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Background: Graves' orbitopathy (GO) is the main extrathyroidal manifestation of Graves' disease (GD). Diabetes mellitus (DM) has been reported to be a risk factor in patients with GO. Moreover, GO can be more frequent and severe in type 2 diabetes patients. High doses of intravenous glucocorticoids represent the first line treatment of moderate-to-severe and active GO according to the international guidelines. However, this therapy is contraindicated in uncontrolled diabetes and in patients with increased cardiovascular risk. Some anti-diabetic drugs can exacerbate GO. We reported the clinical case of an active and moderate-to-severe GO in a patient with uncontrolled type 2 DM and vascular complications. Case Report: A 61-years-old patient came to our ambulatory for a recurrence of GD and a moderate-to-severe bilateral GO. The patient had uncontrolled type 2 DM during insulin therapy and a history of micro and macrovascular complications. At the physical examination, the clinical activity score was 5 and the severity of GO was moderate-to-severe. A blood sample showed overt hyperthyroidism and the persistence of anti-TSH receptor antibodies (TRAb) during treatment with methimazole. A computed tomography scan showed a moderate-to-severe bilateral exophthalmos. We discuss the benefit/risk of treatment of GO in our patient. Conclusion: The available guidelines do not focus on the treatment of diabetic patients with uncontrolled diabetes and severe vascular complications, therefore our patient represents a difficult therapeutic challenge. The screening of thyroid function and the evaluation of GO could be useful in diabetic patients with autoimmune thyroid disease to perform a correct treatment of these disorders.

Background: The management of indeterminate thyroid lesions is controversial. The American Thyroid Association (ATA) guidelines suggest a conservative approach for low risk indeterminate thyroid lesions (TIR3A). Case Report: We report a clinical case of a young girl who had TIR3A in a thyroid nodule located in the isthmus. After considering clinical and ultrasound (US) risk factors, we assessed literature data and guidelines to plan the extension of surgery. We found several studies supporting that the isthmus malignant lesions were associated with a higher rate of multifocality, capsular invasion, extrathyroidal extension, and central lymph node (LN) metastases. These data could predict a more aggressive behavior and a poor prognosis of the isthmus thyroid cancer compared to differentiated thyroid cancer, originating in the thyroid lobes. On the basis of these literature data and considering the familial risk for thyroid cancer of our patient, we decided to perform a total thyroidectomy. The histological examination revealed a follicular variant of papillary carcinoma located in the isthmus with capsular invasion. Conclusion: The isthmus location could be an additional risk factor to consider for a correct surgical approach in indeterminate thyroid lesions and thyroid cancer at fine-needle aspiration (FNA). We suggest that a careful ultrasonography should be carried out in patients with isthmus nodules. Total thyroidectomy should be performed in aggressive nodular disease. Prospective studies are needed to establish the best treatment for these lesions.

Background: Thyroid function abnormalities and thyroid autoantibodies have been frequently described in patients with systemic autoimmune diseases as systemic sclerosis (SSc). Serum TSH levels are higher in SSc patients with more severe skin diseases and a worse modified Rodnan skin score. Asymptomatic esophageal involvement due to SSc has never been described as a cause of severe hypothyroidism due to l-thyroxine (l-T4) malabsorption in patients with Hashimoto's thyroiditis (HT) and SSc., Case Report: Here, we report a case of a 56-year-old female affected by both SSc and HT who developed severe hypothyroidism due to the loss of therapeutic efficacy of l-T4. Therapeutic failure resulted from the altered l-T4 absorption because of SSc esophageal complications. Clinical findings improved after the administration of oral liquid l-T4. Thyroid function completely normalized with a full clinical recovery, the disappearance of the pericardial effusion and the improvement of the pulmonary pressure., Conclusion: A recognition of a poor absorption is crucial in patients with hypothyroidism and SSc to reduce the risk of the subsequent adverse events. This case suggests the importance of clinical and laboratory surveillance in patients with SSc and HT because the systemic complications of these dysfunctions may worsen the prognosis of hypothyroid SSc/HT patients.

