The epidemiology of thyroid disease and implications for screening

Blood coagulation, fibrinolytic activity and lipid profile in subclinical thyroid disease: subclinical hyperthyroidism increases plasma factor X activity

BACKGROUND AND OBJECTIVES

Various abnormalities of coagulation and fibrinolysis occur in patients with thyroid diseases, and may range from subclinical laboratory abnormalities to clinically significant disorders of coagulation and, rarely, major haemorrhage or thromboembolism. The influence of subclinical hypothyroidism (SHypo) on haemostasis is controversial, both hypercoagulable and hypocoagulable states have been reported. A hypercoagulable state might be a risk factor for thromboembolic disease in SHypo. On the other hand, subclinical hyperthyroidism (SCHyper) is associated with enhanced cardiovascular risk. In the English literature, there are no studies on changes in coagulation and fibriolytic status in subjects with SCHyper. Therefore, the aim of the present study was to investigate the markers of endogenous coagulation and fibrinolysis, and to evaluate the relationships between serum lipid profile and thyroid hormones and these haemostatic parameters in subclinical thyroid patients.

DESIGN AND METHODS

Various haemostatic parameters were investigated in 30 patients with SHypo and 20 patients with SCHyper and compared to 20 euthyroid controls. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, factors V, VII, VIII, IX and X activities, vWF, antithrombin III (AT III), protein C, protein S, tissue plasminogen activator (t-PA) and tissue plasminogen activator inhibitor-1 (PAI-1), as well as common lipid variables, were measured. The relationships between serum thyroid hormones and these haemostatic parameters were examined.

RESULTS

Compared with the control subjects, only FX activity was significantly increased in patients with SCHyper (P < 0.01). Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels were significantly higher in patients with SHypo compared with the control group (P < 0.001 and P < 0.01, respectively). TC levels were significantly higher in patients with SCHyper than in controls (P < 0.05). No differences could be found in coagulation/fibrinolysis parameters between subclinical hypothyroid patients and control subjects. In patients with SCHyper, serum TSH level was positively correlated with FX activity (r: 0.58, P < 0.01) and inversely correlated with PAI-1 (r: -0.55. P < 0.05). Serum TG levels were inversely correlated with plasma activities of factors V, VII, VIII, IX, X and vWF (r: -0.83, P < 0.001; r: -0.68, P < 0.05; r: -0.61, P < 0.05; r: -0.77, P < 0.01; r: -0.63, P < 0.05; r: -0.60, P < 0.05, respectively). Serum TC levels were positively correlated with plasma fibrinogen levels (r: 0.72, P < 0.05). Serum HDL-C levels were positively correlated with protein S activity (r: 0.68, P < 0.05) and negatively correlated with F VII activity (r: -0.69, P < 0.05). Also, in patients with SHypo, serum TG levels were positively correlated with serum TSH levels (r: 0.42, P < 0.05), plasma activities of factors V, VII and X (r: 0.42, P < 0.05; r: 0.54, P < 0.01; r: 0.57, P < 0.01, respectively) and negatively correlated with plasma fibrinogen levels (r: -0.41, P < 0.05). Serum TC levels were positively correlated with factors V and X (r: 0.42, P < 0.05; r: 0.58, P < 0.01, respectively) and negatively correlated with t-PA Ag levels (r: -0.44, P < 0.05). Serum HDL-C levels were inversely correlated with F VII activity (r: -0.48, P < 0.05).

INTERPRETATION AND CONCLUSIONS

Some differences were found in the haemostatic parameters and lipid profile between the subclinical thyroid patients and healthy controls. Increased factor X activity in patients with subclinical hyperthyroidism represent a potential hypercoagulable state, which might augment the already existing risk for atheroscleroic complications. Also, subclinical hypothyroid patients exhibit a more atherogenic lipid profile compared with healthy individuals. Therefore, subclinical hypothyroidism is also associated with an increased risk of cardiovascular disease. However, thyroid hormones may play a role at different levels of the complex haemostatic system in subclinical thyroid disease.

Investigations of thyroid hormones and antibodies based on a community health survey: the Busselton thyroid study

OBJECTIVE

Overt or subclinical thyroid dysfunction is common within the community, yet the significance of subtle anomalies in thyroid function tests remains contentious. The aims of this study were to: (a) establish reference intervals for serum-free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid antibodies (antithyroperoxidase, TPOAb and antithyroglobulin, TgAb) in the Busselton community of south-western Western Australia; and (b) determine the prevalence of thyroid hormone anomalies in this community.

SUBJECTS AND DESIGN

In 1981, 2115 adults residing in Busselton participated in a cross-sectional health survey that involved blood collection and a questionnaire on lifestyle and general health history.

MEASUREMENTS

Serum samples were analysed for FT4, TSH, TPOAb and TgAb by immunochemiluminescent assays.

RESULTS

Based on standard statistical approaches and using guidelines recommended by the National Academy of Clinical Biochemistry (NACB), reference intervals were derived for each analyte: 9-23 pmol/l for FT4, 0.4-4.0 mIU/l (TSH), < 35 KIU/l (TPOAb) and < 55 KIU/l (TgAb). The prevalence of elevated thyroid antibodies was 12.4% among subjects without a history of thyroid disease and is more common in women than in men. Elevated thyroid antibody levels were observed at both extremes of TSH abnormality, but were more commonly increased when TSH levels were above 4.0 mIU/l (63% subjects) than for those with TSH levels 0.4-4.0 mIU/l (7.8% subjects).

CONCLUSIONS

This study establishes the prevalence of antibodies to thyroperoxidase and thyroglobulin in a community-based sample and reference intervals for free T4 and TSH. When the NACB decision limits are applied to older men or women, there is a markedly increased number with 'elevated' autoantibody levels compared to sex- and age-specific reference intervals.

Does Treating Subclinical Hypothyroidism Improve Markers of Cardiovascular Risk?

Subclinical hypothyroidism is defined as an elevated serum thyroid-stimulating hormone (TSH) level in the face of normal free thyroid hormone values. The overall prevalence of subclinical hypothyroidism is 4-10% in the general population and up to 20% in women aged >60 years. The potential benefits and risks of therapy for subclinical hypothyroidism have been debated for 2 decades, and a consensus is still lacking. Besides avoiding the progression to overt hypothyroidism, the decision to treat patients with subclinical hypothyroidism relies mainly on the risk of metabolic and cardiovascular alterations. Subclinical hypothyroidism causes changes in cardiovascular function similar to, but less marked than, those occurring in patients with overt hypothyroidism. Diastolic dysfunction both at rest and upon effort is the most consistent cardiac abnormality in patients with subclinical hypothyroidism, and also in those with slightly elevated TSH levels (>6 mIU/L). Moreover, mild thyroid failure may increase diastolic blood pressure as a result of increased systemic vascular resistance. Restoration of euthyroidism by levothyroxine replacement is generally able to improve all these abnormalities. Early clinical and autopsy studies had suggested an association between subclinical hypothyroidism and coronary heart disease, which has been subsequently confirmed by some, but not all, large cross-sectional and prospective studies. Altered coagulation parameters, elevated lipoprotein (a) levels, and low-grade chronic inflammation are regarded to coalesce with the hypercholesterolemia of untreated patients with subclinical hypothyroidism to enhance the ischemic cardiovascular risk. Although a consensus is still lacking, the strongest evidence for a beneficial effect of levothyroxine replacement on markers of cardiovascular risk is the substantial demonstration that restoration of euthyroidism can lower both total and low-density lipoprotein-cholesterol levels in most patients with subclinical hypothyroidism. However, the actual effectiveness of thyroid hormone substitution in reducing the risk of cardiovascular events remains to be elucidated. In conclusion, the multiplicity and the possible reversibility of subclinical hypothyroidism-associated cardiovascular abnormalities suggest that the decision to treat a patient should depend on the presence of risk factors, rather than on a TSH threshold. On the other hand, levothyroxine replacement therapy can always be discontinued if there is no apparent benefit. Levothyroxine replacement therapy is usually safe providing that excessive administration is avoided by monitoring serum TSH levels. However, the possibility that restoring euthyroidism may be harmful in the oldest of the elderly population of hypothyroid patients has been recently raised, and should be taken into account in making the decision to treat patients with subclinical hypothyroidism who are aged >85 years.

Incidence trends for papillary thyroid carcinoma and their correlation with thyroid surgery and thyroid fine-needle aspirate cytology

CONTEXT

Papillary thyroid carcinoma (PTC) is the most prevalent endocrine malignancy. The reported incidence of PTC has more than doubled in many countries during the past half century. In Tasmania, an island state of the Commonwealth of Australia the incidence has increased by 24.7% per annum during the last two decades.

