Characteristics of anemia in subclinical and overt hypothyroid patients

Thyroid dysfunction alters gene expression of proteins related to iron homeostasis and metabolomics in male rats

Thyroid hormones (THs) are crucial in bodily functions, while iron is essential for processes like oxygen transport. Specialized proteins maintain iron balance, including ferritin, transferrin, ferroportin, and hepcidin. Research suggests that THs can influence iron homeostasis by affecting mRNA and protein expression, such as ferritin and transferrin. Our study focused on male rats to assess mRNA expression of iron homeostasis-related proteins and metabolomics in thyroid dysfunction. We found altered gene expression across various tissues (liver, duodenum, spleen, and kidney) and identified disrupted metabolite patterns in thyroid dysfunction. These findings highlight tissue-specific effects of thyroid dysfunction on essential iron homeostasis proteins and provide insights into associated metabolic changes. Our research contributes to understanding the intricate interplay between thyroid hormones and iron balance. By unveiling tissue-specific gene expression alterations and metabolic disruptions caused by thyroid dysfunction, our work lays a foundation for future investigations to explore underlying mechanisms and develop targeted strategies for managing iron-related complications in thyroid disorders.

Hematological Indices in Patients With Goiter: A Cross-Sectional Study in a Tertiary Care Hospital in South India

Introduction A wide range of haematological abnormalities have been observed in patients with goitre. The aim of the study was to evaluate the abnormalities in haematological parameters among patients with goitre in a tertiary care hospital in south India. Methods This was a cross-sectional study carried out in the pathology department of Chengalpattu Medical College from April 1 to June 30, 2019. The lab reports, including the complete blood count (CBC) and serum thyroid profile that included thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) of all the patients with goitre, were retrieved from the laboratory records. Results were tabulated and analysed. Results Out of a total of 200 patients with thyroid dysfunction, 12 (6%) were males and 188 (94%) were females, with the majority (51.5%) of them in the age group of 30-60 years. Serum TSH levels showed a statistically significant association with red cell distribution width (RCDW) (P-value = 0.000), mean corpuscular volume (MCV) (P-value = 0.020), and total white blood cell (WBC) count (P-value = 0.003) among the patients with goiter. There was no significant association between TSH and other parameters like haemoglobin, packed cell volume (PCV), red blood cell (RBC) count, and platelet (PLT) count. Conclusions Red cell distribution width and mean corpuscular volume are useful haematological parameters that will help clinicians in the early diagnosis and proper treatment of haematological abnormalities seen in patients with goitre.

Thyroid Dysfunction in Patients with and Without Venous Thromboembolism: a Case Control Study

Recent studies report an association between thyroid dysfunction and venous thromboembolism (VTE). Considering the high prevalence of thyroid diseases in India, identification of thyroid dysfunction as a risk factor for VTE will have implications in management. The aim of study was to determine if thyroid dysfunction could be considered as risk factor for unprovoked VTE. The study was conducted on 102 patients with unprovoked VTE and 102 age and gender matched controls in a tertiary care centre. Clinical profile and thyroid function tests (Free T3, Free T4, TSH) including antibody profile (Anti TPO and Anti TG) were compared between two groups. Thyroid disease was identified in 34 cases and 14 controls (33.1% vs. 13.7%, P = 0.001) Out of 34 cases with thyroid dysfunction, 17 had subclinical hypothyroidism (SCH) while 6 out of 14 controls had SCH. Both thyroid dysfunction and SCH were found to be associated with unprovoked VTE, as compared with controls; [Odds ratio (OR) = 3.14, 95% CI 1.56-6.33, P = 0.001] and (OR = 3.71; 95% CI 1.4-9.9; P = 0.01) respectively. Thyroid dysfunction was significantly higher among patients with unprovoked VTE. Thyroid dysfunction, SCH were associated with unprovoked VTE.

Rubrometabolic Syndrome

Metabolic syndrome (MS), a conglomeration of several conditions including obesity, type 2 diabetes mellitus (T2DM), insulin resistance, elevated blood pressure, and dyslipidemia is reaching epidemic proportions. Anemia is caused by iron deficiency or dysregulation of iron homeostasis, leading to tissue hypoxia. Coexistence of anemia and MS or its components has been reported in the literature. The term "rubrometabolic syndrome" acts as a unifying entity linking the importance of blood in health and anemia in MS; it justifies two principles - redness of blood and low-grade inflammation. Chronic low-grade inflammation in MS affects iron metabolism leading to anemia. Tissue hypoxia that results from the anemic condition seems to be a major causative factor for the exacerbation of several microvascular and macrovascular components of T2DM, which include diabetic neuropathy, nephropathy, retinopathy, and cardiovascular complications. In obesity, anemia leads to malabsorption of micronutrients and can complicate the management of the condition by bariatric surgery. Anemia interferes with the diagnosis and management of T2DM, obesity, dyslipidemia, or hypertension due to its effect on pathological tests as well as medications. Since anemia in MS is multifaceted, the management of anemia is challenging as overcorrection of anemia with erythropoietin-stimulating agents can cause detrimental effects. These limitations necessitate availability of an effective and safe therapy that can maintain and elevate the hemoglobin levels along with maintaining the physiological balance of other systems. This review discusses the physiological links between anemia and MS along with diagnosis and management strategies in patients with coexistence of anemia and MS.

Vitamin B12 levels in thyroid disorders: A systematic review and meta-analysis

Background and aims

Numerous studies have found an association between vitamin deficiency and thyroid disorders (TD). The presence of anti-parietal cell antibodies is indicative of reduced ability to absorb vitamin B12. Thus, this study reviewed the existing studies with the objective of assessing differences in the serum levels of vitamin B12 among patients with and without TD, the frequency of vitamin B12 deficiency in patients with TD, and the presence of anti-parietal cell antibodies in patients with TD.

Methods

A meta-analysis of random-effects model was conducted to calculate pooled frequencies, mean differences (MD), and their respective 95% confidence intervals (CI). We identified 64 studies that met our inclusion criteria (n = 28597).

Results

We found that patients with hypothyroidism had lower vitamin B12 levels than healthy participants (MD: -60.67 pg/mL; 95% CI: -107.31 to -14.03 pg/mL; p = 0.01). No significant differences in vitamin B12 levels were observed between healthy participants and patients with hyperthyroidism (p = 0.78), autoimmune thyroid disease (AITD) (p = 0.22), or subclinical hypothyroidism (SH) (p = 0.79). The frequencies of vitamin B12 deficiency among patients with hypothyroidism, hyperthyroidism, SH, and AITD were 27%, 6%, 27%, and 18%, respectively.

Conclusions

Patients with hypothyroidism had lower levels of vitamin B12 than healthy participants. No significant differences were observed between vitamin B12 levels and hyperthyroidism, AITD, or SH.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=324422, identifier (CRD42022324422).

Vitamin B12 (Cobalamin) Deficiency in Overt and Subclinical Primary Hypothyroidism

Background:

B12 (cobalamin) deficiency has been reported in hypothyroid patients with variable prevalence rates thus routine screening of hypothyroid patients was recommended by some and discouraged by others. We aimed to assess the prevalence of B12 deficiency among hypothyroid patients and to evaluate for pernicious anemia and celiac disease as etiologies.

Methods:

A total 133 patients were included. Thyroid hormones and thyroid peroxidase (TPO) autoantibodies were measured. Serum B12 was measured and if deficient, intrinsic factor antibodies (IFAB) and tissue transglutaminase (tTG) antibodies were evaluated.

