Takotsubo Cardiomyopathy in the Setting of Myxedema Coma

Myxedema coma and its treatment are potent physical stressors that likely predispose patients to develop Takotsubo cardiomyopathy (TCM). We postulate a multifactorial pathophysiology for TCM that includes a mechanism involving catecholamine-induced potentiation of cardiac adrenoreceptors during thyroid hormone replacement in the setting of severe hypothyroidism. Furthermore, TCM can be difficult to anticipate when presenting as a complication of another diagnosis. In this case report, we aim to improve awareness of TCM as a consequence of extreme hypothyroid states.

Evaluation of Thyroid Hormone Replacement Dosing in Morbidly Obese Hypothyroid Patients after Bariatric Surgery-Induced Weight Loss

The most frequent endocrine disease in obese patients is hypothyroidism. To date, there are no clear data regarding what happens to the dose of levothyroxine (LT4) after bariatric surgery (BS). The objective of the present study was to evaluate thyroid hormone replacement dose in morbidly obese hypothyroid patients after BS-induced weight loss. We explore the best type of measured or estimated body weight for LT4 dosing. We performed an observational study evaluating patients with morbid obesity and hypothyroidism who underwent BS. We included 48 patients (three men). In morbidly obese hypothyroid patients 12 months after BS-induced weight loss, the total LT4 dose or the LT4 dose/kg ideal body weight did not change, while there was a significant increase in LT4 dose/body surface area, LT4 dose/kg weight, LT4 dose/kg adjusted body weight, LT4 dose/kg body fat, and LT4 dose/kg lean body weight. There were no differences in LT4 dose and its variation between sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). The present study strongly suggests that LT4 dosing in obese hypothyroid patients can be individually adapted more precisely if it is based on ideal body weight.

Patient satisfaction and quality of life in hypothyroidism: An online survey by the british thyroid foundation

OBJECTIVE

Dissatisfaction with treatment and impaired quality of life (QOL) are reported among people with treated hypothyroidism. We aimed to gain insight into this.

DESIGN AND PATIENTS

We conducted an online survey of individuals with self-reported hypothyroidism.

RESULTS

Nine hundred sixty-nine responses were analysed. Dissatisfaction with treatment was common (77.6%), and overall QOL scores were low. Patient satisfaction did not correlate with type of thyroid hormone treatment, but treatment with combination levothyroxine (L-T4) and liothyronine (L-T3) or with desiccated thyroid extract (DTE) was associated with significantly better reported QOL than L-T4 or L-T3 monotherapies (P < .001); however, multivariate analysis inclusive of other clinical parameters failed to confirm an association between type of thyroid hormone treatment and QOL or satisfaction. Multivariate analysis showed positive correlations between satisfaction and age (P = .026), male gender (P = .011), being under the care of a thyroid specialist (P < .001), family doctor (GP) prescribing DTE or L-T4 + L-T3 or L-T3 (P < .001) and being well informed about hypothyroidism (P < .001); negative correlations were observed between satisfaction and negative experiences with L-T4 (P < .001) and expectations for more support from the GP (P < .001), for L-T4 to resolve all symptoms (P = .004), and to be referred to a thyroid specialist (P < .001). For QOL, positive correlations were with male gender (P = .011) and duration of hypothyroidism (P = .002); negative correlations were with age (P = .027), visiting the GP more than 3 times before diagnosis (P < .001), sourcing DTE or L-T3 independently (P = .014), negative experiences with L-T4 (P = .013), having expectations for L-T4 to resolve all symptoms (P < .001) and of more support from the GP (P = .006).

CONCLUSIONS

Multiple parameters including prior healthcare experiences and expectations influence satisfaction with hypothyroidism treatment and QOL. Focusing on enhancing the patient experience and clarifying expectations at diagnosis may improve satisfaction and QOL.

Prediction of Thyroid Hormone Replacement Following Thyroid Lobectomy: A Long-term Retrospective Study

Objective

Following thyroid lobectomy, patients are at risk for hypothyroidism. This study sought to determine the incidence of postlobectomy thyroid hormone replacement as well as predictive risk factors to better counsel patients.

Study Design

Retrospective cohort study.

Setting

Patients aged 18 to 75 years treated in a single academic institution who underwent thyroid lobectomy from October 2006 to September 2017.

Methods

Patients were followed for an average of 73 months. Demographic data, body mass index, size of removed and remnant lobe, preoperative thyroid-stimulating hormone (TSH) level, final thyroid pathology, and presence of thyroiditis were collected and analyzed. Risk factors were evaluated with chi-square analyses, t tests, logistic regression, and Kaplan-Meier analysis.

Results

Of the 478 patients reviewed, 369 were included in the analysis, 30% of whom eventually required thyroid hormone replacement. More than 39% started therapy >12 months postoperatively, with 90% treated within 36 months. Patient age ≥50 years and preoperative TSH ≥2.5 mIU/L were associated with odds ratios of 2.034 and 3.827, respectively, for thyroid hormone replacement. Malignancy on final pathology demonstrated an odds ratio of 7.76 for hormone replacement. Sex, body mass index, volume of resected and remaining lobes, and weight of resected lobe were not significant predictors.

