Indications for Intravenous T3 and T4.

Therapy with thyroid hormones normally is restricted to substitution therapy of patients with primary or secondary hypothyroidism. Typically, thyroid hormones are given orally. There are few indications for intravenous use of thyroid hormones. Indications for parenteral application are insufficient resorption of oral medications due to alterations of the gastrointestinal tract, partial or total loss of consciousness, sedation in the intensive care unit or shock. In almost all cases, levothyroxine is the therapy of choice including congenital hypothyroidism. In preterm infants with an altered thyroid hormone status, studies with thyroid hormones including intravenous liothyronine showed a normalisation of T3 levels and in some cases an amelioration of parameters of ventilation. A benefit for mortality or later morbidity could not be seen. Effects on neurological improvements later in life are under discussion. Decreased thyroid hormone levels are often found after cardiac surgery in infants and adults. Intravenous therapy with thyroid hormones improves the cardiac index, but in all other parameters investigated, no substantial effect on morbidity and mortality could be demonstrated. Oral liothyronine therapy in these situations was equivalent to an intravenous route of application. In myxoedema coma, intravenous levothyroxine is given for 3 to 10 days until the patient can take oral medication and normal resorption in the gastrointestinal tract is achieved by restoring at least peripheral euthyroidism. Intravenous levothyroxine is the standard in treating patients with myxoedema coma. A protective effect on the heart of i.v. levothyroxine in brain-dead organ donors may be possible.

The use of triiodothyronine during critical illness.

PURPOSE OF REVIEW: Thyroid hormone physiology changes during critical illness. Circulating concentration of triiodothyronine (T3), the active form of thyroid hormone decreases. It has long been uncertain whether this represents a pathologic change or if it is an adaptive phenomenon. Controlled clinical trials have been required to understand whether replacing and restoring serum T3 levels is therapeutic. RECENT FINDINGS: Clinical trials of T3 have recently been proposed with some completed. These have been conducted in patients with sepsis, myocardial infarction, infants undergoing cardiac surgery, and acute respiratory distress syndrome. Of the completed trials, T3 administration restored serum concentrations, but was not accompanied by significant clinical benefit. Importantly, restoring serum T3 levels did not cause any adverse effects. SUMMARY: If T3 is to be considered a therapeutic target in critical illness, further studies should consider the stage of disease it is administered, and whether there are other surrogate measures to assess adequacy of hormone replacement over and above serum T3 concentrations.

Clinical Review and Update on the Management of Thyroid Storm.

Thyroid storm is a severe manifestation of thyrotoxicosis. Thyroid storm is diagnosed as a combination of thyroid function studies showing low to undetectable thyroid stimulating hormone (TSH) (<0.01mU/L) with elevated free thyroxine (T4) and/or triiodothyronine (T3), positive thyroid receptor antibody (TRab) (if Graves' disease is the underlying etiology), and with clinical signs and symptoms of end organ damage. Treatment involves bridging to a euthyroid state prior to total thyroidectomy or radioactive iodine ablation to limit surgical complications such as excessive bleeding from highly vascular hyperthyroid tissue or exacerbation of thyrotoxicosis. The purpose of this article is a clinical review of the various treatments and methodologies to achieve a euthyroid state in patients with thyroid storm prior to definitive therapy.

The Potential of Thyroid Hormone Therapy in Severe COVID-19: Rationale and Preliminary Evidence.

Tissue hypoxia is one of the main pathophysiologic mechanisms in sepsis and particularly in COVID-19. Microvascular dysfunction, endothelialitis and alterations in red blood cell hemorheology are all implicated in severe COVID-19 hypoxia and multiorgan dysfunction. Tissue hypoxia results in tissue injury and remodeling with re-emergence of fetal programming via hypoxia-inducible factor-1α (HIF-1a)-dependent and -independent pathways. In this context, thyroid hormone (TH), a critical regulator of organ maturation, may be of relevance in preventing fetal-like hypoxia-induced remodeling in COVID-19 sepsis. Acute triiodothyronine (T3) treatment can prevent cardiac remodeling and improve recovery of function in clinical settings of hypoxic injury as acute myocardial infarction and by-pass cardiac surgery. Furthermore, T3 administration prevents tissue hypoxia in experimental sepsis. On the basis of this evidence, the use of T3 treatment was proposed for ICU (Intensive Care Unit) COVID-19 patients (Thy-Support, NCT04348513). The rationale for T3 therapy in severe COVID-19 and preliminary experimental and clinical evidence are discussed in this review.

