Median Thyroid-stimulating Hormone Levels Research Articles

Serum microRNA profiles in athyroid patients on and off levothyroxine therapy

BackgroundLevothyroxine replacement treatment in hypothyroidism is unable to restore physiological thyroxine and triiodothyronine concentrations in serum and tissues completely. Normal serum thyroid stimulating hormone (TSH) concentrations reflect only pituitary euthyroidism and, therefore, novel biomarkers representing tissue-specific thyroid state are needed. MicroRNAs (miRNAs), small non-coding regulatory RNAs, exhibit tissue-specific expression patterns and can be detectable in serum. Previous studies have demonstrated differential expression of (precursors of) miRNAs in tissues under the influence of thyroid hormone.ObjectiveTo study if serum miRNA profiles are changed in different thyroid states.Design and methodsWe studied 13 athyroid patients (6 males) during TSH suppressive therapy and after 4 weeks of thyroid hormone withdrawal. A magnetic bead capture system was used to isolate 384 defined miRNAs from serum. Subsequently, the TaqMan Array Card 3.0 platform was used for profiling after individual target amplification.ResultsMean age of the subjects was 44.0 years (range 20–61 years). Median TSH levels were 88.9 mU/l during levothyroxine withdrawal and 0.006 mU/l during LT4 treatment with a median dosage of 2.1 μg/kg. After normalization to allow inter-sample analysis, a paired analysis did not demonstrate a significant difference in expression of any of the 384 miRNAs analyzed on and off LT4 treatment.ConclusionAlthough we previously showed an up-regulation of pri-miRNAs 133b and 206 in hypothyroid state in skeletal muscle, the present study does not supply evidence that thyroid state also affects serum miRNAs in humans.

Thyroid-Stimulating Hormone Reference Ranges in the First Trimester of Pregnancy in an Iodine-Sufficient Country.

BackgroundThyroid dysfunction is associated with negative neonatal and obstetric outcomes. Large differences in thyroid function reference intervals exist across different populations. These differences can be explained by population-specific factors, such as iodine status. Many countries in Latin America report iodine sufficiency, but relatively few countries have published up-to-date data on iodine levels and thyroid function in the overall population, and especially in pregnant women. We evaluated the iodine status of pregnant women in Chile and determined thyroid hormone reference ranges in this population.MethodsThis was a prospective observational study of healthy Chilean women at their first prenatal visit before week 14. Thyroid-stimulating hormone (TSH), total thyroxine (T4), free T4, antithyroid peroxidase antibody (TPOAb), and iodine levels from spot urine samples were measured. Iodine status and the reference ranges for TSH were calculated.ResultsA total of 1,022 pregnant women in the first trimester were selected. Urinary iodine levels were measured in 302 randomly-selected women. The median urinary iodine concentration was 173.45 µg/L (interquartile range, 108.11 to 249.35).The reference ranges of TSH were calculated in 670 patients selected according to the National Academy of Clinical Biochemistry guidelines. The median TSH level was 1.88 µIU/mL (2.5th percentile: 0.13 to 97.5th percentile: 5.37). Using the reference range in the 1,022 women, the prevalence of clinical hypothyroidism was 1.76%, and that of subclinical hypothyroidism was 3.92%. TPOAb positivity was more common in women with TSH levels above 3.5 µIU/mL.ConclusionWe found adequate iodine intake and a right-shifted distribution of serum TSH levels in pregnant women in Chile. The prevalence of hypothyroidism in our sample of pregnant women was higher than has been described in the literature.

Thyroid Function and Ultrasonography Abnormalities in Lithium-Treated Bipolar Patients: A Cross-sectional Study with Healthy Controls.

