Transient hypothyroidism at 3-year follow-up among cases of congenital hypothyroidism detected by newborn screening

Congenital Hypothyroidism: Screening and Management

ABSTRACT

Untreated congenital hypothyroidism (CH) leads to intellectual disabilities. Prompt diagnosis by newborn screening (NBS) leading to early and adequate treatment results in grossly normal neurocognitive outcomes in adulthood. However, NBS for hypothyroidism is not yet established in all countries globally. Seventy percent of neonates worldwide do not undergo NBS.The initial treatment of CH is levothyroxine, 10 to 15 mcg/kg daily. The goals of treatment are to maintain consistent euthyroidism with normal thyroid-stimulating hormone and free thyroxine in the upper half of the age-specific reference range during the first 3 years of life. Controversy remains regarding detection of thyroid dysfunction and optimal management of special populations, including preterm or low-birth weight infants and infants with transient or mild CH, trisomy 21, or central hypothyroidism.Newborn screening alone is not sufficient to prevent adverse outcomes from CH in a pediatric population. In addition to NBS, the management of CH requires timely confirmation of the diagnosis, accurate interpretation of thyroid function testing, effective treatment, and consistent follow-up. Physicians need to consider hypothyroidism in the face of clinical symptoms, even if NBS thyroid test results are normal. When clinical symptoms and signs of hypothyroidism are present (such as large posterior fontanelle, large tongue, umbilical hernia, prolonged jaundice, constipation, lethargy, and/or hypothermia), measurement of serum thyroid-stimulating hormone and free thyroxine is indicated, regardless of NBS results.

Evaluation of permanent and transient congenital hypothyroidism in cases referred from National Neonatal Screening Program

AIM

The incidence of congenital hypothyroidism (CH) has increased world-wide. Lowering cut-off in screening programs has led to an increase in the rate of transient CH. We aimed to evaluate the rates of permanent and transient CH in cases referred from the screening program and to investigate the clinical and laboratory factors which predict transient CH.

METHODS

In 109 cases referred from the neonatal screening program to our hospital, from September 2015 to April 2018, 52 primarily diagnosed CH cases were prospectively evaluated. Regularly followed up, 44 CH cases were included in the study at the end of 3 years.

RESULTS

38.2 ± 1.31 weeks (w) and mean birthweight 3021.3 ± 389.6 gram (g) in the transient CH group; both were significantly lower compared to permanent CH cases with 39.06 ± 1.33 w and 3375.3 ± 425.3 g (P = 0.025, P = 0.007) respectively. Transient CH rate was found to be 50% (all hypoplastic) in the dysgenesis group and 73.3% in groups with normal and hyperplasic thyroid gland. While fT₄ , thyroid-stimulating hormone, and thyroglobulin levels at diagnosis do not predict transient/permanent CH, levothyroxine (LT-4) dosage was significantly lower in the transient CH group in all years. The optimal cut-off value with highest sensitivity and specificity for LT-4 dosage as a predictive marker to differentiate transient CH from permanent CH was 2.27 μg/kg/day (P = 0.004; sensitivity: 71%, specificity: 83%) at 1st year, 1.85 μg /kg/day (P = 0.013; sensitivity: 66%, specificity: 72%) at 2nd year and 1.69 μg /kg/day at 3rd year (P < 0.0001; sensitivity: 90%, specificity: 83%).

CONCLUSION

Transient CH is more frequent than expected. Our results suggest that LT-4 requirement may be a good marker for predicting transient CH, while thyroid hormone levels at the time of diagnosis do not significantly predict permanent and transient CH. Therefore, infants with CH requiring LT-4 doses <2.27 μg/kg/day at 1st year, <1.85 μg /kg/day at 2nd year may be re-evaluated earlier to discriminate transient CH rather than at 3 years of age.

Transient vs Permanent Congenital Hypothyroidism in Ontario, Canada: Predictive Factors and Scoring System

CONTEXT

The apparent increased incidence of congenital hypothyroidism (CH) is partly due to increased detection of transient disease.

OBJECTIVE

This work aims to identify predictors of transient CH (T-CH) and establish a predictive tool for its earlier differentiation from permanent CH (P-CH).

METHODS

A retrospective cohort study was conducted of patients diagnosed with CH from 2006 to 2015 through Newborn Screening Ontario (NSO).

RESULTS

Of 469 cases, 360 (76.8%) were diagnosed with P-CH vs 109 (23.2%) with T-CH. Doses of levothyroxine predicting T-CH were less than 3.9 μg/kg at age 6 months, less than 3.0 μg/kg at ages 1 and 2 years, and less than 2.5 μg/kg at age 3 years. Descriptive statistics and multivariable logistic modeling demonstrated several diverging key measures between patients with T-CH vs P-CH, with optimal stratification at age 1 year. Thyroid imaging was the strongest predictor (P < .001). Excluding imaging, significant predictors in the first year of life included thyroxine dose/kg (P < .001-.002), increase in thyrotropin (TSH) above the reference interval during treatment (P = .002), screening TSH (P = .03), and a history of maternal thyroid disease (P = .02). Based on the 1-year model without imaging, a risk score was developed to identify children with T-CH who may benefit from an earlier trial off therapy, to reduce excess medicalization and health care costs.

CONCLUSION

A levothyroxine dose of less than 3 μg/kg at ages 1 and 2 years and less than 2.5 μg/kg at age 3 years can be predictive of T-CH. A novel risk score was developed that can be clinically applied to predict the likelihood of a successful trial off therapy for a given patient at age 1 year.

