Endogenous Subclinical Hyperthyroidism Research Articles

Association of thyroid dysfunction in individuals ≥ 65 years of age with subclinical cardiac abnormalities.

The relationship between thyroid dysfunction and measures of myocardial disease in older individuals remains to be defined. To evaluate the impact of thyroid dysfunction on structure and function of the left-heart chambers and blood markers of cardiac disease. Cross-sectional analysis. The Cardiovascular Health Study, a community-based cohort of older individuals recruited from four urban areas in the United States. Of 3163 participants studied, 2477 were euthyroid, 465 had subclinical hypothyroidism (SCH), 47 overt hypothyroidism (OH), 45 endogenous (endo) subclinical hyperthyroidism (endo-SCT), and 129 had exogenous (exo) SCT due to thyroid hormone supplementation. Clinical evaluation, blood sampling and biomarker measurement, 2-dimensional and speckle-tracking echocardiography. Left heart myocardial deformation, circulating biomarkers of diastolic overload (NT-proBNP), fibrosis (sST2, gal-3), and cardiomyocyte injury (hs-cTnT). SCH was associated with higher NT-proBNP (beta = 0.17, p = 0.004), whereas OH was associated with higher hs-cTnT (beta = 0.29, p = 0.005). There were also suggestive associations of SCH with higher sST2, as well as endo-SCT with higher gal-3 and lower (worse) left atrial reservoir strain. Left ventricular longitudinal strain and end-diastolic strain rate did not differ significantly from euthyroid participants in SCH, OH, or exo-SCT. In this free-living elderly cohort, subclinical and overt hypothyroidism were associated with abnormalities of blood biomarkers consistent with diastolic overload and myocardial necrosis respectively, whereas subclinical hyperthyroidism tended to be associated with myocardial fibrosis and decreased left atrial strain. Our findings could represent stage B heart failure and illuminate distinct aspects of the pathobiology of heart disease related to thyroid gland dysfunction with potential clinical implications.

Аналіз впливу субклінічного гіпертиреозу на параметри кісткового метаболізму

Стан субклінічного гіпертиреозу можна розглядати як оптимальну модель для оцінки значення тиреотропного гормона (ТТГ) для кісткової тканини у клінічній практиці. Мета дослідження: здійснити порівняльний аналіз впливу субклінічного гіпертиреозу різного генезу на показники мінеральної щільності кісткової тканини (МЩКТ) і параметри кісткового обміну. Матеріали і методи. У дослідження в амбулаторних умовах було включено 112 жінок з діагнозом «субклінічний гіпертиреоз» і тривалістю менопаузи принаймні 5 років. Із числа обстежених ендогенний субклінічний гіпертиреоз спостерігався у 78 жінок (група I), екзогенний субклінічний гіпертиреоз на тлі супресивної терапії левотироксином (група II) — у 34. До контрольної групи (група III) увійшло 20 жінок без порушення функції щитоподібної залози. Результати. У дослідженні вперше проведений порівняльний аналіз стану кісткового метаболізму, показників МЩКТ, а також показників фосфору і кальцію, ліпідного спектру крові у жінок із субклінічним гіпертиреозом різної етіології. Позитивна кореляція маркерів кісткового метаболізму і вільного трийодтироніну (вТ3) як гормонів, необхідних для розвитку скелета і підтримки його гомеостазу, вказує на фізіологічний вплив паратгормона і вТ3 на кісткову тканину. Показано, що стан кісткового метаболізму і МЩКТ залежить не лише від вмісту ТТГ, але й від причин розвитку субклінічного гіпертиреозу. Висновки. У жінок постменопаузального періоду з ендогенним субклінічним гіпертиреозом спостерігається вірогідне зниження показників МЩКТ, більш виражене в кістках із кортикальною будовою. Виявлена негативна кореляційна залежність між маркерами кісткового метаболізму і ТТГ серед усіх пацієнтів, включених у дослідження.