Lithium has many effects on thyroid physiology. Although these side effects have been known for a long time, large sample studies of lithium-treated patients using ultrasonography are lacking. The aim of this study is to investigate the detailed thyroid morphologies, hormone levels, and antibodies of lithium-treated patients compared with healthy controls. This cross-sectional study involved 84 lithium-treated patients with bipolar disorder and 65 gender and age similar controls who had never been exposed to lithium. Subjects between 18 and 65 years of age were eligible for the study. Venous blood samples were acquired to determine the levels of free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroid antibodies; also, ultrasonographic examinations of the patients' thyroid glands were performed. There were no statistically significant differences in smoking habits, known thyroid disease, thyroid medication use, familial thyroid disease, fT4 level, autoimmunity, thyroid nodule presence, or Hashimoto's thyroiditis between the lithium and control groups. The median TSH level and thyroid volume were significantly higher in the lithium group. In the lithium group, 14 cases (16.7%) of hypothyroidism, seven cases (8.3%) of subclinical hypothyroidism, and one case (1.2%) of subclinical hyperthyroidism were defined; in the control group, seven cases (10.8%) of hypothyroidism and two cases (3.1%) of subclinical hyperthyroidism were defined. Thyroid dysfunction, goiter, parenchymal abnormality, ultrasonographically defined thyroid abnormality, and thyroid disorder were found to be more prevalent in the lithium group. 90% of patients with goiter and 74.3% of patients with ultrasonographic pathologies were euthyroid. It is important to note that 90% of the patients with goiter were euthyroid. This indicates that monitoring by blood test alone is insufficient. The prevalence rates of 47.6% for goiter and 83.3% for ultrasonographic pathology demonstrate that ultasonographic follow-up may be useful in lithium-treated patients. To determine whether routine ultrasonographic examination is necessary, large sample prospective studies are necessary due to the limitations of this study.

Delayed TSH recovery after dose adjustment during TSH-suppressive levothyroxine therapy of thyroid cancer.

Delayed thyroid-stimulating hormone (TSH) recovery during treatment of Graves' disease is caused by long-term excessive thyroid hormone, which results in downregulation of pituitary thyrotrophs. However, it is unknown whether delayed TSH recovery exists after levothyroxine (LT4) dose reduction in patients with differentiated thyroid cancer (DTC) after long-term TSH suppression. We retrospectively reviewed 97 DTC patients with LT4 dose reduction after long-term TSH suppression. TSH levels at baseline (point 1), 6months (point 2) and 12-18months (point 3) after LT4 dose reduction were compared. A delayed TSH recovery group whose TSH levels changed to upper target TSH category (2015 revised ATA guidelines) from point 2 to point 3 was identified, and risk factors were analysed. The median TSH level at point 3 was significantly higher than that of point 2 (0.17 vs 0.09mIU/L; P<.001). The delayed TSH recovery group (44.3%) showed increased body weight (60.84 vs 62.73kg; P=.01), while normal response group did not. Greater reduction (%) in the LT4 dose per weight [HR 1.10, 95% CI (1.00-1.22), P=.04] and higher BMI before thyroid surgery [1.19, 1.03-1.38, P=.01] predicted the occurrence of delayed TSH recovery, while higher dose of LT4 per weight after reduction showed preventive effect [HR 0.01, 95% CI (0.00-0.54); P=.02]. Delayed TSH recovery was common during LT4 dose reduction after long-term TSH suppression for DTC management. Six months may not be enough for TSH recovery and to evaluate thyroid hormone status by serum TSH.

Association of Thyroid Stimulating Hormone with Insulin Resistance in Women with Polycystic Ovarian Syndrome

Introduction: Polycystic Ovarian Syndrome (PCOS) is a major cause of female infertility which is thought to be associated with Insulin Resistance (IR). However the nature and degree of IR have been shown to vary in different populations. PCOS women have also been reported to have increased prevalence of subclinical hypothyroidism which has been postulated to be determinants of IR. The natures of thyroid involvement have also been shown to vary between populations.Objectives: The study was undertaken to explore the distribution of IR and thyroid dysfunction as assessed by Thyroid Stimulating Hormone (TSH) levels among PCOS subjects and also to investigate the association of IR with TSH in women with PCOS.Materials and Methods: One hundred and fifty one PCOS patients (age in years 24±5; M±SD) were studied. PCOS was diagnosed by Rotterdam criteria. Fasting serum C-peptide was measured by Enzyme Linked Immuno Sorbide Essay (ELISA) and serum TSH was measured by Microparticle Enzyme Immunoassay (MEIA). Serum glucose was estimated by Glucose-Oxidase method (GOD-PAP). Insulin sensitivity was assessed by using Homeostasis Model Assessment (HOMA).Results: The mean serum C-peptide (nmol/l) and HOMA%S were 0.67 (±0.35) and 85 (±42) respectively. The median (Range) serum TSH level (?lU/ml) of the study subjects was found to be 2.49 (0.66 to 20.86). Insulin sensitivity was found to be 26%, 47%, 17% and 10% in those who had HOMA%S level at the range of &lt;50, 50-100, 101-150 and &gt;150 respectively. Of the total PCOS subjects, 85% had normal level of TSH value whereas only 15% PCOS subjects had subclinical hypothyroidism. The median serum TSH level of the insulin resistance and non-resistance groups were 2.25 (0.89-5.71) and 2.58 (0.74-20.86) respectively. On Pearson's correlation analysis insulin sensitivity was not found to be any significant association with TSH in the PCOS subjects.Conclusion: The study revealed that there was no significant association with IR and TSH in the PCOS subjects.Journal of Armed Forces Medical College Bangladesh Vol.11(1) 2015: 69-73

