Improvement in screening performance and diagnosis of congenital hypothyroidism in Scotland 1979-2003

Hypothyroidism in First-Degree Relatives of Neonates with Congenital Hypothyroidism: Is there an Association?

Background

Recent studies have shown an increased incidence of congenital hypothyroidism (CH), especially in the middle-east region. The exact etiology is unknown; however, it has been related to several factors, the most noticeable being the high prevalence of transient CH (TCH), parental consanguinity, and the history of hypothyroidism in relatives. We sought to determine the impact of hypothyroidism in the relatives of patients with the observed trend.

Methods

We included all patients with primary CH detected through the Newborn Screening (NBS) Program from 2007 to 2016. We analyzed the impact of consanguinity relationship, parental and siblings' thyroid function, second-degree relatives' thyroid function, parental educational level, age, and maternal gestational diabetes on the development of permanent CH (PCH) and TCH.

Results

A total of 1447 consecutive eligible patients were recruited during the study period. Of this number, 1171 (81%) were diagnosed with CH: 623 (53.2%) had PCH and 548 (46.8%) had TCH. Six hundred thirty-three (54.1%) participants were men, and 814 (69.5%) had a history of relatives' hypothyroidism. Our data analysis revealed a significant difference regarding the male gender, having a history of relatives' hypothyroidism, and parental hypothyroidism compared to TCH ones (P < 0.05). Patients with a history of relatives' hypothyroidism had significantly higher PCH than TCH (P < 0.0001). However, consanguineous marriage was not comparable in patients regardless of their history of relatives' hypothyroidism (P-value >0.884).

Conclusions

Our findings indicated the role of the history of hypothyroidism in neonates' relatives in the evolution of the PCH. Meanwhile, consanguineous marriage did not impress the development of PCH and TCH.

Congenital Hypothyroidism: Space-Time Clustering of Thyroid Dysgenesis Indicates a Role for Environmental Factors in Disease Etiology

Background: The etiology of most cases of congenital hypothyroidism (CHT) due to thyroid dysgenesis (DG) is unknown. If transient environmental factors can impact on thyroid gland development, then clustering of cases in time and/or space may occur, and this would be more likely in thyroid DG than dyshormonogenesis (DHG). Methods: The newborn screening program for CHT in Scotland is linked to a central database that includes case details such as postcode. The etiology of CHT is investigated in many cases of CHT using scintigraphy and/or ultrasonography. We looked for evidence of a change in CHT incidence with year of birth and according to season of the year. We then undertook space-time clustering analysis (using a method based on K-functions, with nearest neighbor thresholds) of CHT in Scotland between 1979 and 2015. We also looked for evidence of overall changes associated with sex and area-based birth density. Results: Of 531 cases with CHT during the study period, 290 cases had been categorized as DG (n = 229) or DHG (n = 61) following more detailed investigation. The incidence of CHT increased with year of birth and was in part linked to changing methodology, but there was no seasonality. There was no evidence of overall space-time clustering (p = 0.06), but there was evidence of clustering in babies with DG (p = 0.007). This picture appeared to be most closely linked to underlying thyroid gland hypoplasia rather than thyroid gland agenesis or ectopia. There was significant space-time clustering for both males and females, but clustering was restricted to lesser birth density areas. There was also evidence of clustering for unknown cases (p < 0.001). Clustering of these cases was restricted to females but was present for cases from both greater and lesser birth density areas. There was no evidence of clustering in cases of DHG. Conclusions: These data suggest that an unidentified environmental factor or factors may be involved in the etiology of thyroid DG in Scotland. The variation in CHT incidence observed internationally may reflect environmental as well as genetic factors.

Newborn screening for congenital hypothyroidism: improvement in short-term follow-up by audit and monitoring

OBJECTIVE

Newborn screening for congenital hypothyroidism (CH) at our hospital during this study was by measurement of thyroid stimulating hormone (TSH) in serum samples. This audit was conducted over a 2 year period, to determine the compliance of reporting of results greater than the screening cutoffs for serum TSH. Gaps of non-compliance were identified, and re-audit was undertaken after the corrective actions were taken.

RESULTS

The critical limit was defined as serum TSH (≥ 20 µIU/ml) following consultation with a pediatric endocrinologist. All results above this limit were reported urgently to physicians. During the audit period, 27,407 tests were performed, 0.7% had a value of ≥ 20 µIU/ml, of those only 62% were reported to the general paediatrician or neonatologist. Reasons for not reporting results included non-availability of contact information, lack of policy awareness by technologists, critical results not highlighted on the computer display, and absence of regular monitoring. Corrective measures were taken, and re-audit was done. During the re-audit period, a total of 22,985 tests was performed, 0.6% had a value of ≥ 20 µIU/ml. Of these, 77% were reported to the general paediatrician or neonatologist. Critical result reporting was improved after the audit, and further enhanced the laboratory service of CH screening.

