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PubMed2001

Thyroid ultrasonography as a tool for detecting thyroid autoimmune diseases and predicting thyroid dsfunction in apparently healthy subjects.

UNLABELLED: In order to establish its usefulness for the diagnosis and follow-up of thyroid autoimmune diseases, thyroid ultrasonography together with free T4 (FT4), free T3 (FT3), TSH, antibodies (Tg Ab) and thyroperoxidase antibodies (TPO Ab) were performed and re-evaluated during a 3-yr follow-up in 482 apparently healthy subjects, living in a borderline iodine-sufficient urban area. Thyroid dysfunction was found in 7 out of 12 (58.3%) subjects with circulating thyroid autoantibodies, who also had thyroid hypoechogenicity (2 had overt and 3 subclinical hypothyroidism at booking; 2 developed subclinical hypothyroidism during the follow-up), and in none of the 12 subjects with normal thyroid echostructure (chi2=7.26, p=0.007). Thyroid dysfunction was found in 4 out of 29 (13.7%) subjects with negative Tg and/or TPO Ab who also had thyroid hypoechogenicity (1 had Graves' disease at booking, 1 developed Graves' disease and 2 subclinical hypothyroidism during the follow-up), and in none of the 429 with normal thyroid echostructure (chi2=82.03, p<0.0001). Although positive TPO and/or Tg Ab were more frequent (24/482, 5%) in subjects with thyroid dysfunction (7/11) than in those who remained euthyroid during the study (17/471, chi2=69.66, p<0.0001), thyroid hypoechogenicity had a higher sensitivity than the positivity of thyroid autoantibody tests (100 vs 63.3%) for diagnosing or predicting thyroid dysfunction. IN CONCLUSION: 1) thyroid ultrasonography is a useful tool to detect thyroid autoimmune disease in apparently healthy subjects; 2) present and future thyroid dysfunction is more readily predicted by a hypoechogenic pattern at thyroid ultrasound than by the occurrence of serum thyroid autoantibodies.

Adolescent↗
PubMed2004

Prospective study of post-partum thyroid immune dysfunctions in type 1 diabetic women and in a healthy control group living in a mild iodine deficient area.

Second to diabetes mellitus, thyroid diseases are the most common endocrinopathies seen in pregnancy. The incidence of post-partum thyroid dysfunction (PPTD) in women with type 1 diabetes mellitus is three-fold increased. We determined the incidence of thyroid abnormalities in a well-defined group of young subjects with type 1 diabetes and in an age-matched healthy controls during and six months after pregnancy in an area of mild iodine deficiency. Twenty-five out of twenty-eight pregnant women completed the study. Fifteen were affected by type 1 diabetes and ten were controls. Our protocol of study consisted of four evaluations of each subject: in the first, in the second trimester, at delivery and six months after. At each control the patients were submitted to physical examination, thyroid ultrasonography, and determination of fT3, fT4, TSH, Antithyroglobulin antibodies (TgAbs), Antithyroperoxidase antibodies (TPOAbs). The variation of thyroid volume is statistically significant in both the diabetics and in the controls during the different times of observations. Four out of the fifteen diabetic pregnant patients (27%) developed a thyroid disease: two cases of post-partum thyroiditis (PPT) and two cases of euthyroid benign nodular goiter, as confirmed by cytological examination. Two out ten controls (20%) developed positive antibodies (TPO Abs and TgAbs) since the first observation and showed an autoimmune thyroiditis six months after delivery. Both of them showed a familial history of thyroid disease. Our study suggests that in an area of mild iodine deficiency the incidence of thyroid autoimmunity in pregnant women is similar, whether diabetic or not; moreover, thyroid volume is increasing in the diabetics as much as in the non diabetics during pregnancy.

Adult↗
PubMed1992

[Incidence of postpartum thyroid function disorders in The Netherlands].

In a longitudinal study the incidence of postpartum thyroid dysfunction in the Netherlands was investigated in an unselected open population. There were 293 women who were screened by repeated assessments of thyroid function until 34 weeks postpartum at 6-week intervals. Thyroid dysfunction was defined as abnormal TSH values accompanied by abnormal FT4 and (or) FT3 values. The frequency of postpartum thyroid dysfunction was 7.2% (n = 21). Most of the thyroid dysfunction occurred between 16 and 28 weeks postpartum. There were five women with subclinical thyroid dysfunction: abnormal TSH values with complementary FT4 and (or) FT3 changes within normal limits. Four of them showed (marked) increase in antimicrosomal antibody titres. With the inclusion of the five women the frequency rose to 8.9%. These data appear representative for the Netherlands as a whole, suggesting that every year 14,000 women suffer from (transient) postpartum thyroid dysfunction.