Субклінічний гіпертиреоз: діагностичні критерії і принципи лікування. Огляд вибраних глав керівництва Європейської тиреоїдної асоціації 2015 року «Diagnosis and treatment of endogenous subclinical hyperthyroidism»

Подано вибрані глави керівництва Європейської тиреоїдної асоціації 2015 року з діагностики і лікування ендогенного субклінічного гіпертиреозу. Оригінальний текст керівництва знаходиться у відкритому доступі на сайті https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4637513/

Metabolic Changes after Radioiodine Correction of Grade 1 and Grade 2 Subclinical Hyperthyroidism

Objective: Endogenous subclinical hyperthyroidism (eSCH) is defined by subnormal serum thyroid-stimulating hormone (TSH) level. There is limited evidence of metabolic changes induced by eSCH. The aim of our work was to evaluate changes in BMI and lipid parameters after radioiodine treatment in patients with grade 1 (TSH: 0.1–0.39 mlU/L) and 2 (TSH <0.1 mlU/L) eSCH. Design: A retrospective study was performed on 74 patients with eSCH caused by benign autonomous nodular goiter which was treated with radioiodine. Methods: We assessed BMI, lipids parameters, and TSH after radioiodine therapy. The 12-month follow-up time point was used to compare the primary outcome variables. TSH was measured by the electrochemiluminescence method. Results: After radioiodine therapy, the absolute and relative increases in BMI at 12 months were significantly higher in the grade 2 group than in the grade 1 group (1.07 ± 0.27 kg/m² vs. 0.26 ± 0.15 kg/m², respectively; p = 0.023 and 4.01 ± 0.98% vs. 1.01 ± 0.56%, respectively; p = 0.026). Compared to baseline, significant increases in the levels of total cholesterol and LDL were observed after treatment in the grade 2 eSCH group (16.7 ± 4.5 mg/dL p < 0.01 and 14.3 ± 4.1 mg/dL p < 0.01, respectively) but not in the grade 1 group. In a multivariate model, a negative correlation was observed between pretreatment TSH levels and absolute BMI gain (p < 0.01). Conclusions: After correction of eSCH, increases in BMI and LDL levels were observed only in patients with grade 2 eSCH. Pretreatment serum TSH was the main independent factor associated with BMI changes after radioiodine treatment.

Subclinical Hyperthyroidism, an Under-Recognized Entity

Subclinical Hyperthyroidism, an Under-Recognized Entity Sindhu Igala, Marivette Machado, Britta Neugaard, Philip R Foulis, Joaquin Gomez-Daspet Abstract Purpose: Determine the medical evaluation completed and the clinical progression observed in subjects with Endogenous Subclinical Hyperthyroidism (ESCH).Method: This is a single site retrospective chart review of subjects who visited the Ambulatory Care Clinics at the James A. Haley VA Hospital (JAHVA), Tampa, Florida. Subjects were selected and charts reviewed using the automatic data mining tool. Inclusion criteria encompassed subjects’ low thyroid stimulating hormone (TSH) and normal T4 and T3 levels.Results: 95 subjects met criteria for inclusion. At the end of one year, 48 (51%) had normal thyroid function tests (TFTs), 43 (45%) had persistent ESCH and 4 (4%) had overt hyperthyroidism. A radioiodine thyroid uptake/scan was completed in 32 (33%) subjects. Only 9 (10%) had thyroid stimulating Immunoglobulin (TSI) or anti-thyroid peroxidase antibody (anti-TPO) studies. A bone density study was not completed. Conclusions: Out of the 95 subjects with ESCH, at the end of one year 51% had normal TFTs, 45% had persistent ESCH and 4% had hyperthyroidism. Less than 50% of the subjects received further tests. It is recommended that subjects with ESCH be followed periodically with TFTs and further evaluation may be required to assess cause, severity, risk of complications and need for treatment. Full Text: PDF DOI: 10.15640/ijmp.v7n1a1