Diagnostic Re-Evaluation and Potential Predictor Factors of Transient and Permanent Congenital Hypothyroidism in Eutopic Thyroid Gland

Background: The incidence of congenital hypothyroidism (CH) has increased over the years, and many predictors for detecting newborns with transient forms (TCH) as early as possible have been considered. Methods: All newborns diagnosed with primary CH and eutopic gland in the Piedmont region of Italy in the period of January 2014–June 2019 were enrolled and re-evaluated at the age of 2 years. Results: 105 newborns were diagnosed with CH during the study period. Dyshormonogenesis was observed in 55/105. At re-evaluation, we found that 52.7% had permanent CH (PCH), while 47.3% had TCH. Male/female rate, TSH levels at diagnosis, levothyroxine requirement at withdrawal and extra-thyroid congenital malformations rate were higher in the PCH group (p = 0.02, p = 0.009, p = 0.02 and p = 0.01), while fT4 levels at diagnosis were lower (p = 0.03). Sensitivity of 72.4% and specificity of 80.7% for serum TSH above 60 mcUI/mL, sensitivity of 73% and specificity of 72.4% for serum fT4 level below 7.2 pg/mL and sensitivity of 66% and specificity of 68% for drug requirement above 2.25 mcg/kg/day were observed in PCH. Conclusions: Demographic, clinical and hormonal data at diagnosis and levothyroxine requirement during the first two years should be adequately monitored to identify infants who are most likely to discontinue therapy after the age of 24 months.

Cognitive and White Matter Microstructure Development in Congenital Hypothyroidism and Familial Thyroid Disorders

CONTEXT

Children with congenital hypothyroidism (CH) are at risk for suboptimal neurodevelopment.

OBJECTIVES

To evaluate neurocognitive function and white matter microstructure in children with permanent or transient CH and to correlate these findings with disease severity.

DESIGN, PARTICIPANTS AND METHODS

A retrospective and prospective observational study was conducted in 39 children with permanent or transient CH, and in 39 healthy children. Cognitive function was assessed by Wechsler Intelligence Scale, Fourth Edition, and by other tests; the white matter microstructure was investigated by 3 Tesla magnetic resonance imaging.

RESULTS

Children with permanent CH have lower cognitive scores at a median age of 9.5 years than those with transient CH and controls. An IQ score between 71 and 84 was found in 28.6% of permanent CH and of <70 (P = 0.06) in 10.7%. The Processing Speed Index (PSI; P = 0.004), sustained visual attention (P = 0.02), reading speed (P = 0.0001), written calculations (P = 0.002), and numerical knowledge (P = 0.0001) were significantly lower than controls. Children born to mothers with Hashimoto's thyroiditis have significantly lower IQ values (P = 0.02), Working Memory Index (P = 0.03), and PSI (P = 0.02). Significantly lower IQ and Verbal Comprehension Index values were found in children with a family history of thyroid disorders (P = 0.004 and P = 0.009, respectively). In children with permanent CH, significant correlations between abnormalities in white matter microstructural, clinical, and cognitive measures were documented.

CONCLUSIONS

These findings indicate that children with CH are at risk of neurocognitive impairment and white matter abnormalities despite timely and adequate treatment. The association between offspring cognitive vulnerability and maternal thyroid disorders requires careful consideration.

Diagnostic re-evaluation and predictors of congenital hypothyroidism with eutopic thyroid gland in Jiangxi, China

OBJECTIVES

An increase in the incidence of congenital hypothyroidism (CH) with eutopic gland has been reported worldwide due to neonatal screening programs. In this study, we aimed to determine the prevalence of transient CH (TCH) and to investigate predictive factors that could distinguish between permanent and transient CH in patients with eutopic thyroid glands.

METHODS

We retrospectively reviewed 508 children treated for CH with eutopic thyroid glands between June 1998 and June 2020 in Jiangxi Newborn Screening Center. All patients were treated with levothyroxine and underwent Diagnostic re-evaluation after 2-3 years of age. Patients were classified as having TCH or permanent CH (PCH) during follow-up.

RESULTS

Of the 508 patients initially treated for CH with a normally located gland, 335 patients (65.9%) were classified in the TCH group and 173 (34.1%) in the PCH group based on the defined criteria. Multivariate analysis revealed that TCH was associated with a lower levothyroxine dose at 24 months of age (p<0.001) and a lower likelihood of having a first-degree family history of CH (p=0.026) than PCH. Gender, prematurity, low birth weight, initial CH severity such as serum TSH and FT4 levels, or bone maturation delay at diagnosis had no effect. Receiver operating characteristics curve analysis showed that a cutoff of 2.3 μg/kg/day for levothyroxine dose requirement at 24 months of age had a sensitivity of 71% and a specificity of 70% for predicting transient CH, with values below this threshold considered predictive of transient CH.

CONCLUSIONS

TCH presents a significant portion of patients with CH. The levothyroxine dose requirement at 24 months of age has a predictive role in differentiating TCH from PCH in CH patients with eutopic thyroid glands.

Development of a risk prediction model for early discrimination between permanent and transient congenital hypothyroidism

OBJECTIVE

To develop a risk prediction model for early discrimination between transient and permanent congenital hypothyroidism (CH).

DESIGN AND SETTING

In a retrospective cohort, 1047 confirmed CH neonates, from 15 randomly selected provinces in Iran, were entered to the study. Clinical and biochemical information of transient and permanent cases, distinct at the age of 3 years were retrospectively gathered.

RESULTS

Among CH neonates, the overall prevalence of permanent CH was 57.1%. Using forward stepwise multivariable logistic regression analysis, confirmatory venous TSH, total T4 < 8.2 ng/dl, requiring levothyroxine dosage increase, venous TSH ≥ 10 mU/l between 6 and 12 months of age, parental consanguinity and family history of thyroid diseases were associated with increased risk of permanent CH. The prediction model achieved a very good power in discriminating patients with transient and permanent CH with an optimism-corrected area under the ROC curve of 0.86 (95% CI:0.84-0.88) with a very good calibration. Integrated discrimination improvement (IDI) test indicated significantly greater diagnostic performance of the model compared to serum TSH alone.

CONCLUSIONS

Using several potential predictors for permanent CH, we developed a relatively powerful risk prediction model as a cost-saving screening tool in order to avoid unnecessary long-term treatment of transient cases which might empower clinicians for prognostication of the CH course and tailoring treatment up to 1 year of age.

Prevalence and predictive factors of transient and permanent congenital hypothyroidism in Fars province, Iran

INTRODUCTION

There is no data on the number as well as the prevalence of congenital hypothyroidism (CH) in the Fars province. Hence, we designed this study to analyze the latest data and the possible predictive factors on transient and permanent CH in this province.

