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Related Concept Videos

Hyperthyroidism I: Introduction01:25

Hyperthyroidism I: Introduction

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Hyperthyroidism is a type of thyrotoxicosis characterized by the thyroid gland's overproduction of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). This hormone excess increases the basal metabolic rate and enhances sensitivity to catecholamines.DiagnosisDiagnosis is based on clinical features and biochemical testing. It typically shows suppressed thyroid-stimulating hormone (TSH) levels below 0.4 mIU/L, with elevated free T3 and/or T4. Additional tests, including thyroid...
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Synthesis and Regulation of Thyroid Hormones01:20

Synthesis and Regulation of Thyroid Hormones

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Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the thyrotropin-releasing hormone (TRH). TRH then reaches the pituitary gland and stimulates the release of thyroid-stimulating hormone(TSH) into the bloodstream.
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The...
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Hyperthyroidism II: Pathophysiology01:27

Hyperthyroidism II: Pathophysiology

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Hyperthyroidism is a hypermetabolic state caused by elevated levels of thyroid hormones, triiodothyronine (T3) and thyroxine (T4). It results from dysregulation at the thyroid, pituitary, or immune system level and affects multiple organ systems.PathophysiologyThe most common cause of hyperthyroidism is Graves’ disease, an autoimmune disorder in which antibodies, specifically thyroid-stimulating antibodies (TSAb), a subtype of TSH receptor antibodies (TRAb), bind to and activate TSH...
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Functions of Thyroid Hormones01:18

Functions of Thyroid Hormones

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The thyroid hormone (TH) plays a pivotal role in the intricate orchestration of physiological processes, exerting profound effects on development, metabolism, and homeostasis throughout different life stages.
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
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Hypothyroidism II: Pathophysiology01:23

Hypothyroidism II: Pathophysiology

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Hypothyroidism is a disorder characterized by insufficient production of thyroid hormones, which regulate metabolism, energy balance, and multiple organ systems.TypesHypothyroidism is classified based on the level of dysfunction. Primary hypothyroidism results from intrinsic thyroid gland dysfunction, causing reduced hormone production despite normal or increased stimulation. Secondary hypothyroidism arises from inadequate thyroid-stimulating hormone (TSH) secretion by the pituitary. Tertiary...
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Graves Disease II: Pathophysiology01:24

Graves Disease II: Pathophysiology

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Graves’ disease is an autoimmune disorder characterized by the production of thyroid-stimulating immunoglobulins (TSI) that activate TSH receptors, leading to excessive synthesis and release of thyroid hormones (T3 and T4) and resulting in hyperthyroidism.Among all causes of hyperthyroidism, Graves’ disease is the most common and can happen at any age, though it is more frequent in women. It produces a hypermetabolic state with features such as weight loss, tachycardia, tremor,...
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A Longitudinal, Real-World Study of the Relationship between Levothyroxine Dose and Suboptimal Hypothyroidism Treatment.

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Related Experiment Video

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Author Spotlight: Integrating Ultrasound Imaging with Biochemical Markers for Thyroid Disease Diagnosis
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Thyroid hormone replacement therapy: three 'simple' questions, complex answers.

Antonio C Bianco1, Sabina Casula1

  • 1Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, Fla., USA.

European Thyroid Journal
|May 1, 2014
PubMed
Summary
This summary is machine-generated.

Levothyroxine is standard treatment for hypothyroidism. Some patients benefit from added liothyronine, especially those with a DIO2 gene variation, suggesting personalized thyroid hormone replacement.

Keywords:
Combined therapyDeiodinationDesiccated thyroidGene polymorphismHypothyroidismLevothyroxineLiothyronineThyroid hormone

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Area of Science:

  • Endocrinology
  • Neuroendocrinology
  • Genetics

Background:

  • Levothyroxine is the standard treatment for hypothyroidism, typically normalizing thyroid hormone levels.
  • A subset of hypothyroid patients experience persistent neurocognitive symptoms despite normalized thyroid hormone levels.
  • Localized brain hypothyroidism, due to impaired local T3 production via type II deiodinase (D2), is a potential cause.

Purpose of the Study:

  • To investigate the potential benefit of adding liothyronine to levothyroxine therapy for symptomatic hypothyroid patients.
  • To explore the role of the DIO2 gene polymorphism in treatment response.

Main Methods:

  • Review of clinical trials examining combined levothyroxine and liothyronine therapy.
  • Analysis of neurocognitive outcomes in relation to DIO2 gene status.

Main Results:

  • Previous trials generally showed no benefit from combined therapy.
  • A recent large trial indicated improved neurocognitive outcomes with combined therapy specifically in hypothyroid patients with a DIO2 gene polymorphism.
  • This finding suggests a potential genetic influence on treatment efficacy.

Conclusions:

  • Combined levothyroxine and liothyronine therapy may benefit a specific subgroup of hypothyroid patients.
  • The DIO2 gene polymorphism appears to be a key factor in determining response to combined therapy.
  • Personalized treatment strategies for hypothyroidism, considering genetic factors, warrant further investigation.