Diagnosis and management of thyroid disorders and thyroid hormone supplementation in adult horses and foals.

Equine thyroid disorders pose a diagnostic challenge in clinical practice because of the effects of nonthyroidal factors on the hypothalamic-pituitary-thyroid axis, and the horse's ability to tolerate wide fluctuations in thyroid hormone concentrations and survive without a thyroid gland. While benign thyroid tumours are common in older horses, other disorders like primary hypothyroidism or hyperthyroidism in adult horses and congenital hypothyroidism in foals are rare. There is a common misunderstanding regarding hypothyroidism in adult horses, especially when associated with the clinical profile of obesity, lethargy, and poor performance observed in dogs and humans. Low blood thyroid hormone concentrations are often detected in horses as a secondary response to metabolic and disease states, including with the nonthyroidal illness syndrome; however, it is important to note that low thyroid hormone concentrations in these cases do not necessarily indicate hypothyroidism. Assessing equine thyroid function involves measuring thyroid hormone concentrations, including total and free fractions of thyroxine (T4) and triiodothyronine (T3); however, interpreting these results can be challenging due to the pulsatile secretion of thyroid hormones and the many factors that can affect their concentrations. Dynamic testing, such as the thyrotropin-releasing hormone stimulation test, can help assess the thyroid gland response to stimulation. Although true hypothyroidism is extremely rare, thyroid hormone supplementation is commonly used in equine practice to help manage obesity and poor performance. This review focuses on thyroid gland pathophysiology in adult horses and foals, interpretation of blood thyroid hormone concentrations, and evaluation of horses with thyroid disorders. It also discusses the use of T4 supplementation in equine practice.

Subclinical hypothyroidism: Let the evidence be your guide.

Patient age, time of day, and supplement use influence screening results; repeat testing is advised. Avoid treating to improve mood, cognition, fatigue, or quality of life.

Achievements in Hypothyroidism Treatment with Herbal Medicine: A Systematic Review of Randomized Controlled Trials.

BACKGROUND: Hypothyroidism is a common endocrine disease in the world that causes morbidity and mortality due to its association with metabolic diseases, especially in old age, and longterm treatment with levothyroxine causes many side effects for patients. Treatment with herbal medicine can regulate thyroid hormones and prevent side effects. OBJECTIVE: The purpose of this systematic review is the evaluation of the effect of herbal medicine on the signs and symptoms of primary hypothyroidism. METHODS: PubMed, Embase, Google Scholar, Scopus, and Cochrane Central Register of Controlled Trials were searched until 4 May, 2021. We selected randomized clinical trials (RCTs) that have assessed the effect of herbal medicine on hypothyroidism. RESULTS: Out of 771 articles, 4 trials with 186 participants were included. In one study, Nigella sativa L. caused a significant decrease in weight (P=0.004) and body mass index (BMI) (P=0.002). TSH levels were reported to be decreased and T3 increased in the treatment group (P =0.03) (P=0.008), respectively. In another study on Nigella sativa L., results did not show a significant difference between the two groups (p=0.02). A significant decrease in total cholesterol (CHL) and fasting blood sugar (FBS) was reported in participants with negative anti-thyroid peroxidase (anti-TPO) antibodies. In patients with positive anti-TPO antibodies, a significant increase in total cholesterol and FBS was observed in the intervention group (p=0.02). In the third RCT, T3 in the ashwagandha group at 4 and 8 weeks significantly increased by 18.6% (p=0.012) and 41.5% (p < 0.001), respectively. A noticeable increase was found in the T4 level from baseline by 9.3% (p= 0.002) and 19.6% (p < 0.001) at 4 and 8 weeks, respectively. TSH levels fell remarkably in the intervention group compared to placebo at 4 weeks (p <0.001) and 8 weeks (p <0.001), respectively. In the last article selected, Mentha x Piperita L. showed no significant difference in fatigue scores between intervention and control groups at the midpoint (day 7), while fatigue scores improved in the intervention group in all subscales compared to the control group on day 14. CONCLUSION: Some herbal remedies, including Nigella sativa L., ashwagandha, and Mentha x Piperita L., can improve the signs and symptoms of primary hypothyroidism, but using a more extensive and advanced methodology will provide us with more complete results.

