIU/l) during 6 - 12 months of treatment. Also three years old patients with TSH level > 10 mU/L during one or three months after discontinuation of levothyroxine treatment were considered as permanent hypothyroidism.ResultsA total of 164 children (49.9% male and 50.6% female) diagnosed with CH completed the study. Female/male ratio was 1.02/1. The incidence of CH was about 1/1250 in Hamadan, West province of Iran. Of the 164 patients, 105 cases (64 %) were diagnosed as permanent CH and other 59 cases (36%) were proven to have transient hypothyroidism. Female to male ratio was 1.14 in patients suffering from permanent CH and 0.8 in patients with transient CH. The initial TSH level was found to be significantly higher in cases with permanent CH compared to the patients with transient CH (P = 0.001). Mean TSH level during the first year of treatment was higher in permanent CH cases compared to transient cases (P = 0.001). Children with transient CH had a lower TSH serum level during the three years of treatment (P = 0.000). A significant statistical difference was not found between the genders and permanent or transient CH (P = 0.352). Co-occurring congenital anomalies and birth order were significantly different between two groups (P = 0.028 and P = 0.024, respectively).ConclusionsOur regional follow-up data showed that about 40% of newborns with primary CH had transient thyroid dysfunction. Our results further clarify our previous research by providing evidences on the incidence rate of CH. The incidence rates of CH as well as transient type of CH in our region were higher than those reported by other studies which have been conducted in other regions of the world. The initial TSH level was the strongest predictor of treatment cessation. Given the high incidence of transient CH in our region, further studies are needed to confirm the etiology and to provide considerable insight into preventive and/or the treatment strategies.

Transient Congenital Hypothyroidism in Turkey: An Analysis on Frequency and Natural Course.

Objective: Prevalence of congenital hypothyroidism (CH) in Turkey at birth was reported to be as high as 1:650 in 2008-2010. Incidence rates of permanent and transient CH separately are unknown due to lack of follow-up data. We aimed to evaluate the impact of transient hypothyroidism on increasing incidence of CH and to determine the natural course and the clinical, biochemical, and imaging characteristics of transient CH.Methods: Baseline and follow-up data of the infants with CH detected at screening in six provinces in the Black Sea Region were analyzed retrospectively during a time period covering the years 2008-2010.Results: Among 138 cases (48% female), 16 (12%) showed transient hyperthyrotropinemia which resolved without intervention. Of the treated 122 cases, 63 (52%) had transient CH. While its frequency was 35% in 2008, it increased to 56% in 2009-2010, following a lowering of the thyroid stimulating hormone cutoff value. The frequency was higher in inland provinces than in coast (67% vs. 43%; p=0.01).Clinical characteristics of permanent and transient cases were similar except female-to-male sex ratios (1.5:1 vs. 0.6:1; p=0.02). L-thyroxine was discontinued in 70% of transient cases before 3 years of age at a median age of 19 (2-36) months. The only indication for early discontinuation of treatment was a low L-thyroxine dose, which was 1.25±0.27 µg/kg/day at withdrawal time.Conclusion: Our regional follow-up data showed that more than half of newborns with primary CH had transient thyroid dysfunction. In the majority of cases, discrimination between transient and permanent CH can be made before age 3 years, as indicated by cessation of L-thyroxine treatment.

96-08: Short-term amiodarone treatment for atrial fibrillation after catheter ablation induces a transient thyroid dysfunction: Results from the placebo-controlled randomized AMIO-CAT trial

Figure: TSH at baseline and follow-up (t-tests)

Short-term amiodarone treatment for atrial fibrillation after catheter ablation induces a transient thyroid dysfunction: Results from the placebo-controlled, randomized AMIO-CAT trial