Iodine status and thyroid nodules in females: a comparison of Cyprus and Romania

ObjectivesThe increased comparative prevalence rates of thyroid cancer in Cyprus (>EU average) led us to conduct this study on possible risk factors of thyroid nodules. Romania served as a reference with a comparative thyroid cancer prevalence < EU average. This study aimed to assess the association between urinary iodine (UI) and thyroid nodules in adult females (n = 208) from Cyprus and Romania. Study designA case-control study (n = 208). MethodsCases were females with ultrasound-confirmed thyroid nodules and controls with confirmed absence of nodules. In both countries, subjects underwent ultrasound medical examinations, completed a questionnaire and offered a spot urine sample. ResultsMedian UI level in Cyprus was 94 μg/L, whereas 32% of the Cypriot UI was < 50 μg/L, classifying the population as mildly iodine deficient. In Romania, both cases and controls were iodine sufficient. No significant differences (P > 0.05) in serum free thyroxin (fT4) and thyroid stimulating hormone (TSH) levels were found between cases and controls. Cases had lower median TSH levels compared with controls (1.4 mIU/L and 1.7 mIU/L, P = 0.060), but serum TSH and free thyroxin levels were within normal range. Albeit non-significant, participants with inadequate UI (<100 μg/L) had increased risk for thyroid nodules (odds ratio = 1.40, 95% confidence interval = 0.70, 2.81, P = 0.346), using multiple logistic regression after adjusting for age, body mass index, education, country and serum TSH. ConclusionsThis was the first study to quantify UI levels in Cyprus. While the Romanian iodine fortification programme reflected onto its UI levels, a representative assessment of iodine status in Cyprus will address the necessity of an iodine fortification programme.

The Association of Thyroid Hormones and Tsh with the Metabolic Syndrome in Euthyroid Taiwanese Individuals

There are conflicting studies in euthyroid males and females regarding associations between thyroidrelated hormones and parameters of the metabolic syndrome (MetS). We investigated the association between serum thyroid hormones and thyroid-stimulating hormone (TSH) concentrations and MetS in euthyroid men and women. Taiwanese subjects aged 20 to 65 years who had undergone a voluntary health examination at a preventive examination agency in Taipei were enrolled in this cross-sectional study. The definition of MetS was suggested by the Bureau of Health Promotion, Department of Health, Taiwan. Euthyroidism was defined as TSH and free thyroxine (FT4) levels within the normal reference ranges while not taking any thyroid medication. We conducted multiple logistic regression to identify the ability of serum triiodothyronine (T3), FT4, and TSH concentrations to identify the relative risk for the presence of MetS and components of the MetS in euthyroid Taiwanese individuals. A total of 8,207 Taiwanese subjects (mean age: men, 45.3 ± 9.9 years; women, 43.5 ± 9.3 years) were enrolled in this study. A total of 1,672 subjects (20.4%) were defined as having MetS; these subjects had significantly higher (P<.0001) mean age (48.4 ± 9.1 years vs. 43.6 ± 10.7 years), prevalence of men (78.7% vs. 53.4%), and smoking (16.8% vs. 11.6%) than those without MetS. The median TSH, FT4, and T3 levels in all subjects were 1.70 mIU/L, 1.41 ng/dL, and 1.20 ng/mL, respectively. Higher T3 and lower FT4 values rather than TSH increased the odds ratio for MetS in men and women after adjusting for smoking and age, particularly for the association of T3 and MetS in women (uppermost quartile versus lowermost quartile: odds ratio, 2.4; 95% confidence interval, 1.6 to 3.5; P for trend <.0001). In euthyroid Taiwanese men and women, relatively high serum T3 concentrations was most strongly associated with the presence of the MetS; relatively low serum T4 was less strongly related, and serum TSH levels were not associated with the MetS. It is not known if the relationship of serum T3 and T4 to the MetS is causal. BMI = body mass index FT4 = free thyroxine MetS = metabolic syndrome OR = odds ratio T3 = triiodothyronine TSH = thyroid-stimulating hormone WC = waist circumference.