Adult↗
PubMed2003

Hypothyroidism and thyroiditis after therapy for Hodgkin's disease.

During the follow-up of thyroid function of 151 patients with Hodgkin's disease in complete remission for at least 1 year, 26 cases of subclinical, 12 cases of manifest clinical hypothyroidism and 2 cases of hyperthyroidism (Graves-Basedow disease) were confirmed. Thyroid dysfunction was more frequent in patients who had undergone mantle or neck radiotherapy. Hypothyroidism was most often revealed from the 6th year on following radiotherapy. Thyroid autoantibody positivity was found to be more frequent in patients with thyroid dysfunction, and conversely, thyroid dysfunction was more frequent among the 28 patients with autoantibody positivity. Ultrasound examination and fine needle aspiration cytology of the thyroid confirmed thyroiditis in 96% of the patients with antibody positivity. No relationship was found between thyroiditis and the form of treatment for Hodgkin's disease. We have found that both neck irradiation and thyroiditis may play a role in the increased number of thyroid dysfunction in patients treated for Hodgkin's disease. Thyroiditis is not caused by neck radiotherapy but may be the result of immune regulation disorders in Hodgkin's disease. For substitution or isohormone therapy, levothyroxine is suggested for use. We suggest that examination of the thyroid should be performed at least once a year during the follow-up of Hodgkin's disease patients.

Adolescent↗
PubMed1998

Efficacy and safety of iodine in the postpartum period in an area of mild iodine deficiency.

BACKGROUND: Iodine deficiency (even moderate) plays a major role in pregnancy associated goiter development, which is only party reversible after pregnancy. The prevalence of post partum thyroiditis is reported to be slightly lower in areas of iodine deficiency. Thus iodine supplementation may be effective in decreasing pregnancy associated increase in thyroid volume, but enhances the risk of increasing the prevalence of thyroid dysfunction in the post partum period. Therefore, we evaluated the effect of iodine supplementation (with two different doses: 50 microg and 250 microg) on the prevalence of post partum thyroiditis and the decrease in thyroid volume up to 8 months post partum in an area of mild iodine deficiency. PATIENTS AND METHODS: Thyroid volume of 56 women was evaluated 5 days and 3 months after delivery (study I). In an intervention study (Study II) 70 women were randomized to receive 50 or 250 microg of potassium iodide for a period of 8 months post partum beginning five days after delivery. Thyroid volume, the echogenecity of the thyroid gland, thyroid hormone parameters (T4, T3, fT4, TSH) and thyroid antibodies (TPO and Tg-Ab) were measured 5 days, 3 and 8 months after delivery. RESULTS: A total number of 11 women developed postpartum thyroid dysfunction: 4 women developed manifest thyroid dysfunction (3 hyperthyroidism and 1 hypothyroidism) 3 months post partum. The remaining seven had subclinical hypo- or hyperthyroidism. All changes were clinically mild and transient as evidenced by normalization of thyroid hormone parameters on reexamination at 8 months. Among the eleven, 6 women in the 50 microg iodine group and 5 women of the 250 microg iodine group developed thyroid dysfunction, suggesting that the iodine dose did not affect post partum thyroiditis. The administration of only 50 microg iodine was associated with a significant fall of thyroid size already 3 months after delivery (25.4 +/- 1.5 ml (mean +/- sem) to 18.2 +/- 1.25 p <0.001). The application of 250 microg iodine was equally effective. 8 months post partum a slight but further decrease could be demonstrated. On the other hand, in study I no significant reduction in thyroid volume was observed in women receiving no supplementary iodine (thyroid volume at delivery 29 +/- 2.2 ml; at 3 months 27.5 +/- 3.0 ml. CONCLUSION: The administration of supplementary iodine (up to 250 microg) to an unselected population, residing in an area of mild iodine deficiency, in the post partum period is save as indicated by a prevalence of 5.7% manifest thyroid dysfunction. These changes are clinically mild and transient. Even the amount of 50 microg of iodine supplementation seems to by very efficient in reducing pregnancy associated increments in thyroid volume.

