Low Serum Thyrotropin Research Articles

Prevalence of Non-autoimmune Hypothyroidism in Steroid Resistant Nephrotic Syndrome in Paediatric Age Group

Introduction: It was observed that approximately 10% of children with Nephrotic Syndrome (NS) are found as Steroid Resistant NS (SRNS). The data on the prevalence of non-autoimmune hypothyroidism among the SRNS in India is limited. Aim: To assess the prevalence of non-autoimmune hypothyroidism in the case of SRNS. Materials and Methods: A case control cross-sectional study was conducted in which 52 cases of SRNS and 52 healthy controls were enrolled. Thyroid profile like serum Thyroid Stimulating Hormone (TSH), Free Triiodothyronine (T3), Free Thyroxine (T4) done in the all cases and controls but anti-Thyroid Peroxidase (TPO), and anti-thyroglobulin antibody test was done in the case and control group with deranged thyroid function test. Low Free T4 (normal: 0.7-2 ng/mL) and elevated serum TSH above the upper limit of the reference range (>4.5 mIU/L) was defined as overt hypothyroidism, whereas elevation in serum TSH with a normal serum FT4 concentration was defined as sub clinical hypothyroidism. MedCalc statistical software Version 19.2.6 was used to do statistical analysis. Results: Prevalence of Non-autoimmune hypothyroidism was 38.46% (20 out of 52), 16 (30.76%) had subclinical and 4 (7.69%) had overt hypothyroidism in case of SRNS in comparison to 1.96% (1 out of 52) in control group. Out of 16 subclinical hypothyroid patients, two cases with grade 1, 12 cases with grade 2, and two cases with grade 3 found. Patients with SRNS had a mean (SD) TSH value of 4.5±4.7 mlU/L which was significantly higher than control (1.8±1.1 mlU/L). Serum levels of FT4 were within normal range. Anti-TPO and anti-thyroglobulin titre were in normal range in children with hypothyroidism. Conclusion: The prevalence of non-autoimmune hypothyroidism was high in cases of idiopathic SRNS. So, on the basis of this study estimation of thyroid profile in children with SRNS seems to be the rational approach which will lead to early diagnosis and timely management of hypothyroidism in SRNS.

Differential Diagnosis of Thyrotoxicosis

Hyperthyroidism is characterized by increased thyroid hormone synthesis and secretion from the thyroid gland, whereas thyrotoxicosis refers to the clinical syndrome of excess circulating thyroid hormones, irrespective of the source. Thyrotoxicosis is characterized by low serum thyroid-stimulating hormone (TSH) level and elevated serum levels of free thyroxine or free triiodothyronine, or both. Therefore, thyrotoxicosis is divided into two subtypes: thyrotoxicosis with hyperthyroidism such as Graves’ disease and Plummer’s disease, and thyrotoxicosis without hyperthyroidism such as painless and subacute thyroiditis. Here, I describe the differential diagnosis of hyperthyroidism; differentiation between Graves’ disease and Plummer’s disease; differentiation between Graves’ disease with and without thyroid storm. Further, I show the differentiation among Graves’ disease, painless thyroiditis and subacute thyroiditis. I believe that the proper diagnosis leads to appropriate treatment and management of thyrotoxicosis. J Endocrinol Metab. 2019;9(5):127-132 doi: https://doi.org/10.14740/jem600

Hypothyroidism in Clinical Practice

Hypothyroidism in Clinical Practice

Hypothyroidism in patients with autoimmune pancreatitis.