Does TSH Trigger the Anti-thyroid Autoimmune Processes? Observation on a Large Cohort of Naive Patients with Thyroid Hemiagenesis.

Thyroid hemiagenesis (THA) is a rare abnormality characterized by the absence of one thyroid lobe. Elevated thyroid stimulating hormone (TSH) level and higher incidence of thyroid diseases were reported in THA. The aim of the study is to evaluate the thyroid autoimmunity incidence in patients with THA and influence of higher than average TSH level on thyroid volume (TV) and its change with age. The study included a group of naive patients with THA and a control group of subjects with bilobate thyroid. All patients underwent clinical examination, thyroid ultrasound, scintiscan and laboratory tests. In the studied and control group the presence of thyroid autoantibodies (TAb) was evaluated. The THA group consisted of 65 patients. In THA group 53.85 % of patients were positive for TAb. Patients with positive TAb were older (46.0 ± 18.3 years) than those with negative (35.0 ± 19.8 years); p = 0.02. The incidence of TAb was lower in controls (13.85 %, p < 0.0001). In the study group, positive correlation between the age and TV (r = 0.46, p = 0.0001), and negative correlations between the age and TSH level (r = −0.31, p = 0.01), and TSH concentration and TV (r = −0.35, p = 0.004) were found. In a subgroup of 30 patients with THA negative for TAb, even stronger correlations were observed. The median single lobe volume and median TSH level were higher in patients with THA when compared to controls (13.60 vs 8.20 ml, p < 0.0001; 3.23 vs 1.48 µU/ml, p < 0.0001, respectively). Patients with THA constitute an in vivo model of long-term thyroid TSH overstimulation. Further studies are needed to reveal, whether TSH overstimulation may be the trigger for thyroid autoimmunity.

Establishment of trimester-specific reference intervals for thyroid hormones in Korean pregnant women.

BackgroundEstablishment of trimester- and assay-specific reference intervals for every population is recommended. The aim of this study was to establish a trimester- and assay-specific reference interval for thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in Korean pregnant women.MethodsFrom April 2012 to December 2012, 531 pregnant women receiving prenatal care and 238 age-matched, non-pregnant women were enrolled in this study. After excluding patients with pregnancy-associated complications or thyroid-specific autoantibody, 465 pregnant and 206 non-pregnant women were included. Non-parametric analysis (2.5-97.5th percentile) was performed to determine the reference interval. Levels of TSH and FT4 were determined by electrochemiluminescence immunoassay (Elecsys thyroid tests, Roche Diagnostics, Germany).ResultsThe TSH reference intervals were 0.01-4.10, 0.01-4.26, and 0.15-4.57 mIU/L for the first, second, and third trimester, respectively. From the first trimester to the third trimester, the median TSH levels showed a significantly increasing trend (P<0.0001). The FT4 reference intervals were 0.83-1.65, 0.71-1.22, and 0.65-1.13 ng/dL for the first, second, and third trimester, respectively, showing a significantly decreasing trend (P<0.0001).ConclusionsEstablishing trimester-specific reference intervals in pregnant women is essential for accurate assessment of thyroid function. Our population-specific and method-specific reference intervals will be useful for screening Korean pregnant women for thyroid disease.

Changes in Body Weight after Treatment of Primary Hypothyroidism with Levothyroxine