Seeking optimization of LT4 treatment in patients with differentiated thyroid cancer.

Levothyroxine sodium (LT4) is the mainstay treatment to replace thyroid hormonal production in thyroidectomized patients, but, depending on the aggressiveness of the cancer and on the risk of recurrence, patients with differentiated thyroid cancer may also be treated in a TSH-suppressive or semi-suppressive mode. The pathophysiological rationale for this LT4 treatment stems from the role of TSH, considered to be a growth factor for follicular cells, potentially inducing initiation or progression of follicular cell-derived thyroid cancer. Therefore, accurate tailoring of treatment, taking into account both patient characteristics (age and comorbidities) and risk of persistent/recurrent disease, is highly recommended. Furthermore, adjustments to traditional LT4 treatment should be made in thyroidectomized patients due to the lack of thyroidal contribution to whole body triiodothyronine (T3) concentration. Since LT4 exhibits a narrow therapeutic index and the side effects of over- and under-treatment could be deleterious, particularly in this category of patients, caution is required in dose individualization, in the mode of ingestion, and in potential pharmacological and other types of interference as well. Our aim was to analyze the current knowledge concerning LT4 dose requirements in patients with thyroid cancer according to different therapeutic approaches, taking into account a number of factors causing interference with LT4 efficacy. Specific mention is also made about the use of the novel LT4 formulations.

Heart Failure and Stroke Risks in Users of Liothyronine With or Without Levothyroxine Compared with Levothyroxine Alone: A Propensity Score-Matched Analysis.

Background: Combination therapy with liothyronine (LT3) and levothyroxine (LT4) is used in patients with persistent symptoms, despite being administered an adequate dose of LT4. LT3 may also be used in some thyroid cancer patients preparing for radioactive iodine therapy. However, there is a controversy regarding the safety of LT3 use, and there has been no definite evidence of long-term safety of LT3 therapy in Asian populations. The aim of this study was to examine the long-term safety of LT3 therapy using the Common Data Model (CDM). Methods: We conducted a retrospective multicenter study across four hospital databases encoded in the Observational Medical Outcomes Partnership (OMOP) CDM. LT3 users were defined as those who received an LT3 prescription for at least 90 days (with or without LT4), and their safety outcomes were compared with those in LT4-only users after 1:4 propensity score matching. Safety outcomes included the incidences of osteoporosis, cardiovascular disease, cancer, anxiety disorder, and mood disorder. Results: We identified 1434 LT3 users and 3908 LT4-only users. There was a statistically significant difference in the incidence rate of safety outcomes between LT3 users and LT4-only users. The risks of heart failure (incidence rate ratio [IRR] = 1.664, 95% confidence interval [95% CI] 1.002-2.764, p = 0.049) and stroke (IRR = 1.757, CI 1.073-2.877, p = 0.025) were higher in LT3 users than in LT4-only users. When subgroup analysis was performed according to the presence/absence of thyroid cancer history and duration of thyroid hormone replacement, the risk of heart failure was higher in LT3 users with a history of thyroid cancer and those who underwent ≥52 weeks of LT3 therapy. In addition, the risk of stroke was higher in LT3 users without thyroid cancer history and those who underwent ≥52 weeks of LT3 therapy. Conclusions: The use of LT3 was associated with increased incidence of heart failure and stroke in patients with a longer duration of LT3 use and history of thyroid cancer. Therefore, clinicians should consider the risk of heart failure and stroke in thyroid cancer patients with long-term use of LT3. These findings require confirmation in other populations.

Thyroid Abnormalities in Heart Failure.