AIMTo examine thyroid function and clinical features of hypothyroidism in autoimmune pancreatitis (AIP) patients.METHODSWe examined thyroid function in 77 patients with type 1 AIP (50 males, 27 females; median age 68 years, range 33-85) diagnosed according to the Japanese diagnostic criteria for AIP 2011. We compared clinical and serological findings between patients with and without various categories of hypothyroidism. The change in hypothyroidism after steroid therapy was also examined.RESULTSEight patients (10%) had hypothyroidism of 6 patients had subclinical hypothyroidism with a normal serum free thyroxine (FT4) and high thyroid stimulating hormone (TSH) level, and 2 patients had central hypothyroidism with low serum free triiodothyronine (FT3), FT4 and TSH levels. A significant goiter of the thyroid was not observed in any patient. There were no significant differences in age; male to female ratio; serum concentrations of IgG and IgG4-related disease (IgG4-RD); presence of anti-thyroglobulin antibody, antinuclear antigen or rheumatoid factor; or presence of extrapancreatic lesions between the 6 patients with subclinical hypothyroidism and patients with euthyroidism. After steroid therapy, both subclinical and central hypothyroidism improved with improvement of the AIP.CONCLUSIONHypothyroidism was observed in 8 (10%) of 77 AIP patients and was subclinical in 6 patients and central in 2 patients. Further studies are necessary to clarify whether this subclinical hypothyroidism is another manifestation of IgG4-RD.

Serum thyroid‐stimulating hormone levels and smoking status: Data from the Korean National Health and Nutrition Examination Survey VI

We aimed to evaluate differences in serum thyroid-stimulating hormone (TSH) levels according to smoking status and urine iodine concentration (UIC) in a healthy Korean population using data from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES VI). Sixth Korean National Health and Nutrition Examination Survey (2013-2015) is a nationwide, cross-sectional survey of the Korean population. Research subjects were selected by two-stage stratified cluster sampling of the population and housing census data. A total of 5639 subjects aged >18years, who were not pregnant, and had undergone thyroid function testing during the survey period, were included. The level of serum TSH according to smoking status, iodine intake and presence of TPOAb were evaluated. In the reference population, mean serum TSH level in current smokers (1.87mIU/L, 95% CI, 0.52-5.37mIU/L) was significantly lower than that in nonsmokers (2.33mIU/L, 95% CI, 0.79-6.69mIU/L, P<.001). The rate of thyroperoxidase antibody (TPOAb) positivity was higher in never smoker (7.7%) than past smokers (5.1%) and current smokers (4.7%), but sex-specific rate of TPOAb was not different according to smoking status. The lower serum TSH levels in current smokers were more apparent in iodine-deficient subjects (UIC<100μg/L), and this change was diminished in subjects with UICs between 100 and 299μg/L. The difference in serum TSH levels in current smokers disappeared in subjects with UICs≥300μg/L. Smoking is associated with a left-shift in serum TSH level that is more apparent in iodine-deficient subjects. Smoking status is not associated with the presence of TPOAb or iodine intake. The results suggest that smoking has a direct effect on thyroid function that is not mediated by autoimmune processes in the thyroid gland.

Associations of thyroid hormone serum levels with in-vivo Alzheimer\u2019s disease pathologies

BackgroundThe present study investigated the relationships between thyroid hormone serum levels or thyroid-stimulating hormone (TSH) and two Alzheimer’s disease (AD)-specific biomarkers, cerebral amyloid beta (Aβ) burden and glucose metabolism, in AD-signature brain regions in cognitively normal (CN) middle-aged and older individuals.MethodsThis study assessed 148 CN individuals who received comprehensive clinical and neuropsychological assessments that included 11C-Pittsburgh Compound B (PiB)-positron emission tomography (PET) scans, 18F-deoxyglucose (FDG)-PET scans, and the quantification of serum triiodothyronine (T3), free T3, free thyroxine (fT4), and TSH levels.ResultsAll participants were clinically euthyroid. Independent negative associations were found between serum fT4 levels and global cerebral Aβ deposition after controlling for the effects of age, gender, and the apolipoprotein E ε4 (APOEε4) genotype. Although serum TSH levels were not associated with global cerebral Aβ deposition, they had a significant negative association with glucose metabolism in the precuneus/posterior cingulate cortex after controlling for age, gender, and the APOEε4 genotype. No other thyroid hormones exhibited relationships with either brain Aβ burden or glucose metabolism.ConclusionsEven in a clinical euthyroid state, low serum fT4 and high serum TSH levels appear to be differentially associated with AD-specific brain changes.

