-
Deutsche Medizinische Wochenschrift... Oct 2021Autoimmune thyroiditis (AIT) is not only one of the most prevalent human autoimmune diseases, but also the most frequent cause of primary hypothyroidism. It is...
Autoimmune thyroiditis (AIT) is not only one of the most prevalent human autoimmune diseases, but also the most frequent cause of primary hypothyroidism. It is characterized by lymphocytic infiltration of the thyroid gland with subsequent gradual destruction and fibrous replacement of thyroid tissue. Genetic predisposition, epigenetic modifications and environmental factors are suspected as disease triggers. Signs and symptoms of hypothyroidism include fatigue, bradycardia, constipation and cold intolerance. In subclinical hypothyroidism, symptoms may be absent. The diagnosis of AIT is based on the presence of antibodies against thyroid specific antigens, primarily anti-thyroid peroxidase antibodies and on a sonographically proven reduced echogenicity of the thyroid parenchyma. The diagnosis of concomitant hypothyroidism is primarily based on clinical signs and symptoms as well as measurement of thyroid-stimulating hormone (TSH)-concentration. Subclinical hypothyroidism is characterized by elevated TSH with normal serum free thyroxine (fT) and triiodothyronine (fT) levels, while in manifest hypothyroidism serum fT and fT levels are reduced. Levothyroxine (LT) treatment in subclinical hypothyroidism is a controversy in the scientific literature and should be discussed individually. It not only depends on the level of TSH-elevation, but also on other factors, such as patient age, presence of comorbidities and clinical symptoms of hypothyroidism. In contrast, overt hypothyroidism and subclinical hypothyroidism with a TSH-level > 10 mIU/L is a strong indication for LT administration, aiming at rapid achievement of euthyroidism. In patients with dissatisfaction due to persistence of symptoms despite optimal LT-treatment LT/T-combination therapy should be considered, based on expert opinion.
Topics: Hashimoto Disease; Humans; Hypothyroidism; Thyrotropin; Thyroxine; Triiodothyronine
PubMed: 34644793
DOI: 10.1055/a-1258-5674 -
Reviews in Endocrine & Metabolic... Jun 2022Levothyroxine (LT4) is a safe, effective means of hormone replacement therapy for hypothyroidism. Here, we review the pharmaceutical, pathophysiological and behavioural... (Review)
Review
Levothyroxine (LT4) is a safe, effective means of hormone replacement therapy for hypothyroidism. Here, we review the pharmaceutical, pathophysiological and behavioural factors influencing the absorption, distribution, metabolism and excretion of LT4. Any factor that alters the state of the epithelium in the stomach or small intestine will reduce and/or slow absorption of LT4; these include ulcerative colitis, coeliac disease, bariatric surgery, Helicobacter pylori infection, food intolerance, gastritis, mineral supplements, dietary fibre, resins, and various drugs. Once in the circulation, LT4 is almost fully bound to plasma proteins. Although free T4 (FT4) and liothyronine concentrations are extensively buffered, it is possible that drug- or disorder-induced changes in plasma proteins levels can modify free hormone levels. The data on the clinical significance of genetic variants in deiodinase genes are contradictory, and wide-scale genotyping of hypothyroid patients is not currently justified. We developed a decision tree for the physician faced with an abnormally high thyroid-stimulating hormone (TSH) level in a patient reporting adequate compliance with the recommended LT4 dose. The physician should review medications, the medical history and the serum FT4 level and check for acute adrenal insufficiency, heterophilic anti-TSH antibodies, antibodies against gastric and intestinal components (gastric parietal cells, endomysium, and tissue transglutaminase 2), and Helicobacter pylori infection. The next step is an LT4 pharmacodynamic absorption test; poor LT4 absorption should prompt a consultation with a gastroenterologist and (depending on the findings) an increase in the LT4 dose level. An in-depth etiological investigation can reveal visceral disorders and, especially, digestive tract disorders.