BackgroundAmiodarone is known to affect the thyroid, but little is known about thyroid recovery after short-term amiodarone treatment. ObjectivesWe aimed to evaluate the impact of 8weeks of amiodarone treatment on thyroid function in patients with atrial fibrillation (AF) undergoing catheter ablation in a randomised, double-blind clinical trial. Methods212 patients referred for AF ablation at two centres were randomized to 8weeks of oral amiodarone or placebo. Thyroid function tests (TSH, thyroid stimulating hormone; T4, thyroxine; T3, triiodothyronine; fT4, free T4; fT3, free T3) were performed at baseline and 1, 3 and 6months. ResultsStudy drug was discontinued due to mild thyroid dysfunction in 1 patient in the placebo vs. 3 in the amiodarone group (p=0.6). In linear mixed models there were significant effects of amiodarone on thyroid function tests, modified by follow-up visit (p<10−9 for both TSH, T4, T3, fT4 and fT3). The amiodarone group had higher TSH, fT4 and T4 after 1 and 3months compared to placebo, whereas T3 and fT3 were lower. In all cases, the amiodarone-induced thyroid dysfunction was largest at 1month, declining at 3months, and with no differences at 6months, compared to baseline. ConclusionWe found amiodarone to have a significant impact on thyroid function after only 1month, but with a fast recovery of thyroid function after amiodarone discontinuation. Our study indicates that short-term amiodarone can be considered safe in patients without prior thyroid dysfunction.

Long-Term Neurodevelopmental Outcome of Children Treated with Tri-Iodothyronine after Cardiac Surgery: Follow-Up of a Double-Blind, Randomized, Placebo-Controlled Study

Background: Transient thyroid dysfunction occurs in children after cardiopulmonary bypass (CPB). We demonstrated significant benefits of acute postoperative tri-iodothyronine (T3) treatment for recovery and myocardial function. Now we report the long-term neurodevelopment of these children. Methods: Twenty-eight children (70% of the original study population) could be recruited for a follow-up examination (median age 10.7 years, range 10-19.6 years) retaining the double-blind, randomized, placebo-controlled protocol. Cognitive function and motor development were tested, as were growth and thyroid and cardiac functions. Results: The median full-scale intelligence quotient of all children was within the reference range and similar in the placebo and T3 groups. Tests for motor and cognitive functions, growth, and thyroid and cardiac functions revealed concurrent results. Conclusions: Overall intellectual development is preserved in adolescents treated with CPB in infancy irrespectively of low postoperative thyroid hormone concentrations. While acute postoperative T3 treatment in children after CPB improves recovery, no significant long-term effects on neurodevelopment could be detected. We therefore speculate that transient postoperative thyroid dysfunction by means of nonthyroidal illness syndrome is predominantly mediated by extranuclear, nongenomic mechanisms and thus acutely affects the cardiovascular system but not the development of the central nervous system mediated by genomic mechanisms.

Postpartum thyroiditis.

Postpartum thyroiditis (PPT) is a syndrome of transient or permanent thyroid dysfunction occurring in the first year after delivery or abortion. It is the most common thyroid disease in the postpartum period with incidence between 5 and 9%. In essence, it is an autoimmune inflammation of the thyroid, caused by changes in humoral and cell-mediated immune response. It has a characteristic biphasic course with an episode of transient thyrotoxicosis followed by transient or permanent hypothyroidism. Of all predisposing factors positive titers of thyroid peroxidase antibodies have the greatest importance. In some of the affected patients the disease course is marked by expressed hormonal disorders causing significant subjective symptoms. This underlines the need for early identification of risk groups aimed at prophylaxis and adequate treatment of thyroid dysfunction in the postpartum period. The frequency of PPT varies between analyses and studies on risk factors do not establish reliable predictive models for progression of the disease. This is due to the different methodology of research and the involvement of a number of genetic and non-genetic factors in different geographic regions. That is why implementation of mass screening programs is now controversial. The discrepancy in the opinions of researchers makes it necessary to have studies of the problem in performed in every clinical center in which the possible risk specific to the region and the population covered might be defined prognostically. The results of these studies can be used to introduce targeted and cost-effective screening for early detection of risk patients and prevention of morbidity and complications of PPT.

Paroxysmal Supraventricular Tachycardia at 1-Month Age and Transient Thyroid Dysfunction in a Preterm Baby Treated for Fetal Tachycardia with Amiodarone

Paroxysmal Supraventricular Tachycardia at 1-Month Age and Transient Thyroid Dysfunction in a Preterm Baby Treated for Fetal Tachycardia with Amiodarone

A systematic review of thyroid dysfunction in preterm neonates exposed to topical iodine

ObjectiveTo determine whether maternal exposure to iodine or neonatal exposure to topical iodine-containing solutions increases the risk of transient thyroid dysfunction in neonates born <32 weeks’ gestation or <1.5 kg.DesignSystematic...