Recurrent hypokalemic paralysis in hypothyroidism.

Hypothyroidism, a commonly encountered thyroid disorder, usually manifests with readily recognizable typical features. However, an unusual presentation of a classic thyroid disorder may hinder accurate diagnosis in certain instances. One such rare initial presentation of hypothyroidism is recurrent hypokalemic paralysis, and existing reports in the literature are sparse. It has been more commonly reported in thyrotoxicosis. We report the case details and clinical outcomes of two middle-aged individuals (a 34-year-old male and a 37-year-old female) with recurrent episodes of hypokalemic paralysis. Their clinical examination revealed pure motor hyporeflexia quadriparesis with hypotonia and diminished deep tendon reflexes without any autonomic dysfunction. They had no significant previous medical history. Biochemical findings revealed hypokalemia in both cases (1.4 and 1.9 mEq/L, respectively) with elevated levels of thyroid­stimulating hormone and thyroid­related antibodies in both individuals, thus, confirming the diagnosis of autoimmune hypothyroidism. Immediate treatment with intravenous and oral potassium correction helped in the recovery. Thyroxine supplementation was considered a follow-up treatment, and for a one-year follow-up period there were no complaints of limb weakness reported in both individual.

Study of the relationship between FT3, FT4, and TSH with bone resorption indices in men with hypothyroidism.

AIM: This study aimed to find the effect of hypothyroidism in men on metabolism and bone mineral density. METHOD: The study included a patients group of 90 men suffering from hypothyroidism and 120 healthy subjects as a control group. The study comprised the estimation of the concentration of Blood free triiodothyronine (FT3), free thyroid hormone (FT4), thyroid stimulating hormone (TSH), bone resorption index type I collagen C-terminal peptide (CTX-1), the serum calcium (Ca2+), serum phosphorus (Pi3+), the bone mineral density of the lumbar spine and femoral neck. RESULTS: In the hypothyroidism men group: (1) the bone mass was lower than the control group with significant differences, (2) the bone resorption index CTX-1 was significantly higher than that in the control group and calcium and phosphorus were not different from those in healthy control subjects, and (3) TSH was positively correlated with CTX-1. Male TSH and CTX-1 levels were positively correlated. CONCLUSIONS: There is bone loss in men with hypothyroidism, which may be related to increased bone resorption.

Thyroid and Parathyroid Conditions: Hypothyroidism.

Hypothyroidism is caused by deficient thyroid hormone production secondary to autoimmune disease or insufficient iodine consumption or as a complication of hyperthyroidism management. Signs and symptoms include fatigue, weight gain, dry skin, constipation, and cold intolerance. The U.S. Preventive Services Task Force found insufficient evidence to recommend for or against screening for hypothyroidism, but some organizations support screening in special populations. If hypothyroidism is suspected, initial laboratory evaluation consists of a serum thyrotropin (TSH) measurement with reflex testing of free thyroxine (T4). Thyroid function tests must be interpreted carefully because acute illness, diet, and drugs may alter values. Overt hypothyroidism occurs when a patient has an elevated TSH level and a low free T4 level with symptoms of hypothyroidism. Management includes thyroid hormone replacement, ideally levothyroxine. Subclinical hypothyroidism is characterized by an elevated TSH level with a normal T4 value. The decision to treat subclinical hypothyroidism should be based on patient characteristics and shared decision-making discussions. Special consideration should be taken in treating patients with high-risk conditions, including heart disease, pregnancy, and myxedema coma, and in patients requiring high-dose levothyroxine. Thyroid hormone should be titrated based on goal TSH values, symptoms, and potential treatment adverse effects.

Use of thyroid hormones in hypothyroid and euthyroid patients: a 2020 THESIS questionnaire survey of members of the Hellenic Endocrine Society.