The effects of hyperthyroidism and hypothyroidism on the heart and cardiovascular system are well documented. It has also been shown that various forms of heart disease including but not limited to congenital, hypertensive, ischemic, cardiac surgery, and heart transplantation cause an alteration in thyroid function tests including a decrease in serum liothyronine (T3). This article discusses the basic science and clinical data that support the hypothesis that these changes pose pathophysiologic and potential novel therapeutic challenges.

Hashimoto thyroiditis: an evidence-based guide to etiology, diagnosis and treatment.

Hashimoto thyroiditis (HT) is a common autoimmune disorder, affecting women 7-10 times more often than men, that develops because of genetic susceptibility, Xchromosome inactivation patterns modulated by environmental factors as well as microbiome composition, and leads to an imbalance in self­tolerance mechanisms. The consequential thyroid infiltration by lymphocytes, potentiated by antibody­mediated autoimmune response through the antibodies against thyroid peroxidase (TPOAbs), leads to a destruction of thyrocytes. The presence of TPOAbs is associated with a 2 to 4­fold increase in the risk of recurrent miscarriages and preterm birth in pregnant women. The clinical presentation of HT includes: (A) thyrotoxicosis, when stored thyroid hormones are released to circulation from destroyed thyroid follicles; (B) euthyroidism, when preserved thyroid tissue compensates for destroyed thyrocytes; and (C) hypothyroidism, when thyroid hormone production by the affected thyroid gland is insufficient. The management of Hashitoxicosis is based on symptoms control usually with ß­blockers, euthyroidism requires periodical thyroid stimulating hormone measurements to assess for progression to hypothyroidism, and hypothyroidism is treated with thyroid hormone replacement therapy. The dose of levothyroxine (LT4) used for treatment is based on the degree of preserved thyroid functionality and lean body mass, and usually ranges from 1.4 to 1.8 mcg/kg/day. There is insufficient evidence to recommend for or against therapy with triiodothyronine (T3), apart from in pregnancy when only levothyroxine is indicated, as T3 does not sufficiently cross fetal blood­brain barrier. HT is associated with 1.6 times higher risk of papillary thyroid cancer and 60 times higher risk of thyroid lymphoma than in general the population.

Role of AMPK in the protective effects exerted by triiodothyronine in ischemic-reperfused myocardium.

Recent studies have provided evidence that triiodothyronine (T3) might play an effective role in the recovery of ischemic myocardium, through the preservation of mitochondrial function and the improvement of energy substrate metabolism. To this respect, it has been suggested that T3 could activate AMP-activated protein kinase (AMPK), the cellular 'fuel-gauge' enzyme, although its role has yet to be elucidated. The aim of the present study was to investigate the effects produced by acute treatment with T3 (60 nM) and the pharmacological inhibition of AMPK by compound C on isolated rat left atria subjected to 75 min simulated ischemia-75 min reperfusion. Results showed that T3 increased AMPK activation during simulated ischemia-reperfusion, while compound C prevented it. At the end of simulated reperfusion, acute T3 treatment increased contractile function recovery and cellular viability conservation. Mitochondrial ultrastructure was better preserved in the presence of T3 as well as mitochondrial ATP production rate and tissue ATP content. Calcium retention capacity, a parameter widely used as an indicator of the resistance of mitochondrial permeability transition pore (MPTP) to opening, and GSK-3ß phosphorylation, a master switch enzyme that limits MPTP opening, were increased by T3 administration. All these beneficial effects exerted by T3 acute treatment were prevented when compound C was co-administrated. The present study provided original evidence that T3 enhances intrinsic activation of AMPK during myocardial ischemia-reperfusion, being this enzyme involved, at least in part, in the protective effects exerted by T3, contributing to mitochondrial structure and function preservation, post-ischemic contractile recovery and conservation of cellular viability.

Liothyronine Use in Hypothyroidism and its Effects on Cancer and Mortality.