OBJECTIVE

Using the Tasmanian population as a model, this study sought to determine the relationship between changes in PTC incidence and trends for utilization of thyroid surgery and thyroid fine-needle aspiration biopsy (FNAB) cytology.

DESIGN

Hospital and pathology services in Tasmania provided data relating to all thyroid surgical, cytologic, and histopathology procedures undertaken between 1988 and 1998. The accuracy of PTC case ascertainment by the Tasmanian Cancer Registry was validated and the relationship between thyroid procedures and PTC incidence assessed.

RESULTS

A total of 3452 individuals underwent a thyroid procedure, comprising 1968 surgical and 1756 FNAB cytologic procedures. Of these, 184 patients were diagnosed with thyroid carcinoma, of whom 121 (65.8%) had PTC. Thyroidectomy and thyroid FNAB increased by 7.0% and 49.7% per annum, respectively. The likelihood of diagnosing PTC in thyroidectomy specimens increased by 99.7% per year in those patients preoperatively assessed by FNAB, compared to 10.1% per year in those for whom a preoperative FNAB was not performed. PTC incidence increased independently of PTC tumor size, although the greatest increase occurred for PTC 1 cm or less with a history of preoperative FNAB.

CONCLUSIONS

These results suggest increasing PTC incidence is largely attributable to greater diagnosis of small PTC, many of which are likely to have been asymptomatic, identified by neck ultrasonography and subsequent FNAB. However, the incidence of PTC larger than 1 cm in patients without history of preoperative FNAB has also risen, suggesting the occurrence of clinically relevant tumors may also have increased.

Cyclooxygenase 1 and 2 expressions in the human thyroid gland

We investigated the expression of COX-1 and COX-2 in normal thyroid tissue, follicular adenoma and well-differentiated thyroid carcinomas and evaluated the difference in COX-1 and COX-2 expression. Ten normal thyroid tissues, ten follicular adenomas, ten papillary carcinomas and ten follicular carcinomas were analyzed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for expression of COX-1 and COX-2 mRNA. In addition, immunohistochemical staining was performed to find the expression of the two enzymes in normal thyroid tissues and thyroid neoplasia. Expression of COX-1 mRNA in the normal thyroid tissues, follicular adenomas and both well-differentiated carcinomas was similar and weak. However, COX-2 mRNA was strongly expressed in the well-differentiated carcinomas compared to those of normal thyroid tissue and follicular adenoma.

Thyroid papillary cancers: microcarcinoma and carcinoma, incidental cancers and non-incidental cancers - are they different diseases?

OBJECTIVE

Tumour size represents a much-debated prognostic factor in papillary cancer, and the necessity to perform a fine-needle aspiration (FNA) on small nodules is a frequent matter of discussion. We compared some prognostic histological features for various sizes of papillary cancers (PCs) and, with regard to these prognostic features, we compared non-incidental with incidental PCs. We also considered the possibility that ultrasonography could detect nodules harbouring the most aggressive cancers.

DESIGN AND PATIENTS

We have studied patients with a histological diagnosis of PC from 1999 to 2003. FNA was performed on all nodules > 1.0 cm and on hypoechoic nodules with irregular margins or microcalcification when the size was < 1.0 cm (3321 FNAs in total). We were able to consider several different types of patients: those with PC diagnosed by FNA before surgery; those with large goitre and PC of small size diagnosed after histological examination and in whom a careful examination of the presurgical ultrasonography could show a distinct highly suspicious nodule that was not subjected to FNA, and patients with real incidental PC (that is, those with nodular goitre who correctly underwent FNA on suspicious nodules but in whom thyroid cancer was discovered only at histological examination). We considered two groups of patients with PC. Group 1 PCs were diagnosed before surgery with FNA (128 cases); in this group we also considered the two cases that were not correctly diagnosed before surgery. Group 2 real incidental PCs (12 cases) were found in goitres at histological examination after thyroidectomy for goitre (282 thyroidectomies). Group 1 was divided into three subgroups according to the maximum size of the PC at histological examination: (a) 44 PCs with maximum size < 10 mm, (b) 47 PCs with maximum size between 10 mm and 20 mm, and (c) 39 PCs with maximum size 20 mm. In all subgroups 1 as well as in group 2, the following four histological features were considered separately: multifocality, extracapsular extension, lymph-node involvement and its extent, and special aggressive features (dedifferentiation and/or insular aspects, tall and columnar variants).

RESULTS

In subgroups 1a, 1b and 1c the results were, respectively: multifocality 56.8, 57.4 and 51.2%; extracapsular extension 27.2, 23.4 and 46.3% (P = 0.01, subgroups 1a and 1b vs. subgroup 1c); lymph-node metastasis 13.5, 23.3 and 46.1% (P = 0.003 subgroup 1a vs. 1c; P = 0.04, subgroup 1b vs. 1c); special aggressive features 11.3, 25.5 and 28.2% (P = ns). Group 2 showed one case of multifocality (8.3%) in a patient with prior exposure to radiotherapy in childhood, while no case was found of extracapsular invasion or lymph-node involvement, and only one patient had a PC with features of dedifferentiation.

CONCLUSIONS

Non-incidental cancer, apart from multifocality, showed a classical progression for all prognostic factors from microcarcinoma to larger cancers. However, real incidental PC seemed to be different from non-incidental PC microcarcinoma regarding the main prognostic features. We conclude that ultrasonography is useful not only in terms of revealing the presence of cancer but also in identifying the most aggressive cancers.

Age-dependent changes in CXC chemokine ligand 10 serum levels in euthyroid subjects

Circulating levels of cytokines are deeply influenced by aging, and few data about serum chemokines are available. The aim of this study was to evaluate the influence of aging on circulating CXCL10. One hundred forty healthy subjects (70 males and 70 females), 10-79 years of age, underwent fasting plasma glucose, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride, and CXCL8 serum assay. Thyroid hormone testing for thyroid-stimulating hormone (TSH), antithyroglobulin (AbTg), and antithyroperoxidase (AbTPO) autoantibodies and thyroid ultrasonography were performed in all subjects to exclude the presence of clinical or subclinical thyroid disease. Serum CXCL10 levels were assayed in all subjects and found to be increased in 14 of 70 females (20%) and in 4 of 70 males (5.7%) (p = 0.01). In a multiple linear regression model including age, body mass index (BMI), systolic and diastolic blood pressure, glycemia, total cholesterol, HDL, LDL, triglycerides, TSH, AbTPO, AbTg, and CXCL8, only age was significantly related to CXCL10 [C.R. 1.30 (0.28-2.33), p = 0.001]. No relationship was present between CXCL8 serum levels and age, suggesting a specificity of CXCL10 elevation as a function of age. Results of this study, performed in healthy subjects on an age gradient, demonstrate an increase in serum CXCL10 with advancing age overall in females, supporting the hypothesis of enhanced Th1 immune responses in aging.

The spectrum of thyroid dysfunction in an Australian hepatitis C population treated with combination Interferon-alpha2beta and Ribavirin

BACKGROUND

The study aims to assess the pattern of thyroid response to combination Interferon-alpha2beta (IFN-alpha) and Ribavirin (RBV) anti-viral therapy in an Australian hepatitis C cohort. These include the prevalence of thyroid dysfunction (TD) including hyperthyroidism and hypothyroidism and their possible predictors, the common overall pattern of thyroid function tests whilst receiving therapy and TD outcomes, and the correlation with HCV status outcome.

METHODS

A retrospective analysis of all medical records was performed to assess thyroid function in Hepatitis C Virus (HCV) patients who were treated at the Hunter Area hepatitis C treatment center between 1995 and March 2004. The centre is part of the John Hunter hospital, a major tertiary referral centre in New South Wales, Australia.

RESULTS

There were 272 cases available for review. The prevalence of TD is 6.7 percent and is made up predominantly of females (80 percent). There were 3 (1.1 percent) cases of hyperthyroidism with 2 (67 percent) females. Thirteen out of fifteen (80 percent) cases of hypothyroidism were females with the overall prevalence of 5.5 percent. The majority of hypothyroid patients still required Thyroxine supplement at the end of follow up.

CONCLUSION

Ninety three percent of HCV treated patients have intact thyroid function at the end of treatment. The predominant TD is hypothyroidism. The predominant pattern of thyrotoxicosis (TTX) is that of thyroiditis although the number is small. Graves' like disease was not observed. People with pre-existing thyroid auto-antibodies should be closely monitored for thyroid dysfunction, particularly hypothyroidism.