Introduction: Radioiodine (RAI) therapy for treatment of differentiated thyroid cancer (DTC) requires high serum thyroid-stimulating hormone (TSH) levels to induce a sufficient iodine uptake within thyroid cells. Recombinant Human TSH (rhTSH) induces an exogenous TSH level increase without LT4 withdrawal. It is a valid alternative to LT4-withdrawal (LT4-W) to achieve the TSH levels required for RAI therapy. According to the recent American Thyroid Association (ATA) guidelines, candidates for RAI therapy should be selected based on their DTC risk of recurrence. Areas covered: In this review, we report the studies assessing the effects of rhTSH on RAI ablation compared to thyroid hormone withdrawal in patients with thyroid cancer at different ATA risk of recurrence. We focus our attention on high risk patients and metastatic disease in which RAI treatment is routinely recommended although there are few controversial data about the best possible way of preparing for it. Expert commentary: rhTSH-aided therapy is associated to a better quality of life and to a lower body radiation exposure. Several studies have reported an equivalent efficacy of RAI ablation after TSH stimulation with rhTSH or LT4-W in patients with DTC at low and intermediate risk of recurrence. Although more studies are required, the results are promising even in patients with high risk DTC and metastatic disease.

The aim was to retrospectively analyse the clinical-histopathological characteristics of patients with newly diagnosis of differentiated thyroid cancer (DTC) referred to two Italian centres, one in Northern and the other in Southern Italy, between 2000 and 2013. 1081 patients were included and subdivided into two groups: group A (474 patients from Novara) and group B (607 patients from Naples). The group A came from the industrial area of Novara, while the Group B came from the areas around Vesuvius and Campi Flegrei. The two groups were comparable for iodine levels, body mass index, diagnostic timing and clinical procedures. For all patients, demographic and clinical data were collected. No difference was found in gender, whereas the age at diagnosis was later in the group A (group A 53.1 ± 15.16 years, group B 41.9 ± 14.25 years, p < 0.001). In both groups, the most frequent histotype was papillary thyroid cancer (PTC) with prevalence of follicular variant in group A (p < 0.0001) and classical variant in group B (p < 0.0001). Aggressive histological features were mainly seen in group A (bilaterality p < 0.0001, multifocality p < 0.0001 and thyroid capsular invasion p < 0.0001). Microcarcinomas were more frequent in group A (p < 0.0001) but mostly characterized by bilaterality (p < 0.001) and multifocality (p < 0.04). In both groups, tumour-associated thyroiditis showed a significant increase over the years (group A p < 0.05, group B p < 0.04). Environmental factors could justify the differences found in our study. These preliminary data should stimulate the need for an Italian Cancer Registry of DTC in order to allow an epidemiological characterization, allowing the identification of specific etiological factors and an improvement in the management of the disease.

Thyroid hormone deficiency can have important repercussions. Treatment with thyroid hormone in replacement doses is essential in patients with hypothyroidism. In this review, we critically discuss the thyroid hormone formulations that are available and approaches to correct replacement therapy with thyroid hormone in primary and central hypothyroidism in different periods of life such as pregnancy, birth, infancy, childhood, and adolescence as well as in adult patients, the elderly, and in patients with comorbidities. Despite the frequent and long term use of l-T4, several studies have documented frequent under- and overtreatment during replacement therapy in hypothyroid patients. We assess the factors determining l-T4 requirements (sex, age, gender, menstrual status, body weight, and lean body mass), the major causes of failure to achieve optimal serum TSH levels in undertreated patients (poor patient compliance, timing of l-T4 administration, interferences with absorption, gastrointestinal diseases, and drugs), and the adverse consequences of unintentional TSH suppression in overtreated patients. Opinions differ regarding the treatment of mild thyroid hormone deficiency, and we examine the recent evidence favoring treatment of this condition. New data suggesting that combined therapy with T3 and T4 could be indicated in some patients with hypothyroidism are assessed, and the indications for TSH suppression with l-T4 in patients with euthyroid multinodular goiter and in those with differentiated thyroid cancer are reviewed. Lastly, we address the potential use of thyroid hormones or their analogs in obese patients and in severe cardiac diseases, dyslipidemia, and nonthyroidal illnesses.