Background: The prescription of liothyronine (LT3) to treat hypothyroidism is increasing worldwide; however, the long-term safety of LT3 use has yet to be determined. Previous studies have suggested a possible association between LT3 use and breast cancer. The aim of this study was to examine the effects of LT3 use on cancer incidence and mortality. Methods: Our sample included the full adult population of individuals living in Sweden with at least three purchases of thyroid hormone therapy between July 2005 and December 2017. Individual-level data on drug purchases were linked to registry data on cancer incidence and mortality. There were 575,461 individuals with at least three purchases, of which 11,147 had made at least three purchases of LT3, including combinations of levothyroxine (LT4) and LT3. Individuals were followed for a median follow-up time of 8.1 years. We applied Cox regression with a time-varying exposure variable, comparing LT3 users (individuals with at least three cumulative purchases of LT3) with LT4-only users (the rest). Outcomes included breast cancer incidence, any cancer incidence, all-cause mortality, any cancer mortality, and breast cancer mortality. We adjusted for age, sex, previous thyroid cancer, previous other cancer, use of antithyroid preparations, use of sex hormones, and dose in multivariate analyses. Results: Multivariate analyses produced a hazard ratio of 0.93 (95% confidence interval [0.75-1.15]) for breast cancer incidence (only females), 0.97 (0.87-1.08) for any cancer incidence, 0.69 (0.61-0.77) for all-cause mortality, 0.78 (0.62-0.98) for any cancer mortality, and 0.91 (0.50-1.66) for breast cancer mortality (only females). Conclusions: In this large, Swedish, long-term registry-based study, the use of LT3 did not lead to increased breast cancer incidence, any cancer incidence, all-cause mortality, any cancer mortality, or breast cancer mortality compared with LT4 use. Somewhat surprisingly, there was evidence of lower mortality in LT3 users in models adjusting for dose, potentially an artifact of underlying associations between dose and health status/diagnosis.

Repositioning liothyronine for cancer immunotherapy by blocking the interaction of immune checkpoint TIGIT/PVR.

BACKGROUND: Inhibitors targeting immune checkpoint were proved effective in cancer immunotherapy, such as PD-1/PD-L1 blockade. The novel immune checkpoint TIGIT/PVR plays critical roles in suppressing the anti-tumor effects of CD8+ T and NK cells, and dual blockade of TIGIT/PVR and PD-1/PD-L1 by antibody can elicit synergistic effects in tumor models and clinical trials. However, small molecules for TIGIT/PVR blockade have not been investigated. METHODS: The expression of PVR in tumors were analyzed by using TCGA, Oncomine and GEO database, and in cancer cell lines examined by flow cytometry. Natural product compounds were docked to PVR for virtual screening by using the software Molecular Operating Environment (MOE). Candidate compounds were further tested by biolayer interferometry-based binding assay, microscale thermophoresis assay and cell based blocking assay. The in vitro activity of the candidate compound was determined by MTT, peripheral blood mononuclear cells (PBMCs) activation assay and coculture assay. The anti-tumor effects and mechanism were also investigated by using MC38 tumor-bearing mice model and immune cell depletion tumor model. RESULTS: PVR was over-expressed in many tumor tissues and cancer cell lines, making it a promising therapeutic target. Through virtual screening, binding, and blocking assay, liothyronine was discovered to bind PVR and block the interaction of TIGIT/PVR. Liothyronine could enhance the function of CD4+ and CD8+ T cells in PBMCs. Besides, in the Jurkat-hTIGIT and CHOK1-hPVR coculture assay, liothyronine could reverse the IL-2 secretion inhibition resulted by TIGIT/PVR ligation. Although had no influence on the proliferation of tumor cells in vitro, liothyronine could significantly inhibit tumor growth when administrated in vivo, by enhancing CD8+ T cell infiltration and immune responses in the tumor bearing mice. The immune cell depletion model showed that the anti-tumor effects of liothyronine depends on CD4+ T cells, CD8+ T cells and NK cells. CONCLUSIONS: A small molecule liothyronine was discovered to serve as a potential candidate for cancer immunotherapy by blocking the immune checkpoint TIGIT/PVR. Video abstract.