Multiple Sclerosis and Hashimoto Thyroiditis

Multiple sclerosis (MS) occurs with immune-mediated mechanisms, but its pathogenesis is not accurately known. The coexistence of MS with other autoimmune diseases has been reported. The hypothesis that MS coexists with other autoimmune diseases has been supported by the reported association of MS with type I diabetes mellitus and inflammatory disorders. Even though there have been only rare reports of associations between Hashimoto thyroiditis and MS, this association is important for its clinical and therapeutic aspects. Proximal muscle weakness, myalgia, and fatigue are symptoms that are common in both MS and hypothyroidism. When MS patients demonstrate these symptoms, thyroid function tests should be performed. The thyroid hormone levels of MS patients being treated with interferon-beta and Campath-1H also should be monitored. The authors report the clinical data of 2 definite MS patients who also fulfilled criteria for Hashimoto thyroiditis.

The thyroid incidentaloma: an increasingly frequent consequence of radiologic imaging

Incidentally discovered thyroid lesions have become increasingly common with the development and more frequent utilization of highly sensitive imaging modalities throughout the clinical practice of medicine. Determining the most appropriate management of these "incidentalomas" has presented a significant challenge to both endocrinologists and endocrine surgeons. Algorithms with which to accurately identify those malignant lesions hidden amongst the overwhelming majority of those which are benign have not yet been established. This article will review the existing literature concerning the subject of thyroid incidentalomas and recommend a methodical approach to evaluating these patients such that the greatest number of malignancies may be detected while subjecting the fewest patients with benign lesions to unnecessary testing. Additionally, the role of the radiologist as an integral part of the multidisciplinary team of surgeons, endocrinologists, and cytologists working together to identify those patients with the highest risk of malignancy will be explored.

Global fibrinolytic capacity in patients with subclinical hypothyroidism

Subclinical hypothyroidism (SH) represents the earliest stages of hypothyroidism but the benefits of detecting and treating SH are not well known. The aim of this study was to evaluate the alterations in global fibrinolytic capacity (GFC), which indicates the overall fibrinolytic activity, in patients with SH. The study group comprised of 15 patients with SH and 15 healthy controls. The GFC was significantly lower in patients with SH than in control group (p<0.002). This result suggests a relative hypercoagulable state in SH.

Rates of malignancy in incidentally discovered thyroid nodules evaluated with sonography and fine-needle aspiration

OBJECTIVE

The purpose of this study was to compare the rate of malignancy in thyroid nodules discovered incidentally on magnetic resonance imaging, computed tomography, and sonography with the rate of malignancy in nonincidentally discovered nodules.

METHODS

All thyroid sonographic and fine-needle aspiration (FNA) procedures performed during a 6-month period were retrospectively reviewed. Study indications were categorized as incidental (thyroid nodules found on magnetic resonance imaging, computed tomography, or sonography performed for nonthyroid indications) or nonincidental (studies prompted by abnormal physical examination findings or laboratory values or signs or symptoms suggestive of thyroid disease). Rates of malignancy in patients with incidentally discovered nodules were compared with rates in patients with nonincidental thyroid abnormalities by the Fisher exact test.

RESULTS

Of 225 thyroid sonographic studies, 35 (16%) were performed for incidentally discovered thyroid nodules, and 190 (84%) were performed for evaluation of nonincidental thyroid abnormalities. A total of 21 patients (60%) in the incidental group and 90 patients (47%) in the nonincidental group underwent FNA. The rate of malignancy in nodules examined by biopsy in the incidental group was 17% compared with 3% in the nonincidental group (P = .020). Patient sex, multiplicity of nodules, nodule size, echo texture, and presence of calcifications did not differ significantly between the groups. The mean age of patients in the incidental group was significantly higher (61 versus 51 years; P = .007); however, advanced age was not associated with a greater rate of malignancy.

CONCLUSIONS

This study identified an unexpectedly high rate of malignancy in incidentally discovered thyroid nodules, suggesting that incidentally discovered thyroid nodules should be evaluated with follow-up thyroid sonography and FNA.

Management of nondiagnostic thyroid fine-needle aspiration biopsy: survey of endocrinologists

OBJECTIVE

To evaluate the approach of endocrinologists in the setting of nondiagnostic thyroid fine-needle aspiration (FNA) biopsies.

METHODS

In 2002, we surveyed physicians attending the national annual meetings of the American Association of Clinical Endocrinologists and the Endocrine Society of North America, using a 13-item questionnaire. The responses were tallied and analyzed.

RESULTS

Of the 143 respondents, 139 were endocrinologists, with a male:female ratio of 2.5:1. Most respondents were involved in a medical practice in North America, but Europe, Asia, New Zealand, and Australia were also represented. Of those performing thyroid FNA biopsy, 31% used thyroid ultrasound guidance. Among the survey respondents, 16%, 49%, 20%, and 15% performed less than 2, 2 to 5, 6 to 10, and more than 10 thyroid FNA biopsies per month, respectively. Among the respondents, 13.5%, 44%, 28.5%, 10%, and 4% had non-diagnostic rates of less than 5%, 5 to 10%, 11 to 20%, 21 to 30%, and more than 30%, respectively. The approach of the respondents to an initially nondiagnostic FNA was repeated FNA biopsy in 87%, observation in 7%, levothyroxine suppression in 4%, and thyroid scintigraphy in 2%. Respondents believed that the most cost-effective approach in a patient with nondiagnostic FNA was repeated biopsy (82%), monitoring the size of the thyroid nodule (17%), and surgical referral (<1%). No one was willing to repeat the thyroid biopsy more than three times.

CONCLUSION

On the basis of findings in our survey, most endocrinologists repeat thyroid FNA at least once when confronted with a nondiagnostic result. No published studies have demonstrated the cost-effectiveness of this approach versus proceeding to surgical intervention or observation. We hope that this survey will encourage further studies on this issue.

Associação de tireopatias em uma população de pacientes com diabetes

OBJETIVO: Avaliar morfológica e funcionalmente a tireóide de pacientes com diabetes mellitus (DM) acompanhados ambulatorialmente no Hospital das Clínicas de Botucatu. MÉTODOS: No período de 1996 a 1998, a todo paciente com DM, exceto os com tireopatia prévia, era solicitada dosagem sérica de T4L, TSH, anti-TPO e TRAb e ultra-sonografia (US) da tireóide. Diagnosticou-se tireopatia quando havia dois ou mais parâmetros séricos ou a US alterados. Procedeu-se igualmente com pacientes ambulatoriais da mesma Instituição, sem DM e não-tireopatas prévios (controle). RESULTADOS: Os 256 pacientes com DM apresentaram maior freqüência de tireopatias que os 75 controles (51,6% vs. 38,7%; P<0,05). Entre os com tireopatias, ambos os grupos não diferiram quanto ao estado funcional da tireóide. Entre os pacientes com DM com e sem tireopatias, os primeiros apresentaram maior freqüência de mulheres, de DM tipo 2 e de história familiar de tireopatia. CONCLUSÕES: A elevada prevalência de tireopatias na população com DM conduz à recomendação de avaliação tireoidiana em todo paciente com DM.

Immunogenetics of Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is an organ-specific T-cell mediated disease. It is a complex disease, with a strong genetic component. To date, significant progress has been made towards the identification and functional characterization of HT susceptibility genes. In this review, we will summarize the recent advances in our understanding of the genetic input to the pathogenesis of HT.

Labirintopatia secundária aos distúrbios do metabolismo do açúcar: realidade ou fantasia?

As vestibulopatias atribuídas aos distúrbios do metabolismo do açúcar são ainda hoje um tema controverso na literatura pela falta de demonstração objetiva que relacione causa e efeito. OBJETIVO: Nosso objetivo é relatar os resultados seriados do Teste de Integração Sensorial no acompanhamento dos pacientes portadores de DMA tratados com dieta fracionada e restrição de glicose. FORMA DE ESTUDO: Retrospectivo, inclui um desenho de descrição de casos. MÉTODO: Foram avaliadas as respostas de 21 pacientes portadores de distúrbios do metabolismo do açúcar e tontura submetidos à dieta fracionada com restrição de glicose. A medição objetiva do equilíbrio corporal dos pacientes foi feita pela Posturografia Dinâmica Computadorizada, utilizando-se o protocolo do Teste de Integração Sensorial. RESULTADOS: Após a instituição da dieta, observou-se melhora objetiva significante nas condições que retratam a função vestibular e o equilíbrio corporal dos indivíduos estudados. CONCLUSÃO: Concluímos que o Teste de Integração Sensorial demonstrou ser uma ferramenta útil na documentação da melhora do equilíbrio corporal de pacientes portadores de DMA submetidos à dieta fracionada com restrição de glicose.