Results:

Our study included 45 patients with overt hypothyroidism (OH), 48 patients with subclinical hypothyroidism (SCH), and 40 patients as controls. Mean age was 34.3 years and 82% were females. TPO antibodies were positive in 73.5% of OH and 51.1% of SCH patients. B12 deficiency was detected in 33.3%, 47.9%, and 37.5% of OH, SCH, and controls, respectively with no significant difference (P = .334). Borderline-to-low B12 level was more prevalent in the OH and the SCH groups compared to controls (68.9%, 85.4%, and 57.5%, respectively; P = .014). Among B12-deficient hypothyroid patients, 7.5% had positive IFAB and 13.3% had positive tTG antibodies. We did not find a significant association of TPO positivity and B12 deficiency (OR, 0.69; 95% CI 0.3-1.57; P = .147).

Conclusion:

We did not find a higher prevalence of B12 deficiency among hypothyroid patients nor an association with TPO positivity. Borderline B12 levels were more prevalent among hypothyroid patients.

Prevalence and Characteristics of Thyroid Abnormalities and Its Association with Anemia in ASIR Region of Saudi Arabia: A Cross-Sectional Study

The thyroid gland plays a significant role in the metabolism and proliferation of blood cells; hematological disorders are frequently observed in patients with thyroid disorders, and the most frequent problem is anemia. The main objective of this research work is to evaluate the prevalence and types of thyroid dysfunction and their association with anemia in different gender stratified by age in the Asir region of Saudi Arabia. Four years of data from July 2016 to July 2020 for 9992 study subjects were collected. Statistical analysis was performed based on thyroid disorder and anemia stratified by gender and age subgroup. The mean age of the study subject was 43.4 ± 15.8 years, and females constituted 61.7% of cases. Thyroid dysfunction was observed in 49.76% (4973), and subclinical hypothyroidism was the most prevalent type (3922/9992), followed by primary hypothyroidism (530/9992). Females have a significantly higher overall prevalence of thyroid dysfunction than males (p < 0.05). Anemia was detected in 1344 females and 465 males with a thyroid disorder, and also, the prevalence was significantly higher (p < 0.05), compared to the normal thyroid group. Thyroid disorders are a common problem in our population, more prevalent in females than males, with the peak age of above 30 years, and are associated with an increased prevalence of anemia.

The Maternal Leucocytes in Thrombophilia and Hypothyroidism and their Influence on Fetal Cells

The literature data show that thrombophilia and maternal dysfunction of thyroid gland during pregnancy are associated with an increased risk of miscarriage, placental abruption, hypertensive disorders and fetal growth retardation. It was shown that thyroid hormones and hypercoagulable states influence onto a leucocyte activity. The aim of this study has been to investigate maternal leucocytes changes and their correlation with frequency of fetal cells micronuclei in pregnant women with thrombophilia and hypothyroidism. The samples of blood and amniotic fluid were collected from healthy pregnant women and pregnant women with inherited thrombophilia and hypothyroidism (16 - 18 weeks of gestation). Hematological characteristics were determined by using standard hematological methods. The frequency of micronuclei was determined in fetal cells after amniocentesis by using standard cytogenetic methods. The results of this study showed significant higher levels of β-hCG, number of monocytes and eosinophils in blood of pregnant women with thrombophilia. A large number of eosinophils was documented in blood of pregnant women with hypothyroidism. Increased percentage distribution of eosinophils and basophils is shown in both investigated groups of pregnant women. The increased fetal cells micronuclei frequency and their correlation with percentage distribution of eosinophils and basophils were indicated in pregnant women with hypothyroidism. The obtained results suggest that an increased percentage of eosinophils and basophils in pregnant women with hypothyroidism contribute to a formation of micronuclei in fetal cells.

Tetrabromobisphenol A Perturbs Erythropoiesis and Impairs Blood Circulation in Zebrafish Embryos

Tetrabromobisphenol A (TBBPA), a ubiquitous environmental pollutant, has been implicated in developmental toxicity of aquatic animals. However, the impact of TBBPA on development and the related mechanism have not been fully elucidated. In this study, using a live imaging technique and transgenic labeling of zebrafish embryos, we described the toxic effects of TBBPA on hematopoietic development in zebrafish. We demonstrated that TBBPA induced erythroid precursor expansion in the intermediate cell mass (ICM), which perturbed the onset of blood circulation at 24-26 hours postfertilization (hpf). Consequently, excessive blood cells accumulated in the posterior blood island (PBI) and vascular cells formed defective caudal veins (CVs), preventing blood cell flow to the heart at 32-34 hpf. We found that the one-cell to 50% epiboly stage was the most sensitive period to TBBPA exposure during hematopoietic development. Furthermore, our results demonstrated that PBI malformation induced by TBBPA resulted from effects on erythroid precursor cells, which might involve THR signaling in complex ways. These findings will improve the understanding of TBBPA-induced developmental toxicity in teleost.

Anemia in Children With Inflammatory Bowel Disease: A Position Paper by the IBD Committee of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition

Anemia is one of the most common extraintestinal manifestations of inflammatory bowel disease (IBD). It can be asymptomatic or associated with nonspecific symptoms, such as irritability, headaches, fatigue, dizziness, and anorexia. In IBD patients, the etiology of anemia is often multifactorial. Various causes include iron deficiency, anemia of inflammation and chronic disease, vitamin deficiencies, hemolysis, or myelosuppressive effect of drugs. Anemia and iron deficiency in these patients may be underestimated because of their insidious onset, lack of standardized screening practices, and possibly underappreciation that treatment of anemia is also required when treating IBD. Practitioners may hesitate to use oral preparations because of their intolerance whereas intravenous preparations are underutilized because of fear of adverse events, availability, and cost. Several publications in recent years have documented the safety and comparative efficacy of various intravenous preparations. This article reviews management of anemia in children with IBD, including diagnosis, etiopathogenesis, evaluation of a patient, protocol to screen and monitor patients for early detection and response to therapy, treatment including parenteral iron therapy, and newer approaches in management of anemia of chronic disease. This report has been compiled by a group of pediatric gastroenterologists serving on the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) IBD committee, in collaboration with a pediatric hematologist, pharmacist, and a registered dietician who specializes in pediatric IBD (IBD Anemia Working Group), after an extensive review of the current literature. The purpose of this review is to raise awareness of under-diagnosis of anemia in children with IBD and make recommendations for screening, testing, and treatment in this population.

Subclinical thyroid dysfunction, bone mineral density, and osteoporosis in a middle-aged Korean population

Thyroid dysfunction is associated with the loss of bone density (osteoporosis). However, the connection between subclinical thyroid dysfunction and osteoporosis remains controversial. This study found no apparent association between subclinical hypothyroidism or subclinical hyperthyroidism and bone mineral density (BMD) in the lumbar spine and femur.

INTRODUCTION

The present study examined the relationship between subclinical thyroid dysfunction and BMD in healthy middle-aged adults.

METHODS

A total of 25,510 healthy Koreans with normal free thyroxine levels were enrolled from January 2011 to December 2016, and 91% of subjects visited only once. The average age of the 15,761 women was 45, and the average age of the 9749 men was 48. Levels of thyroid-stimulating hormone (TSH) and BMD were recorded in all subjects. BMD was measured using dual-energy X-ray absorptiometry.