PURPOSE: To investigate current practices of specialists in the use of thyroid hormone preparations in Greece as part of an ongoing international survey, namely THESIS-Treatment of Hypothyroidism in Europe by Specialists: an International Survey. METHODS: An electronic link leading to an anonymized questionnaire was sent to all (n = 837) members of the Hellenic Endocrine Society. RESULTS: In total, 501 respondents participated in the survey, though only part of the questionnaire was filled in by some participants. A total of 88.2% were endocrinologists and 57.9% worked in private practice. Levothyroxine (LT4) was the first-line choice (98.6%) for the treatment of hypothyroid patients. In total, 70.2% preferred LT4 soft-gel capsules for patients reporting intolerance to various foods. Soft-gel capsules were the preferred LT4 formulation for patients on generic LT4 and with unexplained poor biochemical control of hypothyroidism (66.3%) or inability to take LT4 fasted and separate from food/drink (68.3%). It was found that 48.4% would never use combined LT4 + LT3. However, 25% would use combination therapy for a short period in patients recovering from protracted hypothyroidism or in patients with normal serum TSH but persistent symptoms. Concerning euthyroid individuals, 31.9% considered treatment with thyroid hormones in infertile females with positive thyroid antibodies and 24.4% in patients with growing goiter. Selenium or iodine supplementation was used occasionally, mostly in patients with coexisting autoimmune thyroiditis. CONCLUSIONS: LT4 tablets are the treatment of choice for hypothyroidism in Greece. Several conditions may lead to various other practices, some of which deviate from current evidence-based guidelines and need more scrutiny.

Homeopathic Treatment of Subclinical Hypothyroidism-A Series of 19 Cases.

BACKGROUND: Subclinical hypothyroidism (SCH) is a common clinical problem. Controversy surrounds the definition, clinical importance, and need for prompt diagnosis and treatment of the mild form of SCH. AIM: The aim of the study was to analyze the evolution of serum thyroid stimulating hormone (TSH) levels after a therapeutic homeopathic intervention in women older than 40 years with SCH. METHODS: This study is a retrospective series of 19 cases of SCH, with serum TSH levels between 5 and 10 mIU/L, treated exclusively with homeopathic medicines prescribed on an individualized basis. RESULTS: Nineteen patients were included according to the inclusion and exclusion criteria. Their mean age was 56 years, they were followed for a mean duration of 69 months, the mean number of serum TSH level measurements was 18, and the intervention was successful for 13 patients. CONCLUSION: The homeopathic therapeutic intervention was successful in 68% of the patients, with serum TSH levels back within the normal range (0.5-5.0 mIU/L).

Role of Acupuncture and Fire Cupping in Reducing the Thyroxine Dose and Improving the Thyroid Function in Hypothyroidism Patients: A Case Series.

Hypothyroidism is one of the most common endocrine disorders linked to various systemic diseases ranging from obesity to cancers. The present line of management is insufficient as reports suggest that there is persistence of symptoms and poor adherence that makes the management of said disease challenging. Acupuncture and other Traditional Chinese Medicine (TCM) therapies are proven to alleviate endocrine dysfunctions. However, reports on acupuncture and cupping therapy on hypothyroidism are very scarce. Here, we report 5 cases of hypothyroid patients aged between 38-44 yrs who were treated with acupuncture and fire cupping for a period of three months. At the baseline, the patients presented with either a weak, wiry or vacuum pulse which represents spleen Qi deficiency. Further, they presented with elevated levels of Thyroid Stimulating Hormone (TSH), and higher Body Mass Index (BMI). Acupuncture treatment at ST36, LI4, SP6, and BL20 was given bilaterally whilst CV4, LR3, LR4, SP9, ST40, SP10, GV4, KI3, ST12, and SI17 were punctured unilaterally. At the end of the time period of three months, patients progressed to normal levels of TSH, reduction in BMI and had succeeded in tapering their medication doses. Supplementing this, the patients reported marked improvement in other symptoms like fatigue, hair loss, and cold feet post-treatment. The effects were consistent even during the three month follow-up period post-interventions. The results encourage the utilization of acupuncture and fire cupping in the management of hypothyroidism. However, large scale studies are warranted to strengthen this recommendation.

Herbal preparations in the management of hypothyroidism in Unani medicine.