Endocrinopatías por inmunoterapia oncológica / Endocrinopathies by oncological immunotherapy

La relación entre inmunidad y cáncer es compleja. Las células tumorales desarrollan mecanismos de evasión a las respuestas del sistema inmunitario. Esta capacidad permite su supervivencia y crecimiento. La inmunoterapia ha transformado el tratamiento oncológico mejorando la respuesta inmunitaria contra la célula tumoral. Esta se basa en el bloqueo de los puntos de control inmunitario mediante anticuerpos monoclonales contra la molécula inhibidora CTLA-4 (antígeno 4 del linfocito T citotóxico [CTLA-4]) y la proteína 1 de muerte celular programada y su ligando (PD-1/PD-L1). Aunque los inhibidores de los puntos de control inmunitario (ICIs) son fármacos bien tolerados, tienen un perfil de efectos adversos conocido como eventos adversos inmunorrelacionados (EAI). Estos afectan varios sistemas, incluyendo las glándulas endocrinas. Los eventos adversos endocrinos más frecuentes son la disfunción tiroidea, la insuficiencia hipofisaria, la diabetes mellitus autoinmune y la insuficiencia suprarrenal primaria. El creciente conocimiento de estos efectos adversos endocrinos ha llevado a estrategias de tratamiento efectivo con el reemplazo hormonal correspondiente. El objetivo de esta revisión es reconocer la incidencia de estas nuevas endocrinopatías, la fisiopatología, su valoración clínica y el manejo terapéutico. (AU)

The relationship between immunity and cancer is complex. Tumor cells develop evasion mechanisms to the immune system responses. This ability allows their survival and progression. Immunotherapy has transformed cancer treatment by improving the immune response against tumor cells. This is achieved by blocking immune checkpoints with monoclonal antibodies against cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein 1 and its ligand (PD-1 / PD-L1). Although the immune checkpoint inhibitors (ICIs) are well tolerated drugs, they have a profile of adverse effects known as immune-related adverse events (irAES). These involve diverse systems, including the endocrine glands. The most frequent endocrine immune-related adverse events are thyroid and pituitary dysfunction, autoimmune diabetes mellitus and primary adrenal insufficiency. The increasing knowledge of these irAES has led to effective treatment strategies with the corresponding hormonal replacement. The objective of this review is to recognize the incidence of these new endocrinopathies, the physiopathology, their clinical evaluation, and therapeutic management. (AU)

Is tri-iodothyronine a better choice than activated protein C in sepsis treatment?

BACKGROUND: Sepsis can be defined as a life-threatening organ dysfunction due to a dysregulated host response to infection. In sepsis, the coagulation cascade is activated and the balance shifts to the procoagulant side. Recently, the use of protein C is proposed for the treatment of sepsis. Another therapeutic agent that has been intensively studied is tri-iodothyronine. METHODS: This study aimed to compare the effects of activated protein C and tri-iodothyronine, which are administered at a single dose to sepsis-induced rats at the late phase. Leukocyte, platelet, hemoglobin and antithrombin-III concentrations and histopathological changes in the small intestine, liver and lung were evaluated at 24 hours. RESULTS: Single-dose intraperitoneal recombinant human APC (activated protein C) has a partial curative effect on hematological parameters in the late phase, while it is possible to state that it has significant therapeutic effects on hepatic and intestinal tissues, but more remarkably on the lung tissue. Tri-iodothyronine is also considered to be used for the treatment and has a strong potential to be a therapeutic agent. CONCLUSION: We observed that the T3 hormone has significantly limited and reduced the sepsis-related damage to hepatic and intestinal tissues, but especially the lung tissue. Tri-iodothyronine can be a good alternative to APC, which is partially allowed due to high cost and complication of bleeding in the treatment of sepsis.

Pharmacokinetics of L-Triiodothyronine in Patients Undergoing Thyroid Hormone Therapy Withdrawal.