Determination of thyroid volume in infants with suspected congenital hypothyroidism-the limitations of both subjective and objective evaluation

Objective:

To compare two methods of assessing gland size on thyroid ultrasound in newborn infants with suspected congenital hypothyroidism (CH).

Methods:

Images from infants with eutopic glands referred between 2007 and 2013 were evaluated blind by two sets of observers. Subjective gland size was categorised as small, borderline-small, normal, borderline-large and large. Objective gland volume, calculated as the sum of each lobe using the prolate ellipsoid formula (length x width x depth x π/6), was put into corresponding categories: <0.8, 0.81–1.0, 1.1– <2.2, 2.2–2.4 and >2.4 ml, derived from normative Scottish data.

Results:

Of 36 infants, permanent CH was present in 17, transient CH in 17, status uncertain in 2. Mean (SD) intraobserver error for thyroid volume measurement was 0.11 (0.23) ml [8.3%]. Subjective assessment by two observers was discordant in only four (10.8%) infants. However, subjective vs objective evaluation was discordant in 14 (39%). Eight (three permanent, five transient CH) had large glands subjectively but normal glands objectively; and six (four transient CH) had normal glands subjectively but small glands objectively. The former infants all showed a single flattened curve to the anterior thyroid margin, giving an impression of bulkiness. Gland shape was normal in the latter infants.

Conclusion:

Neither subjective nor objective evaluation predicts permanent vs transient CH. Altered gland shape may confound both methods, and undermine use of the conventional formula for measuring lobe volume.

Advances in knowledge:

Until more refined methods are available for assessing thyroid size, both subjective and objective evaluation are recommended in CH.

Higher prevalence of permanent congenital hypothyroidism in the Southwest of Iran mostly caused by dyshormonogenesis: a five-year follow-up study

OBJECTIVE

The incidence of congenital hypothyroidism (CH) varies globally. This 5-year study aimed to determine the prevalence of permanent CH in the southwest of Iran.

MATERIALS AND METHODS

Between January 2007 and December 2009, all newborns in Ahvaz, the biggest city in the southwest of Iran, were screened for CH using a heel-prick sample for thyrotropin (TSH) levels. Subjects with TSH ≥ 5 mU/L were evaluated for T4-TSH. Infants with T4 < 6.5 µg/dL, TSH > 10 mU/L, and normal T4 but persistent (> 60 days) high TSH were considered to have CH. After the third birthday, treatment was discontinued, and T4-TSH was reevaluated; subjects with TSH ≥ 10 mU/L were investigated using thyroid Tc99 scintigraphy (TS). Based on TS, they were classified as normal, dysgenetic, or athyretic (agenesis).

RESULTS

Screening was performed for 86,567 neonates, and 194 were confirmed to have CH (100 males; F/M = 0.94; overall incidence 1:446). After the third birthday, reevaluation was performed in all (except 18 that were not accessible). From 176 patients, 81 (46%) were diagnosed with permanent CH, and 95 were discharged as transient. Considering the same percentage in the lost cases, the prevalence of permanent CH was found to be 1:970. TS performed for 53 of the permanent subjects found agenesis/dysgenesis in 25 (F:M = 15:10) and a normal result in 28 (F:M = 11:17), indicating dyshormonogenesis as the cause in more than 50% of subjects.

CONCLUSIONS

The incidence of CH in this area was found to be higher than that in other countries but less than the incidence rate reported in central Iran. The large number of transient cases of CH suggests environmental or maternal causes for the incidence rather than a genetic basis.

Trends in Scottish newborn screening programme for congenital hypothyroidism 1980-2014: strategies for reducing age at notification after initial and repeat sampling

OBJECTIVES

To determine ages at first capillary sampling and notification and age at notification after second sampling in Scottish newborns referred with elevated thyroid-stimulating hormone (TSH).

SUBJECTS AND METHODS

Referrals between 1980 and 2014 inclusive were grouped into seven 5-year blocks and analysed according to agreed standards.

RESULTS

Of 2 116 132 newborn infants screened, 919 were referred with capillary TSH elevation ≥8 mU/L of whom 624 had definite (606) or probable (18) congenital hypothyroidism. Median age at first sampling fell from 7 to 5 days between 1980 and 2014 (standard 4-7 days), with 22, 8 and 3 infants sampled >7 days during 2000-2004, 2005-2009 and 2010-2014. Median age at notification was consistently ≤14 days, range falling during 2000-2004, 2005-2009 and 2010-2014 from 6 to 78, 7-52 and 7-32 days with 12 (14.6%), 6 (5.6%) and 5 (4.3%) infants notified >14 days. However 18/123 (14.6%) of infants undergoing second sampling from 2000 onwards breached the ≤26-day standard for notification. By 2010-2014, the 91 infants with confirmed congenital hypothyroidism had shown favourable median age at first sample (5 days) with start of treatment (10.5 days) approaching age at notification.