RESULTS

No apparent association was found between subclinical thyroid dysfunction and BMD in the lumbar spine, femur-neck, and proximal femur sites compared with a euthyroid group. Age, body mass index (BMI), and postmenopausal status affected BMD in women, and only BMI affected BMD in men. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis (odds ratio 0.657, 95% confidence interval 0.464-0.930) in 4710 postmenopausal women.

CONCLUSIONS

No apparent association was found between subclinical hypothyroidism or subclinical hyperthyroidism defined on single TSH measurement and BMD at the lumbar spine and femur in a large cohort of middle-aged men and women. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis in postmenopausal women.

Clinical and Biochemical Characteristics of Severe Hypothyroidism Due to Autoimmune Thyroiditis in Children

Introduction: In the majority of countries, autoimmune thyroiditis is the main cause of acquired hypothyroidism in children. Typically, the natural course of the disease is initially insidious and the diagnosis is incidental. There are some children who develop severe hypothyroidism without a proper diagnosis. The aim of the study was to analyze the clinical and biochemical profiles of children with severe primary hypothyroidism due to autoimmune thyroiditis. Materials and Methods: We analyzed the records of 354 patients diagnosed between 2009 and 2019 with autoimmune thyroiditis. Only patients with TSH above 100 μIU/mL, associated with decreased free thyroxine and the presence of antithyroid antibodies, were enrolled in the study. The analysis encompassed clinical symptoms, thyroid and biochemical status, bone age, and imaging. Results: Twenty-six children were enrolled in the study. The mean age at diagnosis was 10.26 ± 3.3 years, with a female preponderance of 1.8:1. The most frequent symptom was growth impairment (77%) and weight gain (58%). Goiters were present in 42% of patients. Less common findings were pituitary hypertrophy (four patients) and hypertrichosis (three patients). Median values at the time of diagnosis were TSH 454.3 uIU/ml (295.0-879.4), anti-TPO antibodies 1,090 IU/ml, and anti-Tg antibodies 195 IU/ml. Anti-TSHR ab were evaluated only in six out of the 26 patients. The characteristic biochemical profile was correlated with the grade of hypothyroidism, and the strongest correlations were found with CBC parameters, lipid profile, aminotransferases, and creatine. Conclusion: In children with severe hypothyroidism, the most sensitive symptoms are growth arrest and weight gain despite the fact that, in some children, the auxological parameters at presentation could be within normal values for the population. The specific biochemical profile closely correlates to the severity of thyroid hormone deficiency and involves mostly erythropoiesis, liver function, and kidney function. Pituitary enlargement should be considered in each child with severe hypothyroidism. It is necessary to conduct prospective studies evaluating the actual frequency of anti-TSHR antibodies and pituitary enlargement in children with extremely high TSH, especially those presenting without goiters.

Role of ashwagandha methanolic extract in the regulation of thyroid profile in hypothyroidism modeled rats

This study aimed to evaluate the anti-hypothyroidism potential of ashwagandha methanolic extract (AME). This target was performed through induction of animal model of hypothyroidism by propylthiouracil. After 1 month from treatments, blood samples were collected for biochemical determinations, and liver and kidney were removed for the determination of oxidative stress markers and thyroid gland was removed for histopathological examination. The total phenolic compounds in the extract and the in vitro radical scavenging activity of extract were also determined. The results revealed that the induction of hypothyroidism by propylthiouracil induced a significant increase in serum TSH level but it induced significant decreases in the levels of total T3, free T3, free T4, and total T4 hormones compared with the control values. Also, serum glucose, Il-6, and body weight gain increased significantly while Il-10 and blood hemoglobin levels showed significant decrease. Induction of hypothyroidism increased also the levels of hepatic and renal MDA and NO and decreased significantly the values of GSH, GPx and Na⁺/ K⁺-ATPase. Both AME and the anti-hypothyroidism drug significantly ameliorated the changes occurred in the levels of the above parameters and improved histological picture of thyroid gland but with different degrees; where ashwagandha methanolic extract showed the strongest effect. We can conclude that ashwagandha methanolic extract treatment improves thyroid function by ameliorating thyroid hormones and by preventing oxidative stress.

Cytomorphological Spectrum of Hashimoto's Thyroiditis and Its Correlation with Hormonal Profile and Hematological Parameters

Introduction:

Hashimoto's thyroiditis (HT) is a well-known autoimmune disorder of the thyroid diagnosed on fine needle aspiration cytology (FNAC) and a common cause of hypothyroidism in women. Often serological and hematological parameters are additional investigations aiding the diagnosis of this entity.

Aim:

To grade HT based on cytomorphology and to correlate the cytological grades with thyroid hormone status and basic hematological parameters.

Materials and Methods:

During a period of 2.5 years, 1762 patients underwent FNAC of thyroid at our tertiary healthcare center. Cytological evidence of lymphocytic thyroiditis was seen in 102 cases, of which 58 cases in addition had thyroid hormone levels and hematological parameters for correlation.

Results:

Of the 58 cases, 55 were females. Majority of the patients had grade II thyroiditis (56.9%), followed by grade I (34.5%) and grade III (8.6%). Elevated thyroid-stimulating hormone was seen in 74.2% of cases, with 39.7% of patients presenting with subclinical hypothyroidism and 18.9% being euthyroid. Mean hemoglobin was low in all grades, more so in hypothyroid state, while other hematological parameters were normal when correlated with grade and hormonal status without any significant P value.

Conclusion:

Cytomorphological grading of HT can explain the pathogenesis of this autoimmune disease. Subclinical hypothyroidism was significantly observed. There was no significant statistical correlation of cytological grades with thyroid status. In this study, most of the hypothyroid cases had low hemoglobin levels while other basic hematological parameters did not show any statistically significant correlation with the thyroid hormonal status.

Subclinical hypothyroidism or central hypothyroidism-The danger of thyroid function misinterpretation

Correct interpretation of thyroid function tests is critical to providing appropriate care to patients with suspected thyroid disease. It is particularly important to distinguish central hypothyroidism from other types due to the potential of concurrent secondary adrenal insufficiency and thus the need for immediate steroid replacement prior to commencing thyroxine.

Hypothyroidism during pregnancy: Controversy over screening and intervention

Thyroid hormones are critical for foetal neurological development and maternal health. Maternal hypothyroidism during pregnancy is associated with adverse impact on health of the mother as well as the progeny. Reduced thyroid hormone levels predispose the child to develop mental retardation and cognitive delay in early life. In the mother, hypothyroidism during pregnancy is associated with spontaneous abortion, placental abruption, preterm delivery and hypertensive disorders. Therefore, screening and therapeutic intervention is justified to prevent foetal as well as maternal co-morbidities. In view of impact of such a large-scale screening and intervention program on limited healthcare resources, it is debatable if a targeted rather than universal screening program will result in comparable outcomes. In addition, there is an ongoing debate regarding best evidence-based practice for the management of isolated hypothyroxinaemia, subclinical hypothyroidism and euthyroid women with autoimmune hypothyroidism. We have carried out a review of the literature; firstly, to determine whether universal screening for asymptomatic women in early pregnancy would be cost-effective. Secondly, we have retrospectively reviewed the literature to analyse the evidence regarding the impact of therapeutic intervention in women with subclinical hypothyroidism.