Thyroid Function in Aging: A Discerning Approach

Thyroid disease, increasingly common among the general population, is also rising among the elderly, which, given that the global population is aging, constitutes a serious public health issue that needs to be urgently addressed. The most common thyroid disease in younger and older individuals alike is hypothyroidism, including subclinical (SCH) and overt disease. Since TSH tends to increase with age due to intrinsic changes of thyroid metabolism and the gradual resetting of the hypothalamic-pituitary-thyroid axis, the diagnosis of "true" hypothyroidism is challenging, another difficulty being distinguishing disease-specific from aging-associated clinical symptoms. Hypothyroidism in the elderly may cause or exacerbate macrocytic anemia, hypercholesterolemia and kidney dysfunction, therefore careful clinical and biochemical control is necessary. Meanwhile, as an increase of TSH in the old and very old has been associated with longevity, a resetting of the TSH normal range according to age is strongly required before any diagnosis is made and treatment is implemented. Levothyroxine, which remains the treatment of choice, should be initiated in the old at TSH>10 mIU/l, starting with 25 μg/daily followed by cautious upward titration. Recent data (the TRUST study) revealed that treatment of SCH in the elderly does not improve hypothyroid symptoms and the tiredness score when compared with a placebo group. Hyperthyroidism is associated with increased mortality in the aged, this dependent upon type and adequacy of treatment. Treatment should be seriously considered in older patients who have endogenous subclinical hyperthyroidism with a TSH between 0.1 and 0.4 mIU/L, with regular monitoring being strongly advised.

An Overview of Endogenous Subclinical Hyperthyroidism and Cardiac Disease

Abbreviations: CI = confidence interval T3 = tri-iodothyronine T4 = thyroxine TEARS = thyroid epidemiology, audit, and research study TSH = thyroid-stimulating hormone

Subclinical Hyperthyroidism: Diagnostic Criteria and Principles of Treatment

This article presents the European Thyroid Association guidelines for diagnosis and treatment of subclinical hyperthyroidism, 2015. Determination of thyroid1stimulating hormone levels can help to diagnose a variety of pathological conditions: hypertension, cardiac fibrillation, atrial fibrillation, mineral density reduction in bones, menstrual irregularities, infertility, which require specific treatment after detection of hormonal status disorders (subclinical, overt), taking into account the patient’s age.&#x0D; Diagnosis of endogenous subclinical hyperthyroidism is based solely on the results of laboratory tests, not clinical criteria. Endogenous subclinical hyperthyroidism is defined by the presence of sub-normal levels of thyroid-stimulating hormone with normal levels of free thyroxine, total triiodothyronine, and/or free triiodothyronine. There are two categories of endogenous subclinical hyperthyroidism: stage 1 – the level of thyroid-stimulating hormone is 0,1–0,39 mIU/l; stage 2 – the level of thyroid-stimulating hormone is &lt;0.1 mIU/l. The levels of free thyroxine and free triiodothyronine, as a rule, are medium-high value at a subclinical level of thyroid hormone and can help differentiate between endogenous subclinical hyperthyroidism from overt hyperthyroidism.&#x0D; It is recommended to study the thyroid-stimulating hormone level as the first test for the diagnosis of subclinical hyperthyroidism. In identifying low levels of thyroid-stimulating hormone it is necessary to investigate the level of free thyroxine, free or bound triiodothyronine. Patients with primary sub-normal levels of thyroid-stimulating hormone with concentration of thyroid hormones in the upper limit or in normal range should be evaluated within 2-3 months.&#x0D; It is recommended to perform scintigraphy and possible 24-hour test the absorption of radioactive iodine if in patient with 2nd degree endogenous subclinical hyperthyroidism there is nodular goiter to determine treatment strategy.&#x0D; Ultrasonography with color Doppler can be informative for patients with endogenous subclinical hyperthyroidism and nodular goiter.&#x0D; Determining the level of antibodies to thyroid-stimulating hormone receptors can confirm the etiology of autoimmune-induced hyperthyroidism.

