Papillary Thyroid Carcinoma With Thyroid-associated Orbitopathy in a Euthyroid State

PURPOSE

Thyroid cancers with concurrent thyroid-associated orbitopathy (TAO) are extremely rare. The present study reports 5 unusual cases of papillary thyroid microcarcinoma in patients presenting with TAO in an euthyroid state.

METHODS

We retrospectively reviewed the records of 5 patients (4 female, 1 male) with no known history of thyroid disease, who initially presented with TAO and were subsequently found to have thyroid cancer. TAO was diagnosed by a combination of computed tomography and clinical symptoms and signs. All patients underwent routine serologic assessment of thyroid hormones and thyroid-related autoantibodies including thyrotropin-receptor antibodies, as well as imaging studies such as neck ultrasonography or thyroid scintiscan with I.

RESULTS

Patients presented with asymmetric proptosis (cases 1-3), ocular motility restriction (cases 1-3), and eyelid retraction (cases 1-5). None of the patients showed clinical signs of hyperthyroidism, and all returned normal thyroid function test data. Thyroid nodules were detected by neck imaging; subsequent fine-needle aspiration biopsies were performed with the cytologic result of papillary carcinoma. In no cases did ophthalmic symptoms resolve following cancer treatment (e.g., thyroidectomy and radioactive iodine therapy). All patients were positive for thyroid-binding inhibiting immunoglobulin in low titers.

CONCLUSIONS

Although coincident occurrence is rare, patients presenting with TAO should be carefully evaluated for the possible presence of papillary microcarcinoma, which can develop in a setting of systemic autoimmunity without inducing hyperthyroidism.

Correlates of non-thyroidal illness syndrome in chronic obstructive pulmonary disease

Non-thyroidal illness syndrome (NTIS) is frequently detected in chronic, systemic diseases. The objectives of the current study is to assess the alterations of thyroid hormones during exacerbation period, recovery of exacerbation and stable phase of chronic obstructive pulmonary disease (COPD) and correlates of these hormonal alterations. A total of 83 stable COPD patients, 20 patients with acute exacerbation and 30 control subjects were evaluated. TT3, fT3, TT3/TT4 levels of both stable and exacerbation COPD groups were lower than control subjects. TSH was also decreased during exacerbation period. In follow-up of COPD exacerbation group, TSH, TT3, fT3 and TT3/TT4 were found to be increased in measurements on the day of discharge from hospital and after 1 month, compared to baseline values. TT3 and TT3/TT4 were lower in severe COPD; whereas TSH, fT3, TT3 and TT3/TT4 were lower in patients with severe hypoxemia. IL-6 and TNF-alpha were higher in both stable and exacerbation phase COPD groups and IL-6 was correlated to TT3 in stable COPD. As a result, there are significant alterations in thyroid hormones of stable COPD patients, which are related to severity of disease and hypoxemia. The hormonal changes are more significant during exacerbation and partially regress after 1 month when the disease is stabilized. We conclude that COPD patients should not be evaluated for thyroid disease during exacerbation of the disease, and thyroid function alterations during stable phase of the disease should be considered cautiously, since thyroid function abnormalities in non-thyroid illness may mimic or mask biochemical abnormalities observed in true thyroid disease.

[Pathophysiological and clinical correlations between endocrine and cardiovascular systems. An inter-systemic model of internal medicine]

This review focuses on the mechanisms by which thyroid hormones affect the regulation of the cardiovascular system and the thermogenic and hemodynamic variation induced by thyroid disfunction. It is also stressed the hormonal role of the cardiac myocytes realising natriuretic peptides, involved in plasma volume homeostasis and cardiovascular remodelling; its rapid measurement is a useful clinical tool, in the diagnostic and prognostic of left ventricular dysfunction, correlating with the degree of the clinical symptoms. The endothelial layer is a receptor-effector endocrine organ that produces substances that maintain vasomotor balance and vascular-tissue homeostasis. Cardiovascular risk factors causes oxidative stress that alter endothelial function and leads to endothelial dysfunction. On the basis of the present body of evidence there is no doubt that endothelial dysfunction contributes to the initiation, and progression, of atherosclerotic disease and that it could be considered an independent vascular risk factor for the micro- and macrovascular damages in the diabetes disease. In several extrathyroidal pathological condition, as well as in heart failure, the main alteration of the thyroid function is referred to as "low T3 syndrome". This syndrome is due to an adaptative reaction of the metabolic pathway of thyroxine, producing an increased amount of rT3, metabolically inactive, thus decreasing the detrimental metabolic effects of T3, in conditions of critically impaired hemodynamic and metabolic efficiency. Preliminary clinical trials, in heart failure, suggest the prognostic value of the level of circulating T3, as well as usefulness of T3, or of thyromimetic derivatives (DITPA), in chronic treatment of the heart ventricular dysfunction.