Background: L-triiodothyronine (LT3) is a substitute for levothyroxine (LT4) for thyroid cancer (TC) patients during the preparation for nuclear medicine procedures, and it is used in combination with LT4 in patients who do not respond to the standard treatment for hypothyroidism. This therapy is commonly done by using fixed doses, potentially resulting in supraphysiologic levels of triiodothyronine (T3). A good understanding of the LT3 pharmacokinetics (PK) is necessary to design combination treatment schemes that are able to maintain serum T3 levels within the reference range, but data on the PK of LT3 are conflicting. Here, we present a study designed to characterize the PK of LT3 in patients devoid of endogenous thyroid hormone production, and not receiving LT4 therapy. Methods: We performed an open-label, PK study in patients undergoing thyroid hormone withdrawal in preparation for nuclear medicine procedures for the evaluation and treatment of follicular-derived TC. LT3 was substituted for LT4 at a 1:3 mcg/mcg dosage ratio thrice daily for at least 30 days. PK of the last LT3 dose while at steady state and terminal elimination was assessed over 11 days. Thereafter, a PK study was performed following the nuclear medicine procedure in patients who volunteered for a second study. Results: Fourteen patients age 48.5 ± 16.0 years completed the last dose study and five completed the second PK study. PK analysis indicates a time to maximum serum concentration of 1.8 ± 0.32 hours and two distinct phases of linear elimination, with a fast distribution phase and slow elimination phases with half-lives of 2.3 ± 0.11 hours and 22.9 ± 7.7 hours, supporting a two-compartment model. PK modeling predicts that a twice-daily administration of low-dose LT3 (0.07 mcg/kg twice daily) in combination with LT4 can predictably increase the serum T3 concentration without significant peaks above the reference range. Conclusions: The PK of LT3 is well described by a two-compartment model that assumes elimination only from the sampling compartment, with a rapid distribution phase and a slow elimination phase. This information will contribute to design therapeutic strategies for LT3/LT4 combination therapies directed to maintain stable T3 serum levels.

Thyroidectomy Versus Medical Management for Euthyroid Patients With Hashimoto Disease and Persisting Symptoms: A Randomized Trial.

Background: Hashimoto disease is a chronic autoimmune thyroiditis. Despite adequate hormone substitution, some patients have persistent symptoms that may be the result of immunologic pathophysiology. Objective: To determine whether thyroidectomy improves symptoms in patients with Hashimoto thyroiditis who still have symptoms despite having normal thyroid gland function while receiving medical therapy. Design: Randomized trial. (ClinicalTrials.gov: NCT02319538). Setting: Secondary care hospital in Norway. Patients: 150 patients aged 18 to 79 years with persistent Hashimoto-related symptoms despite euthyroid status while receiving hormone replacement therapy and with serum antithyroid peroxidase (anti-TPO) antibody titers greater than 1000 IU/mL. Intervention: Total thyroidectomy or medical management with hormone substitution to secure euthyroid status in both groups. Measurements: The primary outcome was general health score on the Short Form-36 Health Survey (SF-36) at 18 months. Secondary outcomes were adverse effects of surgery, the other 7 SF-36 subscores, fatigue questionnaire scores, and serum anti-TPO antibody titers at 6, 12, and 18 months. Results: During follow-up, only the surgical group demonstrated improvement: Mean general health score increased from 38 to 64 points, for a between-group difference of 29 points (95% CI, 22 to 35 points) at 18 months. Fatigue score decreased from 23 to 14 points, for a between-group difference of 9.3 points (CI, 7.4 to 11.2 points). Chronic fatigue frequency decreased from 82% to 35%, for a between-group difference of 39 percentage points (CI, 23 to 53 percentage points). Median serum anti-TPO antibody titers decreased from 2232 to 152 IU/mL, for a between-group difference of 1148 IU/mL (CI, 1080 to 1304 IU/mL). In multivariable regression analyses, the adjusted treatment effects remained similar to the unadjusted effects. Limitation: Results are applicable only to a subgroup of patients with Hashimoto disease, and follow-up was limited to 18 months. Conclusion: Total thyroidectomy improved health-related quality of life and fatigue, whereas medical therapy did not. This improvement, along with concomitant elimination of serum anti-TPO antibodies, may elucidate disease mechanisms. Primary Funding Source: Telemark Hospital.

Myxedema coma precipitated by diabetic ketoacidosis after total thyroidectomy: a case report.