Topics: Adult; Helicobacter Infections; Helicobacter pylori; Hormone Replacement Therapy; Humans; Hypothyroidism; Thyrotropin; Thyroxine
PubMed: 34671932
DOI: 10.1007/s11154-021-09691-9 -
International Journal of Cancer Oct 2020Whether thyroid dysfunction plays a causal role in the development of cancer remains inconclusive. We conducted a two-sample Mendelian randomization study to investigate... (Meta-Analysis)
Meta-Analysis
Whether thyroid dysfunction plays a causal role in the development of cancer remains inconclusive. We conducted a two-sample Mendelian randomization study to investigate the associations between genetic predisposition to thyroid dysfunction and 22 site-specific cancers. Single-nucleotide polymorphisms associated with four traits of thyroid function were selected from a genome-wide association meta-analysis with up to 72,167 European-descent individuals. Summary-level data for breast cancer and 21 other cancers were extracted from the Breast Cancer Association Consortium (122,977 breast cancer cases and 105,974 controls) and UK Biobank (367,643 individuals). For breast cancer, a meta-analysis was performed using data from both sources. Genetically predicted thyroid dysfunction was associated with breast cancer, with similar patterns of associations in the Breast Cancer Association Consortium and UK Biobank. The combined odds ratios of breast cancer were 0.94 (0.91-0.98; p = 0.007) per genetically predicted one standard deviation increase in TSH levels, 0.96 (0.91-1.00; p = 0.053) for genetic predisposition to hypothyroidism, 1.04 (1.01-1.07; p = 0.005) for genetic predisposition to hyperthyroidism and 1.07 (1.02-1.12; p = 0.003) per genetically predicted one standard deviation increase in free thyroxine levels. Genetically predicted TSH levels and hypothyroidism were inversely with thyroid cancer; the odds ratios were 0.47 (0.30-0.73; p = 0.001) and 0.70 (0.51-0.98; p = 0.038), respectively. Our study provides evidence of a causal association between thyroid dysfunction and breast cancer (mainly ER-positive tumors) risk. The role of TSH and hypothyroidism for thyroid cancer and the associations between thyroid dysfunction and other cancers need further exploration.
Topics: Biological Specimen Banks; Breast Neoplasms; Female; Humans; Hyperthyroidism; Hypothyroidism; Male; Mendelian Randomization Analysis; Polymorphism, Single Nucleotide; Thyroid Function Tests; Thyroid Gland; Thyroid Neoplasms; Thyrotropin
PubMed: 32215913
DOI: 10.1002/ijc.32988 -
Journal of Investigative Medicine High... 2023Medications are known to affect the thyroid physiology and are a known cause of hypothyroidism. There is an ever-growing list of medications that affect the thyroid by 1...
Medications are known to affect the thyroid physiology and are a known cause of hypothyroidism. There is an ever-growing list of medications that affect the thyroid by 1 or more mechanisms. Mifepristone is presently used for the treatment of mild autonomous cortisol secretion (MACS). Hypothyroidism is not a known side effect of this medication. We present a 71-year-old woman with newly diagnosed impaired fasting glucose, dyslipidemia, and osteopenia presenting with a 3-year history of unintentional 15-pound weight gain (despite exercise and a good diet) and increased anxiety. Her physical examination was pertinent for mild lower extremity edema, easy bruising, and skin thinning. Workup revealed adrenocorticotropic hormone (ACTH)-independent MACS from bilateral micronodular hyperplasia of the adrenals. Since she was not a surgical candidate, medical management with mifepristone was chosen. While on mifepristone, she complained of excessive fatigue, a workup done revealed new-onset hypothyroidism. Given her symptoms and bloodwork, she was started on levothyroxine. After stopping mifepristone, she was biochemically and clinically euthyroid and was eventually off levothyroxine. The mechanism by which mifepristone induces hypothyroidism is unknown. Except for a multicenter case series suggesting that mifepristone increases thyroid hormone requirements in patients with central hypothyroidism, to the best of our knowledge, the literature on euthyroid patients developing hypothyroidism secondary to mifepristone is scarce. In conclusion, while the hypothyroidism seems reversible our case highlights the importance of getting baseline thyroid function tests (TFTs) and repeating them while on the medication. Treatment of hypothyroidism is based on symptoms and bloodwork.
