A high prevalence of dual thyroid ectopy in congenital hypothyroidism: evidence for insufficient signaling gradients during embryonic thyroid migration or for the polyclonal nature of the thyroid gland?

BACKGROUND: Thyroid ectopy results from the failure of the thyroid precursor cells to migrate from the primordial pharynx to the anterior part of the neck. Most ectopic thyroids are revealed by congenital hypothyroidism and present as a single round mass at the base of the tongue, with no other thyroid tissue. However, some cases have dual ectopy, with part of the tissue having partially migrated. We hypothesized that this occurs more frequently than previously reported.¦METHODS: To determine the prevalence of dual ectopy, we reviewed the pertechnetate scintigraphies of 81 patients with congenital hypothyroidism from thyroid ectopy diagnosed between 2002 and 2011 at our institution.¦RESULTS: We report a series of seven cases (9%) of dual ectopy, representing an incidence ranging from 1:50,000 to 1:70,000.¦CONCLUSIONS: Almost one in 10 cases with congenital hypothyroidism due to thyroid ectopy has dual ectopy. This suggests that two populations of cells diverged at an early stage of development, which may arise from insufficient signaling gradients in surrounding tissues during early organogenesis or may indirectly support the polyclonal nature of the thyroid.

Subclinical hypothyroidism and the risk of heart failure, other cardiovascular events, and death.

BACKGROUND: Subclinical hypothyroidism has been associated with systolic and diastolic cardiac dysfunction and an elevated cholesterol level, but data on cardiovascular outcomes and death are limited. METHODS: We studied 2730 men and women, aged 70 to 79 years, with baseline thyrotropin (TSH) measurements and 4-year follow-up data to determine whether subclinical hypothyroidism was associated with congestive heart failure (CHF), coronary heart disease, stroke, peripheral arterial disease, and cardiovascular-related and total mortality. After the exclusion of participants with abnormal thyroxine levels, subclinical hypothyroidism was defined as a TSH level of 4.5 mIU/L or greater, and was further classified according to TSH levels (4.5-6.9, 7.0-9.9, and > or = 10.0 mIU/L). RESULTS: Subclinical hypothyroidism was present in 338 (12.4%) of the participants. Compared with euthyroid participants, CHF events occurred more frequently among those with a TSH level of 7.0 mIU/L or greater (35.0 vs 16.5 per 1000 person-years; P = .006), but not among those with TSH levels between 4.5 and 6.9 mIU/L. In multivariate analyses, the risk of CHF was higher among those with high TSH levels (TSH of 7.0-9.9 mIU/L: hazard ratio, 2.58 [95% confidence interval, 1.19-5.60]; and TSH of > or = 10.0 mIU/L: hazard ratio, 3.26 [95% confidence interval, 1.37-7.77]). Among the 2555 participants without CHF at baseline, the hazard ratio for incident CHF events was 2.33 (95% confidence interval, 1.10-4.96; P = .03) in those with a TSH of 7.0 mIU/L or greater. Subclinical hypothyroidism was not associated with increased risk for coronary heart disease, stroke, peripheral arterial disease, or cardiovascular-related or total mortality. CONCLUSIONS: Subclinical hypothyroidism is associated with an increased risk of CHF among older adults with a TSH level of 7.0 mIU/L or greater, but not with other cardiovascular events and mortality. Further investigation is warranted to assess whether subclinical hypothyroidism causes or worsens preexisting heart failure.

Subclinical hypothyroidism and the risk of coronary heart disease and mortality.