An evaluation of thyroid hormone status and oxidative stress in undialyzed chronic renal failure patients

Chronic renal failure (CRF) patients on prolonged dialysis have been found to have significant alteration in their thyroid status, but little is known about the same in undialyzed CRF patients. Oxidative stress has been implicated as the key player in altering the levels of thyroid hormone in euthyroid sick syndrome. This study was performed to evaluate the levels of oxidative stress and thyroid status in undialyzed CRF patients. A case control study was performed on 20 undialyzed CRF patients and 20 control subjects. There was a significant decrease in the levels of T3, T4, total protein and albumin levels in CRF patients when compared to control. There was a significant increase in the level of malondialdehyde and total antioxidant status in CRF patients when compared with control subjects. The present study confirms oxidative stress along with altered thyroid status in CRF patients.

Low T3 syndrome in psychiatric depression

In euthyroid sick syndrome [non-thyroidal illness (NTI)], a number of investigators have described TSH and serum thyroid hormone abnormalities, low T3, low T3 and T4, increased T4, low TSH, etc. Those cases of NTI where there is only T3 decrease [and normal serum T4, free T4 (FT4), and TSH levels] are specifically referred to as low T3 syndrome. However, the information in regard to low T3 syndrome in psychiatric subjects who are clinically euthyroid and do not have any other systemic illness is scanty. In our facility, since thyroid function is routinely assessed in psychiatric patients at admission, this provided the opportunity to study low T3 syndrome in a large group of psychiatric patients. Out of 250 subjects with major psychiatric depression, 6.4% exhibited low T3 syndrome (mean serum T3 concentration 0.94 nmol/l vs normal mean serum concentration of 1.77 nmol/l). The low T3 levels could not be ascribed to malnutrition or any other illness and the metabolic parameters were all normal. Possible mechanisms contributing to low T3 are discussed. The depression might constitute an illness having the same relation to low T3 as found in the low T3 syndrome previously described in euthyroid sick subjects. The present findings, besides describing low T3 syndrome in psychiatric patients without systemic illnesses, suggest the possibility of subgrouping in clinical psychiatric depression which may have a broader clinical significance.

Clinical review: thyroid hormone replacement in children after cardiac surgery--is it worth a try?

Cardiac surgery using cardiopulmonary bypass produces a generalized systemic inflammatory response, resulting in increased postoperative morbidity and mortality. Under these circumstances, a typical pattern of thyroid abnormalities is seen in the absence of primary disease, defined as sick euthyroid syndrome (SES). The presence of postoperative SES mainly in small children and neonates exposed to long bypass times and the pharmacological profile of thyroid hormones and their effects on the cardiovascular physiology make supplementation therapy an attractive treatment option to improve postoperative morbidity and mortality. Many studies have been performed with conflicting results. In this article, we review the important literature on the development of SES in paediatric postoperative cardiac patients, analyse the existing information on thyroid hormone replacement therapy in this patient group and try to summarize the findings for a recommendation.

Thyroid Hormone and Insulin-Like Growth Factor-I in Patients with Multiple Myeloma Treated with Melphalan and Prednisone

BACKGROUND

The relationship between endocrine regulation and immune system has recently become the subject of intense investigations. The aim of this study was the comparative assessment of serum levels of selected hormones and insulin-like growth factor-I (IGF-I) in patients with multiple myeloma (MM) during applied therapy.

METHODS

The levels of prolactin, hGH, TSH, fT3, fT4 and IGF-I in serum of 13 untreated patients with MM and in 16 healthy controls were determined. The patients were treated in cyclic courses with melphalan plus prednisone, and investigations were carried out in the first four courses of this therapy. The results were compared in the following manner: (1) at entry between studied MM group and healthy subjects, and (2) during the therapy intragroup-intracyclic comparisons were made in paired serum samples collected from patients before and after every therapeutic course.