Surprisingly few studies have examined weight change in hypothyroid patients after initiation of levothyroxine (LT4) therapy. Our study aimed to investigate weight change after initiation of LT4 treatment for primary hypothyroidism. Using electronic medical records from Boston Medical Center, Boston, Massachusetts, we performed a retrospective cohort study between January 1, 2003, and February 1, 2011. Adults ≥18 years of age with newly diagnosed primary hypothyroidism with an initial thyroid-stimulating hormone (TSH) level ≥10 mIU/L were identified. Patients with postsurgical hypothyroidism, thyroid cancer, and a history of radioactive iodine or head/neck irradiation, congestive heart failure, anorexia nervosa, end-stage renal disease, cirrhosis, pregnancy, or use of prescription weight-loss medications were excluded. TSH and weight at diagnosis and up to 24 months after LT4 initiation were collected. Weight change was assessed at the first posttreatment serum TSH level <5 mIU/L. A total of 101 patients (mean age, 48 ± 15 years; 71% women) were included. Initial median TSH was 18.3 mIU/L (range, 10.1 to 710.5 mIU/L) and initial median weight was 79.6 kg (range 41.5 to 167.5 kg). Posttreatment median TSH level was 2.3 mIU/L (range, 0.04 to 5 mIU/L), and weight change at a median of 5 months (range, 1.1 to 25.6 months) was -0.1 kg (range, -20.6 to 7.7 kg). Initial median body mass index (BMI) of 95 of the patients was 29.3 kg/m2 (range, 19.5 to 56.1 kg/m2), and the median change in BMI was -0.1 kg/m2 (range, -7.1 to 3.3 kg/m2). Only 52% of patients lost weight, with a mean weight loss of 3.8 ± 4.4 kg. Gender, race, education, insurance type, age, initial TSH level, time to normalization of TSH, and initial weight were not associated with changes in weight or BMI. Contrary to popular belief, our study of 101 patients with primary hypothyroidism showed that no significant weight change occurs after initiation of LT4 treatment.

The role of scintigraphy and ultrasound in the imaging of neonatal hypothyroidism: 5‐year retrospective review of single‐centre experience

Congenital hypothyroidism (CH), as indicated by an elevation of capillary thyroid-stimulating hormone (TSH) at newborn screening, is a preventable cause of mental retardation with varying aetiology; it can be transient or permanent. Radionuclide assessment is currently the gold standard for imaging CH. This study aimed to (i) review the different scintigraphic patterns and correlate them with TSH levels/patient outcomes, (ii) assess the role of sonography in neonates with apparent agenesis as indicated by scintigraphy and (iii) develop a diagnostic investigative algorithm. The technetium thyroid scans of 83 consecutive patients (49 females, average age 32 days) with CH scanned between 2005 and 2009 were retrospectively reviewed. Two nuclear medicine physicians blinded to the clinical details interpreted the scans in consensus. Scintigram appearances were categorised into five groups. Patients scintigraphically diagnosed with thyroid agenesis were evaluated with ultrasound. TSH values and scintigraphic and sonographic findings were correlated with patients' final diagnosis. Based on scintigraphy, 14, 13 and 19 patients out of 83 were assessed as having normal thyroid sites with normal, increased and decreased uptake, respectively. Twenty-two of 83 patients had no uptake, and 15 of 83 patients had ectopic uptake. Higher median TSH levels were seen in no-uptake and ectopic uptake subgroups. Eighteen of 22 patients with no uptake were evaluated with ultrasound. Three of the 18 patients had a normal thyroid gland, and three of 18 patients had a hypoplastic thyroid. Scintigram findings in patients with congenital hypothyroidism fall into five major categories, which have therapeutic implications (lifelong thyroxine in agenesis versus trial of stopping thyroxine in other subgroups). Sonographic demonstration of thyroid tissue in patients scintigraphically diagnosed with thyroid agenesis has major management implications.

The effect of thyroid function on clinical outcome in patients with heart failure

Thyroid dysfunction is known to effect cardiac function and is a risk factor for developing heart failure (HF). Data regarding the clinical significance of thyroid-stimulating hormone (TSH) levels alone as a predictor of outcome in patients with HF is sparse. We evaluated the significance of TSH on clinical outcome in a large cohort of patients with chronic HF. Patients with a diagnosis of HF at a Health Maintenance Organization (n = 5599) were followed for cardiac-related hospitalizations and death. Median TSH levels were 2.2 mIU/L (interquartile range 1.4-3.5). We divided patients into quartiles based on TSH levels. Median follow-up time was 434 days and the overall mortality rate was 13.2%. Both a high and a low TSH level was associated with an increased mortality rate. Cox regression analysis after adjustment for other significant predictors demonstrated that the highest TSH quartile was associated with increased mortality compared with those with the lowest mortality [second quartile: TSH 1.4-2.2 mIU/L, hazard ratio (HR) 1.36, 95% confidence interval (CI) 1.08-1.71, P = 0.01]. TSH was also an independent predictor of death and cardiac-related hospitalization. Analysis of patients not on levothyroxine treatment (78%) demonstrated that TSH was an even stronger predictor of mortality (HR 1.54, 95% CI 1.17-2.03, P = 0.002). Additional analysis based on accepted clinical cut-offs of TSH demonstrated that increasing TSH levels above normal were independently associated with increased mortality and cardiac-related hospitalizations. Increased TSH levels are associated with worse clinical outcome in patients with HF. Thyroid imbalance confers significant risk in HF and warrants attention.