Excess Mortality in Treated and Untreated Hyperthyroidism Is Related to Cumulative Periods of Low Serum TSH.

Cumulative time-dependent excess mortality in hyperthyroid patients has been suggested. However, the effect of antithyroid treatment on mortality, especially in subclinical hyperthyroidism, remains unclarified. We investigated the association between hyperthyroidism and mortality in both treated and untreated hyperthyroid individuals. Register-based cohort study of 235,547 individuals who had at least one serum thyroid-stimulating hormone (TSH) measurement in the period 1995 to 2011 (7.3 years median follow-up). Hyperthyroidism was defined as at least two measurements of low serum TSH. Mortality rates for treated and untreated hyperthyroid subjects compared with euthyroid controls were calculated using multivariate Cox regression analyses, controlling for age, sex, and comorbidities. Cumulative periods of decreased serum TSH were analyzed as a time-dependent covariate. Hazard ratio (HR) for mortality was increased in untreated [1.23; 95% confidence interval (CI), 1.12 to 1.37; P < 0.001], but not in treated, hyperthyroid patients. When including cumulative periods of TSH in the Cox regression analyses, HR for mortality per every 6 months of decreased TSH was 1.11 (95% CI, 1.09 to 1.13; P < 0.0001) in untreated hyperthyroid patients (n = 1137) and 1.13 (95% CI, 1.11 to 1.15; P < 0.0001) in treated patients (n = 1656). This corresponds to a 184% and 239% increase in mortality after 5 years of decreased TSH in untreated and treated hyperthyroidism, respectively. Mortality is increased in hyperthyroidism. Cumulative periods of decreased TSH increased mortality in both treated and untreated hyperthyroidism, implying that excess mortality may not be driven by lack of therapy, but rather inability to keep patients euthyroid. Meticulous follow-up during treatment to maintain biochemical euthyroidism may be warranted.

Low serum thyroid-stimulating hormone levels are associated with lipid profile in depressive patients with long symptom duration

ObjectiveThe current study was designed to investigate the association between serum thyroid hormones and thyroid-stimulating hormone (TSH) levels with lipid profile in depressive disorder. MethodsA total of 370 depressive individuals aged 18 years and above were recruited in this cross-section study. All participants underwent a Structured Clinical Interview for DSM-IV (SCID) and recorded the duration of their symptoms. The serum levels of total cholesterol (TCH), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), lipoprotein A (Lp(a)), high-sensitivity C-reactive protein (hsCRP), free thyroxine (FT4), free triiodothyronine (FT3) and TSH levels were determined and the ratios of TCH/HDL-C were assessed. ResultsDepressed subjects with a symptom duration ≥3 years had higher TG levels, increased TCH/HDL-C ratios and lower levels of HDL-C, FT4 and TSH compared with depressive patients with a symptom duration <3 years. Correlation analysis displayed that TSH is positively and significantly associated with TCH and LDL-C (p<0.05); the above FT4 and FT3 are negatively, significantly and respectively associated with TCH/HDL-C (p<0.05) and TCH, HDL-C, LDL-C (p<0.05). Multiple linear regression analysis indicated that serum TG and TSH levels are associated with depressive symptom duration. ConclusionsAccording to our results,These findings indicate that low serum TSH levels are associated with lipid profile, TG and TSH levels have significant association with symptom duration in depressive patients.

Serum Thyroid-Stimulating Hormone Levels and Frailty in the Elderly: The Progetto Veneto Anziani Study.