Thyroid Dysfunction and Anemia: A Prospective Cohort Study and a Systematic Review

BACKGROUND

Even though the association between thyroid dysfunction and anemia is commonly described, it is not known whether it is clinically relevant. This study set out to quantify the association of thyroid dysfunction on hemoglobin (Hb) concentration and risk of anemia. A systematic review (MEDLINE and EMBASE, from inception until May 15, 2017) was conducted to interpret the findings in context.

METHODS

Participants from the EPIC-Norfolk cohort with available baseline thyrotropin (TSH), free thyroxine (fT4), and Hb were included. Euthyroidism was defined as TSH 0.45-4.49 mIU/L (reference category), hypothyroidism as TSH ≥4.50 mIU/L (subclinical [SHypo] with normal fT4 or overt [OHypo] with low fT4), and hyperthyroidism as TSH ≤0.44 mIU/L (subclinical [SHyper] with normal fT4 or overt [OHyper] with elevated fT4). Anemia was defined as Hb <12 g/dL in women and Hb <13 g/dL in men. In the cross-sectional analyses, multiple linear regression was used to compare Hb across TSH categories. In the prospective analysis, participants with OHypo/OHyper at baseline were excluded, as it was assumed that they were treated for overt thyroid disease. A covariance model was used to determine change in Hb concentration from baseline to last follow-up, and multivariable Cox regression was used to analyze anemia risk.

RESULTS

In the cross-sectional population (n = 12,337), the adjusted Hb was 0.22 g/dL lower [confidence interval (CI) 0.07-0.38] in OHypo compared to euthyroids, and 0.08 g/dL lower [CI -0.23 to 0.38] in OHyper. In the prospective analysis, 460/7031 participants developed anemia over a median follow-up of 4.7 years. The adjusted mean Hb change over time was -0.04 g/dL in SHypo [CI -0.14 to 0.06] and 0.05 g/dL in SHyper [CI -0.10 to 0.20]. The adjusted hazard ratio for anemia was 0.99 [CI 0.67-1.48] in SHypo, and 0.52 [CI 0.23-1.16] in SHyper. The systematic review returned no other prospective studies on this association, but cross-sectional and case-control studies showed comparable results.

CONCLUSION

In this first prospective population-based cohort, subclinical thyroid dysfunction was not associated with a change in Hb concentration during follow-up and was not an independent risk factor for developing anemia; variations in Hb concentration in patients with overt thyroid dysfunction were not clinically relevant.

Thyroid hormone regulates hematopoiesis via the TR-KLF9 axis

Congenital hypothyroidism (CH) is one of the most prevalent endocrine diseases, for which the underlying mechanisms remain unknown; it is often accompanied by anemia and immunodeficiency in patients. Here, we created a severe CH model together with anemia and T lymphopenia to mimic the clinical features of hypothyroid patients by ethylnitrosourea (ENU) mutagenesis in Bama miniature pigs. A novel recessive c.1226A>G transition of the dual oxidase 2 (DUOX2) gene was identified as the causative mutation. This mutation hindered the production of hydrogen peroxide (H₂O₂) and thus contributed to thyroid hormone (TH) synthesis failure. Transcriptome sequencing analysis of the thymuses showed that Krüppel-like factor 9 (KLF9) was predominantly downregulated in hypothyroid mutants. KLF9 was verified to be directly regulated by TH in a TH receptor (TR)-dependent manner both in vivo and in vitro. Furthermore, knockdown of klf9 in zebrafish embryos impaired hematopoietic development including erythroid maturation and T lymphopoiesis. Our findings suggest that the TR-KLF9 axis is responsible for the hematopoietic dysfunction and might be exploited for the development of novel therapeutic interventions for thyroid diseases.

Defective erythropoiesis caused by mutations of the thyroid hormone receptor α gene

Patients with mutations of the THRA gene exhibit classical features of hypothyroidism, including erythroid disorders. We previously created a mutant mouse expressing a mutated TRα1 (denoted as PV; Thra1^PV/+ mouse) that faithfully reproduces the classical hypothyroidism seen in patients. Using Thra1^PV/+ mice, we explored how the TRα1PV mutant acted to cause abnormalities in erythropoiesis. Thra1^PV/+ mice exhibited abnormal red blood cell indices similarly as reported for patients. The total bone marrow cells and erythrocytic progenitors were markedly reduced in the bone marrow of Thra1^PV/+ mice. In vitro terminal differentiation assays showed a significant reduction of mature erythrocytes in Thra1^PV/+ mice. In wild-type mice, the clonogenic potential of progenitors in the erythrocytic lineage was stimulated by thyroid hormone (T3), suggesting that T3 could directly accelerate the differentiation of progenitors to mature erythrocytes. Analysis of gene expression profiles showed that the key regulator of erythropoiesis, the Gata-1 gene, and its regulated genes, such as the Klf1, β-globin, dematin genes, CAII, band3 and eALAS genes, involved in the maturation of erythrocytes, was decreased in the bone marrow cells of Thra1^PV/+ mice. We further elucidated that the Gata-1 gene was a T3-directly regulated gene and that TRα1PV could impair erythropoiesis via repression of the Gata-1 gene and its regulated genes. These results provide new insights into how TRα1 mutants acted to cause erythroid abnormalities in patients with mutations of the THRA gene. Importantly, the Thra1^PV/+ mouse could serve as a preclinical mouse model to identify novel molecular targets for treatment of erythroid disorders.

Patients with mutations of the THRA gene exhibit erythroid disorders. The molecular pathogenesis underlying erythroid abnormalities is poorly understood. In Thra1^PV/+ mice expressing a dominant negative mutant TRα1PV, we found abnormal red blood cell indices similar to patients. Total bone marrow cells, the clonogenic potential of erythrocytic progenitors, and terminal differentiation of erythrocytes were markedly decreased in Thra1^PV/+ mice. We elucidated that Gata-1, a key erythroid gene, was directly positively regulated by TRα1. The erythroid defects in Thra1^PV/+ mice were due, at least partly, to the TRα1PV-mediated suppression of the Gata-1 gene and its down-stream target genes. Over-expression of Gata-1 rescued impaired terminal differentiation. Our studies elucidated molecular mechanisms by which TRα1 mutants caused erythroid disorders in patients. The present study suggests that therapies aimed at GATA1 could be tested as a potential target in treating erythroid abnormalities in patients.

The Relationship between Iron Deficiency and Thyroid Function in Chinese Women during Early Pregnancy

Previous studies have identified an association between iron deficiency and thyroid function. We aimed to determine if there is a relationship between iron deficiency and thyroid function during the first trimester of pregnancy. Two thousand five hundred eighty-one pregnant women who presented for the first prenatal care were enrolled and divided into three groups, the mild iron deficiency (MID) group, iron deficiency anemia (IDA) group and normal control (NC) group, according to serum ferritin and hemoglobin levels. The former two groups can be merged into one iron deficiency (ID) group. Thyroid function parameters were compared among the three groups, including free thyroxine (FT4), thyroid stimulating hormone (TSH), total thyroxine (TT4) and thyroid peroxidase antibodies (TPOAb). Moreover, the rates of thyroid dysfunction were also compared. Our results show that pregnant women in the MID and IDA groups have higher TSH and lower FT4 status than those in the NC group (p<0.01), and the difference between the IDA group and MID group is significant (p<0.05). TPOAb in the IDA group is higher than in the MID group and NC group. Meanwhile, the rate of hypothyroidism or subclinical hypothyroidism in the IDA group was significantly higher than in the MID group and NC group (p<0.01). And the positive rate of TPOAb is also higher in the IDA group than MID group and NC group (p<0.05). Iron deficiency is related to thyroid function and could lead to hypothyroidism during early pregnancy, which could be explained by thyroid autoimmunity.