Субклинический гипертиреоз: диагностические критерии и принципы лечения (Обзор руководства европейской тиреоидной ассоциации 2015 года «Diagnosis and Treatment of endogenous subclinical hyperthyroidism»)

This article presents the European Thyroid Association guidelines for diagnosis and treatment of subclinical hyperthyroidism, 2015. Determination of thyroid-stimulating hormone levels can help to diagnose a variety of pathological conditions: disorders of sexual development, amenorrhea (primary or secondary), infertility, miscarriage, which require specific treatment after detection of hormonal status disorders (subclinical, overt), taking into account the patient’s age. Diagnosis of endogenous subclinical hyperthyroidism is based solely on the results of laboratory tests, not clinical criteria. Endogenous subclinical hyperthyroidism is defined by the presence of sub-normal levels of thyroid-stimulating hormone with normal levels of free thyroxine, total triiodothyronine, and/or free triiodothyronine. There are two categories of endogenous subclinical hyperthyroidism: Class 1 – the level of thyroid-stimulating hormone is 0.1–0.39 mIU/l; class 2 – the level of thyroid-stimulating hormone is &lt; 0.1 mIU/l. The levels of free thyroxine and free triiodothyronine, as a rule, are medium-high value at a subclinical level of thyroid hormone and can help differentiate between endogenous subclinical hyperthyroidism from overt hyperthyroidism. Recommended to study the thyroid-stimulating hormone level as the first test for the diagnosis of subclinical hyperthyroidism. In identifying low levels of thyroid-stimulating hormone it is necessary to investigate the level of free thyroxine, free and bound triiodothyronine. Patients with primary sub-normal levels of thyroid-stimulating hormone with concentration of thyroid hormones in the upper limit or in normal range should be evaluated within 2-3 months. It is recommended to perform scintigraphy and possible 24-hour test the absorption of radioactive iodine if in patient with 2nd degree endogenous subclinical hyperthyroidism there is nodular goiter to determine treatment strategy. Ultrasonography with color Doppler can be informative in patients with endogenous subclinical hyperthyroidism and nodular goiter. Determining the level of antibodies to thyroid-stimulating hormone receptors can confirm the etiology of autoimmune-induced hyperthyroidism. Key words: thyroid, thyroid stimulating hormone, hyperthyroidism, thyrotoxicosis, subclinical hyperthyroidism, Graves’ disease, toxic multinodular goiter.

Total thyroidectomy: a clue to understanding the metabolic changes induced by subclinical hyperthyroidism?

The effects of endogenous subclinical hyperthyroidism (eSCH) on heart and bone have been well documented. There are only limited data available regarding the impact of eSCH on weight regulation and lipid metabolism. Our aim was to evaluate the changes in body weight and metabolic parameters after total thyroidectomy in patients with pre-operative eSCH compared with pre-operative patients with euthyroid (EUT). A retrospective study of 505 patients who underwent total thyroidectomy for benign multinodular goitre in an academic hospital in Brussels (Belgium) was performed. Two hundred and 25 patients were included (eSCH group: n=74; EUT group: n=151). The mean follow-up time was 26·1±0·8months and was similar in both groups. Absolute BMI gain was significantly greater in the eSCH group than in the EUT group (1·11±0·17 vs 0·33±0·13kg/m2 ; P=0·003). A significant increase in LDL cholesterol was observed in the eSCH group (16·1±3·8mg/dl; P<0·001) but not in the EUT group (0·0±3·0mg/dl; P=0·88). In a multivariate model, pre-operative TSH levels were the main factor significantly associated with increases in BMI or LDL cholesterol. Post-operative median TSH levels and L-thyroxine substitution were similar in both groups. After total thyroidectomy, increases in weight and serum cholesterol were observed in the eSCH group. Given that post-operative TSH levels were similar in the two groups, these observations are probably due to the correction of eSCH, suggesting a direct effect of eSCH on body weight regulation and lipid metabolism.