METHOD

This cross sectional study is based on the Fars province screening data from 2013 to 2016. A total of 294,214 newborns were screened with 938 confirmed cases of CH, which were included in this study. After recall and completion of the missing data, follow-up data for 642 CH cases with thyroid stimulating hormone (TSH) concentrations and levothyroxine doses for ten outpatient visits and final transient vs. permanent CH diagnosis were included.

RESULTS

The incidence rate was 1:313.66, and out of the 642 CH cases, 66.04 % had permanent CH, while 33.96 % had transient CH. TSH level trend during the outpatient visits were not statistically different between the two groups (P = 0.312). A cutoff point of > 2.25 levothyroxine µg/kg (sensitivity: 76.11 %, specificity: 58.52 %) at the third year and a TSH concentration of > 43.35 mIU/L at the venous sampling (initial TSH) (sensitivity: 31.66 %, specificity: 90.32 %) were the predictive factors for permanent CH.

CONCLUSION

Fars province has one of the highest incidence rate of CH in Iran. Levothyroxine dose at the 3rd year and the 1st venous TSH sample are the predictive factors for permanent CH in the Iranian population; however, TSH concentrations during follow ups are unreliable predictors.

Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines Update-An ENDO-European Reference Network Initiative Endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology

Background: An ENDO-European Reference Network (ERN) initiative was launched that was endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology with 22 participants from the ENDO-ERN and the two societies. The aim was to update the practice guidelines for the diagnosis and management of congenital hypothyroidism (CH). A systematic literature search was conducted to identify key articles on neonatal screening, diagnosis, and management of primary and central CH. The evidence-based guidelines were graded with the Grading of Recommendations, Assessment, Development and Evaluation system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion. Summary: The recommendations include the various neonatal screening approaches for CH as well as the etiology (also genetics), diagnostics, treatment, and prognosis of both primary and central CH. When CH is diagnosed, the expert panel recommends the immediate start of correctly dosed levothyroxine treatment and frequent follow-up including laboratory testing to keep thyroid hormone levels in their target ranges, timely assessment of the need to continue treatment, attention for neurodevelopment and neurosensory functions, and, if necessary, consulting other health professionals, and education of the child and family about CH. Harmonization of diagnostics, treatment, and follow-up will optimize patient outcomes. Lastly, all individuals with CH are entitled to a well-planned transition of care from pediatrics to adult medicine. Conclusions: This consensus guidelines update should be used to further optimize detection, diagnosis, treatment, and follow-up of children with all forms of CH in the light of the most recent evidence. It should be helpful in convincing health authorities of the benefits of neonatal screening for CH. Further epidemiological and experimental studies are needed to understand the increased incidence of this condition.

Newborn Screening TSH Values Less Than 15 mIU/L Are Not Associated With Long-term Hypothyroidism or Cognitive Impairment

BACKGROUND

It is unclear whether newborns with mild thyrotropin elevation (mTSHe) are at risk of neurocognitive impairment. We assessed whether mTSHe at birth persists during childhood and compared neurocognitive functioning to siblings.

METHODS

This study encompassed children born in the Auckland region (New Zealand) with a newborn screen TSH level of 8 to 14 mIU/L blood, age 6.9 to 12.6 years at assessment, and their siblings. Thyroid function tests (serum TSH and free thyroxine) and neurocognitive assessments were performed, including IQ via the Wechsler Intelligence Scale for Children, fourth edition.

RESULTS

Ninety-six mTSHe individuals were studied, including 67 children recruited with 75 sibling controls. Mean mTSHe newborn TSH level was 10.1 mIU/L blood and 2.4 mIU/L at assessment (range, 0.8-7.0 mIU/L, serum). Although higher newborn TSH levels in the mTSHe group correlated with lower full-scale IQ scores (r = 0.25; P = .040), they were not associated with the magnitude of the IQ difference within sibling pairs (P = .56). Cognitive scores were similar for mTSHe and controls (full-scale IQ 107 vs 109; P = .36), with a minor isolated difference in motor coordination scores.

CONCLUSIONS

Our data do not suggest long-term negative effects of neonatal mild TSH elevation. TSH elevation below the screen threshold appears largely transient, and midchildhood neurocognitive performance of these children was similar to their siblings. We propose that associations between neonatal mild TSH elevation and IQ are due to familial confounders. We caution against the practice of reducing screening CH cutoffs to levels at which the diagnosis may not offer long-term benefit for those detected.

Treatment Discontinuation within 3 Years of Levothyroxine Initiation among Children Diagnosed with Congenital Hypothyroidism

OBJECTIVES

To measure the rates of thyroid gland imaging and levothyroxine (L-T₄) discontinuation and to assess whether discontinuation was monitored with thyroid-stimulating hormone testing in subjects with congenital hypothyroidism.

STUDY DESIGN

This is a retrospective analysis of claims data from the IBM MarketScan Databases for children born between 2010 and 2016 and continuously enrolled in a noncapitated employer-sponsored private health insurance plan or in Medicaid for ≥36 months from the date of the first filled L-T₄ prescription.

RESULTS

There were 263 privately insured and 241 Medicaid-enrolled children who met the inclusion criteria. More privately insured than Medicaid-enrolled children had imaging between the first filled prescription and 180 days after the last filled prescription (24.3% vs 12.9%; P = .001). By 36 months, 35.7% discontinued L-T₄, with no difference by insurance status (P = .48). Among those who discontinued, 29.1% of privately insured children and 47.7% of Medicaid-enrolled children had no claims for thyroid-stimulating hormone testing within the next 180 days (P = .01).

CONCLUSIONS

Nearly one-third of children with suspected congenital hypothyroidism discontinued L-T₄ by 3 years and fewer Medicaid-enrolled than privately insured children received timely follow-up thyroid-stimulating hormone testing. Future studies are indicated to understand the quality of care and developmental outcomes for children with congenital hypothyroidism and barriers to guideline adherence in evaluating for transient congenital hypothyroidism.