BACKGROUND: Myxedema coma is profound decompensated hypothyroidism usually precipitated by stressors, and its occurrence in association with total thyroidectomy or metabolic disorders, such as diabetic ketoacidosis, is unusual. CASE PRESENTATION: A 43-year-old Asian man with history of total thyroidectomy who was scheduled for a second radioactive iodine therapy presented to our hospital with decreased mental status and hyperglycemia. He had a history of thyroid cancer but did not have diabetes mellitus. He was in a hypothermic state and had a Glasgow Coma Scale score of 10 out of 15 at presentation; arterial blood gas analysis revealed a state of metabolic acidosis and laboratory findings suggested hyperglycemia with glycosuria, ketoacidosis, and severe hypothyroidism. A thyroid function test showed thyroid-stimulating hormone of 34.126 uIU/mL, free thyroxine of 1.02 ng/dL, and triiodothyronine of 1.04 ng/mL. The glycated hemoglobin of this patient was checked due to hyperglycemia and the value of glycated hemoglobin was 16.5% which met the criteria for a diagnosis of diabetes. After treatment for myxedema with liothyronine 5 mcg two times per day and levothyroxine 175 mcg once daily via a nasogastric tube and diabetic ketoacidosis with intravenously administered fluid and insulin, his clinical condition rapidly improved including mental status, hyperglycemia, and acidosis. During the hospitalization, a workup for diabetes mellitus was performed and the results suggested that a diagnosis of type 2 diabetes mellitus would be appropriate. CONCLUSIONS: This case demonstrated that diabetic ketoacidosis not only could be a potential contributor to myxedema coma but also mask typical clinical features, making diagnosis more difficult. Considering the possibility of an increasing number of potential patients with hypothyroidism developed after thyroidectomy, constant vigilance is required for a better clinical outcome, including early recognition and management in critical care in advance for unusual diabetic ketoacidosis which could precipitate decompensated hypothyroidism.

[Diagnosis and treatment of intra-abdominal infection complicated with hypothyroidism].

Intra-abdominal infection complicated with hypothyroidism is very common. It mostly featured decreased T3, with or without decreased T4, and without elevated thyroid stimulating hormone(TSH). This particular type of hypothyroidism was called "low T3 syndrome" or "thyroid illness syndrome", and is called "non-thyroid illness syndrome" increasingly in recent years. Its pathogenesis has not been fully understood, and probably is associated with abnormality of hypothalamic-pituitary-thyroid axis, disorder of peripheral thyroid hormone metabolism, change in thyroid hormone binding protein, regulation of triiodothyronine receptors, effect of cytokines, and lack of trace element selenium. Intra-abdominal infection complicated with hypothyroidism should be differentiated from primary hypothyroidism, which may be one cause of mental depression, insufficient anabolism, and poor tissue healing. Therefore, the changes of T3 and T4 levels should be actively monitored in patients with severe or prolonged intra-abdominal infection. Whether treatment is needed for intra-abdominal infection complicated with hypothyroidism remains controversial. T3 replacement therapy may improve prognosis. When low T3 syndrome presents as a disease-mediated hypothyroidism, we recommend the use of levothyroxine(L-T4) or liothyronine (L-T3) treatment to improve the prognosis of critical patients. Enteral nutrition can improve hypothyroidism and has good efficacy for enterocutaneous fistula patients with intra-abdominal infection.

Polyglandular endocrine emergency: lessons from a patient, which a book cannot teach.

A 30-year-old woman with polyglandular autoimmune type 2 syndrome was found collapsed at home with a cardiac arrest, which required direct current cardioversion. On admission, she was hypothermic, hypotensive and bradycardic. Initial biochemical investigations were consistent with a pre-renal acute kidney injury, metabolic acidosis and a possible sepsis. She had significantly elevated thyroid-stimulating hormone levels on admission with the clinical profile consistent with dual Addisonian and myxoedema crisis. She received intravenous liothyronine and hydrocortisone along with supportive therapy. Echo showed severe left ventricular impairment with apical ballooning although coronary angiogram disclosed nothing abnormal. She made a gradual recovery and was discharged home after 2 weeks. She was diagnosed to have primary autoimmune hypothyroidism, Addison's diseaseand type 1 diabetes and coeliac disease in October 2006, July 2007, May 2010 and September 2016, respectively. Her inability to stick to gluten-free diet at her workplace was considered a significant contributory factor for out-of-hospital cardiac arrest.