High or low thyroid-stimulating hormone (TSH) levels seem to be associated with several negative outcomes in the elderly, but the literature about TSH and frailty is still limited. In this article, we investigated whether TSH is associated with prevalent and incident frailty in a cohort of older community-dwelling subjects. Among 3099 initially screened in the Progetto Veneto Anziani Study, 2571 men and women aged ≥65 years (for cross-sectional analyses) and 1732 (longitudinal, mean follow-up period of 4.4 years) were divided into sex-specific quintiles according to baseline serum TSH concentrations within normal range (0.3 and 4.2 mUI/L). Frailty was defined as the presence of three among five Fried's criteria. At baseline, taking those in the third quintile of serum TSH as reference (Q3) and adjusting for potential confounders, participants in the highest (Q5) quintile had an increased odds ratio (OR) of having frailty (OR = 1.55; 95% confidence interval [CI]: 1.03-2.33 for men; OR = 1.97; 95% CI: 1.59-2.45 for women). Men in Q1 had significant higher odds of having muscle weakness and exhaustion, while those in Q5 had muscle weakness and slow gait speed. Women in Q1 had significantly higher odds of having all the Fried's criteria (except for exhaustion), while those in Q5 reported a significantly higher presence of muscle weakness and slow gait speed. At follow-up, men in Q5 had an increased risk of frailty (OR = 1.37; 95% CI: 1.02-1.91) similar to women in Q1 (OR = 1.47; 95% CI: 1.21-1.78). In conclusion, men with higher and women with lower serum TSH levels are at increased risk of frailty.

THYROID HORMONES, COGNITIVE IMPAIRMENT, DEPRESSION AND SUBJECTIVE MEMORY COMPLAINT IN COMMUNITY-DWELLING ELDERS

It was the aim to examine the association of the thyroid-related hormones with cognitive function, depression, and subjective memory impairment in community-dwelling elders with questionable dementia. The sample consisted of 399 community residents with ‘questionable dementia’ aged 60 or over in whom serum thyroid-related hormones [thyroid stimulating hormone (TSH) and thyroxine] had been assayed. Cognitive impairment was defined using the Korean version of the Consortium Establish a Registry for Alzheimer’s Disease. Depression was diagnosed using the Korean version of Geriatric Depression Scale and subjective memory complaint (SMC) was checked using the subjective memory complaints questionnaire (SMCQ). Age, gender, education, and the presence of apolipoprotein E ε4 were included as covariates. There was a significant positive association between verbal fluency test (VFT) score and serum TSH levels (p = 0.01). There was a significant negative association between SMCQ total score and word list memory test (WLMT)(p = 0.002) or word list recall test (WLRT) score (p = 0.013). Lower serum TSH levels were associated with semantic memory (VFT), and we found that SMC was associated with episodic memory (WLMT and WLRT) in this sample.

Association between low thyroid-stimulating hormone, posterior cortical atrophy and nitro-oxidative stress in elderly patients with cognitive dysfunction.

IntroductionCortical atrophy is known to be a valuable sign of cognitive decline. The purpose of this study was to assess the association between low thyroid-stimulating hormone (TSH), posterior cortical atrophy (Koedam score – KS) and nitro-oxidative stress in elderly patients.Material and methodsA study (SG) and a control group (CG), each subdivided by gender, were investigated. Subjects older than 59 years with low serum TSH level and with mild cognitive impairment were included in the SG. The CG was formed by subjects free of significant cortical atrophy and free or thyroid dysfunction. Demographic and clinical characteristics of the patients (Mini Mental State Examination, MMSE), Koedam score on cranial magnetic resonance imaging, and blood parameters (TSH, FT4, and nitric oxide – NOx) were assessed.ResultsSubjects in the study group had fewer years of education above the 8th grade compared with the control group (p < 0.0001). A significantly higher percentage of subjects in the study group had a Koedam score of 2 or 3 compared with controls, who had in the majority of cases a Koedam score of zero (p < 0.02). Significantly higher NOx levels were observed when study groups of both genders were compared with corresponding controls (p < 0.001). No significant differences were observed with regard to FT4 (p > 0.70). Nitric oxide was found to be significantly associated with TSH (p < 0.03) and KS (p < 0.002) when the whole study group was considered as well as when just the non-smoker study group was investigated.ConclusionsOur study revealed an association between subclinical thyroid hypofunction, nitro-oxidative stress, and posterior cortical atrophy as an early stage of global atrophy.