Levothyroxine dosages less than 2.4 μg/kg/day at 1 year and 1.3 μg/kg/day at 3 years of age may predict transient congenital hypothyroidism

Significant differences in levothyroxine (LT4) dosages for congenital hypothyroidism (CH), which can be permanent (P-CH) or transient (T-CH), and their respective cutoff values have been reported. In Japanese children, however, these values are unknown, and were thus determined in this retrospective single-center study, which included 34 patients— 19 with P-CH and 15 with T-CH. The LT4 dosages of the two groups at ages 1 and 3 yr were compared, and receiver operating characteristic (ROC) analysis was performed to identify the cutoff dosages. The results showed that the LT4 dosages of the P-CH and T-CH groups differed significantly at both ages. When LT4 dosage cutoff at 1 yr of age was set at 2.4 μg/kg/d, the sensitivity and specificity were 93% and 74%, respectively, and when it was set at 1.3 μg/kg/d at 3 yr of age, they were 80% and 84%, respectively, suggesting that when LT4 dosages are ≤2.4 μg/kg/d at 1 yr and ≤1.3 μg/kg/d at 3 yr of age, T-CH should be suspected.

Congenital hypothyroidism in different cities of the Isfahan province: A descriptive retrospective study

BACKGROUND

Considering the high prevalence rate of congenital hypothyroidism CH in Iran, an epidemiological study in each region would be helpful in understanding the etiology of the disorder and providing preventative strategies in this field. This study aims to determine the prevalence of CH in different cities of the Isfahan province.

MATERIALS AND METHODS

This descriptive and retrospective study was conducted among 918 primarily diagnosed CH neonates, who have been identified through the neonatal screening program from 2009 to 2015. At the age of ≥3 years, treatment was discontinued for 4 weeks, and T4 and thyroid-stimulating hormone were measured. Permanent (PCH) or transient (TCH) was determined from the results of the thyroid function tests.

RESULTS

From 389,101 screened neonates, 918 were diagnosed with primary CH. The overall prevalence rate of CH was 2.36 in 1000 live birth (ranged 1.58-7.22 in 1000 live birth in different cities). The highest prevalence rate of CH was reported in Ardestan, Khansar, Golpaygan, and Nain cities with prevalence rate of 4.86-7.22 in 1000 live birth and lowest prevalence occurring in Fereydan, Shahreza, Isfahan, and Mobarakeh cities with prevalence rate of 1.58-1.89 in 1000 live birth. In 392 cases which reached to 3 years of age, the rate of TCH was 47.45%. In Chadegan, Natanz, Fereydunshahr, Shahinshahr, Najafabad, Dehaghan, Borkhar, and Mobarakeh, the prevalence of PCH was <50%.

CONCLUSION

The current findings indicate that the incidence rate of both PCH and TCH are high in Isfahan province with significant variability in different cities which could be due to the role of different genetic, prenatal, and different environmental factors. These epidemiological data could be used as baseline date to design more etiological studies.

Neonatal screening in the Czech Republic: increased prevalence of selected diseases in low birthweight neonates

Neonates with low birthweight (LBW) represent a vulnerable population. This retrospective study analyzed the birth frequency of diseases detected by neonatal screening (NBS) in normal and LBW neonates in the Czech Republic. Between years 2002 and 2016, the number of screened disorders in the Czech Republic gradually increased from two to 13. Prevalence of screened diseases was calculated for cohorts ranging from 777,100 to 1,277,283 neonates stratified by birthweight. Odds ratio of the association of LBW with each disease was calculated and statistical significance was evaluated using the chi-square test or Fisher's exact test, as appropriate. Three diseases were associated with higher risk of prevalence in LBW neonates, namely congenital hypothyroidism (OR 2.50, CI 1.92; 3.25), cystic fibrosis (OR 2.44, CI 1.51; 3.94), and long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) (OR 7.74, CI 2.18; 27.42).Conclusion: Although the underlying mechanisms are not well understood, results can be hypothesized that LBW (respectively prematurity) may lead to the secondary and often transitory hypothyroidism while cystic fibrosis and LCHADD may manifest already prenatally and result into preterm birth and LBW. What is Known: • The percentage of low birthweight (LBW) neonates in the Czech Republic has been increasing. • Previously published studies reported positive association between LBW and congenital hypothyroidism and cystic fibrosis. What is New: • The association between LCHADD and LBW has not yet been described. • LBW can be the first manifestation of cystic fibrosis and LCHADD.

Rectal Levothyroxine for the Treatment of Hypothyroidism: A Case Study

Transient hypothyroidism can present itself as clinically asymptomatic or with few symptoms. Early treatment with levothyroxine (L-T4) prevents complications related to this disorder. We report a case of a male infant with concomitant short bowel syndrome and transient hypothyroidism treated with rectal L-T4. A 4-month-and-10-day-old boy with previous gastroschisis underwent multiple surgical approaches for small bowel resection and developed short bowel syndrome. We suspected hypothyroidism because of jaundice (direct bilirubin up to 59 mg/dL), the absence of evacuation, oral diet intolerance, and intestinal dysmotility. Because of a thyrotropin level of 34.45 μIU/mL and a free thyroxine level of 0.64 ng/dL, the diagnosis was confirmed. Because fasting was demanding, we started the patient on rectal diluted L-T4. After 4 weeks, the patient had spontaneous peristalsis, improvement of jaundice (direct bilirubin: 4.6 mg/dL), and normalized free thyroxine and thyrotropin values. In the present case, the patient was diagnosed with hypothyroidism and was on absolute fasting. An alternative route of drug administration was warranted. We empirically prescribed rectal diluted L-T4 when intravenous and suppository L-T4 were not available. This method was proven to be safe and effective in improving the patient's clinical and biochemical status. Rectal L-T4 is a possible alternative route of administration to treat hypothyroidism in patients who are unable to take the medication orally.

Early Determinants of Thyroid Function Outcomes in Children with Congenital Hypothyroidism and a Normally Located Thyroid Gland: A Regional Cohort Study

BACKGROUND

An increase in the incidence of congenital hypothyroidism (CH) with a normally located gland has been reported worldwide. Affected individuals display transient or permanent CH during follow-up in childhood. This study aimed to determine the prevalence of transient CH and to investigate the possibility of distinguishing between transient and permanent CH in early infancy.

METHODS

This observational cohort study included all patients identified by systematic neonatal screening for CH in the northern Parisian region between 2002 and 2012 and treated for CH with a normally sited gland. A standardized data collection form was completed prospectively at diagnosis. Patients were classified during follow-up as having transient or permanent CH.