CONCLUSION

Most standards for newborn thyroid screening are being met by the Scottish programme, but there is a need to reduce age range at notification, particularly following second sampling. Strategies to improve screening performance include carrying out initial capillary sampling as close to 96 hours as possible; introducing 6-day laboratory reporting and use of electronic transmission for communicating repeat requests.

Congenital Hypothyroidism in Neonates of a Tertiary Care Hospital

OBJECTIVE

To determine neonatal congenital hypothyroidism among neonates born in a tertiary care hospital of Lahore Pakistan.

METHODS

This cross-sectional study was carried out at Pathology Department of Allama Iqbal Medical College, Lahore in collaboration with Pediatrics and Gynecology & Obstetrics Department, Jinnah Hospital, Lahore Pakistan. A total of 770 babies were included in this study, both male and female. About 2 ml venous blood samples were collected aseptically from the neonates in sterile clotted tube. Serum was separated and serum TSH was determined by ELISA method.

RESULTS

Out of total 770 neonates, 48.9% were female and 51.0% were males with the ratio of 1:1.04. Neonatal congenital hypothyroidisim (TSH, >30 mIU/L), was observed in 0.4% (Frequency, 1:257) nenates, with the incidence rate of 1:257. Female to male ratio of hypothyroid neonates was 2:1. The mode of delivery vise distribution showed, among n=251 neonates born by normal delivery, only a single case of hypothyroidism was detected, and among n=519 neonates delivered by cesarean section, only two neonates were belong to hypothyroidism.

CONCLUSION

The frequency of Congenital Hypothyroidism is notably higher in pediatric community than reported in most other countries. This result emphasizes the necessity of a nationwide screening program.

How well does the capillary thyroid-stimulating hormone test for newborn thyroid screening predict the venous free thyroxine level?

OBJECTIVES

To determine, in newborn infants referred with elevated capillary thyroid-stimulating hormone (TSH), a threshold below which a frankly subnormal venous free thyroxine (fT4) level of <10 pmol/L is unlikely, so that treatment with levo-thyroxine (L-T4) might be deferred until venous thyroid function tests (TFTs) become available.

SUBJECTS AND METHODS

All infants referred in Scotland since 1979 with capillary TSH elevation were studied, with particular focus on infants screened using the AutoDELFIA assay between 2002 and 2013.

RESULTS

Of the 321 infants referred with capillary TSH elevation using AutoDELFIA, 35 were excluded (fT4/TSH unavailable (12), venous sample either preceding or >10 days after capillary sampling (13, 10)), leaving 286 eligible for analysis (208 definite/probable hypothyroidism, 61 transient TSH elevation, 17 of uncertain thyroid status). Capillary TSH and venous T4 were strongly correlated (Spearman's rank correlation coefficient -0.707355). The optimal capillary TSH threshold for predicting a venous fT4 of <10 pmol/L was found to be >40 mU/L (90.3% sensitivity and 65.9% specificity compared with 90.25% and 59.1% for >35 mU/L and 88.3% and 68.2% for >45 mU/L). 93 infants (32.5%) had capillary TSH ≤40 mU/L at referral of whom 15 (9.7%) had venous fT4 <10 pmol/L, comprising seven with true congenital hypothyroidism, five with transient TSH elevation and three with uncertain status, two of whom died.

CONCLUSION

For infants in whom capillary TSH is ≤40 mU/L, it is reasonable to defer L-T4 treatment until venous TFT results are known provided that the latter become available quickly.

Diagnostic and predictive value of ultrasound and isotope thyroid scanning, alone and in combination, in infants referred with thyroid-stimulating hormone elevation on newborn screening

OBJECTIVE

To determine the diagnostic and predictive value of ultrasound and radioisotope scans of the thyroid, alone and in combination, during a single visit after initial referral by the screening laboratory with thyroid-stimulating hormone (TSH) elevation.

STUDY DESIGN

Retrospective blind review of ultrasound and radioisotope images followed by final diagnosis based on clinical features, biochemistry, imaging, and molecular genetic study.

