Long-term treatment with supraphysiological doses of thyroid hormone in affective disorders - effects on bone mineral density

Role of thyroid hormone therapy in depressive disorders

PURPOSE

The close association among thyroid metabolism, mood disorders and behavior has long been known. The old and modern uses of thyroid hormones to modulate the expression of depression and bipolar disorder and to improve clinical outcome when used in conjunction with psychotropic medications.

METHODS

A literature search was performed to identify studies investigating the effects of thyroid hormone treatment in patient s with mood disorders.

RESULTS

The successful modification of mood disorders with thyroid hormone underscores the association between endocrine and cerebral systems in these disorders. Thyroid hormones have a profound influence on behavior and appear to be capable of modulating the phenotypic expression of major mood disorders. In fact, there is evidence that triiodothyronine (LT3) may accelerate the antidepressant response to antidepressants, and studies suggest that LT3 also may augment the response to antidepressants in refractory depression. Add-on treatment with supraphysiologic doses of levothyroxine (LT4) has shown efficacy in open-label and in placebo-controlled studies, including in rapid cycling and prophylaxis-resistant bipolar disorder, and with acute refractory uni- or bipolar depression. Functional brain-imaging studies (PET) demonstrated that administration of supraphysiologic LT4 improves depressive symptoms in patients with bipolar depression by modulating cerebral activity in the anterior limbic network.

CONCLUSION

The add-on administration of supraphysiologic doses of LT4 is a promising strategy in patients with refractory bipolar and depressive mood disorders.

Treatment of bipolar depression with supraphysiologic doses of levothyroxine: a randomized, placebo-controlled study of comorbid anxiety symptoms

Background

Symptoms of anxiety co-occur in a variety of disorders including in depressive episodes of bipolar disorder and in patients with thyrotoxicosis. Treatment of refractory bipolar disorder with supraphysiologic doses of levothyroxine (L-T4) has been shown to improve the phenotypic expression of the disorder and is associated with an increase of circulating thyroid hormones. However, it might be associated with somatic and mental adverse effects. Here we report the investigation of the influence of treatment with supraphysiologic doses of L-T4 on symptoms of anxiety in patients with refractory bipolar depression.

Methods

Post-hoc analysis from a 6-week, multi-center, randomized, double-blind, placebo-controlled study of the effects of supraphysiologic L-T4 treatment on anxiety symptoms in bipolar depression. Anxiety symptoms were measured weekly with the Hamilton anxiety/somatization factor (HASF) score of the Hamilton Depression Rating Scale (HAMD) and the State- and Trait Anxiety Inventory (STAI).

Results

Treatment of both groups was associated with a significant reduction in anxiety symptoms (p < 0.001) with no statistical difference between groups (LT-4: from 5.9 (SD = 2.0) at baseline to 3.7 (SD = 2.4) at study end; placebo: from 6.1 (SD = 2.4) at baseline to 4.4 (SD = 2.8) at study end; p = 0.717). Severity of anxiety at baseline did not show a statistically significant correlation to the antidepressive effect of treatment with supraphysiologic doses of L-T4 (p = 0.811). Gender did not show an influence on the reduction of anxiety symptoms (females: from 5.6 (SD = 1.7) at baseline to 3.5 (SD = 2.4) at study end; males: from 6.1 (SD = 2.3) at baseline to 4.0 (SD = 2.4) at study end; p = 0.877).

Conclusions

This study failed to detect a difference in change of anxiety between bipolar depressed patients treated with supraphysiologic doses of L-T4 or placebo. Comorbid anxiety symptoms should not be considered a limitation for the administration of supraphysiologic doses of L-T4 refractory bipolar depressed patients.

Trial registration ClinicalTrials, ClinicalTrials.gov identifier: NCT01528839. Registered 2 June 2012—Retrospectively registered, https://clinicaltrials.gov/ct2/show/study/NCT01528839

Lithium-induced Thyroiditis in a Patient Having Bipolar Affective Disorder - A Rare Case Report

A 22-year-old female, previously diagnosed with bipolar affective disorder on lithium therapy, presented to us with manic symptoms. The blood investigations revealed elevated thyroxine and thyroid peroxidase antibodies and reduced thyroid-stimulating hormone with poor tapping function of thyroid on technetium thyroid scintigraphy indicating lithium-induced thyroiditis.

Effects of thyrotropin suppression on lumbar bone mineral density in postmenopausal women with differentiated thyroid carcinoma

Purpose

The aim of this study was to evaluate the effect of postoperative thyroid-stimulating hormone suppression (TSHS) on bone mineral density (BMD) in Chinese postmenopausal women with differentiated thyroid carcinoma (DTC).

