Hypothyroidism

Thyroid hormone treatment counteracts cellular phenotypical remodeling in diabetic organs

Diabetes mellitus and alterations in thyroid hormone (TH) signaling are closely linked. Though the role of TH signaling in cell differentiation and growth is well known, it remains unclear whether its alterations contribute to the pathobiology of diabetic cells. Here, we aim to investigate whether the administration of exogenous T3 can counteract the cellular remodeling that occurs in diabetic cardiomyocytes, podocytes, and pancreatic beta cells. Treating diabetic rats with T3 prevents dedifferentiation, pathological growth, and ultrastructural alterations in podocytes and cardiomyocytes. In vitro, T3 reverses glucose-induced growth in human podocytes and cardiomyocytes, restores cardiomyocyte cytoarchitecture, and reverses pathological alterations in kidney and cardiac organoids. Finally, T3 treatment counteracts glucose-induced transdifferentiation, cell growth, and loss in pancreatic beta cells through TH receptor alpha1 activation. Our studies indicate that TH signaling activation substantially counteracts diabetes-induced pathological remodeling, and provide a potential therapeutic approach for the treatment of diabetes and its complications.

Evaluation of visual functions in Iranian hypothyroid adults

INTRODUCTION

The aim of this study was to investigate the effects of hypothyroidism on visual functions such as visual acuity, refractive errors, colour vision, and contrast sensitivity, among hypothyroid adults.

METHODS

Forty-three patients with clinical hypothyroidism along with 43 age- and sex-matched healthy individuals underwent visual examinations, including visual acuity, refractive errors, eye deviations with the cover test, colour vision with the D15 test, and contrast sensitivity with Pelli-Robson test.

RESULTS

It was indicated that visual acuity, refractive errors, phoria, and colour vision had no significant difference between the hypothyroid and control groups. Contrast sensitivity decreased in hypothyroid subjects as compared with controls. The mean values of binocular contrast sensitivity were 1.85 ± 0.09 log in the hypothyroid group and 1.93 ± 0.09 log in controls, which showed a statistically significant difference (p = .03).

CONCLUSIONS

Our findings illustrated a reduced contrast sensitivity in adult hypothyroidism. Since CS is related to functioning and quality of life, a comprehensive and detailed eye examination may be beneficial for hypothyroidism patients.

Mechanism and efficacy of parathyroid hormone in osteoporosis

Background: Parathyroid hormone (PTH) and teriparatide, which is a PTH analog, are special options of osteoanabolic therapies for osteoporosis treatment. Their efficacy in improving the bone mineral density (BMD) and reducing fracture risk is considered to have a long-awaited justification.Current Concepts: PTH is an 84-amino acid polypeptide that plays a key role in the calcium homeostasis of the human body. It yields anabolic effects on the bone by intermittent injections. During the first 6 months of PTH treatment, bone formation increases rapidly and bone resorption rises gradually. PTH is believed to be maximally anabolic during the anabolic window. In the phase III trial of teriparatide, significant reductions in vertebral and non-vertebral fractures were identified. Teriparatide has been studied in drug-induced osteoporosis, postmenopausal women with osteoporosis, and men with osteoporosis. The data derived from clinical trials with teriparatide showed an increase of the BMD in the treatment group compared to that of the placebo. Selective advantages on fracture healing have been shown in some studies; however, consensus on the relationship between teriparatide and bone healing is unclear.Discussion and Conclusion: Teriparatide has been approved for osteoporosis treatment in various situations, including postmenopausal women, men with osteoporosis, and cases with glucocorticoid-induced osteoporosis. Additionally, it can be useful in high risk for fracture groups, if fractures persist despite bone resorption inhibitor therapy, and if bone resorption inhibitor administration is difficult and contraindicated.

Optimal Hormone Replacement Therapy in Hypothyroidism - A Model Predictive Control Approach

In this paper, we address the problem of optimal thyroid hormone replacement strategy development for hypothyroid patients. This is challenging for the following reasons. First, it is difficult to determine the correct dosage leading to normalized serum thyroid hormone concentrations of a patient. Second, it remains unclear whether a levothyroxine L-T₄) monotherapy or a liothyronine/levothyroxine (L-T₃/L-T₄) combined therapy is more suitable to treat hypothyroidism. Third, the optimal intake frequency of L-T₃/L-T₄ is unclear. We address these issues by extending a mathematical model of the pituitary-thyroid feedback loop to be able to consider an oral intake of L-T₃/L-T₄. A model predictive controller (MPC) is employed to determine optimal dosages with respect to the thyroid hormone concentrations for each type of therapy. The results indicate that the L-T₃/L-T₄ combined therapy is slightly better (in terms of the achieved hormone concentrations) to treat hypothyroidism than the L-T₄ monotherapy. In case of a specific genetic variant, namely genotype CC in polymorphism rs2235544 of gene DIO1, the simulation results suggest that the L-T₄ monotherapy is better to treat hypothyroidism. In turn, when genotype AA is considered, the L-T₃/L-T₄ combined therapy is better to treat hypothyroidism. Furthermore, when genotype CC of polymorphism rs225014 (also referred to as c.274A>G or p.Thr92Ala) in the DIO2 gene is considered, the outcome of the L-T₃/L-T₄ combined therapy is better in terms of the steady-state hormone concentrations (for a triiodothyronine setpoint at the upper limit of the reference range of healthy individuals). Finally, the results suggest that two daily intakes of L-T₃ could be the best trade-off between stable hormone concentrations and inconveniences for the patient.