Chronic anemia and thyroid function

Anaemia is a global public health problem affecting both developing and developed countries with major consequences for human health as well as social and economic development. It occurs at all stages of the life cycle, but is more prevalent in pregnant women and young children. Iron deficiency anaemia (IDA) impairs thyroid metabolism in animals and human and may negatively affect growth and develpment of children. On the other hand both overt and subclinical hypothyroidism are associated with anemia and adding iron to thyroxine therapy improves both conditions compared to thyroxine therapy alone. In addition patients with chronic hemolytic anemia requiring repeated blood transfusion have high prevalence of hypothalamic-pituitary thyroid axis. Both primary hypothyroidism and central hypothyroidism occur in these patients with increasing prevalence with age, severity of the anemia and higher ferritin concentration denoting poor chelation.  Proper blood transfusion and intensive chelation appears to prevent deterioration of thyroid function and in many cases can reverse thyroid pathology. Physicians treating these forms of anemia should be aware of thyroid disorders in these patients for early screening, prevention and proper management of any thyroid dysfunction.

Undertreated hypothyroidism due to calcium or iron supplementation corrected by oral liquid levothyroxine

PURPOSE

The aim of this study was to assess whether oral liquid levothyroxine would correct tablet levothyroxine malabsorption induced by calcium or iron, two sequestrants of levothyroxine.

METHODS

Nineteen adult hypothyroid patients with tablet levothyroxine malabsorption caused by calcium and/or iron supplements were switched from tablet to liquid levothyroxine at the same dose. Primary outcomes were: (1) significantly lower mean serum thyroid-stimulating hormone with the liquid compared with the tablet formulation, and (2) significantly greater rate of serum thyroid-stimulating hormone less than or equal to 4.12 or 2.5 mU/L.The mean follow-up was 25.2 ± 16.5 weeks.

RESULTS

TSH was lower with liquid levothyroxine compared with tablet levothyroxine (7.48 ± 5.8 vs. 1.95 ± 1.3 mU/L, P < 0.001), both in the calcium group (8.74 ± 7.2 vs. 2.15 ± 1.4, P < 0.001) and iron group (8.74 ± 7.2 vs. 1.68 ± 0.9, P < 0.001). Thyroid-stimulating hormone levels ≤4.12 mU/L in all patients, calcium group and iron group were more frequent post-switch (95, 87 and 100%) compared to pre-switch (26, 22 and 29%, P < 0.001), and so were thyroid-stimulating hormone levels ≤2.50 mU/L (66, 59 and 76% compared to 5, 9 and 0%, P < 0.001). The pattern held comparing the first liquid levothyroxine thyroid-stimulating hormone levels and the first tablet levothyroxine thyroid-stimulating hormone levels or the corresponding rates of thyroid-stimulating hormone levels below the target.

CONCLUSIONS

Liquid levothyroxine is resistant to the sequestration by calcium or iron. The high rate of thyroid-stimulating hormone normalization already at the first check (6-8 weeks) should avoid frequent adjustments in levothyroxine doses and assays of thyroid-stimulating hormone, with consequent financial savings.

Thyroid hormones in extreme longevity

The aim of the present review was to summarize knowledge about thyroid hormones (THs) and longevity. Longevity is a complex multifactorial phenomenon on which specific biological pathways, including hormonal networks involved in the regulation of homeostasis and survival, exert a strong impact. THs are the key responsible for growth, metabolism rate and energy expenditure, and help in maintaining cognition, bone and cardiovascular health. THs production and metabolism are fine tuned, and may help the organism to cope with a variety of environmental challenges. Experimental evidence suggests that hypothyroid state may favor longevity by reducing metabolism rate, oxidative stress and cell senescence. Data from human studies involving healthy subjects and centenarians seem to confirm this view, but THs changes observed in older patients affected by chronic diseases cannot be always interpreted as a protective adaptive mechanism aimed at reducing catabolism and prolonging survival. Medications, selected chronic diseases and multi-morbidity can interfere with thyroid function, and their impact is still to be elucidated.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT ON THYROID DYSFUNCTION CASE FINDING

Hypothyroidism and hyperthyroidism can be readily diagnosed and can be treated in a safe, cost-effective manner. Professional organizations have given guidance on how and when to employ thyroid-stimulating hormone testing for the detection of thyroid dysfunction. Most recently, the United States Preventive Services Task Force did not endorse screening for thyroid dysfunction based on a lack of proven benefit and potential harm of treating those with thyroid dysfunction, which is mostly subclinical disease. The American Association of Clinical Endocrinologists (AACE) is concerned that this may discourage physicians from testing for thyroid dysfunction when clinically appropriate. Given the lack of specificity of thyroid-associated symptoms, the appropriate diagnosis of thyroid disease requires biochemical confirmation. The Thyroid Scientific Committee of the AACE has produced this White Paper to highlight the important difference between screening and case-based testing in the practice of clinical medicine. We recommend that thyroid dysfunction should be frequently considered as a potential etiology for many of the nonspecific complaints that physicians face daily. The application and success of safe and effective interventions are dependent on an accurate diagnosis. We, therefore, advocate for an aggressive case-finding approach, based on identifying those persons most likely to have thyroid disease that will benefit from its treatment.

Very early onset of autoimmune thyroiditis in a toddler with severe hypothyroidism presentation: a case report

BACKGROUND

In infants under 3 years of age acquired primary hypothyroidism caused by autoimmune thyroiditis is very rare. Hypothyroidism can manifest with different signs and symptoms and has a wide range of presentations from subclinical hypothyroidism to overt form. We describe a child with acquired autoimmune thyroiditis during a very early period of life and with a severe hypothyroidism presentation.

CASE PRESENTATION

A 22-month-old white male patient with normal neonatal screening presented with a six-month history of asthenia and cutaneous pallor. At general clinical and biochemical exams he showed weight gain, statural growth deceleration, poor movements, sleepy expression, instability while walking, myxoedema, bradycardia, open anterior fontanelle, changes in the face habitus, macrocytic anaemia, ascites, and high CPK, creatinine and cholesterol levels. Acquired autoimmune thyroiditis was the final diagnosis. The thyroxine replacement therapy normalized all the clinical and biochemical abnormalities but at the age of 30 months his mental age showed a delay of 6 months.

CONCLUSIONS

Our case could give useful learning points: i) although the screening for congenital hypothyroidism is routinely performed, a severe hypothyroidism (for example due to autoimmune thyroiditis) can anyway occur early in life and the clinicians should consider this possibility; ii) hypothyroidism can have a misleading and multi-face clinical presentation; iii) anemia, rhabdomyolysis and high creatinine levels should always include the hypothyroidism in the differential diagnosis; iv) thyroxine replacement therapy is able to revert all the clinical manifestations related to the hypothyroidism; v) evaluating the patient's previous pictures could play an important role in resolving a diagnostic conundrum.

Prevalence and Clinical Significance of Low T3 Syndrome in Non-Dialysis Patients with Chronic Kidney Disease

Background

There are few data on the prevalence of low T3 (triiodothyronine) syndrome in patients with non-dialysis chronic kidney disease (CKD) and it is unclear whether low T3 can be used to predict the progression of CKD.