Objectives: To evaluate the diagnostic accuracy of fine-needle aspiration biopsy (FNAB) to preoperatively diagnose medullary thyroid cancer (MTC) among multiple international centers and evaluate how the cytological diagnosis alone could impact patient management., Methods: We performed a retrospective chart review of sporadic MTC (sMTC) patients from 12 institutions over the last 29 years. FNAB cytology results were compared to final pathologic diagnoses to calculate FNAB sensitivity. To evaluate the impact of cytology sensitivity for MTC according to current practice and to avoid confounding results by local treatment protocols, changes in treatment patterns over time, and the influence of ancillary findings (e.g., serum calcitonin), therapeutic interventions based on FNAB cytology alone were projected into 1 of 4 treatment categories: total thyroidectomy (TT) and central neck dissection (CND), TT without CND, diagnostic hemithyroidectomy, or observation., Results: A total of 313 patients from 4 continents and 7 countries were included, 245 of whom underwent FNAB. FNAB cytology revealed MTC in 43.7% and possible MTC in an additional 2.4%. A total of 113 (46.1%) patients with surgical pathology revealing sMTC had FNAB findings that supported TT with CND, while 37 (15.1%) supported TT alone. In the remaining cases, diagnostic hemithyroidectomy and observation were projected in 32.7% and 6.1%, respectively., Conclusion: FNAB is an important diagnostic tool in the evaluation of thyroid nodules, but the low sensitivity of cytological evaluation alone in sMTC limits its ability to command an optimal preoperative evaluation and initial surgery in over half of affected patients.

Context: Levothyroxine therapy is the traditional lifelong replacement therapy for hypothyroid patients. Over the last several years, new evidence has led clinicians to evaluate the option of combined T(3) and T(4) treatment to improve the quality of life, cognition, and peripheral parameters of thyroid hormone action in hypothyroidism. The aim of this review is to assess the physiological basis and the results of current studies on this topic., Evidence Acquisition: We searched Medline for reports published with the following search terms: hypothyroidism, levothyroxine, triiodothyronine, thyroid, guidelines, treatment, deiodinases, clinical symptoms, quality of life, cognition, mood, depression, body weight, heart rate, cholesterol, bone markers, SHBG, and patient preference for combined therapy. The search was restricted to reports published in English since 1970, but some reports published before 1970 were also incorporated. We supplemented the search with records from personal files and references of relevant articles and textbooks. Parameters analyzed included the rationale for combination treatment, the type of patients to be selected, the optimal T(4)/T(3) ratio, and the potential benefits of this therapy on symptoms of hypothyroidism, quality of life, mood, cognition, and peripheral parameters of thyroid hormone action., Evidence Synthesis: The outcome of our analysis suggests that it may be time to consider a personalized regimen of thyroid hormone replacement therapy in hypothyroid patients., Conclusions: Further prospective randomized controlled studies are needed to clarify this important issue. Innovative formulations of the thyroid hormones will be required to mimic a more perfect thyroid hormone replacement therapy than is currently available.

Various studies have demonstrated the safety and efficacy of recombinant human thyroid-stimulating hormone (rhTSH) for radioiodine remnant ablation. On this basis, rhTSH was approved in Europe for the radioiodine ablation of low-risk differentiated thyroid cancer (DTC) during thyroid hormone therapy with L-thyroxine (L-T4). Moreover, in December 2007, the US Federal Drug Administration approved the use of rhTSH for adjuvant treatment with radioiodine in patients with DTC without evidence of metastatic thyroid cancer. Quality of life was found to be better with rhTSH preparation than with L-thyroxine withdrawal, thereby resulting in benefits for society as a whole. Furthermore, rhTSH for radioiodine remnant ablation results in a longer effective radioiodine half-life within remnant thyroid tissue and a lower specific absorbed dose in the blood and exposure of bone marrow to X-rays. More studies are required to establish the amount of radioiodine to be administered especially in high-risk patients.

