https://endoinfo.ru/guidelines/ata_hypothyroidism_adults.pdf

Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association

Background: A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment. Methods: Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related...

Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement

Background Hypothyroidism has multiple etiologies and manifestations. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions. This paper describes evidence-based clinical guidelines for the clinical management of hypothyroidism in ambulatory patients. Methods The development of these guidelines was commissioned by the American Association of Clinical Endocrinologists (AACE) in association with American Thyroid Association (ATA). AACE and the ATA assembled a task force of expert clinicians who authored this article. The authors examined relevant literature and took an evidence-based medicine approach that incorporated their knowledge and experience to develop a series of specific recommendations and the rationale for these recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach outlined in the American Association of Clinical Endocrinologists Protocol for Standardized Production of Clinical Guidelines-2010 update. Results Topics addressed include the etiology, epidemiology, clinical and laboratory evaluation, management, and consequences of hypothyroidism. Screening, treatment of subclinical hypothyroidism, pregnancy, and areas for future research are also covered. Conclusions Fifty-two evidence-based recommendations and subrecommendations were developed to aid in the care of patients with hypothyroidism and to share what the authors believe is current, rational, and optimal medical practice for the diagnosis and care of hypothyroidism. A serum thyrotropin is the single best screening test for primary thyroid dysfunction for the vast majority of outpatient clinical situations. The standard treatment is replacement with L-thyroxine. The decision to treat subclinical hypothyroidism when the serum thyrotropin is less than 10 mIU/L should be tailored to the individual patient.

Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association.

Clinical practice. Subclinical hypothyroidism

Subclinical hypothyroidism is one of subclinical thyroid diseases, which is defined as "a serum thyroid stimulating hormone(TSH) concentration above the statistically defined upper limit of the ref-erence range when serum free T4 concentration is within its reference range". The average worldwide preva-lence has been reported to be in the range of 4%-10% ,mainly among women and the elderly. The most com-monly cause of subclinical hypothyroidism is Hashimoto's thyroiditis. Subclinical hypothyroidism is associated with disorders of serum lipid, development of atherosclerosis and cardiovascular disease, presence of cognitive impairment,infertility and miscarriage. L-thyroxine substitutive therapy is recommended when TSH is above 10 mIU/L. Patients with serum TSH between 4 and 10 mIU/L should be monitored frequently especially if thyroperoxidase antibody is positive. The goal of the therapy for the pregnant women with subclinical hypothy-roidism is serum TSH less than 2.5 mIU/L.

Key words: 
Subclinical hypothyroidism; Thyroid stimulating hormone; L-thyroxine; Thyroperoxidase anti-body

Subclinical hypothyroidism

Background Malabsorption of thyroxine has been described in patients treated with drugs that modify an acidic environment. We determined whether there is an increased need for thyroxine in patients with euthyroid multinodular goiter and impaired secretion of gastric acid. Methods We assessed the dose of thyroxine required to obtain a low level of thyrotropin (0.05 to 0.20 mU per liter) in 248 patients with multinodular goiter. Of these 248 patients, 53 also had Helicobacter pylori–related gastritis and 60 had atrophic gastritis of the body of the stomach (31 with evidence of H. pylori infection and 29 without such evidence). The reference group comprised 135 patients with multinodular goiter and no gastric disorders. In addition, variation in the level of serum thyrotropin was prospectively studied in 11 patients treated with thyroxine before and after H. pylori infection and both before and during treatment with omeprazole in 10 patients treated with thyroxine who had gastroesophageal reflux. Results The...

https://www.nejm.org/doi/pdf/10.1056/NEJMoa043903

Thyroxine in goiter, Helicobacter pylori infection, and chronic gastritis.

Objective: The prevalence of platelet-associated IgG (paIgG) in nonthrombocytopenic patients with autoimmune thyroid disease (AITD) alone or associated with autoimmune polyglandular

Age-related prevalence of platelet-associated immunoglobulins G in nonthrombocytopenic patients with autoimmune thyroid disease and autoimmune polyglandular syndrome

Summary
Objective The prevalence of chronic unexplained anaemia was analysed in patients with autoimmune thyroid disease (ATD).

Design  The presence of chronic unexplained anaemia, defined as anaemia not related to evident or occult bleeding and/or to erythropoietic disorders, was retrospectively assessed and compared in patients with nonautoimmune thyroid disease (NATD) and in patients with ATD.

Subjects and measurements  Biochemical and morphological parameters of anaemia were investigated and characterized in 1643 consecutive Caucasian outpatients with thyroid disease. In 991 patients, thyroid disease had a nonautoimmune origin. ATD was diagnosed in 652 patients (71 had Graves’ disease and 581 had Hashimoto's thyroiditis and its variants). In 145 patients ATD was associated with other autoimmune disorders.