Is thyroid status associated with cognitive impairment in elderly patients in China?

BackgroundThe relationship between alterations in thyroid function and cognitive deficits has been investigated in several previous studies. Hypo-or hyperthyroidism and, to a lesser extent, subclinical thyroid dysfunction can negatively affect cognitive performance. However, limited data are available on the potential association of thyroid function with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) in the elderly Chinese population.MethodsIn the present study focusing on a population of elderly Chinese individuals ≥ 50 years of age, 77 cognitively normal controls, 64 patients with MCI, and 154 patients diagnosed with AD underwent assessment of thyroid status using thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4) levels as variables. Cognitive function was evaluated with the aid of comprehensive neuropsychological tests, such as the Mini-Mental State Examination (MMSE) and Memory and Executive Screening (MES).ResultsOverall, 88.1 % of the subjects displayed normal thyroid function, 4.7 % were diagnosed with clinical hypothyroidism, 3.1 % with subclinical hypothyroidism, and 4.1 % with subclinical hyperthyroidism. After adjusting for covariates (age, sex, education years and body mass index), no association was evident between mild cognitive impairment or AD and thyroid dysfunction. However, lower serum TSH was correlated with risk of AD (odds ratio [OR]: 2.78, 95 % confidence interval [95% CI]: 1.11-6.99).ConclusionNeither hypothyroidism nor subclinical hyperthyroidism was associated with AD and MCI in this population-based elderly Chinese cohort. Our findings need to be confirmed in a longitudinal study.Electronic supplementary materialThe online version of this article (doi:10.1186/s12902-016-0092-z) contains supplementary material, which is available to authorized users.

Low serum thyrotropin level and duration of suppression as a predictor of major osteoporotic fractures - the openthyro register cohort

The relationship between thyrotoxicosis and osteoporotic fractures remains controversial, particularly in men. Register-based cohort study including all patients with a serum thyrotropin (TSH) measurement in the region of Funen 1996–2010. All TSH determinations were done in the same lab, which served all hospitals and General Practice (GP) practices in the region. Persons with raised TSH or a history of thyroid/pituitary disease or use of thyroid medications were excluded. The study population consisted of 222,138 (96%) persons with normal and 9217 (4%) with low TSH (<0.3 mIU/L). A single low TSH at baseline was associated with increased risk of hip fractures (adj HR 1.16, 95% CI 1.07–1.26, p < 0.001) but not major osteoporotic fractures (MOF, adj HR 1.06, 95% CI 0.99–1.12, p = 0.058) over a median follow-up of 7.5 years. When men were analyzed separately, results did not reach statistical significance. We found a significant association between duration of thyrotoxicosis and fracture. For each 6 months in which the mean TSH value was decreased (<0.3 mIU/L), hip fracture risk increased by a factor 1.07 (adj HR, 95% CI 1.04–1.10, p < 0.001) and MOF by 1.05 (adj HR, 95% CI 1.03–1.07, p < 0.001). Overt thyrotoxicosis was associated with an increased risk of hip fractures but not MOF. In euthyroid patients, the risk of fractures increased significantly with each SD unit of TSH decrease: Hip fracture (HR 1.45, 95% CI 1.22–1.71, p < 0.001) and MOF (HR 1.32, 95% CI 1.19–1.46, p < 0.001). In a population-based cohort, a single, first measurement of decreased TSH in patients without known thyroid disease was associated with an increased long-term risk of hip fracture, which remained significant in women but not in men after adjusting for confounders. Moreover, the risk of both hip fracture and MOF increased exponentially by the length of time during which TSH had remained low. © 2014 American Society for Bone and Mineral Research

Low serum thyrotropin level and duration of suppression as a predictor of major osteoporotic fractures-the OPENTHYRO register cohort.