Thyroid carcinomas involving follicular and parafollicular C cells: seventeen cases with characterization of RET oncogenic activation

Recent studies have focused on the occurrence of concomitant medullary-papillary thyroid carcinomas (MTC-PTC). The aims of this report were to compare the frequency of occult PTC in a population with MTC versus a control population that had undergone thyroidectomies and to check whether differences could be related to particular phenotype or genotype. To achieve these goals, we determined the frequency of occult PTC among patients operated for MTC (n = 82) or undergoing total thyroidectomy mainly for goiter and/or nodules (n = 7313) between 1994-2001. We then examined the clinical, histologic, and genetic characteristics (using a bio-chemical family inquiry and screening for RET germline mutations) of patients with associated PTC-MTC. Results show a significantly higher frequency of occult PTC in MTC (14.7%) than in total thyroidectomy (6.8%; p < 0.01). Seventeen cases of MTC or bilateral C-cell hyperplasia (CCH) and separate occult PTC were identified from 16 different families. Although common RET mutations providing evidence of familial forms of MTC were identified in only 3 of 16 families, clinical and histologic features usually seen in inherited forms of MTC such as young age of occurrence, bilateral CCH or associated case in family were found in 11 of the remaining 14 patients. In conclusion, results suggest that the association of MTC-PTC is not only a coincidence. Surprisingly, 11 of 17 MTC-PTC patients exhibited clinical, histologic, and/or family features usually encountered in familial forms despite the fact that no RET defect were present. This suggests the possible involvement of another gene or uncommon abnormality of RET gene.

Management of thyroid incidentalomas

The discovery of a thyroid incidentaloma warrants a systematic approach for those nodules most likely to be cancerous. An optimal management strategy for thyroid incidentalomas should be guided by four questions: (1) Does the incidentally detected thyroid nodule put the patient at risk for an adverse outcome; (2) Can those individuals with malignant thyroid nodules be identified; (3) Is the treatment of thyroid malignancy more effective in presymptomatic patients; and (4) Do the beneficial effects of presymptomatic detection and treatment in these patients justify the costs incurred Physicians caring for patients with thyroid disease should participate in data acquisition in national databases and properly randomized studies, to address the optimal management strategy in the treatment of incidentally-detected thyroid nodules.

Female infertility and the thyroid

Difficulty to conceive or subfertility constitutes a major psychological burden. Assisted reproductive technology changed significantly the outcome of couples faced with subfertility. These techniques consequently increased tremendously our understanding of the mechanisms underlying reproductive failure and opened new perspectives for future interventions, not only to increase cumulative conception rates after ART, but also spontaneous pregnancy rates. Thyroid dysfunction adversely affects fertility. Many studies imply a role for immunology, including thyroid autoimmunity in conception failure. In this review we attempt to update the available information on the adverse effect of thyroid dysfunction and/or thyroid autoimmunity on subfertility and we propose a rationale for testing and potential treatment options.

A patient presenting with spinal cord compression who had two distinct follicular cell type thyroid carcinomas

A 61-yr-old woman presented with complaints of weakness and pain in her legs. A magnetic resonance imaging showed a 3 x 5.6 x 7.8 cm mass lesion destructing the T1 and T2 vertebral bodies and compressing the spinal cord. The mass was excised surgically. It was follicular carcinoma metastasis of the cervicodorsal region. Then, she underwent a total thyroidectomy. Pathological examination showed two different types of carcinomas in two different focuses; follicular carcinoma in the left lobe and follicular variant papillary carcinoma in the isthmic lobe. After the operation she was given 100 mCi 131I. This is the first report of a patient who had both metastatic follicular carcinoma and follicular variant papillary carcinoma together.

Doença nodular de tireóide

A tireóide normal é uma estrutura homogênea na qual, com muita freqüência, observamos a formação de nódulos. Nódulos maiores que 1,0cm costumam ser detectados clinicamente pela palpação. Um exame cuidadoso pode demonstrar a presença de nódulos em, pelo menos, 4% da população. A etiologia da doença nodular de tireóide é multifatorial, compreendendo um espectro que vai do pequeno nódulo achado de forma incidental a um grande bócio multinodular intra-torácico. Os principais aspectos com relação à avaliação diagnóstica estão relacionados à caracterização funcional e morfológica através do TSH sérico e algum tipo de imagem. Para afastar a malignidade, cuja incidência é praticamente a mesma em pacientes com nódulo solitário ou bócio multinodular (BMN), a punção aspirativa com agulha fina (PAAF) é o método de escolha. O nódulo único benigno de tireóide, frio ou quente à cintilografia, pode ser tratado com injeção percutânea de etanol ou cirurgia. O tratamento do BMN pode ser cirúrgico ou com radioiodo, se a captação de 131I for adequada. É provável que a introdução do TSH recombinante humano possa influenciar de forma importante o tratamento com 131I do BMN. O nódulo quente pode, ainda, ser tratado com 131I ou cirurgia. O tratamento supressivo com levotiroxina não é indicado no tratamento do nódulo benigno de tireóide.

Disfunções mínimas da tiróide: hipotiroidismo subclínico e hipertiroidismo subclínico

Hipotiroidismo subclínico (SHT) e hipertiroidismo subclínico (SCH) são definidos pelas concentrações normais de T4 e T3 livres séricos associadas com valores de TSH elevado (SHT) ou suprimido (SCH). As prevalências são baixas e sintomas e sinais de disfunção tiroideana escassos. No SHT, colesterol total e LDL-C estão ligeiramente elevados, e tratamento com levotiroxina pode influir nos valores dos lipídeos. Ocorre diminuição da contratilidade do miocárdio e aumento da resistência vascular periférica, que melhoram com o tratamento. Fibrilação atrial é mais freqüente no SCH, e há aumento do índice de massa do ventrículo esquerdo, da contratilidade cardíaca, disfunção diastólica e indução de batimentos atriais ectópicos que regridem com uso de beta-bloqueadores. No SCH, ocorre diminuição da densidade óssea. Depressão, doença do pânico e alterações de testes cognitivos são freqüentes no SHT. O tratamento do SHT é indicado com TSH sérico maior do que 8mU/L e presença de anticorpos antitiroideanos, e do SCH endógeno, quando existem sintomas, em idosos ou concentração de TSH menor do que 0,1mU/L.

Development of a murine model of autoimmune thyroiditis induced with homologous mouse thyroid peroxidase

Autoimmune thyroid disease (AITD) is a common autoimmune disease. Thyroid peroxidase (TPO) is a well characterized autoantigen in AITD. Autoantibodies and autoreactive T lymphocytes to TPO are believed to play a major role in the pathogenesis of lymphocytic thyroiditis. To understand the pathogenic mechanisms of AITD and the role of TPO, we have established a mouse model of lymphocytic thyroiditis by immunizing C57Bl/6 (H-2(b)), CBA (H-2(k)), and C57Bl/6 x CBA F1 mice with recombinant murine TPO (rmTPO) ectodomain comprising amino acid residue 1-837 produced in Escherichia coli. Mice were immunized with 30 microg purified ectodomain in complete Freund's adjuvant. Antibodies against rmTPO were detected in the serum of all mice from day 21 onward. Draining lymph node cells from rmTPO-immunized animals showed dose-dependent proliferation to TPO stimulation. Mice killed at d 50 and 90 revealed variable degrees of thyroiditis with infiltration of mononuclear cells and destruction of thyroid follicles. C57Bl/6 and the F1 mice, in comparison with CBA mice, showed a greater degree of thyroiditis. There was a lack of correction between the intensity of thyroiditis and the anti-TPO response. Immunotyping of the thyroid cellular infiltrates showed predominantly CD4+ T cells and B220+ B cells but scanty CD8+ T cells. None of the control mice injected with the purified fusion partner developed anti-TPO antibodies and thyroiditis. In conclusion, a genuine autoimmune mouse model of lymphocytic thyroiditis was established using autologous mouse TPO. This new model induced with autologous TPO will lead to a better understanding of the mechanisms in destructive thyroiditis and will assist in the development of new strategies for modulating the pathogenic immune response.

Ultrasonography-guided fine-needle aspiration of thyroid incidentaloma: correlation with pathological findings

BACKGROUND

There are many reports that diagnostic accuracy of fine-needle aspiration (FNA) of thyroid is improved with ultrasound guidance, especially for impalpable nodules. Despite its general acceptance, routine use of ultrasound-guided fine-needle aspiration (USGFNA) has been the source of much controversy due to the lack of large-scale studies and lack of data on the natural course of well-differentiated thyroid cancer of small size.