Quantitative Analysis of the Proteome and the Succinylome in the Thyroid Tissue of High-Fat Diet-Induced Hypothyroxinemia in Rats

Hypothyroidism is a common disease, and its molecular mechanism still needs further investigation. Lysine succinylation is found to be involved in various metabolic processes associated with hypothyroidism. We performed quantitative analysis on lysine succinylome in thyroids of rats with hypothyroxinemia, which was induced through the administration of a high-fat diet. Overall, 129 differentially expressed proteins were quantified. Downregulated proteins were enriched in the thyroid hormone synthesis and thyroid hormone signaling pathways and were mainly localized in the mitochondria. In addition, 172 lysine succinylation sites on 104 proteins were obviously changed. Decreased succinylated proteins were involved in diverse metabolic pathways and were primarily localized in mitochondria. Finally, the mitochondrial oxygen consumption rates of human normal thyroid epithelial cells were measured to further verify the role of lysine succinylation. The mitochondrial oxygen consumption rates were markedly blunted in the cells treated with palmitic acid (all p < 0.05), and the changes were reversed when the cells were treated with palmitic acid and desuccinylase inhibitor together (all p < 0.05). Thus, we theorize that the thyroid differentially expressed proteins and changed succinylation levels played potential roles in the mitochondria-mediated energy metabolism in the high-fat diet-induced hypothyroxinemia rat model.

A High-Fat Diet Rich in Saturated and Mono-Unsaturated Fatty Acids Induces Disturbance of Thyroid Lipid Profile and Hypothyroxinemia in Male Rats

SCOPE

Increasing evidence has shown that the disturbance of lipid metabolism might make a possible contribution to the pathogenesis of organ dysfunction, including thyroid, yet it is unknown whether excess intake of dietary fat interferes in thyroid lipid profile. We investigate the effects of dietary fat toward the thyroid lipid profile and thyroid function.

METHODS AND RESULTS

Male Sprague-Dawley rats are fed with high-fat diet (HFD) rich in saturated and mono-unsaturated fatty acids or chow diet for 18 weeks. LC-MS analysis of thyroid shows that total free fatty acids (FFAs) content is significantly higher in HFD rats. The concentration of highly saturated triglycerides significantly increases in HFD rats, whereas the polyunsaturated triglyceride significantly decreases, indicating the decrease in unsaturation in the HFD group. Significant increase of lysophosphatidylcholines (LPC) is observed in HFD rats. Thyroid function tests show hypothyroxinemia (total thyroxine [TT₄ ] and free thyroxine [FT₄ ]) in HFD rats, and elevated thyrotropin (TSH) concentration. The HFD rats also show decreased thyroid uptake of iodine.

CONCLUSION

Excess intake of dietary fat induces disturbance of thyroid lipid profile and hypothyroxinemia, indicating thyroid dysfunction. We speculate that it may provide a new prospect in understanding the pathogenesis of hypothyroidism.

A RARE CASE OF SEVERE TYPE 4 POLYGLANDULAR AUTOIMMUNE SYNDROME IN A YOUNG ADULT

Objective

The association of type 1 diabetes mellitus with autoimmune thyroiditis or with celiac disease is frequently mentioned in literature, but the concomitant presence of these three autoimmune diseases, especially in adults, represents a rarity.

Case report

We present the case of a young man with severe generalized oedema admitted to the emergency department and diagnosed with severe hypothyroidism (TSH=100 μUI/mL, fT4 = 0.835 pmol/L) in the context of a long-lasting autoimmune thyroiditis (anti-TPO antibodies 64 UI/mL, anti-TG antibodies 17 UI/mL, the thyroid ultrasonography). At the same time, he was diagnosed with type 1 diabetes mellitus. He was also submitted to further tests which confirmed the diagnosis of celiac disease (endoscopy with intestinal mucosa biopsy, confirmed by immunological tests). The association of these three diseases slows down the process of reaching a final diagnosis and delays the adoption of a therapeutic strategy.

Conclusion

This case underlines the difficulty of differential diagnosis of severe oedema syndrome with polyserositis in a patient with polyglandular autoimmune syndrome. Whenever there is a suspicion of the association of these autoimmune diseases, the evolution of the patient is unpredictable and most medical results are highly dependent upon the decision of applying a concomitant treatment.

Hypothyroidism in clinical practice

Background:

Hypothyroidism is the most common endocrine disease that was seen in the clinical practice especially for family physicians.

Methods:

This review article covered the important practical clinical issues for managing overt hypothyroidism, subclinical hypothyroidism and hypothyroidism during pregnancy.

Conclusions:

The clinical issues were addressed by clinical scenario followed by questions and stressed on the important clinical points.

Associations between thyroid function and mortality: the influence of age

OBJECTIVE

The aim of this study was to investigate the influence of age on the association between thyroid function and mortality.

DESIGN

The Nijmegen Biomedical Study is a population-based study, comprising 5816 randomly selected adults of all age groups without previously known thyroid disease.

METHODS

TSH, free thyroxine (FT4) and peroxidase antibodies were measured in 2002-2003. The number of deaths were established in 2012 (median follow-up time 9.4 years).

RESULTS

Subclinical thyrotoxicosis was associated with mortality in subjects aged <65 years (hazard ratio (HR) 2.5, 95% CI 1.1-5.7), but not in subjects aged >65 years. As for thyroid function within the normal range: in the 493 participants aged 80 years or older, an FT4 level in the high-normal range (18.5-22 pmol/l) was associated with a higher mortality in comparison with FT4 levels in the middle range (11.5-15.0 pmol/l): HR 1.7 (95% CI 1.0-2.9). In these elderly, TSH levels within the high-normal range (3.0-4.0 mIU/l) were also associated with a higher mortality in comparison with TSH levels within the middle range (1.0-2.0 mIU/l): HR 1.8 (95% CI 1.0-3.1).

CONCLUSIONS

The relationship between thyroid function and mortality differs according to age. This finding might (partially) explain the discrepant results of previous studies examining the relationship between thyroid function and mortality in different age groups.

Is there a relationship between fatigue perception and the serum levels of thyrotropin and free thyroxine in euthyroid subjects?

BACKGROUND

Thyrotoxicosis and hypothyroidism are associated with fatigue. Here we studied euthyroid subjects to determine if there was a relationship between serum thyrotropin (TSH), free thyroxine (FT(4)) and thyroperoxidase antibodies and fatigue.

