Prevalence and course of thyroid dysfunction in neonates at high risk of Graves' disease or with non-autoimmune hyperthyroidism.

OBJECTIVE: Neonatal hyperthyroidism may be caused by a permanent non-autoimmune genetic disorder or, more frequently, by maternally transmitted high serum TRAb levels. Variable thyroid dysfunction may be observed in this second context. We aimed to evaluate the prevalence of neonatal non-autoimmune hyperthyroidism and of the different types of thyroid function in neonates with a high risk of hyperthyroidism due to maternal Graves' disease (GD). DESIGN AND METHODS: This observational cohort study included all neonates identified in the database of a single academic pediatric care center, over a period of 13 years, as having non-autoimmune hyperthyroidism or an autoimmune disorder with high TRAb levels (above 6 IU/L) transmitted by their mothers. Patients were classified as having neonatal hyperthyroidism, hypothyroidism, or euthyroidism with a permanent or transient disorder. RESULTS: Two of the 34 consecutive neonates selected (6%) had permanent non-autoimmune hyperthyroidism due to germline (n = 1) or somatic (n = 1) mutations of the TSH receptor gene. The patients with high serum TRAb levels at birth had transient hyperthyroidism (n = 23), hypothyroidism (primary n = 2, central n = 3) or persistent euthyroidism (n = 4). CONCLUSION: These original findings highlight the need for careful and appropriate monitoring of thyroid function in the long term, not only for the rare patients with non-autoimmune neonatal hyperthyroidism, but also for repeat monitoring during the first month of life in neonates with maternally transmitted high TRAb levels, to ensure the early identification of thyrotoxicosis in more than two thirds of cases and to detect primary or central hypothyroidism, thereby potentially decreasing associated morbidity.

Association Between Neonatal Thyroid Stimulating Hormone Status and Maternal Urinary Iodine Status.

BACKGROUND: Maternal urinary iodine concentration (MUIC) and percentage of neonates with Thyroid stimulating hormone (TSH) >5 mIU/L are amongst the parameters suggested for assessing adequate iodine status. OBJECTIVE: To assess the correlation between MUIC and neonatal TSH levels. STUDY DESIGN: Cross-sectional. SETTINGS: Tertiary care center in Delhi, India, between November 2015 to November 2016. PARTICIPANTS: Postnatal mother-neonate dyads. METHODS: TSH levels assessed among neonatal samples were stratified as below and above 5 mIU/L. MUIC was measured in 544 mothers, 400 mother-neonate dyads with neonatal TSH levels >5 mIU/L (cases) and 144 mother-neonate newborn mother dyads with neonatal TSH <5 mIU/L (controls). RESULTS: Results: The percentage of mothers with iodine insufficiency (9.8% vs 5.6%) as well as iodine excess (54.3% vs 41.7%) were significant higher in cases than controls. Mean TSH was also higher (P=0.0002) in both the iodine deficient and iodine excess group. There was no correlation between neonatal TSH values and MUIC. CONCLUSION: Lack of correlation between neonatal TSH and MUIC is due to iodine excess together with iodine deficiency.

Neonatal Thyroid Function and Disorders.

Thyroid hormone is essential for normal fetal brain development in utero and for the first 2 years of life. The developing fetus is initially reliant upon maternal thyroid hormones that cross the placenta, until the fetal thyroid begins to supply thyroid hormone for the fetus. Maternal thyroid status affects fetal thyroid function and maternal thyroid dysfunction can have a significant impact on the fetus and neonate. There are also several neonatal factors that can influence thyroid function. Here, we describe thyroid function in the fetus and neonate and discuss the most common thyroid disorders seen in neonates.

Current knowledge of transient hypothyroxinemia of prematurity: to treat or not to treat?