CONTEXT: Data regarding the association between subclinical hypothyroidism and cardiovascular disease outcomes are conflicting among large prospective cohort studies. This might reflect differences in participants' age, sex, thyroid-stimulating hormone (TSH) levels, or preexisting cardiovascular disease. OBJECTIVE: To assess the risks of coronary heart disease (CHD) and total mortality for adults with subclinical hypothyroidism. DATA SOURCES AND STUDY SELECTION: The databases of MEDLINE and EMBASE (1950 to May 31, 2010) were searched without language restrictions for prospective cohort studies with baseline thyroid function and subsequent CHD events, CHD mortality, and total mortality. The reference lists of retrieved articles also were searched. DATA EXTRACTION: Individual data on 55,287 participants with 542,494 person-years of follow-up between 1972 and 2007 were supplied from 11 prospective cohorts in the United States, Europe, Australia, Brazil, and Japan. The risk of CHD events was examined in 25,977 participants from 7 cohorts with available data. Euthyroidism was defined as a TSH level of 0.50 to 4.49 mIU/L. Subclinical hypothyroidism was defined as a TSH level of 4.5 to 19.9 mIU/L with normal thyroxine concentrations. RESULTS: Among 55,287 adults, 3450 had subclinical hypothyroidism (6.2%) and 51,837 had euthyroidism. During follow-up, 9664 participants died (2168 of CHD), and 4470 participants had CHD events (among 7 studies). The risk of CHD events and CHD mortality increased with higher TSH concentrations. In age- and sex-adjusted analyses, the hazard ratio (HR) for CHD events was 1.00 (95% confidence interval [CI], 0.86-1.18) for a TSH level of 4.5 to 6.9 mIU/L (20.3 vs 20.3/1000 person-years for participants with euthyroidism), 1.17 (95% CI, 0.96-1.43) for a TSH level of 7.0 to 9.9 mIU/L (23.8/1000 person-years), and 1.89 (95% CI, 1.28-2.80) for a TSH level of 10 to 19.9 mIU/L (n = 70 events/235; 38.4/1000 person-years; P <.001 for trend). The corresponding HRs for CHD mortality were 1.09 (95% CI, 0.91-1.30; 5.3 vs 4.9/1000 person-years for participants with euthyroidism), 1.42 (95% CI, 1.03-1.95; 6.9/1000 person-years), and 1.58 (95% CI, 1.10-2.27, n = 28 deaths/333; 7.7/1000 person-years; P = .005 for trend). Total mortality was not increased among participants with subclinical hypothyroidism. Results were similar after further adjustment for traditional cardiovascular risk factors. Risks did not significantly differ by age, sex, or preexisting cardiovascular disease. CONCLUSIONS: Subclinical hypothyroidism is associated with an increased risk of CHD events and CHD mortality in those with higher TSH levels, particularly in those with a TSH concentration of 10 mIU/L or greater.

Comment tes médecins de famille prennent-ils en charge l'hypothyroïdie infraclinique [How do Swiss family physicians treat subclinical hypothyroidism?].

L'hypothyroïdie infraclinique est fréquemment rencontrée et sa prévalence augmente avec l'âge. Les recommandations relatives au dépistage et au traitement de l'hypothyroïdie infraclinique sont controversées. Une enquête internationale auprès des médecins de famille, à laquelle la Suisse a participé, a mis en évidence de fortes variations dans la prise en charge de l'hypothyroïdie infraclinique entre les pays. Ces différences de traitement traduisent avant tout le manque de données fiables quant à la prise en charge de cette condition. L'essai clinique randomisé européen TRUST devrait permettre de clarifier les indications pour le dépistage et la substitution par thyroxine. Une collaboration avec les médecins de famille et le soutien des Instituts universitaires de médecine générale à Lausanne et à Berne pour le recrutement des patients devraient permettre d'obtenir des données directement applicables à une population représentative de la médecine ambulatoire. Subclinical hypothyroidism is a common condition, and its prevalence increases with age. Currently, guidelines regarding the screening and treatment of subclinical hypothyroidism are controversial. An international survey of general practitioners (GPs), to which Swiss GPs also contributed, showed large inter-country variations in treatment strategies for subclinical hypothyroidism. These differences are mainly explained by the lack of strong evidence for the management of this condition. The European randomized-controlled clinical trial TRUST should help clarify recommendations for screening and thyroxin replacement for the elderly with subclinical hypothyroidism. Working in close collaboration with GPs in Switzerland for the recruitment of patients will ensure that the findings from this study will be applicable to primary care settings.

Subclinical hypothyroidism and functional mobility in older adults.

BACKGROUND: Health risks associated with subclinical hypothyroidism in older adults are unclear. Our objective was to compare the functional mobility of people aged 70 to 79 years by thyroid function categorized by thyrotropin (TSH) level as euthyroid (>or=0.4 to <4.5 mIU/L), mild subclinical hypothyroid (>or=4.5 to <7.0 mIU/L), or moderate subclinical hypothyroid (>or=7.0 to <or=20.0 mIU/L with a normal free thyroxine level) cross-sectionally and over 2 years. METHODS: A total of 2290 community-dwelling residents participating in the year 2 clinic visit (July 1998-June 1999) of the Health, Aging, and Body Composition (Health ABC) Study, who had measured TSH level, had the capacity to walk 20 m unaided, and were not taking thyroid medication or had TSH levels consistent with hyperthyroidism or hypothyroidism. Main outcome measures included self-reported and performance-based measures of mobility (usual and rapid gait speed and endurance walking ability) assessed at study baseline (year 2) and 2 years later. RESULTS: In age- and sex-adjusted analyses, the mild subclinical hypothyroid group (vs the euthyroid group) demonstrated better mobility (faster mean usual and rapid gait speed [1.20 vs 1.15 m/s and 1.65 vs 1.56 m/s, respectively; P < .001] and had a higher percentage of those with good cardiorespiratory fitness and reported walking ease [39.2% vs 28.0% and 44.7% vs 36.5%, respectively; P < .001]). After 2 years, persons with mild subclinical hypothyroidism experienced a similar decline as the euthyroid group but maintained their mobility advantage. Persons with moderate subclinical hypothyroidism had similar mobility and mobility decline as the euthyroid group. CONCLUSION: Generally, well-functioning 70- to 79-year-old individuals with subclinical hypothyroidism do not demonstrate increased risk of mobility problems, and those with mild elevations in TSH level show a slight functional advantage.