The relationship between thyrotoxicosis and osteoporotic fractures remains controversial, particularly in men. Register-based cohort study including all patients with a serum thyrotropin (TSH) measurement in the region of Funen 1996-2010. All TSH determinations were done in the same lab, which served all hospitals and General Practice (GP) practices in the region. Persons with raised TSH or a history of thyroid/pituitary disease or use of thyroid medications were excluded. The study population consisted of 222,138 (96%) persons with normal and 9217 (4%) with low TSH (<0.3 mIU/L). A single low TSH at baseline was associated with increased risk of hip fractures (adj HR 1.16, 95% CI 1.07-1.26, p < 0.001) but not major osteoporotic fractures (MOF, adj HR 1.06, 95% CI 0.99-1.12, p = 0.058) over a median follow-up of 7.5 years. When men were analyzed separately, results did not reach statistical significance. We found a significant association between duration of thyrotoxicosis and fracture. For each 6 months in which the mean TSH value was decreased (<0.3 mIU/L), hip fracture risk increased by a factor 1.07 (adj HR, 95% CI 1.04-1.10, p < 0.001) and MOF by 1.05 (adj HR, 95% CI 1.03-1.07, p < 0.001). Overt thyrotoxicosis was associated with an increased risk of hip fractures but not MOF. In euthyroid patients, the risk of fractures increased significantly with each SD unit of TSH decrease: Hip fracture (HR 1.45, 95% CI 1.22-1.71, p < 0.001) and MOF (HR 1.32, 95% CI 1.19-1.46, p < 0.001). In a population-based cohort, a single, first measurement of decreased TSH in patients without known thyroid disease was associated with an increased long-term risk of hip fracture, which remained significant in women but not in men after adjusting for confounders. Moreover, the risk of both hip fracture and MOF increased exponentially by the length of time during which TSH had remained low.

Clinical and therapeutic controversies on subclinical hyperthyroidism

Subclinical hyperthyroidism is defined as low or undetectable serum thyrotropin concentration in the presence of levels of free thriiodothyronine and thyroxine within the reference range. Despite the conflicting results from many observational studies, this thyroid disorder has been associated with an increased risk of developing atrial fibrillation, left ventricular hypertrophy, increased heart rate and diastolic function impairment. In addition, a relation between subclinical hyperthyroidism, skeletal disorders and cognitive changes has been reported. Treatment of subclinical hyperthyroidism remains controversial, given the lack of prospective randomized studies showing clinical benefits with restoration of the euthyroid state. Nevertheless, this review recommends the treatment of subclinical hyperthyroidism to individuals aged over 65, postmenopausal women, patients with cardiac risk factors, heart disease, osteoporosis or hyperthyroidism symptoms, whenever TSH is persistently suppressed(<0.1 mU/L). When TSH is between 0.1 - 0.5 mU/L, treatment should be considered for individuals over age 65, patients with heart disease or hyperthyroidism symptoms.

Role of TSH on Urinary Calcium Excretion In Post Menopausal Women of South Indian Population

Unforeseen aberrations in the hormonal status during the early postmenopausal period are responsible for several complications including osteoporosis. Thyroid Stimulating Hormone (TSH) receptors are isolated from various tissues including the bone. A low serum TSH level is known to stimulate osteoclastic activity in bone and accelerate bone resorption. Urinary calcium/creatinine (UCa/Cr) excretion ratio could be an indirect and an early indicator of loss of Bone Mineral Density (BMD). With this background, this study was planned to explore the association of serum TSH levels with the UCa/Cr excretion ratio. Forty eight women in the postmenopausal age group, with their menopausal age not more than seven years of duration were included in this study. Based on their TSH values, these subjects were divided into two groups A (TSH<0.5 mIU/L) and B (TSH>0.5mIU/L). Urinary calcium, UCa/Cr excretion ratio, serum phosphorous, calcium and calcium phosphorous multiplication products were estimated and compared between the two groups. Twenty two (46%) women were biochemically asymptomatic hyperthyroid cases and Twenty six (54%) were euthyroid. This study documents high UCa/Cr in Group A compared to that of Group B (p<0.05). We also observed significant negative correlation of TSH with UCa/Cr excretion ratio (p=0.041, r = -0.43). Low serum TSH levels were associated with increased UCa/Cr excretion ratio in postmenopausal women of South Indian population.