Subclinical thyroid disease (SCTD) is defined as serum free T(4) and free T(3) levels within their respective reference ranges in the presence of abnormal serum TSH levels. SCTD is being diagnosed more frequently in clinical practice in young and middle-aged people as well as in the elderly. However, the clinical significance of subclinical thyroid dysfunction is much debated. Subclinical hyper- and hypothyroidism can have repercussions on the cardiovascular system and bone, as well as on other organs and systems. However, the treatment and management of SCTD and population screening are controversial despite the potential risk of progression to overt disease, and there is no consensus on the thyroid hormone and thyrotropin cutoff values at which treatment should be contemplated. Opinions differ regarding tissue effects, symptoms, signs, and cardiovascular risk. Here, we critically review the data on the prevalence and progression of SCTD, its tissue effects, and its prognostic implications. We also examine the mechanisms underlying tissue alterations in SCTD and the effects of replacement therapy on progression and tissue parameters. Lastly, we address the issue of the need to treat slight thyroid hormone deficiency or excess in relation to the patient's age.

Objective: To evaluate the thyroidal lymphoid infiltrate (TLI) in thyroidal functional status (TFS) for differences among patients with Hashimoto's thyroiditis (HT)., Study Design: Flow-cytometry (FC) was applied to thyroidal fine-needle cytology samples in 57 patients. TLI was analyzed using a fluorescence-activated cell sorter (FACS) scan and fluorescence antibodies CD3, CD4, CD5, CD8, CD10, and CD19 and kappa and lambda light chains. TFS was determined by serum thyroid-stimulating hormone (TSH), FT3 and FT4 immunoassays, in specific clinical settings, to classify the cases as hyperthyroid, euthyroid and hypothyroid. FC assessment was then compared with the corresponding TFS., Results: B-lymphocytes were present in 44 cases (77%). T-lymphocytes were present in all the cases; CD4/CD8 = 2:1 ratio was observed in 16 euthyroid, 1 hyperthyroid and 3 hypothyroid; CD4/CD8 > or = 3:1 ratio in 22 euthyroid, 2 hyperthyroid and 2 hypothyroid cases; CD4/CD8 < or = 1:1 ratio in 1 euthyroid, 3 hyperthyroid and in 7 hypothyroid cases. Grouping hyperthyroid and hypothyroid cases, a significant association was observed with the CD4/CD8 < or = 1:1 ratio (p < 0.01)., Conclusion: Intrathyroidal CD4/CD8 < 1:1 ratio might be the expression of intense apoptosis in the early phases of HT, generally followed by the restoration of CD4/CD8 balance; persistence of increased intrathyroidal CD8 might be related to intense thyroidal damage and thus an increasing risk of hypothyroidism.

Subclinical hyperthyroidism appears to be a common disorder. It may be caused by exogenous or endogenous factors: excessive TSH suppressive therapy with L-thyroxine (L-T4) for benign thyroid nodular disease, differentiated thyroid cancer, or hormone over-replacement in patients with hypothyroidism are the most frequent causes. Consistent evidence indicates that 'subclinical' hyperthyroidism reduces the quality of life, affecting both the psycho and somatic components of well-being, and produces relevant signs and symptoms of excessive thyroid hormone action, often mimicking adrenergic overactivity. Subclinical hyperthyroidism exerts many significant effects on the cardiovascular system; it is usually associated with a higher heart rate and a higher risk of supraventricular arrhythmias, and with an increased left ventricular mass, often accompanied by an impaired diastolic function and sometimes by a reduced systolic performance on effort and decreased exercise tolerance. It is well known that these abnormalities usually precede the onset of a more severe cardiovascular disease, thus potentially contributing to the increased cardiovascular morbidity and mortality observed in these patients. In addition, it is becoming increasingly apparent that subclinical hyperthyroidism may accelerate the development of osteoporosis and hence increased bone vulnerability to trauma, particularly in postmenopausal women with a pre-existing predisposition. Subclinical hyperthyroidism and its related clinical manifestations are reversible and may be prevented by timely treatment.