Subclinical hypothyroidism and the risk of coronary heart disease: a meta-analysis.

PURPOSE: Subclinical hypothyroidism has been associated with elevated cholesterol and increased risk for atherosclerosis, but data on the risk of coronary heart disease (CHD) are conflicting. We performed a systematic review to determine whether subclinical hypothyroidism is associated with CHD in adults. METHODS: We searched MEDLINE from 1966 to April 2005, and the bibliographies of key articles to identify studies that provided risk estimates for CHD or cardiovascular mortality associated with subclinical hypothyroidism. Two authors independently reviewed each potential study for eligibility, assessed methodologic quality, and extracted the data. RESULTS: We identified 14 observational studies that met eligibility criteria. Subclinical hypothyroidism increased the risk of CHD (summary odds ratio [OR]: 1.65, 95% confidence interval [CI], 1.28-2.12). The summary OR for CHD was 1.81 (CI, 1.38-2.39) in 9 studies adjusted or matched for demographic characteristics, and 2.38 (CI, 1.53-3.69) after pooling the studies that adjusted for most cardiovascular risk factors. Sensitivity analyses including only population-based studies and those with formal outcome adjudication procedures yielded similar results. Subgroup analyses by type of study design showed a similar trend, but lower risk, in the 5 prospective cohort studies (OR 1.42, CI, 0.91-2.21), compared with the case-control and cross-sectional studies (OR 1.72, CI, 1.25-2.38). CONCLUSION: Our systematic review indicates that subclinical hypothyroidism is associated with an increased risk of CHD. Clinical trials are needed to assess whether thyroxine replacement reduces the risk of CHD in subjects with subclinical hypothyroidism.

Variation in treatment strategies of Swiss general practitioners for subclinical hypothyroidism in older adults.

QUESTIONS UNDER STUDY: As the best management of subclinical hypothyroidism is controversial, we aimed to assess variations in treatment strategies depending on different Swiss regions, physician and patient characteristics. METHODS: We performed a case-based survey among general practitioners (GPs) in different Swiss regions, which consisted of eight hypothetical cases presenting a female patient with subclinical hypothyroidism and nonspecific complaints differing by age, vitality status and thyroid-stimulating hormone (TSH) concentration. RESULTS: A total of 262 GPs participated in the survey. There was considerable variation in the levothyroxine starting dose chosen by GPs, ranging from 25 µg to 100 µg. Across the Swiss regions, GPs in the Bern region were significantly more inclined to treat, with a higher probability of initiating treatment (60%, p = 0.01) and higher mean starting doses (45 µg, p <0.01) compared with the French-speaking region (44%, 36 µg); the Zurich region had intermediate values (52%, 39 µg). We found no association between treatment rate and other physician characteristics. GPs were more reluctant to initiate treatment in 85-year-old than in 70-year-old women (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.63-0.94), and more likely to treat women with a TSH of 15 mU/l than those with a TSH of 6mU/l (OR 8.71, 95% CI 6.21-12.20). CONCLUSIONS: There are strong variations in treatment strategies for elderly patients with subclinical hypothyroidism across different Swiss regions, including use of higher starting doses than the recommended 25 µg in the Swiss guidelines, which recommend a starting dose of 25 µg. These variations likely reflect the current uncertainty about the benefits of treatment, which arise from the current lack of evidence from adequately powered clinical trials.

Epidemiology of multiple congenital anomalies in Europe: a EUROCAT population-based registry study.