Adult↗
PubMed1987

Thyroid disorders in the general population of Hisayama Japan, with special reference to prevalence and sex differences.

Serum triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) and thyroid autoantibodies (TAA) to either microsome or thyroglobulin were measured in 1251 samples from the general population, 546 males and 705 females, aged 40 or over in Hisayama, a Japanese rural town. TAA was positive in 7.7% of men and 15.0% of women, and the male/female ratio was 1:2. This ratio was markedly different from those in hospital patients with thyroid disorders where ratios such as 1:8 for chronic thyroiditis and 1:4 for Graves' disease were found. Among the study subjects, definite hyperthyroidism was found in 0.2%, borderline hyperthyroidism in 0.7%, overt hypothyroidism in 0.3%, latent hypothyroidism in 4.2%, and non-thyroid illness in 2.4%. Overt thyroid dysfunction was more evident in women, while latent thyroid dysfunction or non-thyroidal illness was equally prevalent in men and women. These results indicate that the incidence of immunologically or functionally latent thyroid disorders is rather higher than expected, in both women and men. Some unknown factor(s) might act as a trigger to manifest thyroid dysfunction, mainly in females.

Autoantibodies↗
PubMed1995

[Interferon-alpha-induced disorders of thyroid function. A retrospective analysis of the literature and personal experiences].

This paper tries to evaluate the importance of IFN-alpha induced thyroid dysfunction. Based on our own experience and reported data we present the results obtained in a total of 588 patients, in whom thyroid function and thyroid antibody occurrence was monitored during therapy with IFN-alpha: About 10% of these patients developed thyroid dysfunction during IFN-alpha treatment. Half of them reacted with hypothyroidism, 3% with hyperthyroidism and in 2% a biphasic (hyperthyroidism followed by hypothyroidism) pattern of reaction was observed. The frequency of these thyroid dysfunctions was increased in female patients and in patients with preexisting thyroid antibodies. The risk to develop thyroid dysfunction is reduced to 7% in patients with no pretherapeutic thyroid antibodies. The evolution of the thyroid ailment is variable and therefore unpredictable. In many patients there is no need to stop treatment with IFN-alpha nor to treat the thyroid dysfunction specifically. IFN-alpha induced autoimmune- phenomena seem to be etiologically important for the development of thyroid disease during IFN-alpha. The reported data allow in our view some basic recommendations for the clinician: thyroid function and thyroid antibodies should be evaluated before the start of treatment with IFN-alpha. During therapy with IFN-alpha these parameters should be regularly (eg every 4 months) monitored. In patients with thyroid autoantibodies or dysfunction already before IFN-alpha the control intervals should not be longer than every two months.

Female↗
PubMed1998

[Amiodarone and thyroid function: clinical implications].

World-wide, the incidence of amiodarone-induced thyroid dysfunction is estimated to be between 2% and 24%. More than 50% of patients who receive long-term amiodarone have abnormal results on thyroid function tests. However, most of these patients are euthyroid. In a euthyroid amiodarone-treated patient, an increase in serum thyroxine levels (total and free) and in serum reverse T3 levels and a decrease in serum T3 levels (total and free), are observed. TSH levels are within the normal range with chronic treatment (more than 3 months). The aim of this study was to identify the frequency of amiodarone prescription by cardiologists, to learn about their clinical practice in screening for thyroid dysfunction, and to formulate guidelines for clinical investigation of thyroid function before and during amiodarone treatment. A questionnaire was sent to 27 cardiologists in private practice in the Geneva area and to 12 cardiologists in Geneva University Hospital (19 and 7 questionnaires returned respectively). Cardiologists in private practice prescribe amiodarone quite frequently (once to twice per month and more). Clinical investigation prior to treatment involves history (95%), clinical examination (63%) or thyroid function tests (37% routinely, 16% where there is clinical suspicion of thyroid dysfunction). Thyroid function is investigated by determination of TSH (100%), free T4 (68%), free T3 (50%), total T3 (32%) or total T4 (26%). Antithyroid antibodies are measured only by 10% of the cardiologists in private practice. Cardiologists would restrict amiodarone prescription in cases of clinical hyperthyroidism (90%), clinical hypothyroidism (74%), in the presence of goitre in a hyper- or hypothyroid patient (79 and 63% respectively), and if antithyroid antibodies were positive (32%). During amiodarone treatment 84% of cardiologists in private practice repeat thyroid function tests occasionally and 16% only in the presence of clinical signs. Hypothyroidism is a reason for withdrawing amiodarone treatment for 58% of the cardiologists and 37% would prescribe substitution. Hyperthyroidism is a reason for immediately suspending treatment for 90% of the cardiologists, only 5% would continue and 16% would prescribe antithyroid drugs. In conclusion, there is considerable divergence of opinion among cardiologists concerning investigation and interpretation of thyroid function before and during amiodarone treatment. Simple and practicable guidelines are needed.