RESULTS

Of the 92 patients initially treated for CH with a normally located gland during the neonatal period, 49 (54%) had a transient form of CH after the cessation of levothyroxine (LT4) treatment at 1.5 (0.6-3.2) years of age. Multivariate analysis revealed that transient CH was associated with a lower likelihood of having a first-degree family history of CH (p = 0.03) and a lower LT4 dose at six months of age (p = 0.03) than permanent CH. Sex, ethnicity, neonatal problems (e.g., prematurity, being small for gestational age, and/or neonatal distress), iodine status, coexisting malformations, initial CH severity, and thyroid morphology at diagnosis had no effect. Receiver operating characteristics curve analysis showed that a cutoff of 3.2 μg/kg/day for LT4 dose requirement at six months of age had a sensitivity of 71% and a specificity of 79% for predicting transient CH, with values below this threshold considered predictive of transient CH.

CONCLUSION

In patients with CH and a normally located gland, these findings highlight the need to evaluate LT4 dose requirements early, at six months of age, particularly in patients with no family history of CH, for early identification of the approximately 50% of patients for whom treatment should be stopped.

Congenital Hypothyroidism 3-Year Follow-Up Project: Region 4 Midwest Genetics Collaborative Results

To identify the 3-year follow-up management and education patterns of primary care clinicians and pediatric endocrinologists for children diagnosed with congenital hypothyroidism (CH) through newborn screening programs, the Region 4 Midwest Genetics Collaborative, made up of seven regional states (Illinois, Indiana, Kentucky, Michigan, Minnesota, Ohio, Wisconsin), performed a survey study of parents and physicians caring for children identified with CH. The clinicians and parents of 409 children with CH regionally identified in 2007 were invited to participate in a voluntary survey. Responses relating to treatment, monitoring practices, educational resources, genetic counseling, and services provided/received were collected from 214 clinicians and 77 parents. In total, 99% had undergone a confirmatory test following positive newborn screening and 55% had imaging at diagnosis, but only 50% were identified as having the etiology identified. Thyroid withdrawal challenge testing was the choice method for re-evaluating thyroid function, but the approach varied. Clinician and parent responses to education and genetic counseling also differed. Clinicians report face-to-face education as the most common method, with less than 50% providing handouts to patients. Only 14% of patients were referred to a genetics counselor. Of parents reporting on their educational experience, 86% received face-to-face education from a pediatric endocrinologist and 4% received education from a genetic counselor. Only 65%, however, were satisfied with their education. These survey data suggest a lack of a standardized approach to diagnosis, follow-up, education, and genetic counseling. This collaborative effort provides insight into developing three-year follow-up, education and genetic counseling guidelines for children diagnosed with CH.

Diagnostic re-evaluation of congenital hypothyroidism in Macedonia: predictors for transient or permanent hypothyroidism

BACKGROUND

Diagnostic re-evaluation is important for all patients with congenital hypothyroidism (CH) for determining the etiology and identifying transient CH cases. Our study is a first thyroxine therapy withdrawal study conducted in Macedonian CH patients for a diagnostic re-evaluation. We aimed to evaluate the etiology of CH, the prevalence of transient CH and identify predictive factors for distinguishing between permanent (PCH) and transient CH (TCH).

MATERIALS AND METHODS

Patients with CH aged >3 years underwent a trial of treatment withdrawal for 4 weeks period. Thyroid function testing (TFT), ultrasound and Technetium-99m pertechnetate thyroid scan were performed thereafter. TCH was defined when TFT remained within normal limits for at least 6-month follow-up. PCH was diagnosed when TFT was abnormal and classified according the imaging findings.

RESULTS

42 (55%) patients had PCH and 34 (45.0%) patients had TCH. Thyroid agenesia was the most prevalent form in the PCH group. Patients with TCH had lower initial thyroid-stimulating hormone (TSH) values (P < 0.0001); higher serum thyroxine levels (P = 0.0023) and lower mean doses of levothyroxine during treatment period (P < 0.0001) than patients with PCH. Initial TSH level <30.5 IU/mL and levothyroxine dose at 3 years of age <2.6 mg/kg/day were a significant predictive factors for TCH; sensitivity 92% and 100%, specificity 75.6% and 76%, respectively.

CONCLUSION

TCH presents a significant portion of patients with CH. Initial TSH value and levothyroxine dose during treatment period has a predictive role in differentiating TCH from PCH. Earlier re-evaluation, between 2 and 3 years age might be considered in some patients requiring low doses of levothyroxine.

Newborn Screening in the US May Miss Mild Persistent Hypothyroidism

OBJECTIVE

To determine if newborn screening (NBS) programs for congenital hypothyroidism in the US use thyroid-stimulating hormone (TSH) cutoffs that are age adjusted to account for the physiologic 4-fold reduction in TSH concentrations over the first few days of life.

STUDY DESIGN

All NBS programs in the US were contacted and asked to provide information on their NBS protocols, TSH cutoffs, and whether these cutoffs were age adjusted.

RESULTS

Of 51 NBS programs, 28 request a repeat specimen if the initial eluted serum TSH concentration is mildly increased (between the cutoff and a median upper limit of 50 mU/L), whereas 14 programs perform a routine second screen in all infants. Although these specimens are typically collected between 1 week and 1 month of life, 16 of the 28 programs with a discretionary second test and 8 of 14 programs with a routine second test do not have age-adjusted TSH cutoffs after the first 48 hours of life.

CONCLUSIONS

There is variation in NBS practices for screening for congenital hypothyroidism across the US, and many programs do not adjust the TSH cutoff beyond the first 2 days of life. Samples are processed when received from older infants, often to retest borderline initial results. This approach will miss congenital hypothyroidism in infants with persistent mild TSH elevations. We recommend that all NBS programs provide age-adjusted TSH cutoffs, and suggest developing a standard approach to screening for congenital hypothyroidism in the US.

Are lower TSH cutoffs in neonatal screening for congenital hypothyroidism warranted?