BACKGROUND: This study describes the prevalence, associated anomalies, and demographic characteristics of cases of multiple congenital anomalies (MCA) in 19 population-based European registries (EUROCAT) covering 959,446 births in 2004 and 2010. METHODS: EUROCAT implemented a computer algorithm for classification of congenital anomaly cases followed by manual review of potential MCA cases by geneticists. MCA cases are defined as cases with two or more major anomalies of different organ systems, excluding sequences, chromosomal and monogenic syndromes. RESULTS: The combination of an epidemiological and clinical approach for classification of cases has improved the quality and accuracy of the MCA data. Total prevalence of MCA cases was 15.8 per 10,000 births. Fetal deaths and termination of pregnancy were significantly more frequent in MCA cases compared with isolated cases (p < 0.001) and MCA cases were more frequently prenatally diagnosed (p < 0.001). Live born infants with MCA were more often born preterm (p < 0.01) and with birth weight < 2500 grams (p < 0.01). Respiratory and ear, face, and neck anomalies were the most likely to occur with other anomalies (34% and 32%) and congenital heart defects and limb anomalies were the least likely to occur with other anomalies (13%) (p < 0.01). However, due to their high prevalence, congenital heart defects were present in half of all MCA cases. Among males with MCA, the frequency of genital anomalies was significantly greater than the frequency of genital anomalies among females with MCA (p < 0.001). CONCLUSION: Although rare, MCA cases are an important public health issue, because of their severity. The EUROCAT database of MCA cases will allow future investigation on the epidemiology of these conditions and related clinical and diagnostic problems.

Congenital heart disease in pregnancies complicated by maternal diabetes mellitus. An international clinical collaboration, literature review, and meta-analysis.

PURPOSE: Investigation of the incidence and distribution of congenital structural cardiac malformations among the offspring of mothers with diabetes type 1 and of the influence of periconceptional glycemic control. METHODS: Multicenter retrospective clinical study, literature review, and meta-analysis. The incidence and pattern of congenital heart disease in the own study population and in the literature on the offspring of type 1 diabetic mothers were compared with the incidence and spectrum of the various cardiovascular defects in the offspring of nondiabetic mothers as registered by EUROCAT Northern Netherlands. Medical records were, in addition, reviewed for HbA(1c) during the 1st trimester. RESULTS: The distribution of congenital heart anomalies in the own diabetic study population was in accordance with the distribution encountered in the literature. This distribution differed considerably from that in the nondiabetic population. Approximately half the cardiovascular defects were conotruncal anomalies. The authors' study demonstrated a remarkable increase in the likelihood of visceral heterotaxia and variants of single ventricle among these patients. As expected, elevated HbA(1c) values during the 1st trimester were associated with offspring fetal cardiovascular defects. CONCLUSION: This study shows an increased likelihood of specific heart anomalies, namely transposition of the great arteries, persistent truncus arteriosus, visceral heterotaxia and single ventricle, among offspring of diabetic mothers. This suggests a profound teratogenic effect at a very early stage in cardiogenesis. The study emphasizes the frequency with which the offspring of diabetes-complicated pregnancies suffer from complex forms of congenital heart disease. Pregnancies with poor 1st-trimester glycemic control are more prone to the presence of fetal heart disease.

Rare chromosome abnormalities, prevalence and prenatal diagnosis rates from population-based congenital anomaly registers in Europe.

The aim of this study is to quantify the prevalence and types of rare chromosome abnormalities (RCAs) in Europe for 2000-2006 inclusive, and to describe prenatal diagnosis rates and pregnancy outcome. Data held by the European Surveillance of Congenital Anomalies database were analysed on all the cases from 16 population-based registries in 11 European countries diagnosed prenatally or before 1 year of age, and delivered between 2000 and 2006. Cases were all unbalanced chromosome abnormalities and included live births, fetal deaths from 20 weeks gestation and terminations of pregnancy for fetal anomaly. There were 10,323 cases with a chromosome abnormality, giving a total birth prevalence rate of 43.8/10,000 births. Of these, 7335 cases had trisomy 21,18 or 13, giving individual prevalence rates of 23.0, 5.9 and 2.3/10,000 births, respectively (53, 13 and 5% of all reported chromosome errors, respectively). In all, 473 cases (5%) had a sex chromosome trisomy, and 778 (8%) had 45,X, giving prevalence rates of 2.0 and 3.3/10,000 births, respectively. There were 1,737 RCA cases (17%), giving a prevalence of 7.4/10,000 births. These included triploidy, other trisomies, marker chromosomes, unbalanced translocations, deletions and duplications. There was a wide variation between the registers in both the overall prenatal diagnosis rate of RCA, an average of 65% (range 5-92%) and the prevalence of RCA (range 2.4-12.9/10,000 births). In all, 49% were liveborn. The data provide the prevalence of families currently requiring specialised genetic counselling services in the perinatal period for these conditions and, for some, long-term care.

Paper 2: EUROCAT public health indicators for congenital anomalies in Europe.