Amiodarone↗
PubMed2000

Postpartum thyroiditis and long-term thyroid status: prognostic influence of thyroid peroxidase antibodies and ultrasound echogenicity.

Postpartum thyroid dysfunction (PPTD) occurs in 5% of women, with hypothyroidism developing in 23% of these after 3-5 yr. We have determined the prognostic significance of thyroid peroxidase antibody (TPOAb), thyroid ultrasound morphology (U/S), human leukocyte antigen haplotype, and postpartum thyroid status on the development of thyroid dysfunction 77-81 months after PPTD. Ninety-eight TPOAb-positive [48 who had developed PPTD (group 1) and 50 without PPTD (group 2)] and 70 TPOAb-negative (group 3) women (derived from 145 TPOAb-positive and 229 TPOAb-negative cohorts at the index pregnancy), with comparable ages, parity, pregnancies after index pregnancy, and follow-up duration, were studied. Thyroid dysfunction occurred in 46% of group 1 vs. 4% of group 2 (P<0.001) and 24.5% of groups 1 and 2 vs. 1.4% of group 3 (P<0.001). Factors predictive of thyroid dysfunction included a hypothyroid form of PPTD, TSH more than 20 mU/L, and higher TPOAb levels (213.8 kIU/L in group 1 vs. 131.8 kIU/L in group 2; P<0.002) during the postpartum period. Although TPOAb was higher in group 1 than in group 2 at follow-up (166 vs. 97.7 kIU/L; P<0.03), there was no significant fall in TPOAb levels within either group during the period of follow-up. The prevalence of ultrasound hypoechogenicity was higher in group 1 than in group 2 at follow-up (76% vs. 52%; P<0.006), but U/S improved in 62.5% of group 1 during the period of follow-up. Human leukocyte antigen DR10 was lower in those who developed late thyroid dysfunction. These data, representing the longest follow-up of PPTD women, clearly show that the hypothyroid form of PPTD, high TPOAb levels, and a hypoechogenic U/S pattern lead to a high risk (relative risk, 32) of long term thyroid dysfunction. This compares with a relative risk of 12.9 for TPOAb- and PPTD-positive women, who remained euthyroid at the end of the first postpartum year, and 2.8 for TPOAb-positive but PPTD-negative women, all compared to TPOAb-negative women. Therefore, long term surveillance of TPOAb- and PPTD-positive women (group 1) is indicated.

Adult↗
PubMed2001

Low headache prevalence amongst women with high TSH values.

The aim of this large cross-sectional population-based study was to examine a possible positive or negative association between thyroid dysfunction and headache. Between 1995 and 1997, all 92 566 adults in Nord-Trøndelag County in Norway were invited to participate in a health survey. A total of 51 383 (56%) responded to a headache questionnaire, whereof thyroid-stimulating hormone (TSH) was measured in 28 058 individuals. These included 15 465 women and 8019 men above 40 years of age, 1767 randomly selected individuals between 20 and 40 years of age, and 2807 (97%) with thyroid dysfunction. Associations between thyroid dysfunction and headache were assessed in multivariate analyses, estimating prevalence odds ratios (OR) with 95% confidence intervals (CIs). High TSH values were associated with low prevalence of headache. This was most evident amongst women with no history of thyroid dysfunction. Amongst these, headache was less probable (OR=0.5, 95% CI 0.3-0.7) if TSH > or = 10 mU/l than in women with normal TSH (0.2-4 mU/l). In all age groups between 40 and 80 years, TSH was lower amongst headache sufferers, especially migraineurs, than in those without headache complaints.

Adult↗
PubMed1978

[Role of thyroid gland dysfunction in the pathogenesis and course of cerebral circulatory disorders].