RESULTS

At entry, significantly lower levels of TSH and fT3 were obtained in MM patients. The means remained within low normal reference range. Slightly increasing levels of TSH and fT3 during treatment with lower concentrations of these hormones after every therapeutic course and a statistically significant difference of fT3 level in the fourth therapy course were revealed. The levels of fT4 were within the normal reference values and showed a tendency to decrease during therapy with significant differences in the first therapeutic course. After the third and the fourth therapy courses, concentrations of IGF-I were statistically significantly higher than initially.

CONCLUSIONS

Euthyroid sick syndrome can exist in MM patients, and the therapy with melphalan plus prednisone is accompanied by slightly expressed serum changes of thyroid hormone concentrations and IGF-I levels.

Euthyroid sick syndrome in meningococcal sepsis: the impact of peripheral thyroid hormone metabolism and binding proteins

CONTEXT AND OBJECTIVES

The objective of this study was to elucidate the influence of disease severity, deiodination, sulfation, thyroid hormone binding, and dopamine use on thyroid function in euthyroid sick syndrome.

SETTING

The study was performed at a university-affiliated pediatric intensive care unit (PICU).

DESIGN

This was an observational cohort study.

PATIENTS

Sixty-nine children with meningococcal sepsis were studied.

MAIN OUTCOME MEASURES

Differences in thyroid function among nonsurvivors, shock survivors, and sepsis survivors on PICU admission were the main outcome measures.

RESULTS

The main study group consisted of 45 non-dopamine-treated children. All children had decreased total T3 (TT3)/rT3 ratios without elevated TSH. T4 sulfate levels were decreased in 88%. Nonsurvivors had paradoxically higher TT3/rT3 ratios than shock survivors (0.71 vs. 0.30); this ratio also correlated with shorter duration of disease (r = -0.43). TT4 and T4-binding globulin (TBG) levels declined with increasing disease severity. TBG levels correlated inversely with elastase levels (r = -0.46). Only TSH levels were significantly lower in 24 dopamine-treated children compared with non-dopamine-treated children (0.65 vs. 0.84), whereas other thyroid hormones did not significantly differ. Both higher TT3/rT3 ratios and lower TT4 levels were predictive for mortality, but this disappeared when IL-6 was entered into the regression model.

CONCLUSIONS

All children with meningococcal sepsis showed signs of euthyroid sick syndrome. Alterations in peripheral thyroid hormone metabolism related inversely to the duration of disease and seemed to be enacted by profound induction of type 3 deiodinase rather than by down-regulation of type 1. Lower TT4 levels were related to increased turnover of TBG by elastase. Dopamine was found to suppress only TSH secretion, not other thyroid hormone levels, on PICU admission. Both the TT3/rT3 ratio and TT4 levels were predictive for mortality, but were not superior to IL-6.

Thyroid function and outcome in children who survived meningococcal septic shock

OBJECTIVE

To investigate the time course of thyroid function, factors that affect it, and its relationship to outcome in children surviving meningococcal septic shock.

DESIGN AND SETTING

Observational cohort study in a university-affiliated pediatric intensive care unit (PICU).

PATIENTS AND PARTICIPANTS

We divided the 44 children admitted to the PICU who survived meningococcal septic shock into those with short-stay (<7 days, n=33) or long-stay (>or=7 days, n=11).

MEASUREMENTS AND RESULTS

Serum thyroid hormone concentrations were determined on PICU admission and after 24 and 48 h. The Pediatric Risk of Mortality score and selected laboratory parameters were used to assess disease severity. On admission all children showed signs of euthyroid sick syndrome: low total triiodothyronine (TT3) and high reverse triiodothyronine (rT3) without compensatory elevated thyrotropin (TSH). Admission rT3 levels and the TT3/rT3 ratio were correlated with C-reactive protein levels and with time from first petechia to admission. Short-stay children only had higher TT3 and lower interleukin 6 levels at admission than long-stay children; after 48 h they showed higher total thyroxin, free thyroxin, TT3, and TSH and lower rT3 than long-stay children. All changes in thyroid parameters within the first 24 h were related to length of PICU stay. In children receiving dopamine TSH levels and TT3/rT3 ratios remained unchanged, whereas both values increased in those who did not receive dopamine or in whom dopamine was discontinued.