METHODS

A total of 5897 participants of the Nijmegen Biomedical Study received a questionnaire and serum TSH (normal range 0.4-4.0 mIU/L) and FT(4) (normal range 8-22 pmol/L) were measured. Fatigue was evaluated by the RAND-36 and the shortened fatigue questionnaire (SFQ).

RESULTS

Euthyroid subjects with a serum TSH level of 0.4-1.0 mIU/L had a lower RAND-36 vitality score (65.2 vs. 66.8; regression coefficient (RC) -1.6 [95% confidence interval (CI) -2.6 to -0.5]; p=0.005) and a higher SFQ score (11.7 vs. 11.0; RC 0.6 [CI 0.2-1.0]; p=0.004) than those with a TSH of 1.0-2.0 mIU/L. Those with a serum FT(4) of 18.5-22 pmol/L reported fatigue more often (52.5% vs. 33.3%; relative risk (RR) 1.4 [CI 1.0-1.9]; p=0.03), had a lower RAND-36 vitality score (61.7 vs. 66.6; RC -4.4 [CI -8.1 to -0.6]; p=0.02) and a higher SFQ score (13.2 vs. 11.0; RC 1.9 [CI 0.4-3.3]; p=0.01) than subjects with a FT(4) level of 11.5-15 pmol/L. In comparison to euthyroid subjects without known thyroid disease, euthyroid subjects with previously known thyroid disease reported fatigue more often (52.3% vs. 34.0%; RR 1.3 [CI 1.0-1.5]; p=0.025), had a lower RAND-36 vitality score (61.4 vs. 66.3; RC -2.9 [CI -5.3 to -0.6]; p=0.015) and a higher SFQ score (13.7 vs. 11.1; RC 1.4 [CI 0.5-2.3]; p=0.002).

CONCLUSION

In euthyroid individuals without a history of thyroid disease, there is a modest relationship between thyroid function and fatigue with subjects having an apparently higher production of T(4) experiencing more fatigue. Subjects with a history of thyroid disease, but with normal TSH and FT(4) concentrations, experience more fatigue than the general population. The reasons for this are unclear, but subtle abnormalities in the dynamics of thyroid hormone secretion should be considered.

Association between thyroid function, thyroid autoimmunity, and state and trait factors of depression

OBJECTIVE

The aim of this study was to investigate whether thyroid function and thyroid peroxidase antibodies (TPOAb) are associated with depression, when using both state and trait parameters of depression.

METHOD

In 1125 participants of the Nijmegen Biomedical Study, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and TPOAb were measured twice. The Beck Depression Inventory (BDI), a self-reported lifetime diagnosis of depression, and the neuroticism scale of the Eysenck Personality Questionnaire Revised Short Scale (EPQ-RSS) were used to evaluate the presence of state and trait features of depression.

RESULTS

We found no association between TSH and FT4 levels and BDI score, current depression, lifetime diagnosis of depression, and EPQ-RSS neuroticism score. Subjects with TPOAb had higher EPQ-RSS neuroticism scores in comparison with subjects without TPOAb, mean score 4.1 vs. 3.2 (regression coefficient 0.70; 95% CI 0.1-1.3; P-value 0.02 after adjustment for confounders). The prevalence of a lifetime diagnosis of depression was higher in subjects with positive TPOAb in comparison with participants without TPOAb: 24.2% vs. 16.7% (relative risk 1.4; 95% CI 1.0-2.1; P-value 0.04 after adjustment for confounders).

CONCLUSION

Thyroid peroxidase antibodies are positively associated with trait markers of depression. The presence of TPOAb may be a vulnerability marker for depression.

A mind-body treatment for hypothyroid dysfunction: a report of two cases

PURPOSE

For many years hypothyroid dysfunction has been treated with standard medical approaches yet some seek newer experimental conservative approaches. This paper describes the management of a new conservative approach to management in two individuals who sought treatment from a practitioner specialising in a new integrative mind-body based treatment. The purpose of this study is to present two case studies of the management of hypothyroid dysfunction using the mind-body neuro-emotional technique (NET).

METHOD

The study was set in a private practice setting in Sydney, Australia. Two cases had been diagnosed with primary hypothyroidism by independent medical and laboratory based assessment, of which conservative management had not resolved the symptoms. Both cases underwent a schedule of NET as a modality to treat their hypothyroidism.

RESULTS

Objective measures such as thyroid stimulating hormone and T(4) levels were reported, along with more subjective measures such as feelings of tiredness and general well being. In both cases, there were improvements in TSH and T(4) levels, both returning to normal levels.

CONCLUSIONS

Thyroid dysfunction has been effectively treated by conventional medicine for many years. Changes in thyroid dysfunction after a course of NET have been described. As the standard medical model is associated with some adverse effects such as long-term medication use and potential side effects, all natural, non-invasive approaches to management should be reviewed. Further research into this mind-body therapy is recommended to evaluate its potential effectiveness for this common condition.

Etiologic discussion and clinical relevance of thyroid ultrasonography in subclinical hypothyroidism. A retrospective study in 1845 patients

BACKGROUND

Acquired subclinical hypothyroidism in adulthood is mainly due to autoimmune thyroiditis. In the absence of a goiter or a palpable firm thyroid, measurement of thyroid antibodies can improve the diagnosis. Whether thyroid antibodies are detected or not, what might be the clinical relevance of ultrasonography in this setting?

METHODS

We studied 1845 cases of subclinical hypothyroidism in adults recruited for symptoms indicative of hypothyroidism or thyroid pathology. All patients were screened for thyroid antibodies and underwent an ultrasonographic thyroid examination. LOCALISATION: Multicentric retrospective study.