Subclinical Hyperthyroidism: Diagnostic Criteria and Principles of Treatment

This article presents the European Thyroid Association guidelines for diagnosis and treatment of subclinical hyperthyroidism, 2015. Determination of thyroid1stimulating hormone levels can help to diagnose a variety of pathological conditions: hypertension, cardiac fibrillation, atrial fibrillation, mineral density reduction in bones, menstrual irregularities, infertility, which require specific treatment after detection of hormonal status disorders (subclinical, overt), taking into account the patient’s age.&#x0D; Diagnosis of endogenous subclinical hyperthyroidism is based solely on the results of laboratory tests, not clinical criteria. Endogenous subclinical hyperthyroidism is defined by the presence of subnormal levels of thyroid-stimulating hormone with normal levels of free thyroxine, total triiodothyronine, and/or free triiodothyronine. There are two categories of endogenous subclinical hyperthyroidism: stage 1 – the level of thyroid1stimulating hormone is 0,1–0,39 mIU/l; stage 2 – the level of thyroid1stimulating hormone is &lt;0.1 mIU/l. The levels of free thyroxine and free triiodothyronine, as a rule, are medium-high value at a subclinical level of thyroid hormone and can help differentiate between endogenous subclinical hyperthyroidism from overt hyperthyroidism.&#x0D; It is recommended to study the thyroid-stimulating hormone level as the first test for the diagnosis of subclinical hyperthyroidism. In identifying low levels of thyroid1stimulating hormone it is necessary to investigate the level of free thyroxine, free or bound triiodothyronine. Patients with primary subnormal levels of thyroid-stimulating hormone with concentration of thyroid hormones in the upper limit or in normal range should be evaluated within 2-3 months. It is recommended to perform scintigraphy and possible 24-hour test the absorption of radioactive iodine if in patient with 2nd degree endogenous subclinical hyperthyroidism there is nodular goiter to determine treatment strategy.&#x0D; Ultrasonography with color Doppler can be informative for patients with endogenous subclinical hyperthyroidism and nodular goiter. Determining the level of antibodies to thyroid-stimulating hormone receptors can confirm the etiology of autoimmune-induced hyperthyroidism.

Endogenous subclinical hyperthyroidism: actual management guidelines (on the base of the latest Guidelines of European Thyroid Association)

In the article the latest recommendations on the management of patients with endogenous subclinical hyperthyroidism are discussed. The newest classification of subclinical hyperthyroidism, based on the levels of thyrotropin, is reviewed. Treatment tactics for this group of patients is inspected. The risk factors in non-treated patients are commented.

Discussion about European Thyroid Association guidelines on diagnosis and treatment of endogenous subclinical hyperthyroidism

The article discusses European Thyroid Association guidelines on diagnosis and treatment of endogenous subclinical hyperthyroidism.

How Does Subclinical Hyperthyroidism Affect Right Heart Function and Mechanics?

Right heart function and mechanics have not been investigated in patients with subclinical hyperthyroidism. Our aim was to investigate right ventricular (RV) and right atrial (RA) function and deformation as evaluated by 3-dimensional echocardiography (3DE) and speckle-tracking 2-dimensional echocardiography (2DE) in these individuals. We included 39 untreated women with endogenous subclinical hyperthyroidism and 39 healthy women matched by age. All participants underwent laboratory analyses that included thyroid hormone levels and comprehensive 2DE and 3DE examinations. Three-dimensional echocardiographic RV volumes were significantly elevated in the patients with subclinical hyperthyroidism (P < .05), whereas the 3DE RV ejection fraction was reduced in this group, but with borderline significance. Two-dimensional echocardiographic longitudinal RV and RA strain were significantly reduced in the patients with subclinical hyperthyroidism. Two-dimensional echocardiographic RV systolic and early diastolic strain rates were reduced, whereas late diastolic strain rates were increased in the patients with subclinical hyperthyroidism. The same changes were detected in RA mechanics among the patients with subclinical hyperthyroidism. The thyrotropin (TSH) level correlated with the left ventricular mass index, transmitral early diastolic peak flow velocity (E)/late diastolic flow velocity (A) ratio, tricuspid E/A ratio, 2DE RV global strain, 2DE RA, strain, and 3DE RV end-diastolic volume. A multivariate regression analysis showed that the mitral E/A ratio, 2DE RV global strain, and 3DE RV end-diastolic volume were independently associated with the TSH level. Right ventricular and RA function as evaluated by 3DE and speckle-tracking 2DE is significantly impaired in patients with subclinical hyperthyroidism. The TSH level correlated with parameters for RV function and mechanics in the whole study population.