RESULTS

Infants (n = 97; 61 female) with median birthweight 3.38 kg (range 2.04-4.86) and gestation 40 weeks (range 33-42), underwent successful dual thyroid ultrasound and technetium-99m pertechnetate radioisotope scan in a single center. Combined scanning at the initial visit resulted in a correct final diagnosis in 79 of 97 (81%) cases. One patient was misdiagnosed initially as having athyreosis as the result of delayed radioisotope scan and the diagnosis of ectopia made later on diagnostic challenge. The specificity/sensitivity for radioisotope scan and for ultrasound was as follows: 100%/97% and 100%/55% for ectopia (n = 39); 81%/100% and 54%/100% for athyreosis (n = 18); and 89%/90% and 80%/95% for dyshormonogenesis (n = 20). Neither modality, alone or in combination, predicted final diagnosis in eutopic glands due to hypoplasia (n = 4), transient TSH elevation (n = 12), and status still uncertain (n = 4).

CONCLUSION

More than 80% of newborn infants with TSH elevation can be diagnosed correctly on initial imaging with combined radioisotope scan and ultrasound. Ultrasound cannot reliably detect thyroid ectopia. Radioisotope scan, especially if performed late, may show no uptake despite the presence of a eutopic gland.

Incidence of congenital hypothyroidism in the city of Uberaba/Minas Gerais and etiological evaluation of the affected subjects

OBJECTIVE

The objective of this study was to determine the incidence and etiology of congenital hypothyroidism (CH) in Uberaba, MG.

SUBJECTS AND METHODS

From 2001 to 2010, by reviewing patient files from a public reference outpatient unit. The screening program covered 88% of live-born children.

RESULTS

CH was diagnosed in 16 children, representing an incidence of 1:2,017 live-born children screened. The etiological evaluation was done in 15 children and revealed seven cases of thyroid dysgenesis, seven of dyshormonogenesis, and one case of transient hypothyroidism. One child moved away from the state before etiological investigation was carried out.

CONCLUSION

We concluded that both the incidence of CH and of dyshormonogenesis as the main causes of CH were increased in the investigated region, but molecular studies are necessary for a better definition of etiology.

Optimising outcome in congenital hypothyroidism; current opinions on best practice in initial assessment and subsequent management

Congenital hypothyroidism (CH), usually of the primary and permanent variety, is an eminently preventable cause of growth retardation and mental handicap whose outlook has been transformed by newborn screening, usually involving the measurement of capillary thyroid stimulating hormone (TSH). Severe primary CH, due for example to athyreosis, may result in subtle cognitive, behavioural and sensori-motor deficits, but the extent to which these can be offset by optimal postnatal diagnosis and management remains uncertain. This is because the available adult follow-up data reflect the outcome of previous management in the 1970's and 1980's, and also because the accurate neuro-psychological assessment of children is difficult, particularly in the preschool population. There is an urgent need to develop new consensus guidelines and to ensure that the children managed according to such guidelines are systematically and prospectively assessed so that good quality outcome data become available. In this review, key recommendations in the management of CH include: screening at day 3 so that severely affected infants can begin treatment within the first 10 days of life; setting the TSH referral cut-off at 8-10 mU/L; adopting a disciplined diagnostic algorithm to evaluate referred cases, with measurement of venous free thyroxine (T4), TSH and thyroglobulin combined with dual ultrasound and radioisotope imaging; initial treatment with a T4 dose of 50 μg daily in infants weighing ≥ 2.5 kg and 15 μg/kg/day in infants weighing < 2.5 kg followed by weekly review until thyroid function is normalised; and maintenance of free T4 levels between 15-26 pmol/L and TSH between 0.5-5 mU/L thereafter to avoid both under- and overtreatment.

Epidemiology and clinical characteristics of congenital hypothyroidism in an Asian population: a nationwide population-based study

Background

The incidence of congenital hypothyroidism (CH) has been increasing in Western countries, and some populations, including Asians, have a higher incidence. Delayed diagnosis and early treatment influence the outcome of CH. We investigated the incidence and clinical characteristics of CH in Taiwan.

Methods

In this retrospective database study we identified cases of CH diagnosed during 1997–2008 in the Taiwan National Health Insurance Research Database (NHIRD). Patients who had a Serious Accidents and Diseases certificate were included in the incidence calculation. We focused on CH patients who were born during 1997–2003 and determined their age at diagnosis and CH-related clinical features. Mental retardation and physiological delays were evaluated with respect to age at diagnosis.

Results

A total of 1482 cases were identified. Incidence during the 12-year period was 5.02 per 10 000 births. Among 1115 patients, the most common clinical features of CH were developmental delay (9.6%), constipation (11.6%), and delayed physiological development (9.1%). Congenital anomalies of the heart (7.7%), epilepsy (2.7%), and infantile cerebral palsy (3.2%) were also noted. Survival analysis showed that the risks of mental retardation (hazard ratio [HR], 3.180) and delayed physiological development (HR, 1.908) were greater when age at diagnosis was greater than 1 year.