The functional state of the thyroid gland was studied in 160 patients with different forms of disturbed cerebral circulation. The observations included studies of the iodine content and its fractions in the blood serum and a scanning of the thyroid gland. The author established the significance of thyroid gland dysfunction in the pathogenesis of hypertensive disease and cerebro-vascular insufficiency. In patients with hypertensive crises these studies detected the existence of a hyperthyroid syndrome. It was also found that in patients with cerebrovascular insufficiency accompanied by thyroid gland dysfunctions the clinical picture becomes more aggravated.

Cerebral Hemorrhage↗
PubMed1999

[Amiodarone and thyroid disorders--prospective study and review of the literature].

A well-known adverse effect of amiodarone is the induction of thyroid dysfunction. The numerous studies evaluating the incidence of amiodarone-induced thyroid dysfunction have given very dissimilar results, because of the variability in the criteria of hyper- and hypothyroidism, on the one hand, and in the iodine intake of the studied population on the other hand. The aim of our study was to evaluate the incidence of amiodarone-induced thyroid dysfunction. One hundred and twelve patients without prior thyroid dysfunction or anterior treatment with amiodarone were included in the study. Thirty-one patients were later excluded from the analysis because of a follow-up duration of less than four months. So our analysis concerned 81 patients (52 men and 29 women), followed for a mean period of 37.3 months. Amiodarone-Induced Thyrotoxicosis (AITT), diagnosed by the association of a low TSH and a high T4 (free and total T4), occurred in 13 patients (16%). Male sex proved to be a statistically significant risk factor of AITT. The normalization of the thyroid tests was obtained by the withdrawal of amiodarone and, for most of the patients, by the addition of thionamides. Amiodarone-Induced Hypothyroidism (AIHT), diagnosed by the elevation of TSH, occurred in 10 patients (12.3%). Female sex proved to be a statistically significant risk factor of AIHT.

Adult↗
PubMed1993

Screening for thyroid diseases in an iodine sufficient area with sensitive thyrotrophin assays, and serum thyroid autoantibody and urinary iodide determinations.

OBJECTIVE: The present study was designed to investigate the prevalence of thyroid dysfunction and its relation to thyroid autoantibodies and urine iodide concentration in apparently healthy people residing in Sapporo, a city of northern Japan, where the iodine intake is high. DESIGN AND SUBJECTS: Serum TSH and thyroid autoantibodies, and urine iodide were measured in 4110 people (2931 men and 1179 women) (age 45.6 +/- 10.3 years (mean +/- SD)) who were recruited at the hospital for medical examinations. RESULTS: The thyroid autoantibodies were positive in 6.4% of males and 13.8% of females with an age-related increase. Of the people with positive antibodies, 87.2% had normal TSH values (0.15-5.0 mU/l) as measured by a sensitive assay. The prevalence of unsuspected hyperthyroidism as defined by suppressed TSH values was 0.61%, of which 64% was diagnosed as Graves' disease based on positive thyrotrophin receptor antibody results. The prevalence of unsuspected hypothyroidism, as evidenced by supranormal TSH, was 0.68% for males and 3.13% for females with an age-related increase. Of those with hypothyroidism, 45.5% were autoantibody positive. The overall prevalence of Hashimoto's thyroiditis was 13.11% for females and 6.15% for males. The urine iodide levels of hypothyroidism with a positive autoantibody of 38.5 (17.7-83.9) mumol/l and a negative autoantibody of 34.9 (17.9-67.9) mumol/l were both significantly higher than that of normal subjects (26.9 (14.6-49.6) mumol/l) (P < 0.01). When iodine intake was restricted for 6-8 weeks for hypothyroid subjects, the elevated TSH and thyroglobulin and low free T4 levels were reversed in the autoantibody negative but not in the positive group. CONCLUSIONS: This study provides further information on the prevalence of thyroid dysfunction and autoimmune thyroid diseases in an iodine sufficient area. In addition, it suggests that more than half of the patients with unsuspected hypothyroidism were negative for autoantibodies and that the excessive iodine intake may be involved in causing latent hypothyroidism.

Adult↗
PubMed1992

[Only limited effect of treatment of thyroid gland diseases on symptoms of musculoskeletal system].