BACKGROUND: Thyroid hormones (THs) play a critical role in normal maturation of the developing brain in the fetus and infant. Continuing advances in neonatal medicine have contributed to an increased survival of extremely premature infants with neonatal morbidities. In these infants, thyroid system immaturities, as well as morbidity-related thyroid dysfunction, contribute to transient hypothyroxinemia of prematurity (THOP), which is characterized by very low total and free thyroxine and normal or low thyroid-stimulating hormone (TSH) levels. REVIEW: Undoubtedly, low levels of THs with elevated TSH are associated with poor neurodevelopmental outcome. However, continuing debate exists regarding whether THOP is harmful to the developing brain. Moreover, no clear effects of TH treatment on neurodevelopmental outcome in preterm infants with THOP have been demonstrated. THs could have unpredictable effects if given unnecessarily. CONCLUSION: The current recommendation is to treat THOP with TH only if THOP is accompanied with TSH elevation.

[Clinical anatomic study on the segment and adjacent of tract of congenital pyriform sinus fistula].

Objective: To investigate the anatomic tract of congenital pyriform sinus fistula (CPSF). Methods: A total of 90 patients with CPSF undergoing open surgery between August, 2007 and March, 2017 at the Department of Guangdong General Hospital were retrospectively analyzed. Results: The tracts of all the fistulas actually walked far different from those of theoretical ones. A whole fistula may be divided into 4 segments according to adjacent anatomy of CPSF. The posterior inner segment to the thyroid cartilage was initial part of the fistula. It originated from the apex of pyriform sinus, then piercing out of the inferior constrictor of pharynx inferiorly near the inferior cornu of the thyroid cartilage (ICTC), and descended between the lateral branch of the superior laryngeal nerve and the recurrent laryngeal nerve. The ICTC segment was the second part of the fistula, firstly piercing out of the inferior constrictor of pharynx and/or cricothyroid muscle, and then entering into the upper pole of thyroid. The relationship between fistula and ICTC could be divided into three types: type A (medial inferior to ICTC) accounting for 42.2% (38/90); type B (penetrate ICTC) for 3.3% (3/90); and type C (lateral inferior to ICTC) for 54.5% (49/90). The internal segment in thyroid gland was the third part of fistula, walking into the thyroid gland and terminating at its upper pole (92.2%, 83/90) or deep cervical fascia near the upper pole of thyroid (7.8%, 7/90). The lateral inferior segment to thyroid gland was the last part of the fisula, most of which are iatrogenic pseudo fistula, and started from the lateral margin of thyroid gland. Conclusions: CPSF has a complicated pathway. Recognition of the tract and adjacent anatomy of CPSF will facilitate the dissection and resection of CPSF in open surgery.

Screening for thyroid disease in pregnancy: a review.

Screening for thyroid disease in pregnancy remains a contentious issue. This review presents these diverging views and discusses their reasons as well as the relevant facts. The final aim is to establish the information gaps and limitations - technological or otherwise - which still need to be eliminated in order to settle the debate conclusively. The prevalence of the more common thyroid dysfunctions that occur in and after pregnancy is discussed. The subsequent impact of these disorders on mother and offspring is also described. Special focus is placed on the benefits and setbacks of currently available and newly proposed investigations, which assay serum hormone levels, serum autoantibody levels, and/or use clinical data. It is pointed out that the relevance of screening varies from one region of the world to the other, based on the content of iodine and selenium in food and water. The review then discusses the current major arguments for and against screening, as well as recommendations and proposed alternatives.

Pyramidal lobe of the human thyroid gland: an anatomical study with clinical implications.