CONCLUSIONS

All children surviving meningococcal septic shock showed signs of euthyroid sick syndrome on admission. Thyroid hormone level changes in the first 24 h were prognostic for length of PICU stay.

Clinical investigation: thyroid function test abnormalities in cardiac arrest associated with acute coronary syndrome

INTRODUCTION

It is known that thyroid homeostasis is altered during the acute phase of cardiac arrest. However, it is not clear under what conditions, how and for how long these alterations occur. In the present study we examined thyroid function tests (TFTs) in the acute phase of cardiac arrest caused by acute coronary syndrome (ACS) and at the end of the first 2 months after the event.

METHOD

Fifty patients with cardiac arrest induced by ACS and 31 patients with acute myocardial infarction (AMI) who did not require cardioversion or cardiopulmonary resuscitation were enrolled in the study, as were 40 healthy volunteers. The patients were divided into three groups based on duration of cardiac arrest (<5 min, 5-10 min and >10 min). Blood samples were collected for thyroid-stimulating hormone (TSH), tri-iodothyronine (T3), free T3, thyroxine (T4), free T4, troponin-I and creatine kinase-MB measurements. The blood samples for TFTs were taken at 72 hours and at 2 months after the acute event in the cardiac arrest and AMI groups, but only once in the control group.

RESULTS

The T3 and free T3 levels at 72 hours in the cardiac arrest group were significantly lower than in both the AMI and control groups (P < 0.0001). On the other hand, there were no significant differences between T4, free T4 and TSH levels between the three groups (P > 0.05). At the 2-month evaluation, a dramatic improvement was observed in T3 and free T3 levels in the cardiac arrest group (P < 0.0001). In those patients whose cardiac arrest duration was in excess of 10 min, levels of T3, free T3, T4 and TSH were significantly lower than those in patients whose cardiac arrest duration was under 5 min (P < 0.001, P < 0.001, P < 0.005 and P < 0.05, respectively).

CONCLUSION

TFTs are significantly altered in cardiac arrest induced by ACS. Changes in TFTs are even more pronounced in patients with longer periods of resuscitation. The changes in the surviving patients were characterized by euthyroid sick syndrome, and this improved by 2 months in those patients who did not progress into a vegetative state.

[Assessment of the release of thyroid hormones in septic shock--prognostic significance]

Septic shock is the reason of human body organs dysfunctions including the hormonal system. There are abnormal thyroid hormones releasing as well. It is also noticed that sepsis caused serious disturbances in pituitary-thyroid axis functions. This is called euthyroid sick syndrom - (ESS).

THE AIM

To qualify the prognostic value of thyroid hormones serum levels changes in patients with septic shock.

MATERIAL AND METHODS

20 patients with septic shock were included into study. Septic shock was diagnosed according to AACP/SCCM criteria. The study group was divided into two subgroups: survivors (n = 10) and nonsurvivors (n = 10). 20 healthy volunteers were the control group. Blood for analysis was taken at the moment of septic shock recognition and on the 1st, 2nd, 5th and 10th day of the observation between 8 a.m. and 9 a.m. We studied thyrotropin (TSH), free triiodothyronine fraction (fT3) and free thyroxin fraction (fT4) serum levels, APACHE II and APACHE III score, acute lung injury (ALI) or acute respiratory distress syndrome (ARDS).

RESULTS

During our study we noticed significant decrease of fT3 and TSH serum levels (respectively 2.36 +/- 0.79 pg/ml and 0.76 +/- 1.12mU/I) according to the control group (respectively 3.28 +/- 0.61 pg/ml and 0.95 +/- 0.46mU/l). Nonsurvivors had significantly lower TSH serum level (0.37 +/- 0.62 mU/I) in comparison to survivors (1.27 +/- 1.45 mU/I) in spite of very similar fT3 serum level (respectively 2.45 +/- 0.87 pg/ml and 2.22 +/- 0.66 pg/ml). It could mean that there were disturbances in the pituitary-thyroid axis function in patients who did not survive. Our study did not show any correlations between thyroid hormones serum levels and APACHE II score, APACHE III score, ALI or ARDS.

CONCLUSIONS

This study show that low TSH serum level could be a significant prognostic factor of death in patient with septic shock especially with low fT3 serum level. The results also suggest that ESS could be a consequence of pituitary TSH releasing disturbances.