The cardiovascular risk in patients with hypothyroidism is related to an increased risk of functional cardiovascular abnormalities and to an increased risk of atherosclerosis. The pattern of cardiovascular abnormalities is similar in subclinical and overt hypothyroidism, suggesting that a lesser degree of thyroid hormone deficiency may also affect the cardiovascular system. Hypothyroid patients, even those with subclinical hypothyroidism, have impaired endothelial function, normal/depressed systolic function, left ventricular diastolic dysfunction at rest, and systolic and diastolic dysfunction on effort, which may result in poor physical exercise capacity. There is also a tendency to increase diastolic blood pressure as a result of increased systemic vascular resistance. All these abnormalities regress with L-T4 replacement therapy. An increased risk for atherosclerosis is supported by autopsy and epidemiological studies in patients with thyroid hormone deficiency. The "traditional" risk factors are hypertension in conjunction with an atherogenic lipid profile; the latter is more often observed in patients with TSH >10 mU/L. More recently, C-reactive protein, homocysteine, increased arterial stiffness, endothelial dysfunction, and altered coagulation parameters have been recognized as risk factors for atherosclerosis in patients with thyroid hormone deficiency. This constellation of reversible cardiovascular abnormalities in patient with TSH levels <10 mU/L indicate that the benefits of treatment of mild thyroid failure with appropriate doses of L-thyroxine outweigh the risk., (Copyright 2004 Humana Press Inc.)

Subclinical hypothyroidism (SH), defined by elevated serum levels of thyroid stimulating hormone (TSH) with normal levels of free thyroid hormones, is common in adults, especially in women over 60 years of age. Among individuals with this condition, up to two-thirds have serum TSH levels between 5-10 mU/L and thyroid autoantibodies; almost half of them may progress to overt thyroid failure, the annual percent risk increasing with serum TSH level. There is evidence that elevated TSH levels in patients with SH do not reflect pituitary compensation to maintain euthyroidism, but a mild tissue hypothyroidism sensu strictu. When lasting more than 6-12 months, SH may be associated with an atherogenic lipid profile, a hypercoagulable state, a subtle cardiac defect with mainly diastolic dysfunction, impaired vascular function, and reduced submaximal exercise capacity. The deviation from normality usually increases with serum TSH level ('dosage effect' phenomenon). Restoration of euthyroidism by levothyroxine (LT4) treatment may correct the lipid profile and cardiac abnormalities, especially in patients with an initially higher deviation from normality and higher serum TSH levels. Importantly, a strong association between SH and atherosclerotic cardiovascular disease, independent of the traditional risk factors, has been recently reported in a large cross-sectional survey (the Rotterdam Study). However, whether SH confers a high risk for cardiovascular disease, and whether LT4 therapy has a long-term benefit that clearly outweighs the risks of overzealous treatment in these individuals, remain topics of controversy. Therefore, until randomized, controlled, prospective, and adequately powered trials provide unequivocal answers to these critical questions, it is advisable to prescribe LT4 therapy on a case-by-case basis, taking into account the risk of progressive thyroid failure and the risk of cardiovascular events.