Hypothyroidism is the most common thyroid disorder, affects women more frequently, and incidence increases with age. The prevalence of hypothyroidism in developed countries is around 4-5%, whereas, in India, it is about 11%. The common symptoms of hypothyroidism in adults are weight gain, fatigue, lethargy, cold intolerance, constipation, change in voice, and dry skin. It can affect all systems of the body. Diagnosis is mainly based on clinical history and laboratory investigations. Untreated hypothyroidism increases morbidity and mortality. In conventional medicine, the treatment of choice is Levothyroxine, whereas in Unani System of Medicine, pharmacotherapy consists of single and compound drugs. Single drugs are selected as per the constitution (Mizaj) of drugs as opposed to the abnormal constitution (Su-e-Mizaj) of disease and its pathology. Some drugs increase the basal metabolic rate whereas some evacuate the morbid material from the body by the action of purgation. The drugs are used either in a single form or as a prescription of more than one drug in the form of decoction (Joshandah), infusion (Kheshandah), or powder (Safoof). This review aims at providing comprehensive information regarding various drugs used in Unani system of medicine that is used in the management of thyroid dysfunction.

Update of hypothyroidism and its management in Unani medicine.

Hypothyroidism is a clinical syndrome caused by thyroid hormone deficiency due to reduced production, deranged distribution, or lack of effects of thyroid hormone. The prevalence of hypothyroidism in developed countries is around 4-5%, whereas it is about 11% in India, only 2% in the UK, and 4·6% in the USA. It is more common in women than in men. Hypothyroidism has multiple etiologies and manifestations. The most common clinical manifestations are weight gain, loss of hair, cold intolerance, lethargy, constipation, dry skin, and change in voice. The signs and symptoms of hypothyroidism differ with age, gender, severity of condition, and some other factors. The diagnosis is based on clinical history, physical examination and serum level of FT3, FT4, and thyroid-stimulating hormone, imaging studies, procedures, and histological findings. The treatment of choice for hypothyroidism is levothyroxine, however; in this review article, we have discussed the epidemiology, etiology, clinical sign and symptoms, diagnosis, complications, and management of hypothyroidism in modern medicine and a comparative treatment by the Unani system of medicine (USM). In the USM, the main emphasis of the principle of treatment (Usool-e-Ilaj) is to correct the abnormal constitution (Su-e-Mizaj) and alter the six prerequisites for existence (Asbab-e-Sitta Zarooriya) to restore normal health. It is a packaged treatment, that is, different components of treatment are given as a package form which includes different drugs, dosages form, and regimens.

Combined mutations of NKX2-1 and surfactant protein C genes for refractory low oxyhemoglobin saturation and interstitial pneumonia: A case report.

RATIONALE: Mutations of the NKX2-1 gene are associated with brain-lung-thyroid syndrome, which is characterized by benign hereditary chorea, hypothyroidism, and pulmonary disease with variable presentation. Surfactant protein C (SFTPC) gene mutations result in chronic interstitial lung disease in adults or severe neonatal respiratory distress syndrome. PATIENT CONCERNS: Recurrent hypoxemia was observed shortly after birth in a baby at a gestational age of 40 weeks and birth weight of 3150 g. The need for respiratory support gradually increased. He had hypothyroidism and experienced feeding difficulties and irritability. DIAGNOSIS: Genetic examination of the peripheral blood revealed combined mutations of the NKX2-1 and SFTPC genes. INTERVENTIONS: The patient was administered respiratory support, antibiotics, low-dose dexamethasone, supplementary thyroxine, venous nutrition, and other supportive measures. OUTCOMES: The patient's guardian stopped treatment 3 months after commencement of treatment, due to the seriousness of his condition and the patient died. LESSONS: Combined mutations of NKX2-1 and SFTPC genes are very rare. Thus, idiopathic interstitial pneumonia with hypothyroidism and neurological disorders require special attention.

Monitoring of Thyroid Malfunction and Therapies in Pregnancy and the Postpartum Period: A Systematic Updated Critical Review of the Literature.