The non-thyroidal illness syndrome after coronary artery bypass grafting: a 6-month follow-up study

The non-thyroidal illness syndrome (NTIS) is considered a transient and completely reversible phenomenon, but it has been shown that it may last for several days postoperatively after coronary artery bypass grafting (CABG) surgery. This study was undertaken to assess thyroid function 6 months after uncomplicated CABG. The thyroid profile was evaluated in 40 consecutive patients undergoing CABG preoperatively, at 0, 12, 48, and 120h postoperatively, and at 6-month follow-up. Triiodothyronine (T

Comparison of serum-free thyroxine concentrations determined by standard equilibrium dialysis, modified equilibrium dialysis, and 5 radioimmunoassays in dogs

Measurement of serum-free thyroxine (fT4) concentration provides a more accurate assessment of thyroid gland function than serum thyroxine (T4) or 3,5,3'-triiodothyronine (T3). Techniques for measuring serum fT4 concentration include standard equilibrium dialysis (SED), radioimmunoassay (RIA), and a combination of both (modified equilibrium dialysis [MED]). This study compared results of serum fT4 measurements by means of SED, MED, and 5 RIAs in 30 healthy dogs, 10 dogs with hypothyroidism, and 31 euthyroid dogs with concurrent illness for which hypothyroidism was a diagnostic consideration. Serum fT4 concentrations were comparable when determined by the SED and MED techniques, and mean serum fT4 concentrations were significantly (P < .01) lower in dogs with hypothyroidism than in healthy dogs and euthyroid dogs with concurrent illness. Significant (P < .05) differences in fT4 concentrations were identified among the 5 RIAs and among the RIAs and MED and SED. Serum fT4 concentrations were consistently lower when fT4 was determined by the RIAs, compared with either equilibrium dialysis technique. Serum fT4 concentrations were significantly lower (P < .01) in dogs with hypothyroidism than in healthy dogs for all RIAs; were significantly lower (P < .05) in dogs with hypothyroidism than in euthyroid dogs with concurrent illness for 4 RIAs; and were significantly lower (P < .01) in euthyroid dogs with concurrent illness than in healthy dogs for 4 RIAs. RIAs had the highest number of low serum fT4 concentrations in euthyroid dogs with concurrent illness. This study documented differences in test results among fT4 assays, emphasizing the importance of maintaining consistency in the assay used to measure serum fT4 concentrations in the clinical or research setting.

Prevalence and pattern of sick euthyroid syndrome in acute and chronic non-thyroidal illness--its relationship with severity and outcome of the disorder

BACKGROUND

Non-thyroidal illness is a common cause of alterations in thyroid hormone economy in absence of underlying intrinsic thyroid disorder.

OBJECTIVE

To study the prevalence and pattern of alterations in thyroid hormone economy in various non-thyroidal illnesses in our region and also to correlate these alterations with the severity and outcome of the non-thyroidal illness.

MATERIAL AND METHODS

We analyzed circulating T3, T4, TSH in 382 patients with non-thyroidal illness (285 acute and 97 acute on chronic) and correlated the alterations with severity and outcome of the non-thyroidal disorder. The patients had one or more organ failure at the time of enrollment to the study. The hormones were estimated at the onset of sickness, and at 3rd and 24th week. T3, T4 and TSH in 75 age and sex matched euthyroid subjects were taken as controls.

RESULTS

T3 (mean +/- SEM) was significantly reduced at the onset of illness, in both acute and chronic patient groups (1.61 +/- 0.05 nmol/l) compared to that in the controls (3.17 +/- 0.06 nmol/l). In spite of clinical improvement in most instances, T3 continued to remain low in the 3rd week (1.49 +/- 0.11 nmol/ l) but increased (2.14 +/- 0.09 nmol/l) in 24th week. Low T3 was found in 93 (32.6%) cases with acute illness in 20 (20.6%) cases with chronic illness. A combination of low T3 and T4 was found in 35 (12.3%) of cases with acute and 15 (15.5%) with chronic illness. Although serum TSH showed noticeable fall and rise in some individuals, no significant difference in mean TSH was observed during any period of illness compared to that in the controls. Severity of illness correlated with decrease in T3 (r=0.58) and T4 (r=0.38). A low T3 and T4 with low or undetectable TSH were associated with increased mortality. At the onset of acute illness low T3 was seen in 113 (29.6%, low T3 -low T4 in 50 (13.1%), high T4 in 28 (7.3%) lowT3-lowT4- low TSH in 10 (2.6%) and low T4 alone in 4 (1%) patients. Fifty one 1 (13.4%) of our patients demonstrated alterations in TSH in presence of normal T3 and T4-26 patients had decreased TSH while as 25 had increased TSH. Of 118 patients who followed at 24 weeks, 11 (9.3%) had low T3, 7(5.9%) had low T3- low T4 and 13 (11%) had elevated TSH.