Patients and methods

A total of 225 postmenopausal women with DTC who had received TSHS were included in the study. Postmenopausal women with postoperative DTC undergoing thyroid residual ablation or metastasis treatment between 2009 and 2015 were enrolled and followed up for 2 years. They were divided into two groups: TSHS group (median thyroid-stimulating hormone [TSH] <0.3 μIU/mL) and postmenopausal control group (median TSH >0.3 μIU/mL). Lumbar 1–4 BMD levels were measured by a dual-energy X-ray absorptiometry (DXA) at baseline and 6, 12 and 24 months. All patients had calcium and vitamin D supplementation. The diagnosis of osteopenia (−1 SD > T >−2.5 SD) and osteoporosis (T <−2.5 SD) was made according to WHO guidelines.

Results

Thyroid cancers included 211 papillary carcinomas and 14 follicular carcinomas. One hundred and fifty-four patients were in the TSHS group, and 71 patients were in the non-suppressed TSH group (postmenopausal controls). No significant differences were found in the BMD of the lumbar spine between baseline and after 6, 12 and 24 months, pre and post treatment in TSHS and non-suppressed TSH patients. Compared with pre-TSHS, there was a reduction in the BMD of 1.9% in the lumbar spine at the 2-year follow-up. Significant difference in the number of osteopenia and osteoporosis patients at 24 months (χ²=2.88, P=0.004) was found between the TSHS (103/152) and postmenopausal control (32/68) groups. TSHS is not a significant risk of bone loss, but it is the incidence of osteopenia in postmenopausal women with DTC.

Conclusion

Our 2-year follow-up data indicated that TSHS had little effect on BMD in postmenopausal women with DTC. Large population with at least 5-year follow-up should be further investigated. BMD in postmenopausal women with DTC should be followed up regularly.

Long-term treatment with supraphysiologic doses of levothyroxine in treatment-refractory mood disorders - A prospective study of cardiovascular tolerability

BACKGROUND

To investigate long-term effects of adjunctive prophylactic treatment with supraphysiologic doses of levothyroxine (L-T4) on cardiovascular tolerability in 23 patients with treatment-refractory mood disorders.

METHODS

Starting point for a comprehensive cardiovascular assessment in patients was the indication for long-term maintenance treatment with L-T4 (mean dose 463 mcg/day). Prospective longitudinal assessment of the cardiovascular risk profile included in addition to a physical examination and blood pressure measurement, several technical investigations: resting electrocardiogram, transthoracic echocardiogram, cardiac stress test, and holter electrocardiogram. Statistical analysis was performed by linear mixed effects models (LMM) for evaluation of longitudinal changes in various heart measures.

RESULTS

During the mean observational period of 20.4 months none of the heart measures reached statistical significance in change over time. None of the assessed cardiac parameters of each single patient was in a range predictive for cardiac dysfunction.

LIMITATIONS

Small sample size, no technical cardiac investigations prior to L-T4 initiation, no patient control group with mood disorders who did not receive L-T4.

CONCLUSIONS

Results of this study indicated no increased risk for cardiovascular disorders during treatment with supraphysiologic L-T4 doses in patients with refractory mood disorders.

Histological and ultrastructural alterations of rat thyroid gland after short-term treatment with high doses of thyroid hormones

The aim of the present study was to investigate histological alterations of rat thyroid gland after short-term treatment with supraphysiological doses of thyroid hormones. Rats from experimental groups were treated with triiodothyronine (T3) or thyroxine (T4) during five days. In both treated groups, thyrocyte height was reduced and follicular lumens were distended. Progressive involutive changes of the thyroid parenchyma were apparent, including follicular remodeling (fusion) and death of thyrocytes. Morphological changes confirmed by quantitative analysis were more pronounced in the T4-treated group. Our results demonstrate that thyrotoxicosis, whether induced by T3 or T4, leads to different grades of thyroid tissue injury, including some irreversible damages. These changes might be explained at least in part by lack of trophic and cytoprotective effects of the thyroid stimulating hormone. Since the period required for morphophysiological recovery may be unpredictable, findings presented here should be taken into consideration in cases where the thyroid hormones are used as a treatment for thyroid and non-thyroid related conditions.

Elevated levels of circulating thyroid hormone do not cause the medical sequelae of hyperthyroidism

BACKGROUND

Clinicians have been reluctant to use high dose thyroid (HDT) to treat affective disorders because high circulating levels of thyroid hormone have traditionally been equated with hyperthyroidism, and understood as the cause of the medical sequelae of hyperthyroidism, such as osteoporosis and cardiac abnormalities. This conclusion is not supported by (HDT) research.