Material/Methods

We retrospectively studied 279 patients who had been definitively diagnosed with CKD, without needing maintenance dialysis. Thyroid function was analyzed in all enrolled subjects and the incidence of thyroid dysfunction (low T3 syndrome, low T4 syndrome, and subclinical hypothyroidism) in patients at different stages of CKD was determined.

Results

Glomerular filtration rate (GFR) of CKD patients was estimated as follows: 145 subjects (52%) had GFR <60 ml/min per 1.73 m²; 47 subjects (16.8%) had GFR between 30 and 59 ml/min per 1.73 m², and 98 subjects (35.1%) had GFR <30 ml/min per 1.73 m². Among all enrolled subjects, 4.7% (n=13) had subclinical hypothyroidism, 5.4% (n=15) had low T4 syndrome, and 47% (n=131) had low T3 syndrome. In 114 CKD patients in stages 3–5, serum T3 was positively related to protein metabolism (STP, PA, and ALB) and anemia indicators (Hb and RBC), and negatively related to inflammatory status (CRP and IL-6).

Conclusions

A high prevalence of low T3 syndrome was observed in CKD patients without dialysis, even in early stages (1 and 2). The increasing prevalence of low T3 as CKD progresses indicates its value as a predictor of worsening CKD. Furthermore, low T3 syndrome is closely associated with both malnutrition-inflammation complex syndrome (MICS) and anemia.

Thyroid dysfunction and anaemia in a large population-based study

OBJECTIVE AND BACKGROUND

Anaemia and thyroid dysfunction are common and often co-occur. Current guidelines recommend the assessment of thyroid function in the work-up of anaemia, although evidence on this association is scarce.

PATIENTS AND METHODS

In the 'European Prospective Investigation of Cancer' (EPIC)-Norfolk population-based cohort, we aimed to examine the prevalence and type of anaemia (defined as haemoglobin <13 g/dl for men and <12 g/dl for women) according to different thyroid function groups.

RESULTS

The mean age of the 8791 participants was 59·4 (SD 9·1) years and 55·2% were women. Thyroid dysfunction was present in 437 (5·0%) and anaemia in 517 (5·9%) participants. After excluding 121 participants with three most common causes of anaemia (chronic kidney disease, inflammation, iron deficiency), anaemia was found in 4·7% of euthyroid participants. Compared with the euthyroid group, the prevalence of anaemia was significantly higher in overt hyperthyroidism (14·6%, P < 0·01), higher with borderline significance in overt hypothyroidism (7·7%, P = 0·05) and not increased in subclinical thyroid dysfunction (5·0% in subclinical hypothyroidism, 3·3% in subclinical hyperthyroidism). Anaemia associated with thyroid dysfunction was mainly normocytic (94·0%), and rarely macrocytic (6·0%).

CONCLUSION

The prevalence of anaemia was higher in overt hyperthyroidism, but not increased in subclinical thyroid dysfunction. Systematic measurement of thyroid-stimulating hormone in anaemic patients is likely to be useful only after excluding common causes of anaemia.

Prevalence of Thyroid Disorders in Children at a Tertiary Care Hospital in Western India

INTRODUCTION

Thyroid hormone abnormalities are the commonest endocrine disorder in India and also the commonest preventable cause of mental retardation. In the absence of neonatal screening, thyroid disorders remain largely unrecognized in Indian children.

AIM

To determine the prevalence, clinical profile, aetiology and associated co-morbidities of thyroid dysfunction in children.

MATERIALS AND METHODS

A prospective, hospital based, observational study was conducted at a tertiary care hospital in Western India. Children below 12 years of age visiting the Pediatric out-patient department (OPD) and in-patient department (IPD) were included if they had clinical suspicion of thyroid dysfunction. Demographic data and clinical features of the recruited children were noted along with family history of thyroid disorders and use of iodized salt. Thyroid profile consisting of Tri-iodothyronin (T3), Thyroxin (T4) and Thyroid stimulating hormone (TSH) levels were tested in all. Investigations were also carried out to look for the cause and complications of hypothyroidism. These children were also followed up with appropriate therapy to look for response of therapy and complications to the same.

RESULTS

Sixty five children were found to have thyroid function abnormalities, 61 having hypothyroidism and 4 having hyperthyroidism. There was a low prevalence of goiter. The clinical feature of patients with hypo and hyperthyroidism was similar to other reported studies. The commonest aetiology of hypothyroidism was found to be dyshormonogenesis. A host of co-morbidities was observed along with thyroid dysfunction. On follow up with appropriate therapy, most of the children became euthyroid and complications were observed in only a minority.

CONCLUSION

There is a high prevalence of thyroid dysfunction in children in western India and need for similar studies from different regions of the country covering larger population are well appreciated.

Delayed Diagnosis of Hypothyroidism in Children: Report of 3 Cases

Introduction:

Hypothyroidism is the most common endocrine disorder in children and presented with various sign and symptoms; its diagnosis needs a high index of suspicion.

Case Presentation:

We report 3 cases with unusual presentations of hypothyroidism and with delay in diagnosis that referred to Pediatric Endocrine Outpatient Clinic in Mashhad University of Medical Sciences, Mashhad, Iran with different clinical manifestations. They had decreased Thyroxin (T4) and increased thyroid stimulating hormone (TSH) levels. One case had mental retardation and deafness, but the other two cases had normal neurodevelopment. Some additional interesting findings were as follows: short stature, delayed bone age, teeth eruption impairment, hair loss, anemia and hypercholesterolemia, persistent and long-term constipation that had led to several abdominal surgeries. After a year of hormonal replacement therapy, their growth parameters and hematological values improved.

Conclusions:

We recommend thyroid hormonal evaluation for any children with short stature, especially with delayed bone age, in order to detect and treat hypothyroidism at the right time. It seems that more attention to pediatric growth is necessary.

Thyroid functional disease: an under-recognized cardiovascular risk factor in kidney disease patients

Thyroid functional disease, and in particular hypothyroidism, is highly prevalent among chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. In the general population, hypothyroidism is associated with impaired cardiac contractility, endothelial dysfunction, atherosclerosis and possibly higher cardiovascular mortality. It has been hypothesized that hypothyroidism is an under-recognized, modifiable risk factor for the enormous burden of cardiovascular disease and death in CKD and ESRD, but this has been difficult to test due to the challenge of accurate thyroid functional assessment in uremia. Low thyroid hormone levels (i.e. triiodothyronine) have been associated with adverse cardiovascular sequelae in CKD and ESRD patients, but these metrics are confounded by malnutrition, inflammation and comorbid states, and hence may signify nonthyroidal illness (i.e. thyroid functional test derangements associated with underlying ill health in the absence of thyroid pathology). Thyrotropin is considered a sensitive and specific thyroid function measure that may more accurately classify hypothyroidism, but few studies have examined the clinical significance of thyrotropin-defined hypothyroidism in CKD and ESRD. Of even greater uncertainty are the risks and benefits of thyroid hormone replacement, which bear a narrow therapeutic-to-toxic window and are frequently prescribed to CKD and ESRD patients. In this review, we discuss mechanisms by which hypothyroidism adversely affects cardiovascular health; examine the prognostic implications of hypothyroidism, thyroid hormone alterations and exogenous thyroid hormone replacement in CKD and ESRD; and identify areas of uncertainty related to the interplay between hypothyroidism, cardiovascular disease and kidney disease requiring further investigation.