RESULTS

Chronic autoimmune thyroiditis was confirmed in 70% of patients. Thyroid antibodies were undetectable in 30% of patients. In all patients, thyroid ultrasound facilitated measurement of the thyroid volume and detection of non-palpable nodules and therefore allowed biopsy. In patients negative for thyroid antibodies, ultrasonography suggested autoimmune thyroiditis in 31% of cases. Ultrasonography did not contribute to diagnosis in a large number of patients without nodules and in case of normal echostructure. The strategy of thyroid hormone replacement therapy was not influenced by ultrasonographic data. Thyroid biopsies detected smears suspected to be cancerous in 10 patients (4%). Cancer was confirmed in nine patients after surgery. Ultrasonography displayed suspicious aspects in six patients.

CONCLUSION

In subclinical hypothyroidism, thyroid ultrasonography is not required for the diagnosis of autoimmune thyroiditis but is useful for patients with abnormal thyroid palpation and allows detection of non-palpable thyroid nodules. For patients that were negative for thyroid antibodies, thyroid ultrasonography can improve diagnosis for some patients, allowing detection of autoimmune thyroiditis.

Importância da ecogenicidade da tireóide no diagnóstico da tireoidite crônica auto-imune

A tireoidite crônica auto-imune é, atualmente, a principal causa de hipotireoidismo e seu diagnóstico baseia-se nas manifestações clínico-laboratoriais. O marcador laboratorial mais importante é a presença de anticorpos antitireoglobulina e antiperoxidase, sendo este último o teste mais sensível. A biópsia aspirativa apresenta alta sensibilidade e especificidade, porém, é um método invasivo e, por isso, reservado para quando há presença de nódulo ou bócio de crescimento rápido. A cintilografia é desnecessária para o diagnóstico, já que apresenta baixa sensibilidade e especificidade. A ultra-sonografia, tanto ao modo B como ao dúplex-Doppler colorido, evoluiu de forma muito rápida e tornou-se um método simples, não-invasivo, reprodutível e com alta sensibilidade para o diagnóstico da tireoidite crônica auto-imune. Ao modo B, a ecogenicidade é um parâmetro de extrema importância, já que, além de apresentar alta correlação com o quadro citopatológico, também apresenta alta sensibilidade para o diagnóstico da tireoidite crônica auto-imune. Embora este parâmetro não seja específico da tireoidite crônica auto-imune, pois também pode estar presente na doença de Graves, na tireoidite pós-parto e na tireoidite subaguda, tais desordens podem ser facilmente diferenciadas tanto pelo quadro clínico-laboratorial quanto pelo dúplex-Doppler colorido. Assim, este artigo tem o objetivo de revisar a importância do estudo da ecogenicidade no diagnóstico da tireoidite crônica auto-imune.

A case of subclinical hypothyroidism developing marked pleural effusions and peripheral edema with elevated vascular endothelial growth factor

A 69-year-old woman was admitted for the treatment of marked pleural effusions and peripheral edema. Analytical studies of the pleural effusion revealed exudates. Culture for bacterial organisms and tuberculosis were negative, and cytology was normal. She had a mediastinal tumor at the age of 61 and regular follow-up showed no evidence of malignancy. She underwent the mediastinal tumor resection, because we thought this was the cause of her symptoms. However, her clinical symptoms persisted after surgery. Next, we noticed subclinical hypothyroidism, in which serum TSH level was elevated with concomitant normal thyroid hormone levels. In addition, serum vascular endothelial growth factor (VEGF) levels, which have been reported to be related to the pathophysiology of the extravascular volume overload, were elevated. Although her TSH level was slightly elevated (15.4 microU/ml), we started thyroid hormone replacement therapy. This therapy gradually ameliorated her clinical manifestation and abnormal laboratory data, including elevated VEGF levels. These observations indicate that even subclinical hypothyroidism may cause severe clinical manifestations. Furthermore, elevated VEGF may be a contributing factor in the pathogenesis of extravascular volume overload in hypothyroid patients.

A rare case of massive pericardial effusion secondary to hypothyroidism

Massive pericardial effusions secondary to hypothyroidism are rarely seen in the emergency department (ED). The case of a patient presenting with a relatively asymptomatic massive pericardial effusion due to hypothyroidism is described. The patient had a history of laryngeal carcinoma post-total laryngectomy and adjuvant radiotherapy 12 years previous. Although underlying malignancy was in the differential diagnosis, hypothyroidism was diagnosed through a detailed history and physical examination, thereby avoiding the need for pericardiocentesis. Thyroid replacement alone is sufficient for resolution of these effusions, although it may take many months. Pericardiocentesis is indicated only if cardiac tamponade develops. This rare but significant condition should be considered, especially when it occurs after acute cold exposure.

Increased risk of developing affective disorder in patients with hypothyroidism: a register-based study

BACKGROUND

Links between thyroid function and depression have been noted in many contexts. We assessed whether hospitalization with hypothyroidism was a risk factor for developing affective disorder.

METHODS

We conducted a prospective cohort study using historical data from Danish registers. The observational period was 1977-1999. Three study cohorts were identified: all patients with a first hospital admittance with the resulting index discharge diagnoses hypothyroidism, osteoarthritis, or nontoxic goiter. A later hospitalization with a resulting discharge diagnosis of affective disorder was used as event of interest, and rates of readmission were estimated and compared using competing risk models in survival analyses.

FINDINGS

We identified 165,307 patients discharged with an index diagnosis. In the observational period, 1041 events occurred. An index diagnosis of hypothyroidism was associated with an increased risk of hospitalization with affective disorder when compared to the control diseases. The risk of hospitalization with affective disorder was greatest in the first year after index hospitalization.

CONCLUSION

Patients hospitalized with hypothyroidism have a greater risk of readmission with depression or bipolar disorder than control patients. This renders epidemiologic support to theories linking thyroid dysfunction with mood disturbances.