PURPOSE: From the very beginning of pregnancy, the maternal thyroid has to adapt to increased thyroid hormone secretion of up to 50%. This is paralleled by changes in thyroid-stimulating hormone secretion and by the thyroid-topic action of human chorionic gonadotropin. Thus, hypothyroidism and hyperthyroidism may occur. Many women exhibit preexisting thyroid diseases. This review tries to add the most recently published approaches to diagnosing thyroid malfunction in pregnancy to existing guidelines. METHODS: Different literature-based approaches to diagnosing thyroid malfunction during pregnancy and the postpartum period were applied. To diagnose thyroid malfunction in pregnancy, trimester-specific reference ranges for thyroid-stimulating hormone and T4 are used. RESULTS: Definitions of thyroid malfunction are given. Treatment schedules for various thyroid diseases were reviewed and, on the basis of recent findings, were revised where necessary. For a daily clinical workup, this outline not only suggests diagnostic and therapeutic steps but also refers to frequent pitfalls and misinterpretations of laboratory data. CONCLUSIONS: Although the body of knowledge is increasing rapidly, the authors believe that this review is able to present new ideas concerning diagnostic and therapeutic tools for thyroid malfunction in pregnancy and the postpartum period. Nevertheless, there seems to remain room for individual approaches based on the personal experience of physicians who deal with these issues regularly.

Diagnosis, treatment, and management of gestational hypothyroidism. The TIROGEST study.

INTRODUCTION: There is no agreement on the procedures to be used for diagnosis and treatment of gestational thyroid dysfunction. Controversy still exists on the normal range of thyroid-stimulating hormone (TSH) levels and use of gestational hypothyroidism (GH) screening. The aim of this study was to assess diagnosis and treatment of thyroid dysfunction during pregnancy in a group of Spanish hospitals. STUDY DESIGN: This was a retrospective, multicenter study in pregnant females with GH attending Spanish healthcare centers from March 2013 to July 2014. Variables analyzed included diagnosis criteria for GH (availability of universal screening for gestational thyroid disorders and TSH reference values (RVs) by trimester of pregnancy): risk factors for GH, iodine intake from food or supplementation, gestational age (at diagnosis/treatment) and l-thyroxine treatment. RESULTS: Fourteen centers participated in the study. Universal screening was performed in only half of the centers, and only 14% had their own TSH RVs. Overall, 257 pregnant women were enrolled, 53.7% with hypothyroidism (HT) diagnosed before pregnancy (pre-GH) and 46.3% with HT diagnosed during pregnancy (intra-GH). A comparison of intra-GH and pre-GH women showed that intra-GH women made their first visit later (59.7% vs. 75.4% respectively before week 12, p=0.007) and had more frequently high TSH levels (>2.5µIU/ml) during the first trimester (94.4% vs. 67.0% respectively, p<0.001). CONCLUSIONS: Our results suggest that GH may be underdiagnosed or inadequately diagnosed in most healthcare centers. These findings suggest the need of improving the current practice in Spain.

Unraveling the Molecular Basis for Successful Thyroid Hormone Replacement Therapy: The Need for New Thyroid Tissue- and Pathway-Specific Biomarkers.

Thyroid function is conventionally assessed by measurement of thyroid-stimulating hormone (TSH) and free circulating thyroid hormones, which is in most cases sufficient for correct diagnosis and monitoring of treatment efficiency. However, several conditions exist, in which these parameters may be insufficient or even misleading. For instance, both, a TSH-secreting pituitary adenoma and a mutation of thyroid hormone receptor ß present with high levels of TSH and circulating hormones, but the optimal treatment is substantially different. Likewise, changes in thyroid hormone receptor α signaling are not captured by routine assessment of thyroid status, as serum parameters are usually inconspicuous. Therefore, new biomarkers are urgently needed to improve the diagnostic management and monitor treatment efficiency for e. g., replacement therapy in hypothyroidism or thyroid hormone resistance. By comparing animal models to human data, the present minireview summarizes the status of this search for new tissue- and pathway-specific biomarkers of thyroid hormone action.

Levothyroxine Therapy in Thyrodectomized Patients.