Symptoms of thyrotoxicosis, bone metabolism and occult atrial fibrillation in older women with mild endogenous subclinical hyperthyroidism.

The objective of this study was to evaluate symptoms of thyrotoxicosis, bone turnover, bone mineral density (BMD) and occult atrial fibrillation (AF) in women ≥65 years with mild endogenous subclinical hyperthyroidism (SCH). Cross-sectional and case-control study. Signs and symptoms of thyrotoxicosis, serum carboxyterminal telopeptide (CTx) and procollagen type I N-terminal propeptide (PINP), BMD, resting electrocardiogram (ECG) and 72-h ECG monitoring were evaluated in 180 women ≥65 years, including 90 with mild SCH (TSH between 0·1 and 0·4 mIU/l) and 90 euthyroid controls matched for age and body mass index. Symptom Rating Scale scores did not differ between patients and controls. None of the patients with SCH scored 20 points, a score compatible with clinical thyrotoxicosis. Eighty patients with SCH (89%) obtained seven or fewer points, a score compatible with euthyroidism. No difference in serum CTx or PINP concentrations was observed between patients and controls. There was also no correlation between these markers and TSH, free T4 or total T3 levels. Finally, no difference in femoral neck or lumbar spine BMD was observed between patients with SCH and controls. Three patients with SCH (3·3%) and two euthyroid women (2·2%) had known AF or AF in the resting ECG. ECG monitoring for 72 h revealed episodes of occult AF in 1/87 patients with SCH and in 1/88 euthyroid women (1·1%). Mild endogenous SCH (TSH between 0·1 and 0·4 mIU/l) was not associated with symptoms of thyrotoxicosis, altered bone metabolism or a higher prevalence of occult AF in women ≥65 years.

Subclinical thyroid dysfunction and fracture risk: a meta-analysis.

Associations between subclinical thyroid dysfunction and fractures are unclear and clinical trials are lacking. To assess the association of subclinical thyroid dysfunction with hip, nonspine, spine, or any fractures. The databases of MEDLINE and EMBASE (inception to March 26, 2015) were searched without language restrictions for prospective cohort studies with thyroid function data and subsequent fractures. Individual participant data were obtained from 13 prospective cohorts in the United States, Europe, Australia, and Japan. Levels of thyroid function were defined as euthyroidism (thyroid-stimulating hormone [TSH], 0.45-4.49 mIU/L), subclinical hyperthyroidism (TSH <0.45 mIU/L), and subclinical hypothyroidism (TSH ≥4.50-19.99 mIU/L) with normal thyroxine concentrations. The primary outcome was hip fracture. Any fractures, nonspine fractures, and clinical spine fractures were secondary outcomes. Among 70,298 participants, 4092 (5.8%) had subclinical hypothyroidism and 2219 (3.2%) had subclinical hyperthyroidism. During 762,401 person-years of follow-up, hip fracture occurred in 2975 participants (4.6%; 12 studies), any fracture in 2528 participants (9.0%; 8 studies), nonspine fracture in 2018 participants (8.4%; 8 studies), and spine fracture in 296 participants (1.3%; 6 studies). In age- and sex-adjusted analyses, the hazard ratio (HR) for subclinical hyperthyroidism vs euthyroidism was 1.36 for hip fracture (95% CI, 1.13-1.64; 146 events in 2082 participants vs 2534 in 56,471); for any fracture, HR was 1.28 (95% CI, 1.06-1.53; 121 events in 888 participants vs 2203 in 25,901); for nonspine fracture, HR was 1.16 (95% CI, 0.95-1.41; 107 events in 946 participants vs 1745 in 21,722); and for spine fracture, HR was 1.51 (95% CI, 0.93-2.45; 17 events in 732 participants vs 255 in 20,328). Lower TSH was associated with higher fracture rates: for TSH of less than 0.10 mIU/L, HR was 1.61 for hip fracture (95% CI, 1.21-2.15; 47 events in 510 participants); for any fracture, HR was 1.98 (95% CI, 1.41-2.78; 44 events in 212 participants); for nonspine fracture, HR was 1.61 (95% CI, 0.96-2.71; 32 events in 185 participants); and for spine fracture, HR was 3.57 (95% CI, 1.88-6.78; 8 events in 162 participants). Risks were similar after adjustment for other fracture risk factors. Endogenous subclinical hyperthyroidism (excluding thyroid medication users) was associated with HRs of 1.52 (95% CI, 1.19-1.93) for hip fracture, 1.42 (95% CI, 1.16-1.74) for any fracture, and 1.74 (95% CI, 1.01-2.99) for spine fracture. No association was found between subclinical hypothyroidism and fracture risk. Subclinical hyperthyroidism was associated with an increased risk of hip and other fractures, particularly among those with TSH levels of less than 0.10 mIU/L and those with endogenous subclinical hyperthyroidism. Further study is needed to determine whether treating subclinical hyperthyroidism can prevent fractures.