Increased or reduced action of thyroid hormone on certain molecular pathways in the heart and vasculature causes relevant cardiovascular derangements. It is well established that overt hyperthyroidism induces a hyperdynamic cardiovascular state (high cardiac output with low systemic vascular resistance), which is associated with a faster heart rate, enhanced left ventricular (LV) systolic and diastolic function, and increased prevalence of supraventricular tachyarrhythmias - namely, atrial fibrillation - whereas overt hypothyroidism is characterized by the opposite changes. However, whether changes in cardiac performance associated with overt thyroid dysfunction are due mainly to alterations of myocardial contractility or to loading conditions remains unclear. Extensive evidence indicates that the cardiovascular system responds to the minimal but persistent changes in circulating thyroid hormone levels, which are typical of individuals with subclinical thyroid dysfunction. Subclinical hyperthyroidism is associated with increased heart rate, atrial arrhythmias, increased LV mass, impaired ventricular relaxation, reduced exercise performance, and increased risk of cardiovascular mortality. Subclinical hypothyroidism is associated with impaired LV diastolic function and subtle systolic dysfunction and an enhanced risk for atherosclerosis and myocardial infarction. Because all cardiovascular abnormalities are reversed by restoration of euthyroidism ("subclinical hypothyroidism") or blunted by beta-blockade and L-thyroxine (L-T4) dose tailoring ("subclinical hyperthyroidism"), timely treatment is advisable in an attempt to avoid adverse cardiovascular effects. Interestingly, some data indicate that patients with acute and chronic cardiovascular disorders and those undergoing cardiac surgery may have altered peripheral thyroid hormone metabolism that, in turn, may contribute to altered cardiac function. Preliminary clinical investigations suggest that administration of thyroid hormone or its analogue 3,5-diiodothyropropionic acid greatly benefits these patients, highlighting the potential role of thyroid hormone treatment in patients with acute and chronic cardiovascular disease.

In this study, we have investigated in vivo the time-dependent effects of TSH on vascular endothelial growth factor (VEGF) production in patients monitored for thyroid carcinoma. Serum VEGF, thyroglobulin (Tg), and TSH levels were assayed at baseline and 6, 24, 30, 48, 72, and 96 h and 1 wk after administration of recombinant human TSH (rhTSH) in 45 thyroidectomized patients affected by differentiated thyroid carcinoma. At baseline, the patients with metastasis (18 cases) showed serum Tg and VEGF values significantly higher than those seen in the cured patients (27 cases). During rhTSH stimulation, the mean VEGF levels decreased significantly in both patient groups. In 60% of patients with metastasis, VEGF nadir occurred at the same time as serum TSH reached the highest values, whereas in 85.7% of the cured patients VEGF decreased after the TSH peak (P = 0.003). In conclusion, we demonstrate for the first time that short-term administration of rhTSH in patients monitored for differentiated thyroid carcinoma induces a significant reduction in serum VEGF values even in the absence of thyroid tissue. This result would suggest that TSH may be able in vivo to regulate VEGF production from tissues other than the thyroid gland.