The presence, position, extent, relationships to neighboring structures and size of the human pyramidal lobe were investigated in 58 human post-mortem specimens in order to determine the variability of this structure. The pyramidal lobe is found in 55.2% of cases as a single conical extension of the thyroid gland. It was present more often in male (53.1%) than in female (46.9%) specimens and located slightly more often on the left side of the midsagittal plane (53.1%). According to the origin and location of its base, we defined five types of pyramidal lobe, with the left-sided types (Types III and IV) being predominant. The pyramidal lobe was 22.6 mm long, 11.2 mm wide and 3.6 mm thick (mean values). The means of all measured parameters were higher in female than in male specimens (pyramidal lobe was 2.3 mm longer, 1.6 mm wider and 0.4 mm thicker in female specimens) but these differences were not significant. In addition, we found that the size of the pyramidal lobe was dependent on the presence of a fibrous or muscular band that may represent a fibrous remnant of the thyroglossal duct or the levator glandulae thyroideae muscle. The pyramidal lobe was four times longer and its base was two and a half times wider and three times thicker when it was associated with this band. We believe that our data can be used to perform safer and more effective partial thyroidectomy in order to preserve thyroid function after surgical treatment.

Neonatal hyperthyrotropinemia is associated with low birth weight: a twin study.

OBJECTIVE: Contradictory reports ascribe neonatal hyperthyrotropinemia (HT) to prematurity or small weight for gestational age. We aimed to evaluate the association between neonatal HT and birth weight (BW), recovery rate of the disorder, and possible association with perinatal stress. DESIGN: Based on a neonatal screening database, a retrospective twin study was designed where within-pair differences in thyroid function were evaluated while controlling for differences in gestational age and thyroid-affecting environmental confounders. METHODS: Two thousand five hundred and ninety-five twin pairs that were screened both for TSH and thyroxine (T(4)) over 3 years were included. TSH and T(4) levels were evaluated along with BW, birth order, gender, and 17-hydroxyprogesterone (17OHP) that was considered as a surrogate marker for stress. RESULTS: Of all the twin pairs, 7.2% had neonatal HT. Among 156 pairs, HT was more prevalent in the smaller twins (64%; P<0.001), especially in the discordant pairs (76%; P=0.001). Seventy-five percent of the twins demonstrated a recovery within the first few weeks of life. 17OHP levels were similarly distributed between twins with and without HT. In a cohort of 1534 twin pairs with normal thyroid function, mean TSH levels were significantly higher in the smaller than in the larger twin in the whole group (4.1±3.2 vs 3.8±2.9 mIU/l; P<0.001) and especially among discordant twins (4.7±3.4 vs 3.8±3.0 mIU/l; P<0.001). CONCLUSIONS: Elevated TSH levels are associated with low BW, both in infants with HT and in normal neonates. A rapid recovery rate is expected in most cases.

Thyroid hormones in the neonate: an overview of physiology and clinical correlation.

This article reviews the pathological actions of the thyroid hormones in the neonate. A review of the thyroid gland, thyroid hormones, fetal thyroid development, and healthy neonatal thyroid actions is explored as a basis to comprehend common thyroid diseases.

Thyroid hemiagenesis: a case series and review of the literature.

PURPOSE: The purpose of this study is to present a case series and review recommendations within the literature concerning thyroid hemiagenesis. MATERIALS AND METHODS: This is a (1) retrospective case series review of 5 patients and (2) literature review (using Medline) on thyroid hemiagenesis. RESULTS: Most reported cases are female with the left thyroid lobe absent. Compensatory hypertrophy occurs in most thyroid remnants. Associated diagnoses in the remaining lobe include hyperthyroidism, hypothyroidism, simple and multinodular goiter, and carcinoma. There is no increased risk for the subsequent development of cancer in the remaining lobe, and empiric thyroidectomy is not justified. CONCLUSIONS: Thyroid hemiagenesis is an uncommon presentation that is frequently asymptomatic and detected incidentally when imaging for another condition. Awareness of its existence can help prevent unnecessary interventions associated with incorrect assumptions in patient care.

Serum thyroid function tests in neonates of mothers with thyroid disease.

Maternal thyroid disease can affect the newborn baby leading to neonatal hyperthyroidism or hypothyroidism. Babies born to mothers with thyroid disease get thyroid function tests (TFT) done randomly irrespective of the nature of maternal thyroid disease and medication .The aim of this study was to determine which babies are at-risk and need thyroid function monitoring besides a simple Newborn screening test and to produce a local guideline for management of this particular cohort of babies. This prospective study done on 30 newborn babies concluded that routine newborn screening test is enough to monitor majority of these babies. A new local guideline is formulated accordingly.