OBJECTIVE

The aim of our study was to define the rate of malignancy in relatively large numbers of patients with incidentally detected impalpable thyroid nodules and to assess the extent of disease in patients with suspicious or malignant cytology on USGFNA of thyroid nodules by surgery.

PATIENTS

We retrospectively reviewed the medical records of the 267 patients who underwent USGFNA of incidental thyroid nodules from January 2000 to December 2001.

RESULTS

Three hundred and seventeen nodules from 267 patients were aspirated. The average size of nodules was 0.9 +/- 0.3 cm, a range of 0.2 cm to 1.5 cm. All 317 lesions were impalpable. Cytological diagnosis included 101 inadequate specimen (32%), 139 benign (44%), 29 indeterminate (9%), four suspicious of follicular or Hürthle cell neoplasm (1%), 42 papillary carcinoma (13%) and two others. The size of the nodule was not related to the probability of getting an adequate specimen for cytological diagnosis. Forty of 48 patients with suspicious or malignant cytology underwent surgery. All 35 patients with a cytological diagnosis of papillary carcinoma were confirmed to have papillary carcinoma on histological results. One of three patients with a cytological diagnosis of follicular neoplasm had a follicular carcinoma. In 36 patients with well-differentiated thyroid cancer, extrathyroidal extension was observed in 44% (16/36), regional lymph node metastasis was found in 50% (18/36) and multifocal tumours were found in 39% (14/36).

CONCLUSIONS

The rate of malignancy in incidentally detected impalpable thyroid nodules was 12% in retrospective analysis of our patients. In this subgroup, 69% (25/36) of patients had either extrathyroidal extension or regional node involvement and 39% had multifocal tumours at surgery. This suggests that the small size alone does not guarantee low risk in incidentally found thyroid cancers. USGFNA is a useful diagnostic method in these patients.

Local factors regulating growth and function of human thyroid cells in vitro and in vivo

In vitro culture of thyroid follicles is often employed to study thyroid cell biology and the control of thyroid follicular cell growth. For acceptance as a valid model, cultures should maintain differentiated function, which can be measured as the organification of [Formula: see text] and/or the de novo synthesis of thyroid hormones. In this article, the properties and merits of the various in vitro cultures of thyroid follicular cells and the potential effects of thyroid-specific, secreted products (thyroid hormones, thyroglobulin) and autocrine factors (proteases, growth factors and inhibitors) on thyroid growth and function, are explored. The regulation of the secretion of autocrine/paracrine factors by thyroid follicular cells is reviewed and methods by which cells may defend themselves from the effects of bioactive growth factors are discussed with particular reference to FGF signalling. The role and regulation of plasminogen activator activity, which may be central to the release and/or activation of growth factors and their receptors, and the secretion of angiogenic factors are described.

The management of subclinical hyperthyroidism by thyroid specialists

Subclinical hyperthyroidism is a relatively common condition for which prospectively derived evidenced-based management guidelines do not exist. We have conducted a case-based mail survey to solicit opinions from members of the American Thyroid Association (ATA) about various issues that arise in the management of patients with this disorder. The survey was completed and returned by 185 of 300 (62%) of the original survey recipients. Four hypothetical cases varying in age, thyrotropin (TSH) level and underlying etiology were presented. The majority of respondents recommended further evaluation of all cases, most commonly choosing a radioactive iodine uptake (42%-71%), thyroid scan (39%-68%) and antithyroid (TPO/Tg) antibodies (49%-55%) as the additional tests to be ordered. The large majority (84%) recommended observation rather than active treatment for a young patient with a low but detectable serum TSH level. A small majority also recommended observation alone for a young woman with an undetectable serum TSH level (58%) and for an older woman with a low but detectable serum TSH value (63%). However, the majority (66%) favored treating an older woman with an undetectable serum TSH. When treatment was advised in the patients with subclinical hyperthyroidism, the respondents strongly favored anti-thyroid drugs when the etiology was Graves' disease and radioactive iodine when the etiology was toxic nodular thyroid disease. In the absence of adequate evidence-based guidelines, it is hoped that this survey of expert opinions may provide useful guidance for physicians providing care for patients with subclinical hyperthyroidism.

Diagnostic utility of thyroglobulin detection in fine-needle aspiration of cervical cystic metastatic lymph nodes from papillary thyroid cancer with negative cytology

Cystic changes in metastatic cervical lymph nodes (CLN) from papillary thyroid cancer (PTC) may be a diagnostic pitfall in fine-needle aspiration biopsy (FNAB) cytology. We investigated in a series of CLN metastases from thyroid cancers (TC), including cystic PTC, and from a wide spectrum of extrathyroidal malignancies, the diagnostic role for metastatic TC of the rapid detection of thyroglobulin in eluates from FNAB (FNAB-Tg) of CLN. The study was carried out in a group of 79 subjects (22/57 M/F; median age, 56 years; range, 20-86 years) with enlarged CLN and thyroid nodules (TN), examined for potential metastatic TC, and harboring a large spectrum of incidentally diagnosed extrathyroidal malignancies (n = 24, mostly represented by lymphomas, lung, and breast cancers), CLN metastases from thyroid cancers (n = 28, including 6 cystic metastatic PTC), 6 specific lymphadenitis and 21 reactive lymphadenitis mostly detected (n = 16) during follow-up of patients with previously ablated TC. Markedly high FNAB thyroglobulin (Tg) values were found in all metastatic CLN TC. Two of the six cases with cystic metastatic CLN PTC were diagnosed by FNAB-Tg but not by cytology. In conclusion, FNAB-Tg has been confirmed as an easy modality and fast procedure to diagnose CLN metastasis from TC and high FNAB-Tg values with nondiagnostic cystic cytology strongly suggest cystic metastatic PTC.

Aumento da expressão do proto-oncogene ras no bócio multinodular: possível envolvimento na patogênese

A transformação neoplásica resulta de uma série de alterações genéticas, envolvendo ativação de proto-oncogenes e inativação de genes supressores tumorais. Ativação do proto-oncogene ras por mutações em ponto é a alteração genética mais freqüente em tumores espontâneos da tireóide. Avaliamos a expressão do gene ras no bócio nodular. Fragmentos de tecido tireoidiano normal e neoplásico foram coletados durante o ato cirúrgico, sendo que 79 pacientes tiveram diagnóstico histopatológico de bócio colóide e foram incluídos no estudo. O RNA total foi extraído pelo método de Trizol e o cDNA sintetizado através do Reverse Trancriptidase. Os genes H-ras e K-ras foram amplificados através de PCR com primers específicos. Do total da amostra, 62% apresentaram aumento da expressão de um dos genes ras estudados. Evidenciou-se aumento da expressão do H-ras em 9 dos 29 (31%) casos e do K-ras em 12 dos 32 (37,5%) tumores estudados. Os resultados demonstraram aumento da expressão do ras na doença nodular da tireóide e sugerem um papel importante desses genes na transformação neoplásica da tireóide.

Biochemical screening in the assessment of erectile dysfunction: what tests decide future therapy?

OBJECTIVES

To evaluate which biochemical tests, performed as screening tests in the assessment of erectile dysfunction (ED), lead to a change in standard treatment.

METHODS

We examined the results of the biochemical and endocrine tests performed as part of the assessment of 1455 men presenting with ED. We also documented the subsequent therapy.

RESULTS

We found abnormal findings in testosterone (5.7%), prolactin (0.5%), thyroid function tests (0.13%), liver function tests (12.8%), glucose (9.3%), cholesterol (15% in a subset of 531 men), and ferritin (1.6%). Hyperprolactinemia was not invariably associated with a suppressed testosterone level. Specific therapy with a dopamine agonist for hyperprolactinemia and with testosterone for hypogonadism was effective in treating ED. For the others, standard ED therapy was used.

CONCLUSIONS

The results of our study showed that screening tests fall into two categories. Testosterone and prolactin have a low yield but specific therapy is effective. Glucose and lipids have a higher yield but specific therapy is not immediately effective for ED. However, they, on their own merits, require management to prevent long-term morbidity and mortality.

Differences between endocrine surgeons and endocrinologists in the management of non-toxic multinodular goitre

BACKGROUND

It is not known whether the management of multinodular goitre differs between endocrinologists and endocrine surgeons.

METHODS

A questionnaire containing a hypothetical case (a 42-year-old euthyroid woman with a 50-80-g multinodular goitre) and 11 variations on the case was sent to endocrinologists and endocrine surgeons in Australia.