Effect of oral anti-thyroid therapy on bone density in premenopausal women with endogenous subclinical hyperthyroidism

Effect of oral anti-thyroid therapy on bone density in premenopausal women with endogenous subclinical hyperthyroidism

Subclinical hyperthyroidism when presenting as initial manifestation of juvenile Hashimoto’s thyroiditis: first report on its natural history

Due to the lack of specific pediatric studies, no data are available about natural history of endogenous subclinical hyperthyroidism (SH) in childhood. (a) To investigate for the first time the natural history of SH [suppressed thyrotropin (TSH) and normal free thyroxine free thyroxine (FT4) levels] when presenting as initial manifestation of Hashimoto's thyroiditis (HT) in childhood (group A); (b) to compare spontaneous evolution of HT-related SH with that observed in age-matched patients with HT-related frank hyperthyroidism (suppressed TSH and elevated FT4 levels), i.e., Hashitoxicosis Htx (group B). In the 11 patients of group A, TSH normalization spontaneously occurred 1-24 months after diagnosis, while in the 10 patients of group B it occurred 3-9 months after diagnosis, with no differences between the 2 groups in terms of time interval from entry to TSH normalization. In group A, this time interval was related to baseline thyroid peroxidase antibodies (r=0.78, p = 0.04). During follow-up, eight patients of each group remained euthyroid, whereas two became hypothyroid (in both groups) and one developed Graves' disease (in group A). (a) HT should be included among the causes of endogenous SH in pediatric age; (b) in children with HT-related SH, spontaneous normalization of TSH levels occurs within the first 24 months after diagnosis, as well as in age-matched patients with Htx; (c) in both these conditions, a further deterioration of thyroid function might re-present in some patients during follow-up; (d) Ht-related SH and Htx might be possibly seen as different biochemical stages along the same continuum.

Subclinical thyroid disease

Subclinical thyroid disease is a common finding on testing of thyroid function and its management remains controversial. Epidemiological data from large population studies from USA and Europe. There is an increased risk of progression to overt hypothyroidism or hyperthyroidism. The treatment of mild thyroid failure is of importance in optimizing pregnancy outcome. Diagnostic criteria differ and there is variation between management guidelines. The difference was found in long-term clinical outcomes between endogenous and exogenous subclinical hyperthyroidism. Meta-analyses have provided epidemiological data in cardiovascular mortality and morbidity in subclinical thyroid disease. Increased use of echocardiography and bone markers in identifying those who benefit from intervention. A randomized controlled trial to identify those subjects identified from screening programmes that benefit from intervention in terms of morbidity and mortality.

The nature of cardiac calcification in aortic stenosis

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