Association of thyroid functional disease with mortality in a national cohort of incident hemodialysis patients

CONTEXT

Hypothyroidism is a common condition that disproportionately affects hemodialysis patients. In the general population, hypothyroidism is associated with higher mortality, particularly in populations with underlying cardiovascular risk. Despite their heightened cardiovascular mortality, the impact of hypothyroidism on the survival of hemodialysis patients remains uncertain.

OBJECTIVE

To examine whether hypothyroidism is independently associated with higher mortality in hemodialysis patients.

DESIGN, SETTING, AND PATIENTS

Among 8840 incident hemodialysis patients receiving care from a large national dialysis provider from January 2007 to December 2011, we examined the association of hypothyroidism (TSH >5.0 mIU/L) with mortality.

MAIN OUTCOME MEASURES

Associations between baseline and time-dependent hypothyroidism with all-cause mortality were determined using case-mix adjusted Cox models. In secondary analyses, we examined the impact of low-normal, upper-normal, subclinical range, and overt range TSH levels (TSH ≥ 0.5-3.0, >3.0-5.0, >5.0-10.0, and >10.0 mIU/L, respectively) on mortality risk.

RESULTS

The study population consisted of 1928 (22%) hypothyroid and 6912 (78%) euthyroid patients. Baseline and time-dependent hypothyroidism were associated with higher mortality: adjusted hazard ratios (95% confidence intervals) were 1.47 (1.34-1.61) and 1.62 (1.45-1.80), respectively. Compared to low-normal TSH, upper-normal, subclinical hypothyroid, and overt hypothyroid TSH levels were associated with incrementally higher adjusted death risk in baseline and time-dependent analyses. In time-dependent analyses, the hypothyroidism-mortality association was increasingly stronger across higher body mass index strata.

CONCLUSIONS

Hypothyroidism as well as upper-normal TSH levels are associated with higher mortality in hemodialysis patients. Further studies are needed to determine whether restoration of TSH to low-normal levels with thyroid hormone replacement therapy ameliorates adverse outcomes in hemodialysis patients.

Perchlorate Exposure is Associated with Oxidative Stress and Indicators of Serum Iron Homeostasis Among NHANES 2005-2008 Subjects

Perchlorate (ClO4 (-)), an oxidizing agent, is a ubiquitous environmental pollutant. Several studies have investigated its thyroid hormone disrupting properties. Its associations with other biological measures are largely unknown. This study, combining 2005-2008 National Health and Nutrition Examination Surveys, investigated associations between urinary perchlorate and biomarkers of iron homeostasis, lipids, blood cell counts, and glucose metabolism. Healthy males (n = 3705), non-pregnant females (n = 2967), and pregnant females (n = 356), aged 12-59 years, were included in the linear regression models, which showed significant positive (+) and negative (-) associations for both males and non-pregnant females with serum uric acid (-), serum iron (-), RBC count (-), blood urea nitrogen (+), and lymphocyte count (+). Other significant associations were observed for either males or non-pregnant females. Among pregnant females, perchlorate was significantly associated with blood urea nitrogen (+) and serum iron (-). These associations may be indicators of perchlorate's potential effect on several biological systems, which when considered in total, may implicate perturbation of iron homeostasis.

Erythrocytosis associated with hyperthyroidism: a rare case report and clinical study of possible mechanism

PURPOSE

To report a rare case of erythrocytosis that occurred in close association with Graves' hyperthyroidism. In order to explore the role of altered erythropoiesis in hyperthyroidism, factors related to erythropoiesis were studied in 30 patients with Graves' hyperthyroidism.

METHOD

The relationship between thyroid hormone level and erythrocytosis was studied in a patient with Graves' hyperthyroidism and erythrocytosis. Later, 30 consecutive patients with proven untreated Graves' hyperthyroidism and 30 age- and sex-matched healthy controls were recruited. All patients received methimazole therapy. Erythrocyte indices, thyroid function, serum erythropoietin (EPO), and hypoxia-inducible factor-1α (HIF-1α) concentrations were measured before and after eight weeks of therapy.

RESULTS

In our case study, erythrocytosis relapsed with elevation of thyroid hormones. Methimazole or subsequent radioiodine therapy reduced the conditions of erythrocytosis and thyroid function returned to normal. In the clinical study, erythrocyte counts, serum erythropoietin, and HIF-1α levels in the hyperthyroid group were significantly higher than those in the control subjects. All subjects were grouped together for correlation analyses and HIF-1α was shown to correlate with total triiodothyronine (TT(3)), total thyroxine (TT(4)), and EPO levels. The correlation between EPO and TT(3) or TT(4) approached significance. After eight weeks of anti-thyroid drug therapy, a small but statistically significant increase in hemoglobin and erythrocyte count with a significant decrease in HIF-1α and EPO level was seen in hyperthyroid subjects.

CONCLUSION

Erythrocytosis may appear in patients with hyperthyroidism, and one possible mechanism is thyroid hormone-induced augmentation of HIF-1α, resulting in increased EPO levels.

The Role of the Multiple Hormonal Dysregulation in the Onset of "Anemia of Aging": Focus on Testosterone, IGF-1, and Thyroid Hormones

Anemia is a multifactorial condition whose prevalence increases in both sexes after the fifth decade of life. It is a highly represented phenomenon in older adults and in one-third of cases is "unexplained." Ageing process is also characterized by a "multiple hormonal dysregulation" with disruption in gonadal, adrenal, and somatotropic axes. Experimental studies suggest that anabolic hormones such as testosterone, IGF-1, and thyroid hormones are able to increase erythroid mass, erythropoietin synthesis, and iron bioavailability, underlining a potential role of multiple hormonal changes in the anemia of aging. Epidemiological data more consistently support an association between lower testosterone and anemia in adult-older individuals. Low IGF-1 has been especially associated with anemia in the pediatric population and in a wide range of disorders. There is also evidence of an association between thyroid hormones and abnormalities in hematological parameters under overt thyroid and euthyroid conditions, with limited data on subclinical statuses. Although RCTs have shown beneficial effects, stronger for testosterone and the GH-IGF-1 axis and less evident for thyroid hormones, in improving different hematological parameters, there is no clear evidence for the usefulness of hormonal treatment in improving anemia in older subjects. Thus, more clinical and research efforts are needed to investigate the hormonal contribution to anemia in the older individuals.

Reversible morbidity markers in subclinical hypothyroidism

IMPORTANCE

Subclinical hypothyroidism (SCH) is a common clinical entity with a putative role in a wide range of disorders. The impact of SCH on mortality and markers of morbidity has been demonstrated, but studies have shown inconsistent results. Evidence regarding the effect of levothyroxine treatment on reversing morbidity markers is emerging, but the value of treatment is still unclear.

OBJECTIVE

The objectives of this review were to assess recent, high-quality studies evaluating the role of SCH in cardiovascular health, cognition, mood, pregnancy, anemia, and renal disease; to examine the effects of levothyroxine on reducing mortality or reversing markers of morbidity in these conditions; and to consider how new research insights may help guide clinical practice.

EVIDENCE REVIEW

A PubMed search was conducted (using 'subclinical hypothyroidism' [Title/Abstract] AND morbidity [MeSH Subheading] as search criteria) and was restricted to human studies published in the English language between 1990 and 2013. Subsequent searches of retrieved articles yielded further studies, which were included based on quality. Emphasis was given to large observational studies, well-conducted meta-analyses, and randomized controlled trials.