Thyroid Stimulating Hormone in Acute Psychiatric Patients with Positive Urine Toxicology Drug Screen: A Retrospective Study

Background: The effect of recent exposure to illicit substances on the hypothalamic-pituitary-thyroid axis hormones during acute psychiatric hospitalization remains largely unknown. The aim of this study was to examine thyroid stimulating hormone (TSH) levels in patients admitted to the Los Angeles County hospital psychiatric emergency room with positive urine toxicology screening [Utox(+)]. Methods: The medical records of all patients admitted to the psychiatric emergency room (ER) (2002-2007) were reviewed (n=18,836) to extract TSH and Utox data. Serum TSH levels are routinely measured by radioimmunoassay and Utox is routinely tested using the enzyme immunoassay technique as part of clinical care. A general linear model was used to compare geometric mean TSH values between Utox(+) and Utox(-) groups adjusting for age, sex, and race. Results: Utox data were available for 57% (n=4,470) of final study cohort. 39% (n=1,726) were Utox(+). A significant race effect on TSH levels was detected regardless of Utox(+) status, with African American patients having significantly lower mean TSH compared with non-Hispanic white patients: 0.98 ± 2.19 vs. 1.29 ± 2.43, mean ± SD, P<0.0001). Furthermore, TSH levels were significantly lower in the Utox(+) group compared with the Utox(-) group (1.01 ± 2.41 vs. 1.26 ± 2.26, P<0.0001) adjusted for age, gender, and race. Within the Utox(+) group, there was no significant gender difference observed (males vs. females: 1.00 ± 2.32 vs. 1.04 ± 2.57, P=0.1). Conclusion: We observed an association between Utox(+) status and low serum TSH levels in both males and females admitted for acute psychiatric conditions. While the stress caused by acute substance intoxication or withdrawal may play a role in altering TSH levels in this group of patients, the neuroendocrinological underpinnings of this observation require further research.

Hyperfunction Thyroid Nodules: Their Risk for Becoming or Being Associated with Thyroid Cancers

ObjectiveTo retrospectively evaluate the risk of thyroid cancer in patients with hyperfunctioning thyroid nodules through ultrasonographic-pathologic analysis.Materials and MethodsInstitutional review board approval was obtained and informed consent was waived. From 2003 to 2007, 107 patients consecutively presented with hot spots on thyroid scans and low serum thyroid-stimulating hormone levels. Among them, 32 patients who had undergone thyroid ultrasonography were analyzed in this study. Thyroid nodules depicted on ultrasonography were classified based on size and categorized as benign, indeterminate, or suspicious malignant nodules according to ultrasonographic findings. The thyroid nodules were determined as either hyperfunctioning or coexisting nodules and were then correlated with pathologic results.ResultsIn 32 patients, 42 hyperfunctioning nodules (mean number per patient, 1.31; range, 1-6) were observed on thyroid scans and 68 coexisting nodules (mean, 2.13; range, 0-7) were observed on ultrasonography. Twenty-five patients (78.1%) had at least one hyperfunctioning (n = 17, 53.1%) or coexisting (n = 16, 50.0%) nodule that showed a suspicious malignant feature larger than 5 mm (n = 8, 25.0%), or an indeterminate feature 1 cm or greater (n = 20, 62.5%) in diameter, which could have been indicated by using fine needle aspiration (FNA). Seven patients were proven to have 11 thyroid cancers in 3 hyperfunctioning and 8 coexisting nodules. All of these had at least one thyroid cancer, which could have been indicated by using FNA. The estimated minimal risk of thyroid cancer was 6.5% (7/107).ConclusionPatients with hyperfunctioning nodules may not be safe from thyroid cancer because hyperfunctioning nodules can coexist with thyroid cancer nodules. To screen out these cancers, ultrasonography should be performed.