RESULTS

The response rate was 55 per cent, including 45 endocrine surgeons and 127 endocrinologists. For the index case, serum thyroid-stimulating hormone (TSH), fine-needle aspiration biopsy and ultrasonography were widely used by both groups. Thyroid antibodies and scintigraphy were ordered by a greater proportion of endocrinologists than surgeons, and computed tomography more frequently by surgeons than endocrinologists. Treatment recommendations differed significantly between specialties for the index case (endocrinologists: no treatment 65 per cent, thyroxine 22 per cent, surgery 10 per cent, radioiodine 3 per cent; surgeons: no treatment 67 per cent, thyroxine 2 per cent, surgery 31 per cent; P < 0.001) and for seven of the variations. In particular, for a patient with suppressed TSH, most endocrinologists (60 per cent) recommended radioiodine treatment, whereas there was no consensus among surgeons (surgery 40 per cent, no treatment 36 per cent, radioiodine 21 per cent). For a patient with a partly intrathoracic goitre, most surgeons (88 per cent) recommended surgery, whereas there was no consensus among endocrinologists (surgery 45 per cent, no treatment 34 per cent, thyroxine treatment 13 per cent, radioiodine 8 per cent).

CONCLUSION

There are clinically significant differences between endocrine surgeons and endocrinologists in the management of multinodular goitre.

Risk factors for and prevalence of thyroid disorders in a cross-sectional study among healthy female relatives of patients with autoimmune thyroid disease

OBJECTIVE

Autoimmune thyroid disease (AITD) is a common disorder especially in women, and both genetic and environmental factors are involved in its pathogenesis. We wanted to gain more insight into the contribution of various environmental factors. Therefore, we started a large prospective cohort study in subjects at risk of developing AITD, for example healthy female relatives of AITD patients. Here we report on their baseline characteristics.

SUBJECTS

Only first- or second-degree female relatives of patients with documented AITD were included.

MEASUREMENTS

Smoking habits, oestrogen use, pregnancy history and iodine exposure were assessed by questionnaires, and correlated to the thyroid function and antibody status.

RESULTS

Of 803 subjects, 440 came from families with more than one patient with documented AITD. Of these families, 33% had documented cases of both Graves' disease and Hashimoto's thyroiditis. Although the subjects were in self-proclaimed good health, 3.6% were found to have hypothyroidism (overt disease in 1.3%) and 1.9% had hyperthyroidism (overt disease in 0.4%). These patients were older than the euthyroid subjects and were mostly positive for thyroid peroxidase (TPO) antibodies. Oestrogen use was associated with a lower rate of hyperthyroidism [relative risk (RR) 0.169; 95% confidence interval (CI) 0.06-0.52], whereas having been pregnant was associated with a higher relative risk for hyperthyroidism (RR 6.88; 95% CI 1.50-30.96). Of the 759 euthyroid subjects, 24% had TPO antibodies. Smoking and oestrogen use were negatively correlated with the presence of TPO antibodies. In the euthyroid subjects, TPO antibody titre correlated positively with TSH levels (r = 0.386; P < 0.001).

CONCLUSIONS

The high prevalence of evidence for autoimmune thyroiditis at baseline supports the importance of genetic factors in its pathogenesis. The co-occurrence of Hashimoto's thyroiditis and Graves' disease within one family suggests a common genetic basis for these diseases. Oestrogen use is associated with a lower risk, and pregnancy with a higher risk for developing hyperthyroidism. The positive correlation between TPO antibody titres and TSH levels in euthyroid subjects suggests that TPO antibodies are indeed a marker of future thyroid failure.

Conduta conservadora no carcinoma papilífero da glândula tireóide

OBJETIVO: Avaliar os resultados do tratamento do carcinoma papilífero limitado a um lobo da glândula tireóide, através de tireoidectomia parcial com seguimento superior a cinco anos. MÉTODO: Estudo retrospectivo de 105 prontuários de pacientes portadores de carcinoma diferenciado da glândula tireóidea operados no Departamento de Cirurgia de Cabeça e Pescoço e Otorrinolaringologia do Hospital Heliópolis, Hosphel, São Paulo de 1977 a 1997 e selecionados 31 casos que apresentavam nódulos limitados a um lobo da glândula com seguimento superior a cinco anos e submetidos à lobectomia total mais istmectomia. RESULTADOS: Observamos somente um caso (3%) de disfonia transitória com paresia de prega vocal unilateral que regrediu espontaneamente. Não houve casos de hipoparatireoidismo transitório ou definitivo. O seguimento médio foi de 12,6 anos, sendo todos com seguimento superior a cinco anos; 10 casos (32%) com seguimento entre 10 e 15 anos e 10 casos (32%) com seguimento além de 15 anos. Não foram observados casos com recorrência loco-regional ou metástase à distância, estando todos eles assintomáticos e sem doença. CONCLUSÃO: Nesta série, a tireoidectomia parcial para carcinoma papilífero limitado a um lobo, mostrou-se eficaz.

Evidence and thoughts about thyroid nodules that grow after they have been identified as benign by aspiration cytology

Coherent management of thyroid nodules that grow after being identified as benign will vary depending on their biology. Some are thyroid-stimulating hormone (TSH) regulated, so a dose of levothyroxine that reduces TSH to the lower limits of normal (subsuppression) may prevent or reverse enlargement; others are controlled by poorly understood mechanisms that must be elucidated before effective medical treatment can be designed; a few are autonomous requiring obliteration, and a very few are "missed" malignancies that should be excised.

Nonpalpable thyroid carcinoma: clinical controversies on preoperative selection

This article emphasizes some controversies concerning the preoperative selection of nonpalpable thyroid tumors. The prevalence of occult thyroid carcinoma in surgical series (1.8-10%) is not higher than in autopsy thyroid series (2.7-24%). The prevalence of occult thyroid carcinoma in thyroid glands examined in the same institution by ultrasound, for a clinical thyroid abnormality or for investigation of other neck structures without clinically evident or suspected thyroid disease, varies from 3% to 8% and is very similar independent of the fact that a thyroid abnormality is or is not the indication for ultrasonography. These data suggest that the presence of a thyroid disease is not a risk factor for harboring an occult thyroid carcinoma (except for C-cell hyperplasia in the rare case of MEN 2 syndromes). As it is not cost effective to examine all the nonpalpable lesions with fine-needle aspiration (FNA) guided by ultrasounds, it is necessary to define to which extent ultrasound is useful in selecting those lesions to be examined cytologically by FNA. The use of ultrasound to select these lesions is very controversial. Ultrasound-guided cytologic diagnosis of nonpalpable nodules is not as accurate as in the case of palpable nodules. Sampling of material adequate for cytologic analysis depends on the lesion size; it is 64% for a 0.7-cm lesion and it increases to 86.7% for a mean size of 1.1 cm. For the diagnosis of occult thyroid carcinomas (< or =1 cm), sensitivity is 35.8% and false-negative results are 49.3%. Nonpalpable nodules with a size of 1.5 cm represent an absolute indication to perform an ultrasound-guided FNA because this is the size limit for dividing thyroid nodules in probably innocuous or potentially dangerous categories and because the cytologic diagnosis of nodules of this size is sufficiently reliable. For the smaller incidentally discovered thyroid nodules following ultrasound, physicians should discuss with the patient whether and when to perform an ultrasound-guided FNA considering the patient's data (risk factors, age, health state, etc.), the natural history of a small thyroid carcinoma, as well as the accuracy of ultrasound and ultrasound-guided FNA in the specific institution.