[Acquired childhood and juvenile subclinical hypothyroidism with or without goitre]

OBJECTIVE

Primary acquired childhood and juvenile hypothyroidism is mainly due to chronic thyroiditis or to the after effects of cervical radiotherapy for cancer. In the presence of clinically evocative signs, with a palpable goitre or firm thyroid, hypothyroidism is searched for. However, cases of childhood and juvenile hypothyroidism without goitre have been described.

METHOD

We retrospectively studied childhood and juvenile sub-clinical hypothyroidism in those in whom antithyroid antibodies had been searched for and thyroid ultrasonographic examination had been performed.

RESULTS

In this age group, we studied 34 cases of subclinical hypothyroidism (plasma TSH: 3.6-20 microIU/ml, normal free thyroxin level). In a first group (17 girls/1 boy, mean age: 14.4 years), 50% of patients had an abnormal palpable thyroid and 100% have auto-immunity markers. In the other group (7 girls/9 boys, mean age: 12.0 years), there was no goitre and no auto-immunity marker had been found. The clinical signs that prompted consultation were identical in the two groups and, if no goitre existed, measurement of TSH levels established the diagnosis of the onset of hypothyroidism.

DISCUSSION

It seems that second group patients constituted an unusual entity: predominance of boys, thyroid usually small and lack of auto-immunity markers.

High prevalence of subclinical hypothyroidism in patients with Anderson-Fabry disease

Anderson-Fabry disease is a rare lysosomal storage disorder. It results from a deficiency of the lysosomal alpha-galactosidase A and leads to progressive accumulation of globotriaosylceramide in the endothelium and tissue cells of various organs. Some of the typical clinical findings such as tiredness, dry skin, myalgia and arthralgia as well as vague gastrointestinal complaints are also symptoms of hypothyroidism. Therefore, we studied the thyroid function in patients with Anderson-Fabry disease. Thyroid function was studied in 11 patients (6 female, 5 male) with Anderson-Fabry disease by measuring thyroid-stimulating hormone (TSH) and free thyroxine serum levels. Nine patients had chronic kidney disease with stage 1 and two with stage 5. Subclinical hypothyroidism (normal serum free thyroxine concentrations along with elevated serum TSH levels) was found in 4 of 11 patients (36.4%). Subclinical hypothyroidism was observed in both male and female patients as well as in patients with stage 1 and stage 5 kidney disease. Subclinical hypothyroidism is a common finding in patients with Anderson-Fabry disease, showing an excess prevalence as compared to the normal population. The high frequency seems to be relevant regarding the potential consequences of a hypothyroid state.

Hypothyroidism Presenting as Psychosis: Myxedema Madness Revisited

Hypothyroidism is a medical condition commonly encountered in a variety of clinical settings. The clinical presentations of thyroid hormone deficiency are diverse, complicated, and often overlooked. Hypothyroidism is a potential etiology for multiple somatic complaints and a variety of psychological disturbances. The physical complaints are primarily related to metabolic slowing secondary to lack of thyroid hormone. Psychiatric presentations include cognitive dysfunction, affective disorders, and psychosis. The realization that hypothyroidism might be the potential etiology of an assortment of symptoms is critical in the identification and treatment of the hypothyroid patient. Once hypothyroidism is identified, symptoms usually respond to appropriate thyroid hormone supplementation. This article presents a case of clinical hypothyroidism that came to clinical attention due to psychotic symptoms consisting of auditory and visual hallucinations. The case is followed by a brief discussion of the literature describing the relationship of hypothyroidism and psychiatric symptomatology. References were identified with an English language-based MEDLINE search (1966-2003) using the terms thyroid, hypothyroid, depression, dementia, delirium, mania, bipolar disorder, psychosis, and myxedema and utilization of referenced articles.

Hyperprolactinaemia in hypothyroidism: clinical significance and impact of TSH normalization

OBJECTIVES

Menstrual irregularities in hypothyroidism have been reported to occur less frequently than previously described. We therefore studied the influence of serum PRL in patients with newly diagnosed subclinical and overt hypothyroidism and in hyperprolactinaemic patients treated with T4 to distinguish the impact of hypothyroidism from that of confounding drugs on hyperprolactinaemia and menstrual irregularities.

PATIENTS AND METHODS

PRL was determined in 1003 consecutive hypothyroid patients (TSH > 4.0 mU/l) at referral, and after TSH normalization in 84 (8%) initially hyperprolactinaemic (female, > 480 mU/l; male, > 432 mU/l) subjects. Medical history (psychotropic drugs and oestrogens) and menstrual patterns were assessed at referral and after 8 +/- 5 (mean +/- SD) months of T4 therapy. Pituitary magnetic resonance imaging (MRI) was offered to patients with persistently elevated PRL.

RESULTS

Menstrual disturbancies (oligomenorrhoea/secondary amenorrhoea, O/A) were not more common (P = NS) in hyper- than in normoprolactinaemic women (26% and 16%, respectively). We observed no galactorrhoea and no correlation between PRL and TSH or O/A except in pregnant or lactating women (N = 11). Oestrogens or antidepressants (including selective serotonin reuptake inhibitors) did not cause hyperprolactinaemia but antipsychotic drugs did. PRL decreased with T4 therapy (P < 0.01) in patients not using confounding drugs (from 720 +/- 288 to 360 +/- 192 mU/l) but menstrual irregularities persisted. PRL remained unchanged in patients receiving antipsychotic treatment. PRL was also unchanged in patients with pituitary abnormalities (seven micro-, one macroadenoma).

CONCLUSIONS

Hyperprolactinaemia was not an important feature in patients with newly diagnosed hypothyroidism. Neuroleptic drugs may cause persisting hyperprolactinaemia after TSH normalization. In addition, menstrual disturbancies do not relate to hyperprolactinaemia in hypothyroidism.