When newborn screening (NBS) for congenital hypothyroidism (CH) using thyroid-stimulating hormone (TSH) as a primary screening test was introduced, typical TSH screening cutoffs were 20-50 U/L of whole blood. Over the years, lowering of TSH cutoffs has contributed to an increased prevalence of detected CH. However, a consensus on the benefit deriving from lowering TSH cutoffs at screening is lacking. The present paper outlines arguments both for and against the lowering of TSH cutoffs at NBS. It includes a review of recently published evidence from Australia, Belgium and Italy. A section focused on economic implications of lowering TSH cutoffs is also provided. One issue that bears further examination is the extent to which mild iodine deficiency at the population level might affect the association of neonatal TSH values with cognitive and developmental outcomes. A debate on TSH cutoffs provides the opportunity to reflect on how to make NBS for CH more effective and to guarantee optimum neurocognitive development and a good quality of life to babies with mild as well as with severe CH. All authors of this debate article agree on the need to establish optimal TSH cutoffs for screening programs in various settings and to ensure the benefits of screening and access to care for newborns worldwide.

Transient hypothyroidism in the newborn: to treat or not to treat

Transient congenital hypothyroidism (CH) refers to a temporary deficiency of thyroid hormone identified after birth, with low thyroxine (T4) and elevated thyrotropin (TSH), which later recovers to improved thyroxine production, typically in first few months of infancy. Approximately 17% to 40% of children diagnosed with CH by newborn screening (NBS) programs were later determined to have transient hypothyroidism. Causes of transient CH are prematurity, iodine deficiency, maternal thyrotropin receptor blocking antibodies, maternal intake of anti-thyroid drugs, maternal or neonatal iodine exposure, loss of function mutations and hepatic hemangiomas. The classic clinical symptoms and signs of CH are usually absent immediately after birth in vast majority of infants due to temporary protection from maternal thyroxine. NBS has been largely successful in preventing intellectual disability by early detection of CH by performing thyroid function tests in infants with abnormal screening results. In this review we present the evidence for decision making regarding treatment vs. withholding treatment in infants with transient CH and present a rational approach to identifying transient CH based on American Academy of Pediatrics (AAP) recommendation.

Three-year follow-up of children with abnormal newborn screening results for congenital hypothyroidism

BACKGROUND

To analyze predictive factors suggesting transient congenital hypothyroidism (TCH) compared to permanent congenital hypothyroidism (PCH) or transient thyroid function test (TFT) abnormalities among children who had positive screening results at our centers over the past decade.

METHODS

A retrospective chart review of 105 subjects who presented elevated TSH levels on a newborn screening test (NST) was done. TCH was defined when a trial-off therapy was successful, and PCH was defined when a trial failed or when the subject was kept on medication beyond 3 years of age. A transient TFT abnormality was defined when follow-up TFTs were normalized without levothyroxine (LT4) therapy.

RESULTS

Congenital hypothyroidism (CH) was diagnosed in 75.2% (TCH 35.2% and PCH 40.0%) of all subjects; the others (24.8%) showed transient TFT abnormalities. Initial NST-TSH levels (optimal cutoff point, 31.0 μIU/mL), the LT4 dose at 2 years of age (4.1 μg/kg/day), and the maximal LT4 dose (50 μg/day) merged as significant predictive factors discriminating between TCH and PCH. The initial serum level of free T4 (1.06 ng/dL) and not TSH (27.2 μIU/mL) was the only discriminating factor between transient TFT abnormalities and TCH.

CONCLUSION

Earlier re-evaluation might be possible when a patient's initial NST-TSH levels and maximal or 2-year LT4 doses are low, as both are important predictors of successful trial-off therapy in CH patients. When the initial serum level of free T4 is above the average value in neonates with mildly elevated TSH levels, TFTs may be more likely to normalize on their own.

Primary Care Provider Management of Congenital Hypothyroidism Identified Through Newborn Screening

OBJECTIVE

To assess Primary Congenital Hypothyroidism (CH) management patterns and feasibility of providing long-term care for patients with CH identified through newborn screening by Primary Care Providers (PCPs) in California and Hawaii.

STUDY DESIGN

A survey was mailed to all physicians (N=823) listed as the referral doctor for confirmed patients with CH identified through newborn screening programs in both states between 01/01/2009-12/31/2013. Information was collected on CH management patterns, barriers to providing care, and knowledge on CH treatment. Descriptive statistics and bivariate logistic regression results were reported.

RESULTS

206 PCPs completed the survey. Among these, 78% currently have patients with CH and 91% indicated willingness to provide long-term care to new patients with CH. Among PCPs currently caring for patients with CH, 17% managed CH by themselves with limited assistance from endocrinologists; 63% were involved in managing CH but endocrinologists played a larger role than PCPs; 19% were not involved in CH care. Only 49% of PCPs correctly answered questions regarding recommended follow-up frequencies and 23% knew the correct age for a trial off levothyroxine for suspected transient CH. Top two perceived barriers to providing long-term care included "need guidance or support from endocrinologists" (61%) and "not familiar with CH treatment guidelines" (28%).

CONCLUSION

The majority of PCPs surveyed are willing to provide long-term care to patients with CH, but need support from endocrinologists and increased knowledge about current treatment guidelines.

Feasibility of an Early Discontinuation of Thyroid Hormone Treatment in Very-Low-Birth-Weight Infants at Risk for Transient or Permanent Congenital Hypothyroidism

BACKGROUND/AIMS

This prospective study was conducted to investigate the feasibility of an early discontinuation of thyroid hormone treatment in very-low-birth-weight (VLBW) infants with congenital hypothyroidism (CH).

METHODS

We enrolled VLBW infants between January 2011 and December 2012. The infants were divided into the hypothyroid and normal thyroid function groups according to the results of a thyroid function test. We performed an early off-therapy trial at 24 months of age.

RESULTS

Of the 182 VLBW infants enrolled, 15 were lost to follow-up and 167 were finally enrolled. In total, 24 infants (14.4%) were assigned to the hypothyroid function group and were treated with thyroid hormone. Younger gestational age and a lower birth weight were associated with hypothyroid function. In the hypothyroid function group, hypothyroidism (HT) and hyperthyrotropinemia (HTT) were observed in 13 and 11 infants, respectively. There were no differences in the clinical characteristics between the HT and HTT groups. Overall, 24 infants discontinued thyroxine medication at 24 months of age after normal results had been confirmed by radiologic work-ups, including thyroid ultrasonography and technetium-99m scans. All infants were successfully weaned off thyroxine and maintained euthyroid function.