Estrogen receptors (alpha and beta) and 17beta-hydroxysteroid dehydrogenase type 1 and 2 in thyroid disorders: possible in situ estrogen synthesis and actions

Both epidemiological and experimental findings suggest the possible roles of sex steroids in the pathogenesis and/or development of various human thyroid disorders. In this study, we evaluated the expression of estrogen receptors (ER) alpha and beta in normal thyroid glands (N = 25; female: n = 13, male: n = 10, unknown: n = 2) ranging in age from fetus to adult. Furthermore, using immunohistochemistry, we investigated the expression of ERalpha and beta in 206 cases of thyroid disorders, including 24 adenomatous goiters, 23 follicular adenomas, and 159 thyroid carcinomas. In addition, we also studied the mRNA expression of ERalpha and beta and 17beta-hydroxysteroid dehydrogenase Type 1 and 2, enzymes involved in the interconversion between estrone and estradiol, using reverse transcription polymerase chain reaction (RT-PCR), in 48 of these 206 cases (10 adenomatous goiters, 10 follicular adenomas, and 28 papillary thyroid carcinomas) in which fresh frozen tissues were available for examination to further elucidate the possible involvement of intracrine estrogen metabolism and/or actions in thyroid disorders. ERalpha labeling index, or percentage of cells immunopositive for ERalpha, was significantly higher in adenomatous goiter (14.2 +/- 6.4), follicular adenoma (13.4 +/- 5.1), and thyroid carcinoma (16.4 +/- 2.1) than in normal thyroid gland (0; P <.05). Few follicular cells were positive for ERalpha in normal thyroid glands. In papillary carcinoma, ERalpha labeling index was significantly higher in premenopausal women (28.1 +/- 4.5) than in postmenopausal women (14.2 +/- 2.9) and in men of various ages (7.6 +/- 2.7; P <.05). In other histological types of thyroid carcinoma, no significant correlations were detected. ERbeta immunoreactivity was detected in both follicular and C-cells of normal thyroid glands, including those in developing fetal thyroid glands. In addition, ERbeta immunoreactivity was detected in the nuclei of various thyroid lesions. But no significant correlations were detected between ERbeta labeling index and clinicopathological findings including age, menopausal status, gender, and/or histological type of thyroid lesions. 17beta-hydroxysteroid dehydrogenase Type 1 expression was detected in 31/48 (64.0%) of the cases examined, whereas Type 2 was detected only in 3/46 (6.3%) of all the cases examined. These results demonstrated that estrogens may influence the development, physiology, and pathology of human thyroid glands, and these effects, especially through ERalpha, may become more pronounced in neoplasms, particularly in papillary carcinoma arising in premenopausal women.

Thyroid dysfunction in patients with type 1 diabetes: a longitudinal study

OBJECTIVE

Cross-sectional studies have reported that the risk of thyroid dysfunction in patients with type 1 diabetes is two- to threefold higher than in the general population. However, longitudinal studies to determine the natural history of thyroid dysfunction in patients with type 1 diabetes are lacking.

RESEARCH DESIGN AND METHODS

We analyzed the incidence of thyroid dysfunction over time in a cohort of 58 patients (26 men and 32 women) enrolled in the Diabetes Control and Complications Trial at the University of Tennessee Health Science Center in 1983 and prospectively followed for 18 years. Patients underwent measurement of thyroid function tests (thyroid-stimulating hormone [TSH], thyroxine, and triiodothyronine) every year and thyroid peroxidase (TPO) antibodies at 4-year intervals.

RESULTS

A total of 18 patients had hypothyroidism, and 1 patient experienced transient hyperthyroidism. Two subjects developed hypothyroidism 7 and 18 years before the development of diabetes and were excluded from the analysis. The mean age of diagnosis was 19 +/- 2 years for type 1 diabetes and 29 +/- 3 years for hypothyroidism. Hypothyroidism was more common in female (41%) than in male (19%) subjects and in patients with positive TPO antibodies. Patients who were TPO positive were 17.91 times as likely to develop hypothyroidism as patients who were TPO negative (95% CI 3.89-82.54). There were no differences in BMI, lipid profile, and HbA(1c) between patients with and without thyroid dysfunction.

CONCLUSIONS

This longitudinal study confirms the association between autoimmune thyroid dysfunction and type 1 diabetes. Our results indicate that all subjects with type 1 diabetes should undergo annual screening by serum TSH measurement to detect asymptomatic thyroid dysfunction, particularly those with positive TPO antibodies.

Management of simple nodular goiter: current status and future perspectives

The simple nodular goiter, the etiology of which is multifactorial, encompasses the spectrum from the incidental asymptomatic small solitary nodule to the large intrathoracic goiter, causing pressure symptoms as well as cosmetic complaints. Its management is still the cause of considerable controversy. The mainstay in the diagnostic evaluation is related to functional and morphological characterization with serum TSH and (some kind of) imaging. Because malignancy is just as common in patients with a multinodular goiter as patients with a solitary nodule, we support the increasing use of fine-needle aspiration biopsy (cytology). Most patients need no treatment after malignancy is ruled out. In case of cosmetic or pressure symptoms, the choice in multinodular goiter stands between surgery, which is still the first choice, and radioiodine if uptake is adequate. In addition to surgery, the solitary nodule, whether hot or cold, can be treated with percutaneous ethanol injection therapy. If hot, radioiodine is the therapy of choice. Randomized studies are scarce, and the side effects of nonsurgical therapy are coming into focus. Therefore, the use of the optimum option in the individual patient cannot at present be based on evidence. However, we are of the view that levothyroxine, although widely used, should no longer be recommended routinely for this condition. Within a few years, the introduction of recombinant human TSH and laser therapy may profoundly alter the nonsurgical treatment of simple nodular goiter.

Prevalência das alterações metabólicas em pacientes portadores de queixas vestibulares

FORMA DE ESTUDO: Clínico prospectivo. MATERIAL E MÉTODO: Os autores avaliam a prevalência de alterações metabólicas em 325 pacientes que procuraram o Setor de Otoneurologia do Hospital das Clínicas da FMUSP com queixas vestibulares. Os pacientes foram consecutivamente atendidos entre janeiro de 1997 e janeiro de 2002. Foram avaliados os primeiros exames referentes ao protocolo clássico de investigação das tonturas, que compreende a dosagem de LDL colesterol, TSH, T3 e T4 e glicemia de jejum. As alterações encontradas foram então comparadas às observadas na população geral. As alterações mais significativas encontradas foram a elevação dos níveis de LDL colesterol, a presença de níveis alterados de hormônios tireoideanos e a maior freqüência do diabetes mellitus na população estudada. CONCLUSÃO: Conclui-se que é válida a investigação destes dados, visto que são mais freqüentes na população de risco e que a correta abordagem dessas alterações melhora o prognóstico e o controle da tontura.

Telomerase activity in well-differentiated papillary thyroid carcinoma correlates with advanced clinical stage of the disease

Clinical relevance and stage correlation of telomerase activity in well-differentiated papillary thyroid carcinoma (WD PTC) has not been well determined, as its reported activity could be due to the analysis of tumors with lymphocytic infiltrates or aggressive variants of papillary carcinomas. We conducted a prospective study of telomerase activity in WD PTC without inflammatory infiltrates and correlated it with clinical stage. Fifty WD PTCs were analyzed for telomerase activity by PCR-based TRAP (telomeric repeat amplification protocol) assay. Results were correlated with stage and other clinicopathologic variables. Twenty-one (42%) WD PTCs demonstrated telomerase activity. The enzyme was detected more frequently in stage III/IVa WD PTCs (p = 0.02) and in tumors with extra thyroidal extension (p = 0.04). The risk of presenting advanced disease (stage III/IVa) and extrathyroidal growth was significantly increased in telomerase-positive tumors (p = 0.01; odds ratio [OR] 4.4 [95%CI 1.3-14.7]) and (p = 0.04; OR 3.6 [95%CI 1.1-11.7]), respectively. Also, a correlation was found between telomerase activity and age. There was no correlation of telomerase activity with gender, histologic variant, tumor size, or cervical lymph node metastasis. Telomerase activity was observed in 42% of WD PTC and was detected more frequently in AJCC TNM stage III/IVa cases. This finding suggests that telomerase deregulation could be involved in tumor progression.

Thyroid dysfunction and autoimmunity in infertile women

A prospective study was undertaken in 438 women (ages, 32 +/- 5 years) with various causes of infertility, and in 100 age-matched (33 +/- 5 years) healthy parous controls with the aim of assessing the prevalence of autoimmune thyroid disease (AITD) and hitherto undisclosed alterations of thyroid function. Female origin of the infertility was diagnosed in 45% of the couples, with specific causes including endometriosis (11%), tubal disease (30%), and ovarian dysfunction (59%). Male infertility represented 38% and idiopathic infertility 17% of the couples. Overall, median thyrotropin (TSH) was significantly higher in patients with infertility compared to controls: 1.3 (0.9) versus 1.1 (0.8) mIU/L. Serum TSH above normal (>4.2 mIU/L) or suppressed TSH (<0.27 mIU/L) levels were not more prevalent in the infertile women than in controls. The prevalence of positive thyroid peroxidase antibody (TPO-Ab) was higher in all investigated women of infertile couples, compared to controls (14% vs. 8%), but the difference was not significant. However, in infertility of female origin, a significant higher prevalence of positive TPO-Ab was present, compared to controls: 18% versus 8%. Furthermore, among the female causes, the highest prevalence of positive antibodies was observed in women with endometriosis (29%). When thyroid antibodies were positive, both hypothyroidism and hyperthyroidism were more frequent in all women of infertile couples and in the women with a female infertility cause, compared to women in the same groups but without positive TPO-Ab. The present study shows that in infertile women, thyroid autoimmunity features are significantly more frequent than in healthy fertile controls and this was especially the case for the endometriosis subgroup.