Conclusions

CH incidence was higher in Taiwan than in Western countries. Early diagnosis may decrease the risk of mental and physiological delay.

[Newborn Screening Program for congenital hypothyroidism of the State of Santa Catarina, Brazil: etiological investigation in the first visit]

OBJECTIVE

To evaluate the etiology of primary congenital hypothyroidism (PCH) identified in the Newborn Screening Program from the state of Santa Catarina, Brazil, from July 2007 to June 2009 in the first visit.

SUBJECTS AND METHODS

A prospective study was performed in 45 patients with PCH. For the etiological diagnosis, history, physical examination, and additional tests (TSH, free thyroxine, thyroglobulin, bone age assessment, thyroid ultrasound) were carried out in the first visit.

RESULTS

The etiology was established in the first visit in 53.3% of cases. Thyroid dysgenesis represented 51.11% of the cases, from which 20% showed hypoplastic thyroid, 13.3% showed athyreosis, and 17.7% showed ectopic glands; 2.2% were diagnosed with dyshormonogenesis. Umbilical hernia was the most prevalent sign (48.89%) and 20% had no clinical manifestations. Patients with dysgenesis showed significant differences (p < 0.05) in terms of cesarean section delivery, delayed bone age, and very high serum TSH.

CONCLUSIONS

The diagnostic approach used at first visit for PCH patients may determine the etiology in 53.3% of cases. Half of patients had thyroid dysgenesis.

Congenital hypothyroidism with neurological and respiratory alterations: a case detected using a variable diagnostic threshold for TSH

We report a case of congenital hypothyroidism (CH) with neurological and respiratory alterations due to a heterozygotic c.374-1G > A mutation of TITF1/NKX2-1. The hypothyroidism was detected using a neonatal screening protocol in which the thyroid stimulating hormone (TSH) threshold is re-set each day on the basis of within-day variability and between-day variation. In this case, the threshold on the day of the initial analysis was 8.2 mIU/L, and the measured TSH level in heel-prick blood was 8.3 mIU/L.

Space-time clustering of elevated thyroid stimulating hormone levels

Previous studies of congenital hypothyroidism (CHT) have reported an increasing incidence which may suggest that environmental factors play an aetiological role. If so, then cases may exhibit space-time clustering, where cases occur at similar times and close proximities to other cases. In this study we investigated whether space-time clustering of elevated thyroid stimulating hormone (TSH) in newborns exists. All infants born in the Northern Region of England are screened by measuring levels of circulating TSH using a blood spot assay. Data on 207 cases of elevated TSH values, as a proxy for CHT, in newborns born from 1994 to 2006 inclusive were available and analysed using rigorous space-time clustering statistical methods. Analysis showed statistically significant evidence of space-time clustering. The strength of clustering was most marked for cases born within 0.1-0.7 year (1-8 months) of one another. This is the first study to find significant space-time clustering of cases of elevated TSH levels in newborns, a surrogate for space-time clustering of CHT. Whilst the reasons for the clustering are unclear, it would appear from this analysis that transient environmental exposures are likely to be involved, although environmental determinants of genetic mutations and epigenetic factors cannot be ruled out. Further research is required to a) validate these results in other populations and b) to assess in more detail the potential environmental determinants of increased CHT risk.

Prevalence of congenital hypothyroidism--current trends and future directions: workshop summary

In response to published newborn-screening data that have shown an increase in the incidence (birth prevalence) rate of primary congenital hypothyroidism (CH) in the United States, a workshop was held in Atlanta, Georgia, on February 27 and 28, 2008, to examine this issue. Topics of the meeting included pathophysiology, medical management, and follow-up of CH; transient hypothyroidism (etiology, clinical implications, management, and changes in prevalence); risk factors for CH; laboratory approaches to newborn screening for CH; state-specific evaluations of trends in incidence rates of CH; and concluding discussions on future directions to resolve outstanding issues. Through presentations and discussion, gaps in knowledge were identified, such as the lack of consistent definitions for CH and transient hypothyroidism and the effects of preventable risk factors on incidence rates of CH. One outcome of the meeting was a series of accompanying articles that examined (1) trends in the incidence rates of CH in individual states and nationally, (2) effects of newborn-screening practices on CH-incidence rates, (3) the contribution of transient hypothyroidism to CH-incidence rates, and (4) future research directions. In this summary, we briefly touch on the topics of these articles and examine highlights of other presentations from the workshop that illuminated the secular trends in reported CH-incidence rates in the United States.