In order to assess the long term effect of treatment for thyroid dysfunction on musculoskeletal symptoms, 102 patients were traced by a computer search; these patients visited two outpatient clinics of rheumatology and were known to have thyroid disorders. Of these 102 patients, 58 patients met the study criteria of having abnormal thyroid function tests at first visit to the outpatient clinic; 46 patients participated in the study. They were interviewed with a structured questionnaire about their past and current musculoskeletal complaints. The 46 patients (45 females, 1 male) had a mean age at interview of 58 years (range 21-81); 37 and 9 patients had been treated for hypothyroidism and hyperthyroidism respectively. The thyroid dysfunction was considered the only explanation of the original musculoskeletal symptoms in 24 patients (group I), in 19 patients an additional (rheumatological) diagnosis was made (group II), and in 3 patients no apparent relation between musculoskeletal complaints and thyroid dysfunction was found. After treatment for thyroid dysfunction the original complaints decreased in 52% and 47% of the patients in group I and II, respectively. At the time of the follow-up study (mean follow-up duration 67 months) 91% of the patients had musculoskeletal symptoms, 80% of the patients said their present complaints were similar to their original symptoms. Treatment for thyroid dysfunction resulted in a temporary beneficial effect on musculoskeletal symptoms in 50% of the patients; in 91% symptoms persisted.

Adult↗
PubMed2005

Long-term follow-up of 106 multiple sclerosis patients undergoing interferon-beta 1a or 1b therapy: predictive factors of thyroid disease development and duration.

BACKGROUND: Conflicting data have been reported on the association between interferon (IFN)-beta therapy of multiple sclerosis (MS) patients and thyroid disease development. AIMS: The goals of this study are as follows: to assess the actual occurrence of thyroid dysfunction and autoimmunity during long-term IFN-beta therapy; to establish the possible presence of predictive factors for thyroid dysfunction development and duration; and to suggest an effective follow-up protocol for patients receiving long-term IFN-beta therapy. STUDY PROTOCOL: A total of 106 MS patients (76 women) underwent IFN-beta 1a or 1b therapy for up to 84 months (median, 42 months). Thyroid function and autoimmunity were assessed at baseline and every 3-6 months throughout the treatment course. RESULTS: Baseline thyroid autoimmunity was detected in 8.5% of patients and hypothyroidism in 2.8%. Thyroid dysfunction (80% hypothyroidism, 92% subclinical, 56% transient) developed in 24% (68% with autoimmunity) of patients and autoimmunity in 22.7% (45.5% with dysfunction), without significant differences between the two cytokines; 68% of dysfunctions occurred within the first year. Autoimmunity emerged as the only predictive factor for dysfunction development (relative risk, 8.9), whereas sustained disease was significantly associated with male gender (P < 0.003). CONCLUSIONS: Both incident thyroid autoimmunity and dysfunction frequently occur in MS patients during IFN-beta therapy, particularly within the first year of treatment. Thyroid dysfunction is generally subclinical and transient in over than half of cases; preexisting or incident autoimmunity emerged as the only significant predictive factor for thyroid dysfunction development. Thyroid function and autoimmunity assessment is mandatory within the first year of IFN-beta therapy; thereafter, serum TSH measurement only in patients with thyroid disease could be sufficient.

Adult↗
PubMed2003

Thyroid function testing in outpatients: are both sensitive thyrotropin (sTSH) and free thyroxine (FT4) necessary?

BACKGROUND AND OBJECTIVES: Despite improved thyroid function testing assays, appropriate use of these commonly ordered tests to detect thyroid dysfunction remains controversial. This study determined if a normal sensitive thyroid stimulating hormone (sTSH) test alone is sufficient to rule out thyroid dysfunction in outpatients. METHODS: This was a retrospective analysis of initial sTSH and free thyroxine index (FT4) tests ordered during a 26-month period. Test results were classified as concordant if both the sTSH and FT4 indicated the same findings (ie, euthyroid, hyperthyroid, or hypothyroid). The results were classified as discordant if the sTSH and FT4 did not indicate the same findings. RESULTS: There were 1,392 paired sTSH and FT4 results. Of 1,340 results classified as concordant (96.2%), 1,187 specimens were consistent with euthyroidism, 41 with hyperthyroidism, and 112 with hypothyroidism. Of the remaining 52 (3.8%) discordant results, 47 met the definition of subclinical thyroid dysfunction. Excluding these 47 results yielded a concordance rate of 99.6%. Of the 1,192 normal sTSH results, FT4 was low in two and high in three. If FT4 tests had not been ordered on the 1,192 specimens with normal sTSH levels, the savings over the study period would have been more than dollars 3,360. CONCLUSIONS: If the sTSH is normal, the likelihood of an abnormal FT4 is very small. sTSH alone is adequate to screen outpatients for thyroid dysfunction. Limiting FT4 tests to those with abnormal sTSH results will result in cost savings.