CONCLUSION

Early discontinuation of thyroid hormone replacement therapy is possible in the majority of VLBW infants with CH.

Evolution to permanent or transient conditions in children with positive neonatal TSH screening tests in Sergipe, Brazil

OBJECTIVES

To assess the evolution to permanent or transient conditions in children with positive neonatal TSH tests in Sergipe, Brazil, from 2004 to 2010.

SUBJECTS AND METHODS

Out of 193,794 screened newborns, 713 presented a neonatal TSH level higher than the local cutoff (5.2 µU/mL). From the confirmatory serum TSH values, the children were diagnosed with initial congenital hypothyroidism (CH) or suspect CH. From the evolution, they were classified as permanent CH, hyperthyrotropinemia, or transient TSH elevation. The mean incidence of each final condition was calculated for the total period of time.

RESULTS

The initial diagnosis included 37 CH (18.1%) and 167 suspect CH (81.9%) cases. The final diagnosis included 46 cases of permanent CH (22.5%), 56 of hyperthyrotropinemia (27.5%), and 102 of transient TSH elevation (50.0%). Out of the 37 cases of initial CH, 23 (62.2%) had permanent CH, nine (24.3%) had hyperthyrotropinemia, and five (13.5%) had transient TSH elevation. Out of the 167 suspect CH cases, 23 (13.8%) had permanent CH, 47 (28.1%) had hyperthyrotropinemia and 97 (58.1%) had transient TSH elevation. The mean incidence after the follow up was 1:4,166 for permanent CH, 1:3,448 for hyperthyrotropinemia, and 1:1,887 for transient TSH elevation. Eighty-six percent of the children with an initial diagnosis of CH and 41.9% with suspect CH had a permanent condition (CH or hyperthyrotropinemia).

CONCLUSIONS

The follow-up of children with an initial diagnosis of CH or suspect CH is necessary to determine whether the disorder is permanent because predicting the evolution of the condition is difficult.

Permanent and Transient Congenital Hypothyroidism in Hamadan West Province of Iran

BACKGROUND

Primary 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.

METHODS

The 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.

RESULTS

A 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).

CONCLUSIONS

Our 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.

Transient versus Permanent Congenital Hypothyroidism after the Age of 3 Years in Infants Detected on the First versus Second Newborn Screening Test in Oregon, USA

BACKGROUND/AIMS

The newborn screening (NBS) program in Oregon, USA, collects two routine specimens in all infants. The aim of our study was to determine the incidence of permanent versus transient congenital hypothyroidism (CH) in infants detected on the first versus second screening test.

METHODS

Thyroid function was determined in infants after the age of 3 years diagnosed with CH and born in Oregon between 2005 and 2011. Permanent hypothyroidism was defined as a TSH rise >10 mIU/ml after the first year on treatment or a TSH rise >6 mIU/ml with temporary discontinuation of l-thyroxine after the age of 3 years.

RESULTS

Of the cases detected on the first test, 72 of 87 (83%) were permanent and 15 of 87 (17%) were transient, while of the cases detected on the second test, 5 of 22 (23%) were permanent and 17 of 22 (77%) were transient (OR 16.3, p < 0.001). There was a female preponderance detected on the first screen versus a male preponderance on the second screen. Blood spot and serum thyroid function tests at diagnosis, before treatment, were not meaningfully different between the two groups. The mean l-thyroxine dose at the age of 3 years was greater on the first screen: 61.2 versus 36.6 μg/day.

CONCLUSIONS

Infants detected on the second NBS specimen have a higher incidence of transient CH. © 2016 S. Karger AG, Basel.

Natural history and management of congenital hypothyroidism with in situ thyroid gland

BACKGROUND/OBJECTIVE

Normally sited glands account for increasing congenital hypothyroidism (CH). Mechanisms often remain unknown. To report the incidence of CH with in situ thyroid gland (ISTG) and describe the natural history of the disease without known etiology.

METHOD

Clinical, biochemical and imaging data at diagnosis were retrospectively analyzed in 285 children positively screened for CH in Ile-de-France between 2005 and 2008. If treatment was discontinued, management of hormonal substitution and follow-up of biochemical thyroid function was performed.

RESULTS

93 full-term CH neonates displayed ISTG (40.6%), including 50 with unexplained mechanism. Follow-up data were available in 32 of them. Therapy was withdrawn from 20 children at a median age of 23.5 months (6-66), among whom 18 remained still untreated over a median duration of 15.3 months (4.4-29.6). In 11 children, levothyroxine (L-T4) dosage was increased over time to maintain biochemical euthyroidism. No statistical differences in initial TSH or FT4 levels, iodine status or birth weight were found between children with transient and permanent hypothyroidism.

CONCLUSION

Withdrawal of L-T4 substitution was feasible in 56.2% of full-term children with CH with ISTG but unexplained mechanism, emphasizing the need for systematic therapy withdrawal. However, further studies are warranted to standardize withdrawal protocol.

Ultrasonography of various thyroid diseases in children and adolescents: a pictorial essay

Thyroid imaging is indicated to evaluate congenital hypothyroidism during newborn screening or in cases of a palpable thyroid mass in children and adolescents. This pictorial essay reviews the ultrasonography (US) of thyroid diseases in children and adolescents, including normal thyroid gland development, imaging features of congenital thyroid disorders (dysgenesis, [aplasia, ectopy, hypoplasia], dyshormonogenesis, transient hypothyroidism, thyroglossal duct cyst), diffuse thyroid disease (Grave's disease, Hashimoto's thyroiditis, and suppurative thyroiditis), and thyroid nodules. The primary imaging modalities for evaluating thyroid diseases are US and radionuclide scintigraphy. Additionally, US can be used to guide aspiration of detected nodules.