FINDINGS

The difficulty of diagnosing SCH, particularly in the elderly, may underlie many of the conflicting results seen in the literature. Increased understanding of the at-risk patient population will result in better selection of study subjects and, likely, unequivocal results. Regardless of the current confusion, emerging evidence suggests that certain markers of morbidity are reversed by levothyroxine therapy across the disorders examined here.

CONCLUSION AND RELEVANCE

Future large, well-controlled studies will not only clarify the role of SCH but also help identify patients for whom levothyroxine treatment will provide the most benefit.

Anaemia, a common but often unrecognized risk in diabetic patients: a review

Anaemia in patients with diabetes, both type 1 and type 2, is a frequent clinical finding. The mechanisms of anaemia are multifactorial and often not very well understood. Iatrogenic causes, including oral antidiabetic drugs, ACE inhibitors and ARBs, and renal insufficiency are the major causes of anaemia in patients with type 2 diabetes. In patients with type 1, the cause is often an associated autoimmune disease, and screening for autoimmune gastritis, pernicious anaemia, Hashimoto's thyroiditis, coeliac disease and Addison's disease is recommended. Other rare causes - including G6PD deficiency, microangiopathic haemolytic anaemia and thiamine-responsive megaloblastic anaemia - should be suspected in young patients or when the classical causes are excluded. Early detection and recognition of the cause(s) of anaemia in patients with diabetes could help to prevent other clinical manifestations as well as the complications of diabetes.

Rhabdomyolysis and acute renal impairment in a patient with hypothyroidism: a case report

We report the case of a 33-year-old male with hypothyroidism who developed acute renal impairment with rhabdomyolysis after strenuous physical activity (snow shoveling). His thyroid function test confirmed marked hypothyroidism. Severe elevation of serum CK consistent with rhabdomyolysis was noted and an elevated creatinine indicated acute renal impairment. Patient's condition improved significantly after starting him on thyroid hormone replacement therapy and aggressive hydration. Acute renal impairment with rhabdomyolysis in patients with hypothyroidism is quite rare and we expect that this case report adds to the existing literature on this subject. We also emphasize that thyroid status should be evaluated in patients with unexplained acute renal impairment and presenting with the symptoms of muscle involvement.

Clinical Consequences of Mutations in Thyroid Hormone Receptor-α1

Thyroid hormone (TH) exerts its biological activity via the TH receptors TRα1 and TRβ1/2, which are encoded by the THRA and THRB genes. The first patients with mutations in THRB were identified decades ago. These patients had a clinical syndrome of resistance to TH associated with high serum TH and nonsuppressed thyroid-stimulating hormone levels. Until recently, no patients with mutations in THRA had been identified. In an attempt to predict the clinical phenotype of such patients, different TRα1 mutant mouse models have been generated. These mice have a variable phenotype depending on the location and severity of the mutation. Recently, the first humans with mutations in THRA were identified. Their phenotype consists of relatively low serum T4 and high serum T3 levels (and thus an elevated T3/T4 ratio), growth retardation, delayed mental and bone development, and constipation. While, in retrospect, certain features present in humans can also be found in mouse models, the first humans carrying a defect in TRα1 were not suspected of having a THRA gene mutation initially. The current review focuses on the clinical consequences of TRα1 mutations.

Clinical conundrums in management of hypothyroidism in critically ill geriatric patients

CONTEXT

Articles in various international and national bibliographic indices were extensively searched with an emphasis on thyroid and hypothyroid disorders, hypothyroidism in elderly hospitalized patients, hypothyroidism in critically ill geriatric population, thyroxine in elderly hypothyroid, drug interactions and thyroid hormones, and thyroid functions in elderly.

EVIDENCE ACQUISITION

Entrez (including PubMed), NIH.gov, Medscape.com, WebMD.com, MedHelp.org, Search Medica, MD consult, yahoo.com, and google.com were searched. Manual search was performed on various textbooks of medicine, critical care, pharmacology, and endocrinology.

RESULTS

Thyroid function tests in elderly hospitalized patients must be interpreted with circumspection. The elderly are often exposed to high iodide content and critical care settings. This may occur because of either decreased iodine excretion or very high intake of iodine. This is especially true for elderly population with underlying acute or chronic kidney diseases or both. Amiodarone, with a very high iodine content, is also often used in this set of population. Moreover, other medications including iodinated contrast are often used in the critical care settings. These may affect different steps of thyroid hormone metabolism, and thereby complicate the interpretation of thyroid function tests.

CONCLUSIONS

The current review is aimed at analyzing and managing various clinical aspects of hypothyroidism in hospitalized elderly, and critically ill geriatric patients.

Clinical phenotype of a new type of thyroid hormone resistance caused by a mutation of the TRα1 receptor: consequences of LT4 treatment

CONTEXT

Recently the first patients with inactivating mutations in T₃ receptor (TR)-α1 have been identified. These patients have low free T₄, low T₄, high T₃, low rT₃, and normal TSH serum levels, in combination with growth retardation, delayed bone development, and constipation.

OBJECTIVE

The aim of the current study was to report the effects of levothyroxine (LT4) treatment on the clinical phenotype of 2 patients (father and daughter) with a heterozygous inactivating mutation in TRα1.

SETTING AND PARTICIPANTS

Both patients were treated with LT4 for the last 5 years. To evaluate the effect of LT4 treatment, LT4 was withdrawn for 35 days and subsequently reinitiated. Data were collected from medical records, by reanalysis of serum collected over the last 6 years, and by a detailed clinical evaluation.

RESULTS

Treatment with LT4 resulted in a suppression of serum TSH and normalization of serum free T₄ and rT₃, whereas T₃ levels remained elevated in both patients. In addition, there was a normalization of the dyslipidemia as well as a response in serum IGF-I, SHBG, and creatine kinase in the index patient. All these parameters returned to pretreatment values when LT4 was briefly stopped. LT4 also resulted in an improvement of certain clinical features, such as constipation and nerve conductance. However, cognitive and fine motor skill defects remained.

CONCLUSION

This study reports the consequences of LT4 treatment over a prolonged period of time in 2 of the first patients with a heterozygous mutation in TRα1. LT4 therapy leads to an improvement of certain but not all features of the clinical phenotype.

Etiology of anemia in primary hypothyroid subjects in a tertiary care center in Eastern India

INTRODUCTION

The association of anemia with primary hypothyroidism has been common knowledge for many years. However; its pathogenesis is far from clear in many cases. Often the causes of anemia are manifold.

AIMS AND OBJECTIVES

In this study, we evaluated the causes of anemia in patients with primary hypothyroidism.

MATERIALS AND METHODS

Sixty adult nonpregnant untreated primary hypothyroid patients with anemia without any obvious cause were included. All patients were subjected to full medical history, clinical examination, biochemical and imaging studies. Serum iron profile, vitamin B12, folic acid, anti parietal cell antibody, anti TPO antibody, bone marrow study, and stool for occult blood, Coomb's test, HPLC for hemoglobinopathies and complete hemogram with reticulocyte count were done and analyzed.

RESULTS

Normocytic, normochromic anemia was present in 31 patients (51.6%) followed by microcytic anemia in 26 patients (43.3%). Six patients (10%) had megaloblastic anemia with vitamin B12 deficiency including 3 cases of pernicious anemia. Two patients had combined deficiency of iron and vitamin B12.

CONCLUSION

Normocytic normochromic anemia with normal bone marrow was commonest type of anemia in this study, followed by iron deficiency anemia.