Conclusion

Nearly a third of patients may ultimately require thyroid hormone replacement. Age at the time of surgery, preoperative TSH, and final pathology are strong, clinically relevant predictors of the need for future thyroid hormone replacement. After lobectomy, patients should have long-term thyroid function follow-up to monitor for delayed hypothyroidism.

The effect of oral triiodothyronine supplementation on lactate and pyruvate after paediatric cardiac surgery

OBJECTIVE

To determine if triiodothyronine alters lactate, glucose, and pyruvate metabolism, and if serum pyruvate concentration could serve as a predictor of low cardiac output syndrome in children after cardiopulmonary bypass procedures.

METHODS

This study was ancillary to the Oral Triiodothyronine for Infants and Children undergoing Cardiopulmonary bypass (OTICC) trial. Serum pyruvate was measured in the first 48 patients and lactate and glucose were measured in all 208 patients enrolled in the OTICC study on the induction of anaesthesia, 1 and 24 hours post-aortic cross-clamp removal. Patients were also defined as having low cardiac output syndrome according to the OTICC trial protocol.

RESULT

Amongst the designated patient population for pyruvate analysis, 22 received placebo, and 26 received triiodothyronine (T3). Lactate concentrations were nearly 20 times greater than pyruvate. Lactate and pyruvate levels were not significantly different between T3 and placebo group. Glucose levels were significantly higher in the placebo group mainly at 24-hour post-cross-clamp removal. Additionally, lactate and glucose levels peaked at 1-hour post-cross-clamp removal in low cardiac output syndrome and non-low cardiac output syndrome patients, but subsequently decreased at a slower rate in low cardiac output syndrome. Lactate and pyruvate concentrations correlated with glucose only prior to surgery.

CONCLUSION

Thyroid supplementation does not alter systemic lactate/pyruvate metabolism after cardiopulmonary bypass and reperfusion. Pyruvate levels are not useful for predicting low cardiac output syndrome. Increased blood glucose may be regarded as a response to hypermetabolic stress, seen mostly in patients with low cardiac output syndrome.

Design of the Optimal Trial of Combination Therapy

Patients who take levothyroxine monotherapy to treat hypothyroidism frequently experience residual symptoms despite TSH testing at target levels. Trials have been conducted to evaluate the potential benefit of combination therapy with levothyroxine and liothyronine, though results have not consistently demonstrated benefit. In addition to randomization, placebo-control, and masking, four additional design choices to consider include the study population, dosing strategy for levothyroxine and liothyronine, primary and secondary outcome selection, and statistical power. A thoughtful design that considers these features will increase the likelihood that a combination trial will be considered definitive and finally resolve the important question of whether combination therapy with levothyroxine and liothyronine is a better thyroid replacement strategy than levothyroxine monotherapy.

Management of Subclinical and Overt Hypothyroidism Following Hemithyroidectomy in Children and Adolescents: A Pilot Study

Background: To reduce surgical complications and avoid lifelong thyroid hormone replacement, hemithyroidectomy is preferred in children and adolescents with benign nodular thyroid disease. However, hypothyroidism following hemithyroidectomy may occur, and postoperative thyroid hormone replacement for hypothyroidism following hemithyroidectomy is usually administered without a full understanding of the clinical characteristics of hypothyroidism. Methods: To investigate the incidence and risk factors of hypothyroidism after hemithyroidectomy in children and adolescents, and to identify whether postoperative thyroid hormone replacement is necessary, a retrospective review of 43 patients under 18 years of age who underwent hemithyroidectomy from January 2009 to October 2016 was conducted. All hypothyroid patients were retrospectively analyzed to determine the incidence and predisposing factor(s) of postoperative hypothyroidism. All patients were measured regarding age, sex, serum thyrotropin (TSH), anti-thyroid antibody, and histological evidence of lymphocytic infiltration. Hypothyroid patients were measured for symptoms, timing of diagnosis, and thyroid hormone replacement. Results: The mean age at the time of surgery was 13.65 ± 3.04 years. Of the cohort, 34 patients were female (79.07%), and the mean follow-up time was 28 ± 9 months. Hypothyroidism was diagnosed in 11 of the 43 patients. The mean postoperative TSH level was 7.17 ± 2.13 μIU/ml. The mean preoperative TSH level was 3.11 ± 0.59 μIU/ml in hypothyroid patients compared with 1.92 ± 0.72 μIU/ml in euthyroid patients (P < 0.05). A preoperative TSH level >2.2 μIU/l and lymphocytic infiltration graded 3 or 4 were found to be independent risk factors for the development of hypothyroidism. There were no significant differences between groups in terms of patient age or sex. Conclusions: In the pediatric and adolescent population, patients with elevated preoperative TSH levels or the presence of lymphocytic infiltration may increase the risk of risk of hypothyroidism. In our study, postoperative levothyroxine (L-T4) treatment was necessary in 16.28% of cases after hemithyroidectomy. Patients with mild postoperative hypothyroidism should be followed up, without the need for immediate L-T4 replacement, so as to expect patients to recover spontaneously.