OBJECTIVE: The purpose of this article is to present the specific public health indicators recently developed by EUROCAT that aim to summarize important aspects of the public health impact of congenital anomalies in a few quantitative measures. METHODS: The six indicators are: (1) congenital anomaly perinatal mortality, (2) congenital anomaly prenatal diagnosis prevalence, (3) congenital anomaly termination of pregnancy, (4) Down syndrome livebirth prevalence, (5) congenital anomaly pediatric surgery, and (6) neural tube defects (NTD) total prevalence. Data presented for this report pertained to all cases (livebirths, fetal deaths, or stillbirths after 20 weeks of gestation and terminations of pregnancy for fetal anomaly [TOPFA]) of congenital anomaly from 27 full member registries of EUROCAT that could provide data for at least 3 years during the period 2004 to 2008. Prevalence of anomalies, prenatal diagnosis, TOPFA, pediatric surgery, and perinatal mortality were calculated per 1000 births. RESULTS: The overall perinatal mortality was approximately 1.0 per 1000 births for EUROCAT registries with almost half due to fetal and the other half due to first week deaths. There were wide variations in perinatal mortality across the registries with the highest rates observed in Dublin and Malta, registries in countries where TOPFA are illegal, and in Ukraine. The overall perinatal mortality across EUROCAT registries slightly decreased between 2004 and 2008 due to a decrease in first week deaths. The prevalence of TOPFA was fairly stable at about 4 per 1000 births. There were variations in livebirth prevalence of cases typically requiring surgery across the registries; however, for most registries this prevalence was between 3 and 5 per 1000 births. Prevalence of NTD decreased by about 10% from 1.05 in 2004 to 0.94 per 1000 in 2008. CONCLUSION: It is hoped that by publishing the data on EUROCAT indicators, the public health importance of congenital anomalies can be clearly summarized to policy makers, the need for accurate data from registries emphasized, the need for primary prevention and treatment services highlighted, and the impact of current services measured.

Cardiopathies congénitales de l'âge adulte: nouvelle population de patients, prise en charge multidisciplinaire [Adults with congenital heart diseases: a growing population, a multidisciplinary approach].

Untill recently, congenital heart disease was considered as a childhood's disease. With improvement in pediatric survival, adults with a congenital heart disease (ACHD) represent an emerging group of patients who need specialized medical care. In 2010, the ESC published newguidelines on global and specific management of adults with congenital heart disease. ACHD centers organize appropriate medical care for these patients, promote specialist training and national scientific research in collaboration with other national ACHD centers.

Subclinical hypothyroidism and the risk of coronary heart disease and mortality: an individual participant data analysis from nine prospective cohort studies

Texte intégral: http://www.springerlink.com/content/3q68180337551r47/fulltext.pdf

Treatment of congenital aortic valve stenosis: impact of the Ross operation.

GOAL: To evaluate the impact of the Ross operation, recently (1997) introduced in our unit, for the treatment of patients with congenital aortic valve stenosis. METHODS: The period from January 1997 to December 2000 was compared with the previous 5 years (1992-96). Thirty-seven children (< 16 yrs) and 49 young adults (16-50 yrs) with congenital aortic valve stenosis underwent one of these treatments: percutaneous balloon dilatation (PBD), aortic valve commissurotomy, aortic valve replacement and the Ross operation. The Ross operation was performed in 16 patients, mean age 24.5 yrs (range 9-46 yrs) with a bicuspid stenotic aortic valve, 7/10 adults with calcifications, 2/10 adults with previous aortic valve commissurotomy, 4/6 children with aortic regurgitation following PBD, and 1/6 children who had had a previous aortic valve replacement with a prosthetic valve and aortic root enlargement. RESULTS: PBD was followed by death in two neonates (fibroelastosis); all other children survived PBD. Although there were no deaths, PBD in adults was recently abandoned, owing to unfavourable results. Aortic valve commissurotomy showed good results in children (no deaths). Aortic valve replacement, although associated with good results (no deaths), has been recently abandoned in children in favour of the Ross operation. Over a mean follow-up of 16 months (2-40 months) all patients are asymptomatic following Ross operation, with no echocardiographic evidence of aortic valve regurgitation in 10/16 patients and with trivial regurgitation in 6/16 patients. CONCLUSIONS: The approach now for children and young adults with congenital aortic valve stenosis should be as follows: (1) PBD is the first choice in neonates and infants; (2) Aortic valve commissurotomy is the first choice for children, neonates and infants after failed PBD; (3) The Ross operation is increasingly used in children after failed PBD and in young adults, even with a calcified aortic valve.