The impact of transient hypothyroidism on the increasing rate of congenital hypothyroidism in the United States

The reported incidence rate of primary congenital hypothyroidism (CH) has been increasing in the United States over the past 2 decades. We have considered the possibility that the inclusion of cases of transient hypothyroidism has inflated the reported incidence rate of CH. Assessing the effects of cases of transient hypothyroidism on the incidence rate is problematic, because the definitions, diagnostic criteria, and differentiation from transient hyperthyrotropinemia vary widely among state newborn screening programs. Among the 4 etiologies for transient hypothyroidism (maternal thyrotropin receptor-blocking antibodies, exposure to maternal antithyroid medications, iodine deficiency, and iodine excess), there is little evidence of increases in the incidence rate from thyrotropin receptor-blocking antibodies. Exposure to antithyroid drugs could contribute significantly to the incidence rate of transient CH, given the high estimated incidence of active maternal hyperthyroidism. Iodine deficiency or excess in the United States seems unlikely to have contributed significantly to the incidence rate of CH, because the secular trend toward lower iodine intake among women of reproductive age in the 1980s and 1990s seems to have plateaued, and perinatal iodine exposure has presumably declined as a result of recommendations to discontinue using iodine-containing disinfectants. Although the female-to-male sex ratio among newborns with thyroid agenesis or dysgenesis (the most common causes of CH) is typically 2:1, analysis of the sex ratio of newborns diagnosed with presumed CH in the United States suggests that a substantial proportion might have transient hypothyroidism or hyperthyrotropinemia, because the sex ratio has been well below the expected 2:1 ratio. Combined ultrasonography and (123)I scintigraphy of the thyroid gland are effective tools for identifying cases of thyroid agenesis and dysgenesis and can help to differentiate cases of transient hypothyroidism from true CH. Imaging is also a vital component in evaluating children who, at 3 years of age, undergo a trial of discontinuation of levothyroxine treatment to test for persistence of hypothyroidism. Ultimately, thyroid gland imaging, in conjunction with long-term follow-up studies that appropriately assess and report whether there was permanence of hypothyroidism, will be necessary to address the true incidence rate of CH and any contribution to the observed rate by transient cases of hypothyroidism or hyperthyrotropinemia.

Discontinuation of thyroid hormone treatment among children in the United States with congenital hypothyroidism: findings from health insurance claims data

BACKGROUND

Thyroid hormone treatment in children with congenital hypothyroidism can prevent intellectual disability. Guidelines recommend that children diagnosed with congenital hypothyroidism through newborn screening remain on treatment to at least 3 years of age, after which a trial off therapy can determine which children have transient hypothyroidism. The purpose of this study was to describe the rate at which children with congenital hypothyroidism in the United States discontinue thyroid hormone treatment in early childhood.

METHODS

Retrospective analysis of the 2002-2006 MarketScan(R) Commercial Claims and Encounters research databases and the 2001-2005 MarketScan Multi-State Medicaid databases. Children were classified as having congenital hypothyroidism based on billing codes and having filled a prescription for thyroid hormone treatment. Kaplan-Meier curve analysis was used to determine discontinuation rates.

RESULTS

There were a total of 412 Medicaid-enrolled children and 292 privately-insured children with presumed congenital hypothyroidism included in this study. The overall birth prevalence of congenital hypothyroidism across both datasets was about 1 per 2,300. By 36 months, the percentage who had discontinued thyroid replacement treatment was 38% (95% Confidence Interval: 32%-44%). Medicaid-enrolled children had a more rapid decline in the first 24 months of treatment compared to those with private insurance (P = 0.02).

CONCLUSIONS

More than one-third of children treated for congenital hypothyroidism discontinued treatment within 36 months, which is inconsistent with current guidelines. It is not known how many of these children required continued treatment or experience adverse effects from discontinuation. These findings emphasize the critical need for follow-up systems to monitor the outcome of newborn screening.

Increasing Incidence, but Lack of Seasonality, of Elevated TSH Levels, on Newborn Screening, in the North of England

Previous studies of congenital hypothyroidism have suggested an increasing incidence and seasonal variation in incidence, which may suggest nongenetic factors involved in aetiology. This study describes the incidence of elevated thyroid stimulating hormone (TSH) values in newborns, a surrogate for congenital hypothyroidism, measured as part of the screening programme for congenital hypothyroidism, over an eleven-year period (1994-2005), and assesses whether seasonal variation exists. All infants born in the Northern Region of England are screened by measuring levels of circulating TSH using a blood spot assay. Data on all 213 cases born from 1994 to 2005 inclusive were available. Annual incidence increased significantly from 37 per 100,000 in 1994 to a peak of 92.8 per 100,000 in 2003. There was no evidence of seasonal variation in incidence. The reasons for the increasing incidence are unclear, but do not appear to involve increasing exposure to seasonally varying factors or changes in measurements methods.