METHODS

A literature review of research related to the morbidity and mortality of HDT treatment was performed.

RESULTS

There exists a large body of research involving the use of HDT treatment to prevent the recurrence of differentiated thyroid cancer and to treat affective disorders. A review of this literature finds a lack of support for HDT as a cause of osteoporosis, nor is there support for an increase in morbidity or mortality associated with HDT. This finding contrasts with the well-established morbidity and mortality associated with Graves' disease, thyroiditis, and other endogenous forms of hyperthyroidism.

DISCUSSION

The lack of evidence that exogenous HDT causes osteoporosis, cardiac abnormalities or increases mortality compared with the significant morbidity and mortality of hyperthyroidism requires an alternative cause for the medical sequelae of hyperthyroidism. One possibility is an autoimmune mechanism.

CONCLUSION

High circulating levels of thyroid hormone is not the cause of the sequela of hyperthyroidism. The reluctance to using high dose thyroid is unwarranted.

A hypothesis on the mechanism of action of high-dose thyroid in refractory mood disorders

Multiple lines of evidence suggest the hypothesis that high dose thyroid therapy corrects for cellular hypothyroidism found in bipolar disorders. Evidence indicates that bipolar disorders are associated with mitochondrial dysfunction which results in low cellular adenosine 5'-triphosphate (ATP) levels. Transport of thyroid hormones into cells is energy intensive and dependent on ATP except in the pituitary gland. Inadequate ATP levels makes it difficult to get thyroid hormone into cells leading to cellular hypothyroidism. This creates a condition where the blood and pituitary levels of thyroid hormone are normal but low in other tissues. High dose thyroid therapy produces a gradient that is sufficient for thyroid hormone to diffuse into cells correcting cellular hypothyroidism. If this hypothesis is correct there are number of implications. The two most important are: On average patients suffering from a bipolar disorder die 10-20years earlier than the general population. The medical sequelae associated with bipolar disorders cause far more deaths than suicide. If high dose thyroid corrects for cellular hypothyroidism it could well decrease the medical morbidity and mortality associated with bipolar disorders that are the result of cellular hypothyroidism. Thus high dose thyroid would be a first treatment that decreases the considerable medical morbidity and mortality associated with the bipolar disorders. This would stand in stark contrast to most psychiatric medications that can that increase morbidity and mortality. It would also reinforce the safety of HDT. The second implication is thyroid hormone blood levels in patients suffering from a bipolar disorder do not accurately reflect the true thyroid status.

Levothyroxine effects on depressive symptoms and limbic glucose metabolism in bipolar disorder: a randomized, placebo-controlled positron emission tomography study

Adding supraphysiologic doses of levothyroxine (L-T4) to standard treatment for bipolar depression shows promise, but the mechanisms underlying clinical improvement are unknown. In a previous pilot study, L-T4 treatment reduced depression scores and activity within the anterior limbic network. Here we extended this work in a randomized, double-blind, placebo-controlled study of patients with bipolar depression. Cerebral glucose metabolism was assessed with positron emission tomography and [F-18]fluorodeoxyglucose before and after 6 weeks of treatment with L-T4 (n=15) or placebo (n=10) in 12 volumes of interest (VOIs): the bilateral thalamus, amygdala, hippocampus, dorsal striatum and ventral striatum, and midline cerebellar vermis and subgenual cingulate cortex. Radioactivity in the VOIs, normalized to whole-brain radioactivity was taken as a surrogate index of glucose metabolism, and markers of thyroid function were assayed. Changes in brain activity and their association with clinical response were assessed using statistical parametric mapping. Adjunctive L-T4 treatment produced a significant decline in depression scores during the 6-week treatment. In patients treated with L-T4, we found a significant decrease in regional activity at P<0.05 after Bonferroni correction in the left thalamus, right amygdala, right hippocampus, left ventral striatum and the right dorsal striatum. Decreases in the left thalamus, left dorsal striatum and the subgenual cingulate were correlated with a reduction in depression scores (P<0.05 after Bonferroni correction). Placebo treatment was associated with a significant decrease in activity only in the right amygdala, and no region had a change in activity that was correlated with change in depression scores. The groups differed significantly in the relationship between the changes in depression scores and in activity in the thalamus bilaterally and the left ventral striatum. The findings provide evidence that administration of supraphysiologic thyroid hormone improves depressive symptoms in patients with bipolar disorder by modulating function in components of the anterior limbic network.