Background: Gender differences in tumor size are supposed to exist in hyperprolactinemia since microadenomas are more commonly found in women and macroadenomas in men. Whether this reflects only a delay in diagnosis in men or a true gender difference in tumor pathogenesis is still unclear., Objective: To prospectively analyze gender differences in the presentation and response to cabergoline treatment in 219 consecutive newly diagnosed patients with hyperprolactinemia., Design: An open prospective design., Subjects: Of the 219 patients of which 145 were women; 107 patients had macroprolactinoma, 97 had microprolactinoma, and 15 had non-tumoral hyperprolactinemia., Methods: Presenting clinical symptoms, prolactin levels and tumor size at magnetic resonance imaging were measured before and 3-6 Months after cabergoline therapy., Results: Prevalence of microprolactinomas (56% vs 22%, P=<0.0001) and non-tumoral hyperprolactinemia (10% vs 0%, P=0.01) was higher in women than in men. Men and women were of similar age (median 32 vs 29 Years; P=0.2) and a similar number had gonadal/sexual dysfunction (85 vs 83%, P=0.6); weight gain (70 vs 46%; P=<0.0001) and galactorrhea (52 vs 19%; P=<0.0001) were more common in women. Prolactin levels were higher in men than in women, whether exhibiting macro- (2848+/-2954 vs 1132+/-2351 microg/l, P=<0.0001) or microadenomas (187.8+/-51.8 vs 135.4+/-60.5 microg/l, P=0.009) and the size of the adenoma was larger in men than in women irrespective of macro- (25.8+/-12.4 vs 17.2+/-7.2 mm, P=<0.0001) or microadenoma diagnosis (8.0+/-1.4 vs 7.1+/-1.6 mm, P=0.04). After treatment, prolactin levels decreased by 89.2-96.4% in all groups, and normalized more frequently in micro- than in macroadenoma patients (86 vs 64%, P<0.0001), regardless of gender (70% vs 69%, P=0.9). Menses resumed in 82% of women, libido disturbances improved in 57% of men. Tumor size was reduced by 45+/-25% and 52+/-24% in macroprolactinoma patients and by 44+/-31 and 38+/-29% in microprolactinoma patients in women and men respectively. Visual field defects disappeared in 61% of women and in 71% of men (P=0.6)., Conclusions: Prevalence of macroprolactinomas was similar in men and women; microprolactinomas and non-tumoral hyperprolactinemia were more frequent in women. Clinical symptoms at presentation differed according to gender, with galactorrhea and weight gain more frequent in women. The successful response to cabergoline treatment for 6 Months was higher in micro- than in macroprolactinoma patients and was similar in women and men.

Eleven patients who had undergone total thyroidectomy for differentiated thyroid cancer and who were on chronic TSH-suppressive therapy with levothyroxine (L-T4), underwent 24-h Holter electrocardiogram and Doppler-echocardiography before and after acute recombinant human TSH (rhTSH) administration for disease staging. The treatment, which was generally well tolerated, did not affect circulating thyroid hormones levels, nor did it have measurable effects on heart rate, rhythm, left ventricular morphology, or systo-diastolic function. Notably, arterial blood pressure tended to be slightly reduced after rhTSH administration, although in no instance did the patients become frankly symptomatic. Our data demonstrate that rhTSH does not alter cardiovascular function acutely. Consequently, it can safely be used in the routine staging of patients affected by differentiated thyroid cancer.

Background: Mounting evidence indicates that subclinical thyroid dysfunction has important clinical effects and prognostic implications, supporting the view that it is not a compensated biochemical change sensu strictu., Purpose: To review clinical information on the effects of subclinical thyroid dysfunction on the heart., Data Sources: English-language articles identified from files and a MEDLINE search (1970-September 2001), references of relevant articles, textbooks, and meeting abstracts., Study Selection: Reports on the effects of subclinical hypothyroidism and subclinical hyperthyroidism on the cardiovascular system in humans., Data Extraction: Data on cardiac structure and performance, arrhythmias, and risk for coronary artery disease were independently assessed by all authors and summarized., Data Synthesis: Subclinical hypothyroidism is associated with impaired left ventricular diastolic function at rest, systolic dysfunction on effort, and enhanced risk for atherosclerosis and myocardial infarction. Subclinical hyperthyroidism is associated with increased heart rate, atrial arrhythmias, increased left ventricular mass with marginal concentric remodeling, impaired ventricular relaxation, reduced exercise performance, and increased risk for cardiovascular death. All abnormalities were reversed by restoration of euthyroidism (subclinical hypothyroidism) or were blunted by beta-blockade and tailoring of the l -thyroxine dose (subclinical hyperthyroidism)., Conclusion: The heart responds to the minimal but persistent changes in circulating thyroid hormone levels typical of subclinical thyroid dysfunction. Thus, the condition is not a compensated biochemical change sensu strictu, and timely treatment should be considered in an attempt to avoid adverse cardiovascular effects.