CONCLUSION

Pattern and prevalence of sick euthyroid syndrome in this part of the world, a recognized iodine deficient region, appears to be similar to that reported elsewhere. Important finding in our study was higher percentage of TSH elevation, which we believe to reflect the underlying iodine deficiency state of our community. Besides a significant number of subjects persisted with alterations in thyroid functions even after 6 months of therapy. Though the severity of thyroid hormone derangement correlated with severity of sickness, the derangement was similar in acute vs. acute on chronic nonthyroidal illnesses.

Effects of moderate to severe osteoarthritis on canine thyroid function

Several nonthyroidal illnesses in euthyroid dogs can affect the results of thyroid function testing, making interpretation of the results more difficult with an increased risk of overdiagnosing hypothyroidism. The purpose of this study was to evaluate the effect of chronic, moderate to severe, osteoarthritis on canine thyroid function. Ninety-six, healthy, client-owned dogs, 65 of which were suffering from moderate to severe osteoarthritis and 31 euthyroid dogs without any physical evidence of osteoarthritis, were used in this study. Blood samples were collected to evaluate serum basal total thyroxine (TT4), free thyroxine (FT4), and thyrotropin (TSHc) concentrations. Basal serum TT4 concentration was not affected by osteoarthritis in dogs. Mild, but statistically significant, differences were noticed in FT4 and TSHc concentrations among the 2 groups. However, this had limited clinical relevance, since virtually all values were within their reference range, and no dogs would have been misdiagnosed as hypothyroid. Therefore, based on the results of our study, osteoarthritis does not need to be considered a factor influencing thyroid function evaluation in dogs.

Circulating IL-8 and IL-10 in euthyroid sick syndromes following bone marrow transplantation

It is generally agreed that euthyroid sick syndromes (ESS) are associated with an increased production of cytokines. However, there has been scarce data on the relationship thyroid hormone changes and cytokines among the patients undergoing bone marrow transplantation (BMT). Because interleukin-8 (IL-8) has been identified as a potent proinflammatory and interleukin-10 (IL-10) as an antiinflammatory cytokine, we studied the relation between thyroid hormone parameters and these cytokines following BMT. We studied 80 patients undergoing allogeneic BMT. Serum T3 decreased to nadir at post-BMT 3 weeks. Serum T4 was the lowest at the post-BMT 3 months. Serum TSH sharply decreased to nadir at 1 week and gradually recovered. Serum free T4 significantly increased during 3 weeks and then returned to basal level. Mean levels of serum IL-8 significantly increased at 1 week after BMT. Mean levels of serum IL-10 significantly increased until 4 weeks after BMT. No significant correlation was found between serum thyroid hormone parameters and cytokines (IL-8, IL-10) after adjusting steroid doses during the entire study period. In conclusion, ESS developed frequently following allogeneic BMT and cytokine levels were increased in post-BMT patients. However, no significant correlation was found between serum thyroid hormone parameters and these cytokines.

Heart failure accompanied by sick euthyroid syndrome and exercise training

Sick euthyroid syndrome is defined as the decrease of serum free triiodothyronine with normal free L-thyroxin and thyrotropin. Its appearance in patients with chronic heart failure is an indicator of severity. Exercise training through a wide variety of mechanisms reverses sick euthyroid syndrome (normalization of free triiodothyronine levels) and improves the ability to exercise. There is a connection during exercise among dyspnea, hyperventilation, fatigue, catecholamines, a decrease in the number and function of beta-blocker receptors, and elevation of serum free triiodothyronine. It is not known whether sick euthyroid syndrome contributes to the development of heart failure or is only an attendant syndrome.

Serum thyroxine level and cognitive decline in euthyroid older women

BACKGROUND

Clinical and subclinical hypothyroidism is associated with cognitive impairment.