Thyroid hormone replacement therapy

Thyroid hormone replacement has been used for more than 100 years in the treatment of hypothyroidism, and there is no doubt about its overall efficacy. Desiccated thyroid contains both thyroxine (T(4)) and triiodothyronine (T(3)); serum T(3) frequently rises to supranormal values in the absorption phase, associated with palpitations. Liothyronine (T(3)) has the same drawback and requires twice-daily administration in view of its short half-life. Synthetic levothyroxine (L-T(4)) has many advantages: in view of its long half-life, once-daily administration suffices, the occasional missing of a tablet causes no harm, and the extrathyroidal conversion of T(4) into T(3) (normally providing 80% of the daily T(3) production rate) remains fully operative, which may have some protective value during illness. Consequently, L-T(4) is nowadays preferred, and its long-term use is not associated with excess mortality. The mean T(4) dose required to normalize serum thyroid stimulating hormone (TSH) is 1.6 microg/kg per day, giving rise to serum free T(4) (fT(4)) concentrations that are slightly elevated or in the upper half of the normal reference range. The higher fT(4) values are probably due to the need to generate from T(4) the 20% of the daily T(3) production rate that otherwise is derived from the thyroid gland itself. The daily maintenance dose of T(4) varies widely between 75 and 250 microg. Assessment of the appropriate T(4) dose is by assay of TSH and fT(4), preferably in a blood sample taken before ingestion of the subsequent T(4) tablet. Dose adjustments can be necessary in pregnancy and when medications are used that are known to interfere with the absorption or metabolism of T(4). A new equilibrium is reached after approximately 6 weeks, implying that laboratory tests should not be done earlier. With a stable maintenance dose, an annual check-up usually suffices. Accumulated experience with L-T(4) replacement has identified some areas of concern. First, the bioequivalence sometimes differs among generics and brand names. Second, many patients on T(4) replacement have a subnormal TSH. TSH values of < or =0.1 mU/l carry a risk of development of atrial fibrillation and are associated with bone loss although not with a higher fracture rate. It is thus advisable not to allow TSH to fall below--arbitrarily--0.2 mU/l. Third, recent animal experiments indicate that only the combination of T(4) and T(3) replacement, and not T(4) alone, ensures euthyroidism in all tissues of thyroidectomized rats. It is indeed the experience of many physicians that there exists a small subset of hypothyroid patients who, despite biochemical euthyroidism, continue to complain of tiredness, lack of energy, discrete cognitive disorders and mood disturbances. As organs vary in the extent to which their T(3) content is derived from serum T(3) or locally produced T(3) from T(4), these complaints may have a biologic substrate; for example, brain T(3) content is largely determined by local deiodinase type II activity. Against this background it is of interest that a number of psychometric scores improved significantly in hypothyroid patients upon substitution of 50 microg of their T(4) replacement dose by 12.5 microg T(3). Confirmatory studies on this issue are urgently awaited. It could well be that a slow-release preparation containing both T(4) and T(3) might improve the quality of life, compared with T(4) replacement alone, in some hypothyroid patients.

Hyperhomocysteinemia and hypercholesterolemia associated with hypothyroidism in the third US National Health and Nutrition Examination Survey

Hypothyroid (thyroid stimulating hormone (TSH)> or =20 mIU/l; N=32) participants in the third National Health and Nutrition Examination Survey, Phase 2 (1991-1994) were compared with non-hypothyroid subjects (0.5 mIU/l<TSH<20 mIU/l; N=6490) to examine the relationship between hypothyroidism and hyperhomocysteinemia (serum total homocysteine>12 micromol/l) and hypercholesterolemia (serum total cholesterol>6.2 mmol/l). After controlling for age, gender, and race ethnicity, the odds ratios (95% confidence interval (CI)) relating hypothyroidism to hyperhomocysteinemia and high total cholesterol were 4.9 (1.8-14.0) and 8.0 (2.9-21.9), respectively. Based on 26 hypothyroid and 5811 non-hypothyroid subjects with triglyceride concentration < or =2.82 mmol/l, the odds ratio for the relationship between hypothyroidism and high low-density lipoprotein (LDL)-cholesterol (>4.6 mmol/l by the Friedewald equation) was 5.3 (95% CI, 1.3-20.9). Adding additional terms to the multivariate logistic regression model had little effect on the odds ratios relating hypothyroidism to high total or LDL-cholesterol, but adding terms for serum creatinine concentration >123.8 micromol/l and for red blood cell folate and serum vitamin B-12 concentrations resulted in an attenuated, but still significant (P<0.05), odds ratio relating hypothyroidism to hyperhomocysteinemia (2.5; 95% CI, 1.0-6.1). Controlling for cigarette smoking, heart attack/stroke history, body mass index, and serum albumin concentration did not affect the odds ratios. Hyperhomocysteinemia and hypercholesterolemia could help to explain the increased risk for arteriosclerotic coronary artery disease in hypothyroidism.

What is the optimal treatment for hypothyroidism?

Standard treatment of primary hypothyroidism is with thyroxine, with the aim of relieving symptoms and bringing the serum TSH (thyroid-stimulating hormone) concentration to within the reference range. Recent research suggests that in some patients symptoms of hypothyroidism persist despite standard thyroxine replacement therapy. The optimal treatment of these patients is not known. Adjusting the thyroxine dose until the serum TSH concentration is in the lower part of the reference range (eg, 0.3-2.0 mU/L) may be beneficial. Animal studies and a single small clinical trial suggest that a combination of thyroxine and T3 (triiodothyronine), rather than thyroxine alone, may be required for optimal thyroid replacement therapy. Further research is needed to determine why some patients appear to have a suboptimal response to thyroxine, and whether combined thyroxine/T3 treatment is preferable to thyroxine alone in these patients.

Hypothyroidism and depression: a therapeutic challenge

OBJECTIVE

To describe a patient with longstanding depression and hypothyroidism who had marked mood improvement only after triiodothyronine (T3) was added to her thyroxine (T4) replacement therapy.