Topics: Female; Humans; Aged; Thyroxine; Mifepristone; Hypothyroidism; Thyroid Function Tests
PubMed: 37565673
DOI: 10.1177/23247096231191874 -
Nature Reviews. Disease Primers May 2022
Topics: Humans; Hypothyroidism
PubMed: 35589732
DOI: 10.1038/s41572-022-00364-8 -
Ugeskrift For Laeger May 2023Acquired hypothyroidism is the most common thyroid disease in paediatric patients and in iodine-replete areas mainly due to autoimmune thyroiditis (AIT). Symptoms of... (Review)
Review
Acquired hypothyroidism is the most common thyroid disease in paediatric patients and in iodine-replete areas mainly due to autoimmune thyroiditis (AIT). Symptoms of hypothyroidism are unspecific and insidious for which reason thyroid function tests are often part of a general paediatric assessment. Consequently, only few patients present with pronounced symptoms which include a stunted growth pattern and multiorgan involvement when most extreme. This review provides an overview of the current knowledge on this common endocrinopathy in childhood.
Topics: Humans; Child; Adolescent; Hypothyroidism; Thyroid Diseases; Thyroiditis, Autoimmune; Iodine
PubMed: 37264859
DOI: No ID Found -
Indian Journal of Pediatrics Oct 2023Acquired hypothyroidism is generally also referred to as juvenile hypothyroidism. Hypothyroidism is due to the deficient secretion of thyroid hormones causing metabolic... (Review)
Review
Acquired hypothyroidism is generally also referred to as juvenile hypothyroidism. Hypothyroidism is due to the deficient secretion of thyroid hormones causing metabolic and neurological sequelae at the cellular level. It can present as overt hypothyroidism wherein the thyroid hormones (T4 and T3) secretion fall and thyrotropin (TSH) rises. Acquired hypothyroidism frequently presents between 9 and 11 y of age and is rarely seen before 4 y of age. Approximately 80% of the children and adolescents are asymptomatic at the time of diagnosis. Children with moderate to severe hypothyroidism often present for evaluation of poor growth, constipation, lethargy and/or dry skin. A detailed history and examination will provide us with enough clues for diagnosing hypothyroidism. Primary hypothyroidism can be diagnosed with raised TSH with subnormal levels of T3 and T4. Titres of thyroid antibodies - Anti-thyroperoxidase (TPO) and anti-thyroglobulin (ATG) antibodies, will be high in autoimmune hypothyroidism. Subclinical hypothyroidism is diagnosed with mildly elevated or high normal levels of TSH with free T4 being in the normal range. Insufficient secretion of thyrotropin from the pituitary causes central hypothyroidism. Acquired hypothyroidism is treated by replacement with levothyroxine. Regular monitoring of thyroid profile is necessary for adjusting doses of levothyroxine. Close monitoring and individualization of levothyroxine therapy is essential for normal growth and development of the child.
Topics: Adolescent; Child; Humans; Thyroxine; Hypothyroidism; Thyroid Hormones; Thyrotropin
PubMed: 37256446
DOI: 10.1007/s12098-023-04578-w -
Diabetes & Metabolic Syndrome Nov 2023Female infertility is defined as the inability to achieve pregnancy following one year of consistent, unprotected sexual intercourse. Among the various endocrine factors... (Review)
Review
INTRODUCTION
Female infertility is defined as the inability to achieve pregnancy following one year of consistent, unprotected sexual intercourse. Among the various endocrine factors contributing to this complex issue, thyroid dysfunction assumes a pivotal and noteworthy role.
METHODS
A narrative review, encompassing 134 articles up to 2023, was conducted utilizing the PubMed/Medline, EMBASE, and Scielo databases. The primary focus of this review was to investigate the effects of thyroid dysfunction on female infertility.
RESULTS
Thyroid disorders exert a significant influence on folliculogenesis, fertilization, and implantation processes. Thyroid autoimmunity, although associated with diminished ovarian reserve, does not typically necessitate levothyroxine therapy. On the other hand, both subclinical and overt hypothyroidism often require levothyroxine treatment to enhance fertility and optimize obstetric outcomes. Hyperthyroidism warrants prompt intervention due to its heightened risk of miscarriage. Furthermore, thyroid dysfunction exerts notable effects on assisted reproductive technologies, underscoring the importance of achieving euthyroidism prior to ovarian stimulation.
CONCLUSION
Women presenting with thyroid dysfunction must undergo meticulous and individualized assessments since fertility outcomes, whether achieved through natural conception or assisted reproductive technologies, can be significantly influenced by thyroid-related factors.