Subclinical Cushing's syndrome (SCS) is increasingly being reported in incidentally discovered adrenal adenomas; its hallmark is mild autonomous cortisol hyperproduction without specific clinical signs of cortisol excess. Increased prevalence of hypertension, obesity, and impaired glucose tolerance have been described in SCS, but there is no specific study of the risk factors for cardiovascular diseases. In this cross-sectional study we assessed the cardiovascular profile in 28 consecutive SCS patients (19 women and 9 men; aged 56 +/- 10.6 yr) compared with 100 controls matched for age, gender, and body mass index. Systolic (P < 0.001) and diastolic (P < 0.005) blood pressures were higher in patients, as were fasting glucose, insulin, total cholesterol, triglycerides (all P < 0.001), and fibrinogen (P < 0.05). Moreover, the insulin resistance index was increased in patients as was the waist to hip ratio and mean carotid artery intima-media thickness (all P < 0.001). Of the patients, 60.7% had arterial hypertension, 71.4% had lipid abnormalities, 28.6% had impaired glucose tolerance, 35.7% type 2 diabetes mellitus, and 53.6% had abnormalities in hemostatic parameters. Atherosclerotic plaques were more frequent in patients (P < 0.0001). Only 4 (14.3%) patients did not have multiple risk factors for cardiovascular events. Six (21.3%) had clinical evidence of cardiovascular disease; another 11 (39.3%) had cardiovascular abnormalities as revealed by ultrasound scanning of carotid arteries and/or electrocardiogram records. These results strongly suggest that an increased cardiovascular risk profile, similar to that described in overt Cushing's syndrome, is present in SCS subjects. This finding supports the concept that chronic mild endogenous cortisol excess may have important systemic effects on the human body.

The cardiovascular system is sensitive to the action of thyroid hormone. However, although a wide spectrum of cardiac abnormalities has long been recognized in patients with overt thyroid dysfunction, the question of cardiac involvement in patients with subclinical thyroid dysfunction has been investigated only in the last two to three decades. Most clinical studies have shown that subclinical hypothyroidism or hyperthyroidism is associated with changes in several cardiac parameters. More specifically, the literature on cardiac involvement in subclinical hypothyroidism consistently shows that patients have resting left ventricular diastolic dysfunction evidenced by delayed relaxation, and impaired systolic dysfunction on effort that results in poor exercise capacity. Whether or not subclinical hypothyroidism also affects left ventricular systolic function at rest remains controversial. Studies of subclinical hypothyroid patients before and after euthyroidism was achieved with levothyroxine replacement provided evidence of impaired resting left ventricular systolic function. Indeed, at-rest left ventricular systolic function was substantially normal in most studies of subclinical hypothyroid patients compared to normal control subjects. Drawing on these data, it appears that subclinical hypothyroidism should be considered a mild form of thyroid failure, associated with initial signs of cardiovascular hypothyroidism. Therefore, it would seem appropriate to initiate timely treatment of patients with mild thyroid failure to prevent cardiac involvement.

Mounting evidence suggests that increased circulating aldosterone levels, despite angiotensin-converting-enzyme inhibitors therapy, may exert deleterious cardiovascular effects in heart failure, leading to clinical deterioration and poor prognosis. In the past decades, a number of experimental investigations have provided major insight into the mechanism(s) of action and the biological effects of aldosterone on the cardiovascular system, indicating that aldosterone participates in the structural and functional remodeling of cardiac and vascular tissue. In particular, it has emerged that aldosterone plays a key role in the regulation of myocardial extracellular matrix composition and endothelial function with important pathophysiological implications. Such evidence, coupled with the recent beneficial effects of spironolactone, a competitive aldosterone receptor antagonist, in reducing cardiac mortality and morbidity in patients with severe chronic heart failure treated with angiotensin-converting-enzyme inhibitors and loop diuretics, highlights the importance of aldosterone in the pathophysiology of human heart failure. The purpose of this review is to provide an overview of the regulation of aldosterone production and metabolism in heart failure, the basic mechanism of aldosterone action, and the pathophysiological implications of aldosterone in heart failure, and to discuss recent evidence supporting the efficacy of aldosterone receptor blockade in the treatment of chronic heart failure in humans.