CASE SUMMARY

A 50-year-old white woman had a long history of depression and documented hypothyroidism since 1991. Despite treatment with T4 with dosages up to 0.3 mg/d, she continued to be depressed, have symptoms of hypothyroidism, and have a persistently elevated thyroid-stimulating hormone concentration. Addition of a low dose of T3 to her regimen resulted in significant mood improvement.

DISCUSSION

The relationship between hypothyroidism and depression is well known. It is possible that this patient's long history of depression may have been a consequence of inadequately treated hypothyroidism, due either to poor patient compliance or resistance to T4. Nevertheless, her depression responded to addition of a low dose of T3 to her regimen. This case emphasizes the importance of screening depressed patients for hypothyroidism. Her clinical course also suggests that depression related to hypothyroidism may be more responsive to a regimen that includes T3 rather than to replacement with T4 alone. This is consistent with the observation that T3 is superior to T4 as adjuvant therapy in the treatment of unipolar depression.

CONCLUSIONS

Depressed patients should be screened for hypothyroidism. In hypothyroid patients, depression may be more responsive to a replacement regimen that includes T3 rather than T4 alone. Therefore, inclusion of T3 in the treatment regimen may be warranted after adequate trial with T4 alone.

Aorto-coronary dissection during angioplasty in a patient with myxedema

A 67-year-old man with overt hypothyroidism and medically controlled hypertension was admitted for coronary angiography because of exertional angina. His triiodothyronine (T3) and thyroxine (T4) levels had been low for 4 years. Although signs and symptoms of hypothyroidism were apparent, his hypercholesterolemia was mild. Coronary angiography revealed an eccentric stenosis in the distal portion of the right coronary artery and it was decided to perform angioplasty because his angina had continued in spite of medication. The dissection appeared at the lesion site after the first nominal inflation, and a subsequent image disclosed a spiral dissection from the dilated site to the aortic sinus and peripheral coronary artery. Although emergency stenting could not prevent the extension near the origin of the brachiocephalic artery, the false lumen thrombosed and then diminished with conservative therapy. Aorto-coronary dissection is potentially life-threatening and has been recently reported as a complication during cardiac catheterization procedures. Chronic hypothyroid insufficiency may be one of the risk factors for this complication.

Pituitary disorders. Drug treatment options

Pituitary diseases are relatively common entities in the general population. They include pituitary adenomas and hypopituitarism. Pituitary tumours can cause symptoms of mass effect and hormonal hypersecretion that can be reversed with surgical resection or debulking of the adenoma, radiotherapy, or medical treatment. Transsphenoidal adenomectomy is the treatment of choice for acromegaly, Cushing's disease, gonadotropin-secreting tumours; and thyrotropin (TSH)-secreting adenomas. Pituitary irradiation and medical therapy are secondary options. Conversely, medical treatment is the primary choice for prolactinomas. Dopamine agonists are very effective in the treatment of prolactin (PRL)-secreting tumours, with rates of control as high as 80 to 90% for microprolactinomas (< 10 mm) and 60 to 75% for macroprolactinomas (> or = 10 mm). Somatostatin analogues have also shown efficacy in patients with acromegaly who have not responded to surgery or in patients with TSH-secreting adenomas who have not improved with surgery and radiotherapy. In patients with Cushing's disease, who are not cured surgically or who relapse after pituitary adenomectomy and irradiation, steroidogenic inhibitors can be an efficient method of controlling the hypercortisolism. Pituitary insufficiency is the partial or complete loss of the anterior hypophyseal function, which is due to hypothalamic or pituitary disease. Although the classic sequence of loss of pituitary secretion is growth hormone (GH), gonadotropins, TSH, and corticotropin (ACTH), the order to begin the replacement therapy of the deficient hormone(s) is cortisol, thyroxine, androgens/estrogens and, if necessary, GH. There are multiple preparations that can be used to achieve clinical and biochemical improvement. In general, the hormone replacement therapy is lifelong.

Cardiac function at rest in hypothyroidism evaluated by equilibrium radionuclide angiography

OBJECTIVE

Previous studies have suggested that hypothyroidism affects both systolic and diastolic cardiac function. We have applied equilibrium radionuclide angiography to the study of heart function at rest in hypothyroidism.

DESIGN

A prospective study, evaluating cardiac function at rest in primary hypothyroidism.

METHODS

Cardiac function was studied by means of equilibrium radionuclide angiography. Screening echo-Doppler examinations were performed on each patient.

PATIENTS

Twenty-six consecutive untreated hypothyroid patients without clinical or echocardiographic cardiac disease and 20 healthy matched controls.

RESULTS

Between patients and controls, the time to peak emptying rate (161 +/- 6 msec vs. 144 +/- 6 msec, P < 0.05) and the time to peak filling rate (188 +/- 6 msec vs. 170 +/- 5 msec, P < 0.05), were the only discriminatory parameters. In hypothyroid patients, a trend towards a decrease in diastolic cardiac function, expressed as peak filling rate, was observed: 2.6 +/- 0.1 End Diastolic Volume (EDV)/s vs. 3.0 +/- 0.1 EDV/s, P = 0.06. Within the hypothyroid patient group, the time to peak emptying rate was more prolonged in patients with lower free thyroxine levels (R = -0.60, F = 13.5, P < 0.001). Peak filling rate was decreased in patients with lower free thyroxine levels (R = 0.51, F = 8.4, P < 0.01) whereas the time to peak filling rate was more prolonged (R = -0.62, F = 15, P < 0.001).

CONCLUSION

In a large group of consecutive patients presenting with primary hypothyroidism, even in the absence of clinical cardiac disease and echocardiographic abnormalities, clear changes in myocardial performance at rest were observed. The most obvious effect of thyroid hormone deficiency on the heart was a lengthening of both systolic and early diastolic time characteristics. Diastolic rather than systolic cardiac function was influenced by hypothyroidism.