Cost Savings↗
PubMed1991

Thyroid function abnormalities associated with the chronic outpatient administration of recombinant interleukin-2 and recombinant interferon-alpha.

We prospectively examined thyroid function during and following chronic, outpatient therapy with recombinant interleukin-2 (rIL-2) and Roferon-A (rIFN-alpha 2a). Twenty-two of 30 patients with advanced renal cell carcinoma treated on a phase II open pilot study of concomitant rIL-2 and rIFN-alpha 2a were included. Serum levels of thyroxine, triiodothyronine, free thyroxine index, thyrotropin, antithyroid antibodies, and thyrotropin (TSH) receptor binding antibodies were measured before therapy and after every other cycle. Selected patients underwent studies after every cycle and following completion of therapy. Twenty patients (91%) developed laboratory evidence of thyroid dysfunction, 11 (50%) developed hypothyroidism, five (23%) had a biphasic pattern, and four (18%) had hyperthyroidism. The incidence of thyroid dysfunction increased with increased number of treatment cycles. Transient hyperthyroidism was noted in six of the 11 patients studied after the first cycle and persisted after cycle three in only two patients. Hypothyroidism was not observed after cycle 1, but became increasingly frequent between cycles 2 (56%) and 6 (90%). Thyroid function normalized following therapy in nine of 12 patients tested. Antithyroid antibodies were identified pretherapy in five patients (23%) and de novo in none; TSH receptor binding antibodies were not detected. This study demonstrates a remarkably high frequency of reversible thyroid dysfunction in patients with advanced renal cell carcinoma treated with repeated cycles of rIL-2 plus rIFN-alpha 2a. We conclude that chronic therapy with rIL-2 and rIFN-alpha 2a produces thyroid dysfunction in virtually all patients most likely secondary to a nonspecific, nonautoimmune, toxic manifestation of prolonged treatment. IL-2 therapy may, therefore, produce thyroid dysfunction by more than one mechanism.

Adult↗
PubMed1999

The prevalence of subclinical hypothyroidism at different total plasma cholesterol levels in middle aged men and women: a need for case-finding?

OBJECTIVE: In order to determine whether screening of thyroid function is justified in patients with hypercholesterolaemia, we determined the prevalence of subclinical hypothyroidism at different levels of total plasma cholesterol in middle-aged men and women. DESIGN AND METHODS: 1200 participants were selected from a population based cross sectional study on risk factors for cardiovascular diseases. The participants were divided into three groups: total plasma cholesterol < 5 mmol/l, total plasma cholesterol 5-8 mmol/l, total plasma cholesterol > 8 mmol/l. Each group was comparable in size and sex distribution. Subclinical hypothyroidism was defined as plasma TSH levels higher than 4 mU/l, in the presence of normal free thyroxine (FT4(4)) concentration. RESULTS: Plasma samples of a total of 1191 participants were analyzed. The overall prevalence of subclinical hypothyroidism was 1.9% in men and 7.6% in women of middle age. In women the prevalence of subclinical hypothyroidism increased from 4.0 percent in the lowest, to 10.3 percent in the highest cholesterol stratum (P = 0.02). In men, the mean prevalence was 1.8 percent and roughly similar in the various strata. After age correction, an increase of 1 mU/l TSH in women was associated with an increase of 0.09 mmol/l total plasma cholesterol (95% confidence interval (CI) 0.02-0.16 mmol/l). A similar trend was found in men (0.16 mmol/l, 95% CI -0.02-0.34 mmol/l). CONCLUSIONS: In the population, the prevalence of subclinical hypothyroidism is up to 10 percent in middle aged women with high levels of total plasma cholesterol and may justify case-finding. In these women approximately 0.5 mmol/l of total plasma cholesterol can be attributed to the subclinical thyroid dysfunction. In men a similar correlation between thyroid dysfunction and total plasma cholesterol is seen, but the prevalence of thyroid dysfunction is considerably lower.

Cholesterol↗