OBJECTIVE

This study investigated the association between thyroxine (T(4)) and thyroid-stimulating hormone (TSH) level and change over time in cognitive performance in a sample of older women with normal thyroid gland function.

METHODS

T(4) and TSH were measured at baseline in 628 women (> or = 65 years) enrolled in the Women's Health and Aging Study, a community-based study of physically impaired women. Cognitive function was assessed at baseline and after 1, 2, and 3 years, using the Mini-Mental State Examination (MMSE). Incident cognitive decline was defined as a decrease of more than one point/year in MMSE score between baseline and the end of the follow-up. The analysis included 464 subjects with normal thyroid gland function with a baseline and at least one follow-up MMSE.

RESULTS

At baseline there was no association between T(4) and TSH level and cognitive function. In longitudinal analysis, adjusting for age, race, level of education, and other covariates, compared with women in the highest T(4) tertile (8.1 to 12.5 microg/dL), those in the lowest tertile (4.5 to 6.5 microg/dL) had a greater decline in MMSE score (-0.25 point/year vs -0.12 point/year; p = 0.04). A total of 95 women (20.5%) had cognitive decline during the study period (mean MMSE decline, 5.5 points). Compared with women in the highest T(4) tertile, those in the lowest tertile had a twofold risk of cognitive decline (adjusted relative risk, 1.97; 95% CI, 1.10 to 3.50). The results were not modified by baseline cognitive and physical function. There was no association between baseline TSH level and change in cognitive function.

CONCLUSIONS

In older women, low T(4) levels, within the normal range, were associated with a greater risk of cognitive decline over a 3-year period. Thyroid hormone levels may contribute to cognitive impairment in physically impaired women.

Interferon-gamma administration does not affect human thyroid hormone metabolism in the post-surgical euthyroid sick syndrome

Cytokines are thought to be involved in the pathogenesis the euthyroid sick syndrome. Experimental data from in vitro and animal in vivo studies suggest that interferon-gamma (IFN-gamma) could be another cytokine that might influence thyroid hormone metabolism, although in a previous study in healthy subjects we could not demonstrate an effect of IFN-gamma on thyroid hormone indices. Possibly, however, a non-stressed system is not a representative environment to study the effects of a mediator, which might exert its role during pathological circumstances in which it may interact synergistically with other inflammatory mediators. Therefore, we studied the effects of a single dose of recombinant human IFN-gamma (Immukine, 100 microg/m2, sc) on thyroid hormone concentrations in a placebo-controlled trial in 13 major surgery patients. Basal IFN-gamma levels did not increase. IFN-gamma induced a significant increase in monocyte HLA-DR expression (post-operative 50%; 24 h after IFN-gamma 90%), but did not affect thyroid hormone and thyroid stimulating hormone concentrations. We therefore conclude that IFN-gamma does not appear to be involved in the major changes in thyroid hormone metabolism in patients with non-thyroidal illness.

Hemithyroidectomy: long-term effects on parathyroid function--preliminary report

Early hypocalcemia after thyroid surgery has frequently been reported, whereas data regarding long-term effects on calcium homeostasis are scarce. We have previously studied patients after hemithyroidectomy with an oral calcium load test and found normal parathyroid hormone (PTH) suppression. However, the 1,25-dihydroxyvitamin D concentration was decreased and the phosphate concentration increased, implying parathyroid insufficiency. We therefore proceeded to investigate PTH secretion and suppression in 10 euthyroid patients subjected to hemithyroidectomy due to benign thyroid disease before and at 1 year after surgery. In addition, biochemical variables known to influence calcium homeostasis were analyzed. Basal, maximal, and total PTH secretion were unaltered 1 year postoperatively. However, maximal PTH secretion was reached at a lower serum level of ionized calcium, and there was a tendency toward increased parathyroid sensitivity to ionized calcium. Furthermore, compared to preoperative, total serum calcium, 1,25-dihydroxyvitamin D, and free thyroxine (T4) concentrations were decreased at follow-up. Total serum calcium and 1,25-dihydoxyvitamin D concentrations were decreased 1 year after hemithyroidectomy. These changes were not due to parathyroid insufficiency. Instead, our results imply increased parathyroid sensitivity to calcium and possibly reduced peripheral sensitivity to PTH.