Hemoglobin, iron, and vitamin B12 deficiencies and high blood homocysteine levels in patients with anti-thyroid autoantibodies

Autoimmune thyroiditis can be diagnosed by measuring patients' serum levels of thyroid stimulating hormone (TSH), anti-thyroglobulin antibody (TGA), and anti-thyroid microsomal antibody (TMA). This study evaluated whether there were hematinic deficiencies, high blood homocysteine levels, and serum gastric parietal cell antibody (GPCA) positivity in patients with TGA or TMA. The blood hemoglobin (Hb), iron, vitamin B12, folic acid, homocysteine and TSH concentrations and the serum GPCA level in 190 TGA- or TMA-positive patients were measured and compared with the corresponding levels in 190 age- and sex-matched healthy control subjects. We found that 31 (16.3%), 27 (14.2%), 12 (6.3%), and 2 (1.1%) TGA- or TMA-positive patients had deficiencies of Hb (Men<13g/dL, Women<12g/dL), iron (< 60μg/dL), vitamin B12 (< 200pg/mL), and folic acid (< 4ng/mL), respectively. Moreover, 25 (13.2%) and 48 (25.3%) TGA- or TMA-positive patients had abnormally high blood homocysteine level and serum GPCA positivity, respectively. TGA- or TMA-positive patients had a significantly higher frequency of Hb (p<0.001), iron (p<0.001), or vitamin B12 deficiency (p=0.001), of abnormally elevated blood homocysteine level (p=0.001), or of serum GPCA positivity (p<0.001) than healthy control subjects. Of 190 TGA- or TMA-positive patients, 8 (4.2%) had lower serum TSH level (< 0.1μIU/mL, suggestive of hyperthyroidism), 163 (85.8%) had serum TSH level within normal range (0.1-4.5μIU/mL), and 19 (10%) had higher serum TSH level (>4.5μIU/mL, suggestive of hypothyroidis). There are significant deficiencies of hemoglobin, iron, and vitamin B12, abnormally high blood homocysteine levels, and serum GPCA positivity in TGA- or TMA-positive patients. In addition, the majority (85.8%) of TGA- or TMA-positive patients had euthyroid and only a small portion (14.2%) of TGA- or TMA-positive patients had either hypothyroidism or hyperthyroidism.

Thyroid Function and Risk of Atrial Tachyarrhythmia Occurrence after Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation

Backgrounds: Recent evidence demonstrated that serum free thyroxine (FT4) concentration was independently associated with the development of atrial fibrillation (AF), even in euthyroid persons with TSH levels in the normal range. We examined the impact of thyroid function on the risk of recurrent and newly developed atrial tachyarrythmias after catheter ablation for AF. Methods: This study included 156 consecutive patients with paroxysmal AF who underwent initial pulmonary vein antral isolation with elimination of dormant conduction induced by isoproterenol and adenotriphosphate injection. Patients with prior or current thyroid dysfunction were excluded. We examined the occurrence of documented recurrent or newly developed atrial tachyarrhythmia after the ablation. Results: After a mean follow-up of 27 months, 12.2% (19/156) of the studied subjects had AF recurrence. Although the AF recurrence rates of the highest FT4 quartile tended to be higher, there was no significant difference in recurrence rates among those quartiles. Patients with newly developed atrial tachycardia/flutter had significantly higher serum FT4 level and lower serum thyroid-stimulating hormone. The higher FT4 level was significantly associated with newly documented atrial tachycardia/flutter. Conclusions: Patients with high-normal thyroid function were not at an increased risk of AF recurrence but associated with newly developed atrial tachycardia/flutter after catheter ablation.