Administration of the optimal dose of levothyroxine (LT4) is crucial to restore euthyroidism after total thyroidectomy. An insufficient or excessive dosage may result in hypothyroidism or thyrotoxicosis, either one associated with a number of symptoms/complications. Most literature regarding the LT4 dosage deals with the treatment of primary hypothyroidism, whereas a limited number of studies handle the issue of thyroxin replacement after total thyroidectomy. A literature review was performed focusing on all papers dealing with this topic within the last 15 years. Papers that reported a scheme to calculate the proper LT4 dose were collected and compared to set up a review exploring limits and drawbacks of LT4 replacement therapy in the wide population of patients who had undergone thyroidectomy. Most of the methods for monitoring and adjusting thyroid hormone replacement after thyroidectomy for benign disease use LT4 at an empirical dose of approximately 1.6 µg/kg, with subsequent changes according to thyroid function test results and assessments of the patient's symptoms. Approximately 75% of patients require a dose adjustment, suggesting that factors other than body weight play a role in the determination of the proper LT4 dose. Hence, several schemes are reported in the literature for the proper initial dose of LT4. An inadequate level of thyroid hormone levels in these patients can be due to several factors. The most common ones that lead to the necessity of LT4 dose adjustments include lack of compliance, changes in LT4 formulation, dosage errors, increased serum levels of T4-binding globulin, body mass changes, and dietary habits. Moreover, concomitant ingestion of calcium supplements, ferrous sulfate, proton-pump inhibitors, bile acid sequestrants, and sucralfate might influence LT4 absorption and/or metabolism. Furthermore, some gastrointestinal conditions and their treatments can contribute to suboptimal LT4 performance by altering gastric acidity and thereby reducing its bioavailability, particularly in the solid form. Beyond the classic tablet form, new formulations of LT4, such as a soft gel capsule and an oral solution, recently became available. The liquid formulation is supposed to overcome the food and beverages interference with absorption of LT4 tablets.

Lack of association between hypothyroxinemia of prematurity and transient thyroid abnormalities with adverse long term neurodevelopmental outcome in very low birth weight infants.

INTRODUCTION: The association between hypothyroxinemia of prematurity with neurodevelopment was controversial. OBJECTIVES: To compare 5 year neurodevelopmental outcomes of very low birth weight (VLBW) infants with hypothyroxinemia of prematurity against those without. METHODS: Retrospective cohort study in a single tertiary neonatal centre of VLBW infants born between the year 2008 to 2011. Comparisons were made between all abnormal and normal thyroid function controls using cord thyroid function tests, thyroid function tests during admission and pre-discharge thyroid function test done at term equivalent age. At 2 years corrected age, Bayley scales of infant and toddler development-third edition and Vineland II adaptive behaviour scales (VABS) were collected. At 5 years, Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III), Bracken School Readiness Assessment, VABS and Beery Test of Visual-Motor Integration were collected. RESULTS: 110 subjects were studied at 2 years corrected age and 80 subjects at 5 years old. 29 infants had abnormal thyroid function test (10 infants with hypothyroxinemia of prematurity and 19 infants with transient thyroid abnormalities). There were no significant difference in the 2 years and 5 years developmental outcome between infants with and without hypothyroxinemia of prematurity (p-value>0.05); and between infants with and without transient thyroid abnormalities (p-value>0.05). There were no significant difference in neurological, visual and hearing impairment between infants with or without hypothyroxinemia of prematurity (p-value>0.05). CONCLUSIONS: Hypothyroxinemia of prematurity or transient thyroid abnormalities in VLBW infants were not associated with poorer neurodevelopment and did not support the need for levothyroxine supplementation.

Compliance with Deferoxamine Therapy and Thyroid Dysfunction of Patients with ß-Thalassemia Major in Syria.