The reference intervals of thyroid stimulating hormone in healthy individuals with normal levels of serum free thyroxine and without sonographic pathologies

Introduction: The aim of the present study was to investigate the reference intervals for thyroid stimulating hormone (TSH) in healthy individuals with normal levels of serum free thyroxine (fT4) and without sonographic pathologies, and determine the effects of age, gender, and residence on the TSH reference intervals. Subjects and methods: This research was a population-based study conducted in 70 regions. The random sampling method was used to select the 1095 subjects of the study among inhabitants aged 18 and above. Patients who had a previous history of thyroid disease and had been taking medication were excluded from the study as this may have affected their fT4 or TSH levels. In addition, subjects who had serum fT4 without a reference range and abnormal ultrasonography findings were also excluded. A total of 408 subjects were used for establishing the reference intervals for TSH. Results: The data for TSH in the study group were not normally distributed according to the Kolmogorov–Smirnov index. The geometric mean was 1.62 mIU/L, the median was 1.40 mIU/L, and the 95% reference intervals were 0.38–4.22 mIU/L. The median TSH level was higher in females compared to males (p < 0.05). In the female subjects 2.5th percentile of TSH was lower and 97.5th percentile was higher than those of males. The reference intervals of TSH were of lower values in subjects over 50 years old (p < 0.001). Discussion: Studies suggest that determination of the TSH reference intervals may differ due to environmental influences or due to age, gender, and race. It is suggested that the lower limit of normal TSH for the adult Turkish population would be 0.38 mIU/L and the upper limit similar to the traditional value of 4.2 mIU/L. If each clinician uses their population-specific reference interval for TSH, thyroid function abnormalities can be accurately estimated.

Levels of T4 and TSH in mother's blood and in cord blood at the time of delivery

Background: In conditions of maternal iodine deficiency, the frequency distribution of neonatal thyroid stimulating hormone (TSH) is shifted towards elevated values. Elevated serum TSH in the neonates indicates insufficient supply of thyroid hormones to the neonates, a major complication of iodine deficiency. Objectives: To determine the cord blood serum T4 and TSH levels and interrelationships with maternal thyroid hormones. Method: cord blood serum T4 and TSH levels of 45 consecutive newborns born at BPKIHS, Dharan, Nepal and maternal T4 and TSH levels were analyzed using ELISA based kits. Results: The mean age of mothers was 23.73± 3.86 years and average weight of the neonates was 3.038±0.45 Kg. The median levels of maternal and neonatal T4 were 1.09 ng/dl and 1.26 ng/ dl respectively. The corresponding median TSH levels were 3.71 mIU/L and 11.9 mIU/L. The maternal and neonatal levels of T4 were positively correlated. In 36 mothers who had TSH level within euthyroid range (0.3-6.2 mIU/L, Thyroid lab of BPKIHS), 22 neonates (61.11%) had TSH levels above 10 mIU/L. Among 9 mothers having TSH levels above 6.2 mIU/L, 7 (77.77%) neonates had TSH levels above 10 mIU/L. Conclusion: Overall 29 (64.44%) neonates had TSH level above 10 mIU/L which indicates mild degree of iodine deficiency. Iodine supplementation is required before pregnancy in majority of women of reproductive age. Health Renaissance, January-April 2013; Vol. 11 No.1; 6-10 DOI: http://dx.doi.org/10.3126/hren.v11i1.7593

Newborn thyroid-stimulating hormone in children with optic nerve hypoplasia: Associations with hypothyroidism and vision

To assess in children with optic nerve hypoplasia (ONH) whether newborn screening (NBS) thyroid-stimulating hormone (TSH) measurements can detect central hypothyroidism and whether newborn TSH or subsequent thyroidal status is associated with visual function. From a registry of children with ONH at Children's Hospital Los Angeles, post-natal thyroidal status was retrospectively compared with NBS TSH levels in the subset of subjects born in California. The subset of subjects with outcome data at age 5 years was assessed for relationship of vision to NBS TSH levels and ultimate thyroidal status. A total of 135 subjects from the ONH registry were included in this study. Approximately 50% of subjects in each analysis were hypothyroid. Those diagnosed with hypothyroidism had lower median NBS TSH levels than did euthyroid subjects (3.2 vs 4.5 μIU/mL; P = 0.006) and significantly worse quantitative vision outcomes (median visual acuity, logMAR 3.0 vs 1.0; P = 0.039). Receiver operating characteristic analysis suggested an optimal NBS TSH cut-point of 3.3 μIU/mL. Serum TSH levels greater than this (30/43) were associated with relatively better vision outcomes (median visual acuity, logMAR 1.2 vs 3.3; P = 0.04). Children with ONH and lower NBS TSH levels are more likely to have central hypothyroidism and less likely to experience good vision than those with greater NBS TSH levels.