Outcome of treatment of hyperthyroidism

This is a retrospective study designed to evaluate the initial response to carbimazole in patients with Graves' disease (GD), possible determinants of that response, the frequency of occurrence of adverse effects during treatment with carbimazole and the frequency of transient and permanent hypothyroidism after treatment with 131I in patients with GD and multinodular goiter (MNG). Data were collected from patients who first presented with GD or MNG at the Department of Endocrinology of the Royal Infirmary of Edinburgh between 1 January 1993 and 31 August 1996. Patients were divided into three groups: patients with GD treated with a daily dose of 40 mg carbimazole, patients with GD treated with a single dose of 400 MBq 1311, and patients with MNG treated with the same dose of 131I. Of the patients younger than 30 years, 50% remained biochemically hyperthyroid after 4-6 weeks of treatment with carbimazole, compared to 14% of patients over 30. Other determinants of the response to carbimazole expressed as the fall in thyroid hormone levels after 4-6 weeks were: pretreatment levels of FT4, T3, TRAb and the 4 h 131I uptake, patients with the higher levels responding significantly better to carbimazole. Adverse effects were reported in 11.5% of patients. Of the patients with GD treated with 1311, 62.6% became hypothyroid, transient hypothyroidism occurred in only 2.4% of these cases. The main predictors of development of hypothyroidism were positive titres of antithyroid peroxidase antibodies (AbTPO) and antithyroglobulin antibodies (AbTg), with positive predictive values of 79.5 and 91.6 respectively. None of the patients with MNG became hypothyroid after treatment with 131I, a response significantly different from patients with GD. In conclusion, GD younger patients might benefit from higher initial doses of carbimazole. In patients with positive titres of AbTPO and AbTg, lower doses of 1311 might prevent hypothyroidism. Transient hypothyroidism was underestimated in this study. No permanent thyroxin replacement therapy should be started within the first six months after 131I treatment.

Are thyroid function tests too frequently and inappropriately requested?

In spite of data supporting the use of the serum thyrotropin (TSH) concentration as the best test to detect abnormal thyroid function, measurement of circulating thyroid hormones with or without a serum TSH continues to be frequently requested to evaluate thyroid function. We have analyzed how combinations of thyroid function tests were ordered by referring physicians and the results of the tests in order to offer some suggestions as to how to use thyroid function tests in a cost effective manner. During 1995, 19,181 inpatient and outpatient requests (45,865 different tests) for thyroid function tests were received by the laboratory of a 1600 bed University Hospital in Parma, Italy. The following tests were carried out: T4, free T4, T3, free T3 and TSH. Serum TSH values below and above the normal range were considered to reflect abnormal thyroid function i.e. hyperthyroidism, or hypothyroidism including subclinical disease independent of the results of the other tests. Combinations of ordered tests and the percent of the total for each combination were: TSH+T4+T3 (56%), TSH+FT4+FT3 (14%), TSH (12%), TSH+FT4 (9%), TSH+T4 (1%), TSH+T4+T3+FT4+FT3 (5%), others (3%). The T4+T3+TSH panel (10,780 requests) had normal serum TSH values in 80.6% and the FT4+ FT3+TSH panel (2,590 requests) had normal TSH values in 73.2%. Elevated serum TSH concentrations were observed more frequently in hospitalized than in ambulatory patients (9.7% vs 7.4% p<0.001). T3 (elevated serum T3, normal T4 and low TSH concentrations) and T4 (elevated serum T4, normal T3 and low TSH concentrations) toxicosis were observed in 8.1% and 9.4%, respectively, of the requested test (NS). FT3 and FT4 toxicosis, defined as for T3 and T4 toxicosis, were observed in 7.5% and 4.9%, respectively (NS). The low T3 and low FT3 syndrome in hospitalized patients was present in 1.6% and 2.3% of the requests, respectively (NS). The low T4+low T3 and low FT4+low FT3 syndrome was present in only 0.3% and 0.2%, respectively, of the requests. Our study shows that a) in hospitalized patients thyroid function tests were requested in 20% of the patients and only one in 14 of these patients at the highest could have abnormal thyroid function, as indicated by abnormal TSH value b) FT4 (or T4) is as useful as FT3 (or T3) in the diagnosis of hyperthyroidism, c) in hospitalized patients the low T3 syndrome was far less common than that reported in the literature, probably due to the lower severity of illness, d) panels which include T3 and FT3 are not justified, and e) serum TSH alone is the most appropriate initial thyroid function test.

Long-term outcomes of treatment of hyperthyroidism in Ireland

We investigated the long-term outcome of treatment in 159 patients with hyperthyroidism first seen between 1979 and 1992. Median duration of follow-up was 10 1/2 years. We also inquired into current practice for the follow-up of hyperthyroidism by other endocrinologists in Ireland. Seven cases of unrecognised hyperthyroidism (4 per cent) and one of unrecognised hypothyroidism were identified. Among patients with Graves' disease, of those treated with an antithyroid drug, 28 per cent were in remission, 68 per cent had relapsed and 4 per cent had become hypothyroid. Of those treated by sub-total thyroidectomy, 31 per cent were in remission, 19 per cent had relapsed, 19 per cent were hypothyroid and 31 per cent were sub-clinically hypothyroid. Among patients treated with radioiodine, 19 per cent were euthyroid, 3 per cent were still hyperthyroid and three-quarters had become hypothyroid. In contrast, after radioiodine for toxic nodular goitre, 63 per cent were euthyroid and only 32 per cent had become hypothyroid (Chi Squared v. Graves' disease, P = 0.001). Of 73 patients receiving thyroxine replacement, plasma TSH was normal in only 41 per cent, although 82 per cent of patients had been seen by the family doctor within the previous 12 months. Seven of 17 other endocrinologists undertook long-term follow-up of hyperthyroid patients in their specialist clinics but none was using a computerised system to co-ordinate this. The findings confirm that careful follow-up is required for all hyperthyroid patients. The family doctor is well positioned to undertake this, but education and auditing are required.