Hypothyroidism is one of the common endocrine complications described in patients with ß-thalassemia major (ß-TM). Studies have reported its incidence and severity depending on the region, quality of management and treatment protocols. The reported thyroid dysfunction includes overt hypothyroidism, subclinical hypothyroidism and rarely, central hypothyroidism. The main aims of this study were to identify the incidence of hypothyroidism in 82 patients with ß-TM in Syria, and also to evaluate the effect of compliance with deferoxamine (DFO) therapy on the patients' thyroid function. Out of the 82 patients included in this study, 24 had subclinical hypothyroidism (29.27%) and one patient had overt hypothyroidism (1.22%). It was demonstrated by this study that noncompliance with DFO therapy increases the risk of thyroid dysfunction 6.38-times compared to compliance with DFO [risk ratio (RR) = 6.385; 95% confidence interval (95% CI) 2.40-16.95)]. These results emphasize the importance of compliance with chelation therapy to minimize the burden of thyropathy on patients' quality of life, and also augment the rationale for a routine follow-up and endocrine evaluation for early detection and management of these complications.

Patient Requests for Tests and Treatments Impact Physician Management of Hypothyroidism.

Background: Levothyroxine is one of the most commonly prescribed medications in the United States. Although prior research focused on over- and undertreatment and patient dissatisfaction with thyroid hormone, little is known about physician-reported barriers to managing thyroid hormone therapy. In addition, the impact of patient requests for tests and treatments on hypothyroidism management remains unexplored. Methods: We randomly surveyed physician members of the Endocrine Society, American Academy of Family Practice and American Geriatrics Society. Respondents were asked to rate barriers to management of thyroid hormone therapy. We conducted multivariable logistic regression analyses to determine correlates with physician report of the most commonly reported barriers, including patient requests. Results: Response rate was 63% (359/566). Almost half of the physicians reported that patient requests for tests and treatments were somewhat to very likely to being a barrier to appropriate management of thyroid hormone therapy (46%). Endocrinologists (odds ratio [OR] = 2.29 [95% confidence interval, CI 1.03-5.23], compared with primary care physicians) and physicians with more than 25% of patients on thyroid hormone therapy per year (OR = 1.90 [CI 1.05-3.46], compared with those with <25% patients per year) were more likely to report patient requests as a barrier. Physicians with more years in practice were less likely to do so (11-20 years: OR = 0.44 [CI 0.21-0.89]; >20 years: OR = 0.24 [CI 0.12-0.46], compared with ≤10 years). Physician-reported patient requests included requests for preparations other than synthetic thyroxine (52%), adjusting thyroid hormone dose based on symptoms when biochemically euthyroid (52%), maintaining thyrotropin level below the reference range (32%), and adjusting dose according to serum T3 level (21%). Physicians who reported receiving patient requests for the former three unconventional practices were more likely to execute them (p < 0.001, p = 0.014, p < 0.001, respectively). Conclusions: Physicians reported patient requests for tests and treatments as a common barrier to appropriate thyroid hormone management. In some scenarios, physician adherence to patient requests may be a driver for inappropriate care and lead to harm. Understanding physician-reported barriers to thyroid hormone management and factors associated with physician perception that patient requests are a barrier is key to improving patient care.

Excess iodine intake: sources, assessment, and effects on thyroid function.

Iodine is essential for thyroid hormone synthesis. High iodine intakes are well tolerated by most healthy individuals, but in some people, excess iodine intakes may precipitate hyperthyroidism, hypothyroidism, goiter, and/or thyroid autoimmunity. Individuals with preexisting thyroid disease or those previously exposed to iodine deficiency may be more susceptible to thyroid disorders due to an increase in iodine intake, in some cases at intakes only slightly above physiological needs. Thyroid dysfunction due to excess iodine intake is usually mild and transient, but iodine-induced hyperthyroidism can be life-threatening in some individuals. At the population level, excess iodine intakes may arise from consumption of overiodized salt, drinking water, animal milk rich in iodine, certain seaweeds, iodine-containing dietary supplements, and from a combination of these sources. The median urinary iodine concentration (UIC) of a population reflects the total iodine intake from all sources and can accurately identify populations with excessive iodine intakes. Our review describes the association between excess iodine intake and thyroid function. We outline potential sources of excess iodine intake and the physiological responses and consequences of excess iodine intakes. We provide guidance on choice of biomarkers to assess iodine intake, with an emphasis on the UIC and thyroglobulin.