Turner syndrome and its variants

Case records of female patients with karyotype proven turner syndrome were analyzed. 11 patients had classic Turner karyotype (Group 1) and 13 patients had karyotype suggestive of one of the variants of Turner syndrome (Group 2). There was a median difference of 3 years between the age of presentation and the age of diagnosis in Group 2. Out of the thirteen patients in Group 2, 4 had no clinical stigmata of Turner Syndrome; the rest (n=9) had one or more of the typical clinical stigmata of Turner Syndrome. One patient with a complex mosaic karyotype also had an intracranial medulloblastoma. One patient in each group had coarctation of the aorta. 5 patients in Group 1 and 3 patients in Group 2 had primary hypothyroidism and received levothyroxine. The median Thyroid Stimulating Hormone levels were significantly higher among patients in group 1 than in group 2.

Thyroid hormone metabolism in pediatric cardiac patients treated by continuous povidone-iodine irrigation for deep sternal wound infection.

The purpose of this study was to assess the influence of povidone-iodine mediastinal irrigation used for the treatment of deep sternal wound infection (DSWI) on thyroid function. Thyroid function was studied in 18 pediatric cardiac patients treated with continuous povidone-iodine irrigation for DSWI. The median age of patients was 8 months (18 days-5.3 years). Serum concentrations of total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), reverse triiodothyronine (rT3) and thyroxine-binding globulin (TBG) were measured at three time points: (a) prior to mediastinal reexploration (before povidone-iodine exposure); (b) immediately after discontinuation of povidone-iodine irrigation; (c) 2 weeks after discontinuation of mediastinal irrigation. Urinary iodine excretion was examined on the last day of povidone-iodine exposure. Prior to the mediastinal reexploration, the median TT3 and TT4 levels were below the normal range, then increased significantly to concentrations within the normal range. The median serum FT3 levels were within the normal range throughout the observation period, though a significant increase of FT3 levels was observed after discontinuation of irrigation. The median serum FT4 concentrations were within the normal range prior to irrigation and did not change significantly. The median rT3 levels were within the normal range, close to upper normal limit. The median TBG levels were within the normal range throughout the observation period, though a significant increase of TBG levels was observed during the period of mediastinal irrigation. The median TSH level was within the normal range prior to mediastinal irrigation and did not change significantly. Urinary iodine concentrations in infants with povidone-iodine irrigation were significantly higher 6700 microg/l (range, 1600-15000 microg/l) than in the group of 53 healthy infants 200 microg/l (range, 20-780 microg/l, P<0,001). Our data showed that the use of povidone-iodine irrigation in the patients with DSWI has not lead to any significant alteration in thyroid function within the study period.

Cyclical combination chemotherapy and thyroid function in patients with advanced Hodgkin's disease.

Clinical and biochemical assessment of thyroid function was undertaken in patients with Hodgkin's disease at designated points following diagnosis. At diagnosis, two of 20 patients had either abnormally low routine thyroid indices, or elevated thyroid stimulating hormone (TSH) levels that were not due to iodine-based investigations. Following lymphography, 76.5% of patients had TSH levels that remained elevated for a median period of 3 months. No detectable thyroid dysfunction was induced during chemotherapy. Fifty-four patients were studied at a median time of 35 months after chemotherapy. One euthyroid patient had a nodular goitre, and one had abnormal thyroid indices. Tsh levels were elevated in 44% of patients, although the median TSH level for the group was normal. Half the patients had abnormal TRH stimulation tests. Sixty patients were studied after irradiation and chemotherapy. Four patients had clinical thyroid dysfunction, and 10% of routine thyroid indices were abnormal. TSH levels were abnormal in 80%, with a markedly elevated median level. All thyroid releasing hormone stimulation tests were abnormal.