Update on some aspects of neonatal thyroid disease.

This article explores the basic development and pathophysiology of the thyroid gland. New factors in the normal development of the thyroid in the neonate are mentioned. The incidence of congenital hypothyroidism continues to increase. We describe congenital hypothyroidism, its possible etiologies, treatment and outcomes. We explore hypothyroxinanemia in pre-term neonates and the risk/benefit of prophylactic thyroid hormone replacement. We discuss the late rise of thyrotropin (TSH) in ill infants and those with very low birth weight. Ill infants or those born premature should have their thyroid function tests routinely monitored. On the occasion of borderline thyroid function test results, TRH testing can be useful in identifying those infants with either persistent or transient hypothyroidism. TRH testing is also helpful in identifying those patients with secondary hypothyroidism. With the early identification and prompt and proper treatment, neonates with congenital hypothyroidism, transient or persistent, should have positive long-term outcomes.

When should we be conducting thyroid function tests in newborns and young infants?

An audit of local practice was undertaken as regards requests for thyroid function tests (TFT) in children aged between birth and 3 months at two local hospitals in South West England between 2005 and 2008. A total of 406 tests were performed (2.6 tests per week) over a 2-year period at a teaching hospital (70 tests per 1000 live births yearly), with 233 tests (1.5 tests per week) performed over a 3-year period at a local district hospital (39 tests per 1000 live births yearly). The highest proportion of all the tests was performed as routine investigation of prolonged neonatal jaundice (64% and 55%, respectively). Other common indications were maternal thyroid disorders (5.4% vs 4.7%) and suspected neonatal thyroid disorders (3% vs 9%). There was no confirmed diagnosis of infantile thyroid disease. Available evidence and this audit suggest that too many thyroid function tests are unnecessarily performed in young infants.

Left thyroid hemiagenesis in a patient with primary hyperparathyroidism.

The case of a patient with primary hyperparathyroidism with the incidental finding of left thyroid hemiagenesis with isthmus involvement is presented. Thyroid hemiagenesis is a rare congenital abnormality. There have been approximately 310 cases reported in the literature to date. It has been reported as an incidental finding with a wide range of associated pathological conditions. It is important to consider this in patients being prepared for thyroid lobectomy due to the inevitability of postoperative hypothyroidsm. Due to the female predominance of thyroid disease, hemiagenesis was first thought to be more common in women. Left lobe cases accounts for the majority of instances and isthmus is absent in half the cases. Ultrasonography is the diagnostic tool of choice.

Modified approach for lingual thyroid transposition: report of two cases.

Lingual thyroid is a rare congenital anomaly of thyroid development resulting from failure of the thyroglossal duct to migrate from the foramen cecum to the prelaryngeal site. The lingual thyroid associated with a fetal adenoma is even more unusual. We presented two cases of lingual thyroid, one associated with fetal adenoma. The ectopic gland was transposed into the muscle space at the floor of the mouth using an extraoral midline lower lip, mandible and tongue-splitting approach in case 1, and a transoral lower lip degloving and midline mandibulotomy and tongue-splitting approach in case 2. Sixteen-year follow-up of case 1 and 6-month follow-up of case 2 showed that the transposed thyroids achieved normal function. Case 2 had no visible scar in the lower lip and mental area. Surgical transposition of the lingual thyroid to the floor of the mouth with the vascular supply intact offers a promising approach for the treatment of this anomaly. The transoral lower lip degloving and midline-splitting approach is recommended because of its better cosmetic outcome.

Management of neonatal endocrinopathies--best practice guidelines.

Neonatal emergencies are uncommon, but may lead to significant morbidity and mortality if not recognised and managed promptly. Disorders of sex development, hypoglycaemia, thyrotoxicosis and calcium balance are discussed, with emphasis on the clinical assessment, investigations and management of these disorders in the acute setting.