Hypothyroidism due to Hashimoto's thyroiditis masked by anorexia nervosa

Anorexia nervosa (AN) is typically associated with altered thyroid function tests, notably a low total and free T3 , and lower, but within normal range, free T4 and TSH. A 16-year-old girl with a four-year history of AN presented with elevated TSH that fluctuated with changes in weight. TSH was within normal limits (1.7-3.64 mIU/L) following periods of weight loss and elevated with weight gain (5.9-21.66 mIU/L). Antithyroperoxidase antibodies were markedly elevated, suggesting chronic Hashimoto's thyroiditis. Of note, the elevated TSH that would be expected in Hashimoto's thyroiditis was blunted by weight loss associated with AN. Physicians should be aware that AN may contribute to masking thyroid abnormalities in Hashimoto's thyroiditis.

A favorable risk-benefit analysis of high dose thyroid for treatment of bipolar disorders with regard to osteoporosis

High dose thyroid hormone has been in use since the 1930s for the treatment of affective disorders. Despite numerous papers showing benefit, the lack of negative trials and its inclusion in multiple treatment guidelines, high dose thyroid has yet to find wide spread use. The major objection to the use of high dose thyroid is the myth that it causes osteoporosis. This paper reviews the literature surrounding the use of high dose thyroid, both in endocrinology and in psychiatry. High dose thyroid does not appear to be a significant risk factor for osteoporosis while other widely employed psychiatric medications do pose a risk. Psychiatrists are uniquely qualified to do the risk-benefit analyses of high dose thyroid for the treatment of the bipolar I, bipolar II and bipolar NOS. Other specialties do not have the requisite knowledge of the risks of alterative medications or of the mortality and morbidity of the bipolar disorders to do a full risk benefit analysis.

Gender differences in thyroid system function: relevance to bipolar disorder and its treatment

OBJECTIVES

Thyroid hormones play a critical role in the functioning of the adult brain, and thyroid diseases impair both mood and cognition. This paper reviews gender differences in thyroid system function that are relevant to the diagnosis and treatment of bipolar disorder.

METHODS

The study comprised a comprehensive literature review of gender differences in thyroid disease that are pertinent to mood disorders.

RESULTS

The prevalence of thyroid disease was found to be much higher in females than males, and to increase with age. The most commonly detected abnormality was subclinical hypothyroidism, which was found to occur in up to 20% of postmenopausal women. Females also had higher rates of thyroid autoimmunity. Individuals at risk for thyroid disease, such as adult females, may have had less ability to compensate for additional challenges to thyroid metabolism, including lithium treatment. Thyroid abnormalities were associated with a poorer response to standard treatments for mood disorders. Females with treatment-resistant mood disorders may have responded better than males to adjunctive therapy with thyroid hormones.

CONCLUSIONS

Disturbances of thyroid system function, which occur commonly in females, may complicate the diagnosis and treatment of mood disorders. In particular, this is clinically relevant during lithium treatment because lithium may impair vital thyroid metabolic pathways secondary to its anti-thyroid activity.

Mechanisms of action of thyroid hormones in the skeleton

BACKGROUND

Thyroid hormones regulate skeletal development, acquisition of peak bone mass and adult bone maintenance. Abnormal thyroid status during childhood disrupts bone maturation and linear growth, while in adulthood it results in altered bone remodeling and an increased risk of fracture

SCOPE OF REVIEW

This review considers the cellular effects and molecular mechanisms of thyroid hormone action in the skeleton. Human clinical and population data are discussed in relation to the skeletal phenotypes of a series of genetically modified mouse models of disrupted thyroid hormone signaling.

MAJOR CONCLUSIONS

Euthyroid status is essential for normal bone development and maintenance. Major thyroid hormone actions in skeletal cells are mediated by thyroid hormone receptor α (TRα) and result in anabolic responses during growth and development but catabolic effects in adulthood. These homeostatic responses to thyroid hormone are locally regulated in individual skeletal cell types by the relative activities of the type 2 and 3 iodothyronine deiodinases, which control the supply of the active thyroid hormone 3,5,3'-L-triiodothyronine (T3) to its receptor.

GENERAL SIGNIFICANCE

Population studies indicate that both thyroid hormone deficiency and excess are associated with an increased risk of fracture. Understanding the cellular and molecular basis of T3 action in skeletal cells will lead to the identification of new targets to regulate bone turnover and mineralization in the prevention and treatment of osteoporosis. This article is part of a Special Issue entitled Thyroid hormone signaling.