Triiodothyronine replacement in critically ill adults with non-thyroidal illness syndrome.

PURPOSE: Non-thyroidal illness syndrome is commonly encountered in critically ill patients, many of whom are treated with thyroid hormones despite uncertainty regarding their safety and effectiveness. This retrospective observational study sought to evaluate the utilization, safety, and effectiveness of triiodothyronine (T3) supplementation in critically ill adults admitted to either of two non-cardiac surgery mixed-medical/surgical intensive care units (ICU). METHODS: Consecutive adults admitted to an ICU and treated with enterally administered T3 were identified over a two-year period. Data pertaining to demographics, T3 utilization, safety, and clinical outcomes were collected. RESULTS: Data were extracted from the medical records of 70 consecutive patients. All had baseline serum free T3 concentrations below the lower limit of our laboratory's reference range and 22 (31%) patients also had low thyroxine (T4) concentrations. The most commonly prescribed replacement doses were 25 and 50 µg for a median of seven days and almost half of the patients also received concomitant T4 supplementation. Serum thyroid hormones were available in 48 of 70 patients (69%) at a median [interquartile range (IQR)] of 7 [6-38] days. Normalization of free T3 serum concentrations occurred in 30 of 48 patients (63%) at a median [IQR] of 8 [7-33] days. A dose-response relationship was identifiable. New adverse events (atrial fibrillation/flutter, hypertension, sinus tachycardia, myocardial infarction) during therapy were less frequent than at baseline. CONCLUSIONS: This study suggests that with T3 supplementation there was evidence of serum free T3 normalization without evidence of associated harms. A definitive trial is needed to evaluate clinical effectiveness.

Comparison of Therapeutic Triiodothyronine Versus Metoprolol in the Treatment of Myocardial Infarction in Rats.

BACKGROUND: Beta blockers are standard therapy for myocardial infarction (MI). Preclinical studies have shown efficacy and safety of thyroid hormone (TH) treatment of cardiovascular disorders. Since THs interact with the sympathoadrenergic system, this study aimed to compare triiodothyronine (T3) and metoprolol (Met) in the treatment of rats with MI on pathophysiology and TH-adrenergic signaling. METHODS: Female Sprague-Dawley rats aged 12 weeks underwent left anterior descending coronary artery ligation (MI) or sham surgeries. T3 (5 µg/kg/day) or Met (100 mg/kg/day) was given in drinking water immediately after surgery for eight weeks. At the terminal of the experiments, the rats were subjected to morphological, functional, and molecular examination. RESULTS: T3 and Met significantly enhanced left ventricular contractility (left ventricular fractional shortening 21.37 ± 2.58% and 21.14 ± 3.71%, respectively) compared to untreated MI (17.88 ± 1.23%), and decreased the incidence of inducible atrial tachyarrhythmia by 87.5% and 62.5%, respectively. Although both treatments showed efficacy, T3 but not Met showed statistically significant improvements compared to MI in arrhythmia duration, left atrial diameter (T3 vs. MI 4.33 ± 0.63 vs. 5.65 ± 1.32 mm; p < 0.05), fibrosis (6.1 ± 0.6%, 6.6 ± 0.6% vs. 8.2 ± 0.7%, T3, Met vs. MI, respectively), and aortic vasorelaxation responsiveness to acetylcholine (pD2 6.97 ± 0.22, 6.83 ± 0.21 vs. 6.66 ± 0.22, T3, Met vs. MI, respectively). Quantitative polymerase chain reaction showed that T3 and Met attenuated expression of genes associated with inflammation and oxidative stress and restored expression of ion channels and contractile proteins. CONCLUSION: These results support comparable efficacy of T3 and Met treatments, suggesting that T3 may provide a therapeutic alternative to standard ß-receptor blockade, especially for patients intolerant to treatment with ß-blockers after MI.