Congenital Hypothyroidism Long-Term Follow-up Project: Navigating the Rough Waters of a Multi-Center, Multi-State Public Health Project

The Region 4 Midwest Genetics Collaborative, made up of seven regional states (Illinois, Indiana, Kentucky, Michigan, Minnesota, Ohio, and Wisconsin), brought together pediatric endocrinologists, state laboratory experts, public health follow-up specialists, and parents of children with congenital hypothyroidism (CH) to identify the three-year follow-up management and education patterns of primary care clinicians and pediatric endocrinologists in the care of children diagnosed with CH by state newborn screening (NBS) programs. Among a number of challenges, each state had different NBS methods, data systems, public health laws, and institutional review board (IRB) requirements. Furthermore, the diagnosis of CH was complicated by the timing of the NBS sample, the gestational age, weight, and co-morbidities at delivery. There were 409 children with CH identified through NBS in 2007 in the seven state region. The clinician of record and the parents of these children were invited to participate in a voluntary survey. Approximately 64 % of clinician surveys were collected with responses to questions relating to treatment, monitoring practices, educational resources, genetic counseling, and services provided to children with confirmed CH and their families. Nearly one-quarter (24 %) of parents surveyed responded to questions relating to treatment, education, genetic counseling, resources, and services they received or would like to receive. De-identified data from six of the seven states were compiled for analysis, with one state being unable to obtain IRB approval within the study timeline. The data from this collaborative effort will improve state follow-up programs and aid in developing three-year follow-up guidelines for children diagnosed with CH. To aid in the facilitation of similar public health studies, this manuscript highlights the challenges faced, and focuses on the pathway to a successful multi-state public health endeavor.

Mild neonatal hyperthyrotrophinaemia: 10-year experience suggests the condition is increasingly common but often transient

OBJECTIVE

To examine a large population of infants with mild neonatal hyperthyrotrophinaemia (MNH) and determine prevalence, clinical characteristics and treatment history.

METHODS

Retrospective study of infants with MNH followed at The Hospital for Sick Children between 2000 and 2011. MNH was defined by an abnormal newborn screen followed by thyroid-stimulating hormone (TSH) between 5 and 30 mU/l and normal free T4 (FT4) on confirmatory tests.

RESULTS

Mild neonatal hyperthyrotrophinaemia represented 22·3% of patients (103/462; 60 boys, 43 girls) within our clinic. Incidence increased from two of 20 in 2000 to 31 of 74 cases in 2010. Seventy eight percent of patients started L-thyroxine (initial dose: 8·3 ± 2·5 mcg/kg). The treated group had higher confirmatory TSH levels (P = 0·001) and had undergone thyroid scintigraphy more often (P = 0·0001) compared with the nontreated group. Evidence of overtreatment was detected in 45% of thyroid function tests obtained during treatment. Among the treated infants who had reached 3 years of age, 45% (N = 14) underwent a trial-off medication. Compared with those not trialled-off therapy, these infants were less likely to have had dose escalations during treatment (P = 0·001). The trial-off treatment was successful in 50% of cases. In the subset of infants with confirmatory TSH >10 mU/l, trial-off therapy was successful in 40%. None of the assessed variables predicted success of trial-off therapy.

CONCLUSIONS

Mild neonatal hyperthyrotrophinaemia is an increasingly common diagnosis. It is more common in males and is often transient, but predictors of success of trial-off therapy were not identified. Further studies are needed to determine optimum L-thyroxine dosing and to determine whether treatment improves neurocognitive outcomes.

Permanent and transient congenital hypothyroidism in Fayoum, Egypt: a descriptive retrospective study

BACKGROUND

Congenital hypothyroidism (CH) is one of the most common preventable causes of mental retardation. One important challenge in understanding the epidemiology of CH is that some newborns will have transient CH, a temporary depression of thyroid hormone concentrations that can last from several days to several months. Studies from other countries have reported that 10 to 15% of children treated for CH ultimately prove not to need treatment past 3 years of age to maintain normal hormone concentrations, and thus have transient hypothyroidism. The purpose of this study was to determine the prevalence of permanent and transient congenital hypothyroidism in Fayoum, Egypt.

METHODS

Cases detected by Fayoum neonatal screening program (NSP) between January 2003 and December 2011, and followed up at health insurance center were included. Permanent or transient CH was determined using results of thyroid function tests.

RESULTS

Of the 248 patients diagnosed primarily with CH by NSP; 204 (82.3%) patients were diagnosed to have permanent CH (prevalence 1/3587 live birth), and 44 (17.7%) patients were diagnosed to have transient CH (prevalence 1/16667 live birth). Initial TSH levels were higher in permanent CH cases than transient cases (p<0.004). Female to male ratio was 0.8 and 0.7 in permanent and transient CH respectively. 161 (65%) patients had thyroid dysgenesis (107 ectopic thyroid gland, 28 athyreosis and 26 thyroid hypoplasia). 87 (35%) patients had intact gland in thyroid scan and were considered to have dyshormonogenesis. Of these 87 patients 44 proved to have transient CH and 43 had permanent CH.

CONCLUSION

The preliminary data from our study revealed that the incidences of CH as well as the permanent form were similar to worldwide reports. Although the high incidence of transient CH in our study could be explained by iodine deficiency further studies are needed to confirm the etiology and plan the treatment strategies.

Hipotireoidismo congênito: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia

O hipotireoidismo congênito (HC) é o distúrbio endócrino congênito mais frequente, com incidência variando de 1:2.000 a 1:4.000 crianças nascidas vivas e uma das principais causas de retardo mental que pode ser prevenida. Os Programas de Triagem Neonatal para a doença permitem a identificação precoce dos afetados e seu tratamento de modo a evitar as complicações da falta do hormônio. A maioria dos casos de hipotireoidismo congênito é decorrente de disgenesias tireoidianas (85%), entre elas a ectopia, hipoplasia ou agenesia tireoidianas, e os demais resultam de defeitos de síntese hormonal. As crianças afetadas (> 95%) geralmente não apresentam sintomas sugestivos da doença ao nascimento. Os sintomas e sinais mais comuns são: icterícia neonatal prolongada, choro rouco, letargia, movimentos lentos, constipação, macroglossia, hérnia umbilical, fontanelas amplas, hipotonia e pele seca. Várias estratégias são utilizadas para a triagem do HC. No Brasil, esta é obrigatória por lei e geralmente é feita com a dosagem de TSH em sangue seco coletado do calcanhar. A idade recomendada para sua realização é após as 48 horas de vida até o quarto dia. A confirmação diagnóstica é obrigatória com as dosagens de TSH e T4 livre ou T4 total.