[Thyroid scintigraphy: its place in preoperative diagnosis of thyroid nodules?]

AIM OF THE STUDY

To evaluate the real contribution of the thyroid radionuclid scanning in the preoperative evaluation of the thyroid nodules.

MATERIAL AND METHOD

The authors prospectively studied 369 patients who underwent surgical intervention: 160 (43.4%) for isolated nodules and 209 (56.6%) for multinodular goiters.

RESULTS

The scintigraphy of the thyroid was performed in 281 (76.2%) patients: 39 (13.8%) patients with nodules less than 1.5 cm in diameter and 242 (86.2%) patients with nodules more than 1.5 cm in diameter. In 234 patients (83.3%) the scintigraphic evaluation did not bring any utile information for the therapeutic decision. The scintigraphy proved its utility only in 47 patients, which represents 16.7% from the scintigraphic exams performed, or 12.7% from the patients that underwent a surgical procedure.

CONCLUSIONS

In the presence of thyroid nodule or multinodular goiter, the scintigraphy is indicated only in decreased TSH level, suspicion of ectopic thyroid or retrosternal goiter.

The results of ultrasound-guided fine-needle aspiration biopsy for evaluation of nodular thyroid disease

BACKGROUND

The purpose of this study was to determine whether ultrasonography (US) improves the accuracy and reduces the rate of nondiagnostic fine-needle aspiration biopsy (FNAB) of thyroid nodules.

METHODS

A review of 536 consecutive patients evaluated for nodular thyroid disease from 1990 to 2001 was completed to determine the results for US vs palpation-guided FNAB.

RESULTS

FNAB was used to evaluate 458 patients. US-guided FNAB was performed in 66 (12%) patients: 48 with a nonpalpable nodule, 14 with nondiagnostic standard FNAB, and 4 with a palpable nodule. US-guided FNAB was nondiagnostic in 15 (23%) patients. There were no false-positive or false-negative results. Standard FNAB was performed in 407 patients, 57 (14%) of whom had a nondiagnostic result. There were 2 (3%) false-positive and 3 (1.6%) false-negative results. In 14 patients with a nondiagnostic standard FNAB, US-guided FNAB yielded an adequate specimen in 7 (50%). Nodules evaluated by standard FNAB were 4.1 +/- 0.1 cm (mean +/- SEM) in size compared with 2.5 +/- 0.1 cm for nodules evaluated by US-guided FNAB (P <.05).

CONCLUSIONS

US improves the diagnostic yield in selected patients with nondiagnostic standard FNAB. The higher frequency of nondiagnostic US-guided FNAB was related to its selective use in patients with smaller nodules.

Use of chronic medications among a large, commercially-insured US population

PURPOSE

To examine use of chronic therapies by females and males of all ages.

METHODS

Participants were 1,295,948 members of a large US pharmacy benefit manager. The use of chronic medications by males and females during 1999 was examined overall and within 16 commonly-used chronic drug groups. Dependent variables were use of a drug group, number of drug groups used, number of prescriptions filled and sum of costs, both within each drug group and overall. Combination therapy was defined as using at least two of the 16 chronic therapy groups during 1999.

RESULTS

Females were more likely than males to use chronic medications during the study year (36.5 vs. 22.4%, p < 0.001). Generally, the likelihood of using a chronic medication increased with age for both sexes. Commonly-used chronic medications accounted for 54 and 50% of prescriptions for females and males respectively, and for 53% of total drug costs for both sexes. There were few meaningful sex differences in the likelihood of using particular drug groups. Of those who took chronic drugs 14% used combination chronic therapy.

CONCLUSIONS

This study provides demographic information regarding treatment of chronic conditions that can be used to aid policy decisions and to provide an impetus for future research.

Subclinical hypothyroidism and cardiac function

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.

The influence of parity on multinodular goiter prevalence in areas with moderate iodine deficiency

Despite the observation that parity may increase the risk of thyroid carcinoma, very few studies have investigated the possible repercussion of parity on thyroid benign pathology. Recently, parity has been identified as one of the factors contributing to a larger thyroid size in healthy females. The aim of this work was to investigate a possible role for parity on the prevalence of multinodular goiter in iodine deficient areas. For this purpose, the reproductive histories of 2 cohorts of women, normal (Group I, 235 cases) and non-toxic multinodular goiter (NTMNG) affected (Group II, 274 cases) were compared. All subjects were euthyroid and had no previous history of thyroid function abnormalities. The number of full-term previous pregnancies (2.55+/-0.11 vs 1.77+/-0.10) and age (47.7+/-0.76 vs 42.3+/-0.83 yr) were found significantly higher (p<0.001) in multinodular goiter (MNG) patients than controls. Parity and age were found to be directly correlated (p<0.001), nevertheless the partial correlation coefficients demonstrated an independent and statistically significant difference for both variables between normal and NTMNG. Therefore, the independent effects of parity and age were further investigated. The effect of age on NTMNG prevalence seems to be weaker, in fact significant differences (p<0.001) for age between patients and controls were detected only when the effect of parity was absent (nulliparous), while with increasing gestations the effect of age disappeared. Our results indicate that age plays a minor role compared to parity which can therefore be considered as a stronger risk factor. In conclusion, the present study shows that, at least in iodine deficient regions, non-toxic multinodular goiter women show a statistically significant higher parity rate than healthy controls. Age may play a certain role but only when additional stronger risk factors are absent.

Hypothyroidism in elderly people

Abnormal thyroid function tests are common for older adults, but the clinical significance of abnormal results and the need for treatment vary. Nonthyroidal illness (eg, low T3 and T4 syndromes) needs to be ruled out before making the diagnosis of hypothyroidism. Overt hypothyroidism and myxedema coma always require treatment, but treatment of subclinical hypothyroidism is not as clear. The purpose of this review article is to summarize existing data in the elderly population on the etiology, diagnosis, and management of overt hypothyroidism and subclinical hypothyroidism.

Temporal trends for thyroid carcinoma in Australia: an increasing incidence of papillary thyroid carcinoma (1982-1997)

The incidence of papillary thyroid carcinoma (PTC) has increased in many countries over the past 60 years. In Tasmania (an island state of the Australian Commonwealth with a well-documented history of iodine deficiency, subsequent supplementation and more recently a return to deficiency), there has been a fourfold rise in PTC incidence over the past two decades. The aim of this study was to evaluate thyroid carcinoma (TC) incidence trends in Australia, with particular reference to the roles of iodine nutrition, ionizing radiation, and ascertainment bias. Data from Australia's regional cancer registries were used to determine national TC incidence and mortality trends for the period 1982-1997. There were 9,053 new diagnoses of TC. Papillary, follicular, medullary, anaplastic, and "other diagnoses," accounted for 65.8%, 17.8%, 4.6%, 1.3%, and 10.5% of registered cases, respectively. TC incidence rates increased by 6.7% per year for females and 4.4% per year for males between 1982-1997 (p < 0.001). The increase was primarily because of a 10.7% per year and 8.3% per year rise in PTC incidence for females and males respectively (p < 0.001). The increase in PTC incidence was most significant for the population residing on Australia's eastern seaboard. The greatest relative and absolute increase in PTC (24.7% per year) occurred in Tasmania. These findings are consistent with a true increase in underlying PTC incidence rates. A link between current incidence trends and past iodine deficiency/radioiodine exposure during the 1950s and early 1960s is possible.

Apoptosis: life through planned cellular death regulating mechanisms, control systems, and relations with thyroid diseases

Apoptosis is an active biologic process that represents a form of programmed cellular suicide, activated either by genetic factors or by cellular lesions caused by various extracellular traumatic agents. The alterations of its functional mechanisms control cellular homeostasis are involved in the genesis of many illnesses. There are different control systems that can both stimulate and inhibit apoptosis, such as the p53 and Bcl-2 proteins. Different injuries may cause a rapid increase in the levels of p53 and the activation of the complex mechanism which leads either to damage repair or cellular apoptosis. The concept of tumor growth as a dynamic balance between cellular development and death is well applicable to differentiated thyroid carcinomas, which are generally not highly invasive and present excellent prognosis. On the contrary, in aggressive anaplastic thyroid carcinoma there is an increase in p53, whereas in normal thyroid cells there is a high expression of Bcl-2, so as to interfere with apoptosis when physiologic hormone levels are normal. However, only some of the biomolecular mechanisms behind the genesis of thyroid tumors have been explained, and the role of apoptosis in thyroid diseases has not been well defined. This review provides information about relationship between apoptosis and thyroid diseases.