Topics: Pregnancy; Female; Humans; Thyroxine; Infertility, Female; Thyroid Diseases; Hypothyroidism
PubMed: 37866272
DOI: 10.1016/j.dsx.2023.102876 -
The Journal of Clinical Endocrinology... Jan 2022Thyroid dysfunction is associated with higher anemia prevalence, although causality remains unclear. (Observational Study)
Observational Study
CONTEXT
Thyroid dysfunction is associated with higher anemia prevalence, although causality remains unclear.
OBJECTIVE
This study aimed to investigate the association between thyroid function and anemia.
METHODS
This cross-sectional and Mendelian randomization study included 445 482 European participants from the UK Biobank (mean age 56.77 years (SD 8.0); and 54.2% women). Self-reported clinical diagnosis of hypothyroidism was stated by 21 860 (4.9%); self-reported clinical diagnosis of hyperthyroidism by 3431 (0.8%). Anemia, defined as hemoglobin level of < 13 g/dL in men and < 12 g/dL in women, was present in 18 717 (4.2%) participants.
RESULTS
In cross-sectional logistic regression analyses, self-reported clinical diagnoses of hypo- and hyperthyroidism were associated with higher odds of anemia (OR 1.12; 95% CI, 1.05-1.19 and OR 1.09; 95% CI, 0.91-1.30), although with wide confidence intervals for hyperthyroidism. We did not observe an association of higher or lower genetically influenced thyrotropin (TSH) with anemia (vs middle tertile: OR for lowest tertile 0.98 [95% CI, 0.95-1.02]; highest tertile 1.02 [95% CI, 0.98-1.06]), nor of genetically influenced free thyroxine (fT4) with anemia. Individuals with genetic variants in the DIO3OS gene implicated in intracellular regulation of thyroid hormones had a higher anemia risk (OR 1.05; 95% CI, 1.02-1.10); no association was observed with variants in DIO1 or DIO2 genes.
CONCLUSION
While self-reported clinical diagnosis of hypothyroidism was associated with higher anemia risk, we did not find evidence supporting a causal association with variation of thyroid function within the euthyroid range. However, intracellular regulation of thyroid hormones might play a role in developing anemia.
Topics: Aged; Anemia; Biological Specimen Banks; Causality; Cohort Studies; Cross-Sectional Studies; Female; Genome-Wide Association Study; Humans; Hypothyroidism; Male; Mendelian Randomization Analysis; Middle Aged; Prevalence; Self Report; Thyroid Gland; Thyrotropin; United Kingdom
PubMed: 34514498
DOI: 10.1210/clinem/dgab674 -
Expert Review of Endocrinology &... May 2024Adverse reactions to tuberculosis treatment can impact patient adherence and prognosis. Hypothyroidism is a frequent adverse reaction caused using ethionamide,... (Review)
Review
INTRODUCTION
Adverse reactions to tuberculosis treatment can impact patient adherence and prognosis. Hypothyroidism is a frequent adverse reaction caused using ethionamide, prothionamide, and para-aminosalicylic acid and is often underdiagnosed.
AREAS COVERED
We searched Scielo, Scopus, and EMBASE databases, including 67 articles. Antitubercular drug-induced hypothyroidism has a prevalence of 17%. It occurs after 2 to 3 months of treatment and resolves within 4 to 6 weeks after discontinuation. It is postulated to result from the inhibition of thyroperoxidase function, blocking thyroid hormone synthesis. Symptoms are nonspecific, necessitating individualized thyroid-stimulating hormone measurement for detection. Specific guidelines for management are lacking, but initiation of treatment with levothyroxine, as is customary for primary hypothyroidism, is recommended. Discontinuation of antitubercular drugs is discouraged, as it may lead to unfavorable consequences.
EXPERT OPINION
Antitubercular drug-induced hypothyroidism is more common than previously thought, affecting one in six MDR-TB patients. Despite diagnostic and treatment recommendations, implementation is hindered in low-income countries due to the lack of certified laboratories. New drugs for tuberculosis treatment may affect thyroid function, requiring vigilant monitoring for complications, including hypothyroidism.
Topics: Humans; Hypothyroidism; Antitubercular Agents; Tuberculosis
PubMed: 38258451
DOI: 10.1080/17446651.2024.2307525