Update: newborn screening for endocrinopathies

Congenital hypothyroidism and congenital adrenal hyperplasia are included in many newborn screening (NBS) panels worldwide and in all state-sponsored programs in the United States. Both conditions meet the fundamental prerequisites for NBS: high incidence in the population; biomarkers in the dried blood specimen that are easily detected; and, effective therapies to lessen, if not prevent, the sequelae of late or no treatment. In this review, the history of NBS is discussed for these 2 conditions. The technologies and protocols used in their detection, and related subjects such as genetics, and treatment and outcomes, are also discussed.

Audit of initial management of congenital hypothyroidism in the United Kingdom--comparison of UK practice with European and UK guidelines

BACKGROUND

Prompt and adequate management of newly diagnosed congenital hypothyroidism (CH) has been shown to optimise intellectual outcome.

METHODS

A questionnaire survey of the British Society for Paediatric Endocrinology and Diabetes (BSPED) membership was undertaken, examining current clinical practice in neonatal CH. Results were compared with published management guidelines from Europe and the UK.

RESULTS

The response rate was 86%. The majority were largely compliant with both guidelines. 43% review newly referred infants on the day of notification. However, 26% treat severe CH with < 10 microg/kg/day thyroxine and nearly 20% do not follow up until at least 14 days after initiating treatment, in contrast to both guidelines. Despite a new liquid T4 preparation being licensed, respondents preferred tablet T4.

CONCLUSION

Rapidity of assessment and adequate follow up of suspected CH is critical to outcome. Existing European and UK guidelines should be reviewed and expanded to incorporate new evidence, together with increased advice on preparation and administration of T4.

Programa de Triagem Neonatal do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil

O Programa de Triagem Neonatal do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil, instituído em 1994 diagnosticou, até 2005, 76 crianças com hipotireoidismo congênito, 10 com fenilcetonúria e 25 com hemoglobinopatias, o que representou uma incidência de 1:2.595, 1:19.409, 1:4.120, respectivamente. Foram diagnosticadas 2.747 crianças com traço falciforme (1:37,5 nascidos vivos). A cobertura média do programa foi de 94,5%. Houve uma considerável melhora nos parâmetros de avaliação da qualidade do programa no período, porém, sem atingir os índices ideais. Campanhas visando à maior divulgação da importância da triagem neonatal são necessárias para aumentar a cobertura e a instituição do 3º dia de vida do recém-nascido como sendo o Dia do Teste do Pezinho poderia contribuir para que idades mais precoces de tratamento fossem atingidas, melhorando o prognóstico das crianças acometidas.

Birth prevalence of congenital hypothyroidism in Mexico

The Mexican Institute of Social Security (IMSS) provides care for more than 40% of the Mexican population. This report constitutes the first study of the incidence of congenital hypothyroidism (CH) in Mexican children. We performed a prospective study with a population base. CH screening began in 1997 with blood samples from the heel taken 72 h after birth; from 2000, the detection strategy was changed nationwide and blood samples were taken from the umbilical cord in all newborns for determination of thyroid-stimulating hormone (TSH) concentration. We evaluated the annual coverage. TSH concentration was measured by chemoluminescence; TSH values > or =30 microIU/mL in umbilical cord blood and 15 microIU/mL in capillary blood were considered positive cases and were confirmed through hormonal studies. The incidence and 95% confidence intervals [95% CI] were calculated. We found that coverage within the IMSS population was 53% from 1997 to 2000 and had increased to 95% by 2001. A total of 2,777,292 children from 2,975,157 births (93%) were studied between 2000 and 2004. Of these, 4050 had a high TSH concentration leading to suspicion of CH; CH was confirmed in 1286 (32%). The resulting incidence was 4.3/10,000 livebirths [95% CI 3.6, 5.1]. With the results obtained, we conclude that the IMSS strategy of CH screening at birth ensured 95% coverage of children in the system. The birth prevalence of CH reported is among the highest in the world.

Programa de triagem neonatal para hipotireoidismo congênito no nordeste do Brasil: critérios diagnósticos e resultados