Subclinical Hypothyroidism in Women Planning Conception and During Pregnancy: Who Should Be Treated and How?

Subclinical hypothyroidism (SCH), a mild form of hypothyroidism defined as elevated TSH with normal free thyroxine levels, is a common diagnosis among women of reproductive age. In some, but not all, studies, it has been associated with infertility, an increased risk of adverse pregnancy and neonatal outcomes, and possibly with an increased risk of neurocognitive deficits in offspring. Despite well-established recommendations on treatment of overt hypothyroid pregnant women, a consensus has not yet been reached on whether to treat women with SCH. This review focuses on examining the evidence informing the clinical strategy for using levothyroxine (LT4) in women with SCH during pregnancy and those who are planning conception. A crucial first step is to accurately diagnose SCH using the appropriate population-based reference range. For pregnant women, if this is unavailable, the recommended TSH upper normal limit cutoff is 4.0 mIU/L. There is evidence supporting a decreased risk for pregnancy loss and preterm delivery for pregnant women with TSH > 4.0 mIU/L receiving LT4 therapy. LT4 treatment has been associated with better reproductive outcomes in women with SCH undergoing artificial reproductive techniques, but not in those who are attempting natural conception. Thyroid function tests need to be repeated throughout pregnancy to monitor LT4 therapy. In addition to potential harms, LT4 contributes to treatment burden. During a consultation, clinicians and patients should engage in a careful consideration of the current evidence in the context of the patients’ values and preferences to determine whether LT4 therapy initiation is the best next step.

Variation in the biochemical response to l-thyroxine therapy and relationship with peripheral thyroid hormone conversion efficiency

Several influences modulate biochemical responses to a weight-adjusted levothyroxine (l-T4) replacement dose. We conducted a secondary analysis of the relationship of l-T4 dose to TSH and free T3 (FT3), using a prospective observational study examining the interacting equilibria between thyroid parameters. We studied 353 patients on steady-state l-T4 replacement for autoimmune thyroiditis or after surgery for malignant or benign thyroid disease. Peripheral deiodinase activity was calculated as a measure of T4-T3 conversion efficiency. In euthyroid subjects, the median l-T4 dose was 1.3 μg/kg per day (interquartile range (IQR) 0.94,1.60). The dose was independently associated with gender, age, aetiology and deiodinase activity (all P<0.001). Comparable FT3 levels required higher l-T4 doses in the carcinoma group (n=143), even after adjusting for different TSH levels. Euthyroid athyreotic thyroid carcinoma patients (n=50) received 1.57 μg/kg per day l-T4 (IQR 1.40, 1.69), compared to 1.19 μg/kg per day (0.85,1.47) in autoimmune thyroiditis (P<0.01, n=76) and 1.08 μg/kg per day (0.82, 1.44) in patients operated on for benign disease (P< 0.01, n=80). Stratifying patients by deiodinase activity categories of <23, 23-29 and >29 nmol/s revealed an increasing FT3-FT4 dissociation; the poorest converters showed the lowest FT3 levels in spite of the highest dose and circulating FT4 (P<0.001). An l-T4-related FT3-TSH disjoint was also apparent; some patients with fully suppressed TSH failed to raise FT3 above the median level. These findings imply that thyroid hormone conversion efficiency is an important modulator of the biochemical response to l-T4; FT3 measurement may be an additional treatment target; and l-T4 dose escalation may have limited success to raise FT3 appropriately in some cases.

Impact of elevated thyroid-stimulating hormone levels in polycystic ovary syndrome

The objective of this study was to analyse the impact of elevated thyroid-stimulating hormone (TSH) levels on the metabolic and endocrine phenotype in 583 women with polycystic ovary syndrome (PCOS). Endocrine and metabolic parameters were measured in all patients and compared between women with and without elevated TSH levels. Of the 583 women with PCOS, 125 women (21.4%) had thyroid disturbances (thyroid replacement therapy: 109 women, subclinical hypothyroidism: 16 women). Patients with elevated TSH levels had significantly increased fasting insulin, area under the curve-insulin, homeostatic model assessment-insulin resistance, and total cholesterol (TC)/high-density lipoprotein cholesterol (HDL) ratio and lower free thyroxin, insulin sensitivity and HDL (p < 0.05 for all). Euthyroid PCOS women with thyroid hormone substitution showed significant differences in TSH, age, body mass index, HDL and systolic blood pressure compared to those without hormone replacement therapy (p < 0.05 for all). We conclude that hypothyroid disturbances and elevated TSH levels are common findings in PCOS, which are associated with an adverse metabolic profile. Therefore, women with diagnosed PCOS should be screened for thyroid dysfunction.