Avaliamos as concentrações do TSH em papel-filtro colhido no calcanhar (TSHneo) de 48.039 crianças triadas do programa de triagem neonatal (PTN) para o hipotireoidismo congênito (HC) de Sergipe, as concentrações de TSH, T4 total e T4 livre colhidas em sangue periférico nas crianças convocadas suspeitas de HC, a idade nas diversas fases do programa, a cobertura e a freqüência do PTN de janeiro de 2005 a agosto de 2006, comparando-as com dados da literatura. Utilizamos para análise os seguintes parâmetros: média, mediana, coeficiente de variação e distribuição de freqüência. A idade da criança por ocasião da coleta em papel filtro no calcanhar foi 10 ± 9 dias (média ± desvio-padrão) e a idade na reali-zação do ensaio do TSHneo foi de 31 ± 13 dias. Em 2005, a cobertura do PTN, para o interior e para a capital de Sergipe, foi de 77% e 73%, respectivamente. Verificamos que em 99,484% das crianças triadas as concentrações do TSH coletado em papel-filtro encontravam-se entre 0,01 e 5,20 µU/mL. As concentrações do TSH decrescem com o aumento da idade até estabilizar entre 11 e 15 dias de vida. Foram convocadas 248 crianças a partir do TSH coletado em papel-filtro (1/194). Na convocação, as concentrações do TSH, T4 e T4 livre coletado por punção venosa estavam normais em 119 crianças (1/404). A freqüência de HC suspeito foi de 1/485 (99 casos), de HC foi de 1/6.005 (8 casos) e de hipotiroxinemia foi de 1/16.013 (3 casos). A terapia para o HC foi iniciada com 51 ± 12 dias.

The implementation of revised guidelines and the performance of a screening programme for congenital Hypothyroidism

Objectives

To see whether revised screening standards and health-professional training are associated with changes in the performance of a neonatal screening programme for congenital hypothyroidism (CHT).

Methods

Screening data from the regional screening service in Durham and Newcastle, which covers north-east England and North Cumbria.

Setting

We assessed the timing of the different stages of the screening process leading up to the introduction of the revised guidelines between April 2004 and March 2005 (year 1) and afterwards between April 2005 and March 2006 (year 2) in all babies notified as having CHT. We also assessed the interval between sampling and specimen arrival in the laboratory at the beginning and end of year 2 in all babies screened.

Results

Twenty-three babies tested positive or borderline in year 1 and 18 babies in year 2. There was reduced variability in the overall time from birth to notification in year 2 versus year 1 ( P = 0.001). This reduction was a consequence of a reduced interval between sample collection and arrival in the laboratory ( P = 0.047) and for the laboratory to notify the positive test result ( P = 0.003). There was a reduction in the mean time from sampling to receipt by the laboratory in the 2997 babies screened in the final month compared with the 2498 babies screened in the first month of year 2 ( P = 0.01).

Conclusion

There was an improvement in neonatal screening programme performance around the time that revised neonatal screening guidelines were introduced. This highlights the importance of ongoing education and training for those involved in screening programmes.

Quality performance of newborn screening systems: strategies for improvement

Newborn metabolic screening is a public health activity with the potential to realize significant health gains for infants affected with a range of congenital conditions. Many of these are inborn errors of metabolism. The activities required to achieve the gains are diverse and carried out by a number of organizations, by families and by many health care professionals. Laboratories have the best-developed quality strategies, which include quality assurance programmes, guidelines, protocols and standards. Two-tier testing and use of multiple markers improve sensitivity and specificity. There are international initiatives to harmonize assay materials and definitions to allow better benchmarking between programmes. Outside the laboratory, standards, education and protocols improve the quality of specimen collection, diagnosis and treatment, which together produce the health gains.

Combined ultrasound and isotope scanning is more informative in the diagnosis of congenital hypothyroidism than single scanning

BACKGROUND

Thyroid imaging is helpful in confirming the diagnosis of congenital hypothyroidism and in establishing the aetiology. Although isotope scanning is the standard method of imaging, ultrasound assessment may be complementary.

AIM

To determine the strengths and weaknesses of thyroid ultrasound and isotope scanning in neonates with thyroid stimulating hormone (TSH) elevation.

METHODS

Babies from the West of Scotland with raised capillary TSH (>15 mU/l) on neonatal screening between January 1999 and 2004 were recruited. Thyroid dimensions were measured using ultrasonography, and volumes were calculated. Isotope scanning was carried out with a pinhole collimator after an intravenous injection of 99m-technetium pertechnetate.

RESULTS

40 infants (29 female) underwent scanning at a median of 17 days (range 12 days to 15 months). The final diagnosis was athyreosis (n = 11), ectopia (n = 12), hypoplasia (n = 8; 3 cases of hemi-agenesis), dyshormonogenesis (n = 5), transient hypothyroidism (n = 2), transient hyperthyrotropinaemia (n = 1) and uncertain status with gland in situ (n = 1). 6 infants had discordant scans with no isotope uptake but visualisation of thyroid tissue on ultrasound. This was attributed to TSH suppression from thyroxine (n = 3); maternal blocking antibodies (n = 1); cystic degeneration of the thyroid (n = 1); and possible TSH receptor defect (n = 1).

CONCLUSIONS

Isotope scanning was superior to ultrasound in the detection of ectopic tissue. However, ultrasound detected tissue that was not visualised on isotope scanning, and showed abnormalities of thyroid volume and morphology. We would therefore advocate dual scanning in newborns with TSH elevation as each modality provides different information.