Results  The presence of chronic unexplained anaemia was diagnosed in 123 patients (7·5%). Forty-eight had a thalassaemic trait, representing 2·9% of the whole sample. A true chronic unexplained anaemia was recorded in 75/1643 (4·6%). The occurrence of unexplained anaemia was similar in patients with NATD (1·9%) and in those with isolated ATD (2·96%; P = NS) but increased in patients with ATD and autoimmune related disorders (ARD) compared to patients with isolated ATD and/or with NATD (28·3%; both P < 0·0001; RR = 9·56 and 14·75, respectively). Chronic unexplained anaemia was virtually absent in hyperthyroid patients and was more prevalent in hypothyroid than in euthyroid patients with ATD (P = 0·0047; RR = 2·104).

Conclusions  These results indicate that the increased frequency of chronic anaemia in patients with ATD is essentially due to the presence of concomitant autoimmune gastrointestinal diseases.

Chronic unexplained anaemia in isolated autoimmune thyroid disease or associated with autoimmune related disorders

OBJECTIVE The aim of the study was to analyse the relationship between the ocular parameters, namely intraocular pressure (IOP), and the early forms of subclinical hypothyroidism. DESIGN Fifty-three subjects (9 male and 44 female) aged from 18 to 45 years (mean 32 +/- 7 years) were selected for this study. Twenty-nine met the criteria of subclinical hypothyroidism and 24 euthyroid subjects, age- and sex-matched, were used as controls. METHODS All individuals underwent a complete ocular examination, including visual field examination and serial measurement of IOP by means of a Goldmann tonometer. A tonographic examination was also performed. RESULTS The hypothyroid patients showed a substantially higher pressure in both eyes compared with control subjects (right eye = 17.52 +/- 4.74 vs 13.42 +/- 1.95 mmHg, P < 0.0001; left eye = 17.55 +/- 3.99 vs 13.71 +/- 1.55 mmHg, P < 0.0001). Indeed, the tonometric pressure exceeded 18 mmHg in 11 out of the 29 (38%) patients in the right eye and in 8 out of 29 (27%) patients in the left eye. The outflow index was normal in all subjects except in two hypothyroid patients. After two months of L-thyroxine (L-T4) replacement therapy, only one patient continued to show tonometric values above 18 mmHg and the hypothyroid patients showed a significant reduction in mean IOP in both eyes compared with pre-treatment values (right eye = 14.96 +/- 1.32 mmHg, P < 0.0097; left eye = 15.03 +/- 1.38 mmHg, P < 0.0018). Treatment did not lead to any change in the outflow indices; however, the C value (outflow coefficient at the sclerocorneal corner) returned to normal in the two patients with increased pre-treatment tonographic values. CONCLUSIONS These findings indicate that the intraocular pressure is increased even in subclinical hypothyroid patients and that, at this early stage, the impairment is fully reversible with L-T4 therapy.

Reversible increase of intraocular pressure in subclinical hypothyroid patients.

Objective: We have studied the effect of tryptophan on cellular [ 125 I]tri-iodothyronine (T3) uptake by mouse thymocytes. Materials and methods: Mouse thymocytes (20 · 10 6 cells/ml) were suspended in Krebs‐Ringer solution buffered by Tris‐HCl and incubation (23 8C at pH 7.45 6 0.6), in the presence or absence of 1 mM tryptophan, was started by adding 25 pM [ 125 I]T3. At the end of incubation, samples were cooled in ice, centrifuged over a 30% sucrose cushion and the cell-associated radioactivity was measured in the pellet. Results: Tryptophan reduced both the total and the saturable fraction of [ 125 I]T3 uptake by 44% (P a 0.0009) and 60% (P a 0.0006) respectively, following 1 min of incubation. This effect was specific and dose-dependent, being maximal at 5 mM concentration (ˇ82%). In contrast, the preexposure of cells to tryptophan for up to 2 h had no effect on the subsequent uptake of [ 125 I]T3, in the absence of tryptophan. The effect of D-tryptophan on saturable T3 uptake was not different from that obtained using the L-stereoisomer. Tryptophan reduced the Vmax of the initial rate of saturable [ 125 I]T3 uptake by two-thirds without affecting the apparent Km (2.2 nM) of the process, thus indicating the non-competitive nature of the inhibition. In sodium-free medium the saturable [ 125 I]T3 uptake was reduced by 43%. The inhibitory effect of tryptophan on [ 125 I]T3 uptake was exerted in both the presence and the absence of sodium. In fact, the inhibitory effect of tryptophan on T3 transport was greater and significantly different (P a 0.0046) from that obtained by sodium depletion alone. Conclusions: Tryptophan interferes with both the sodium-dependent and -independent components of [ 125 I]T3 uptake by a dose-dependent, non-competitive mechanism which operates in cis-modality at the plasma membrane level of mouse thymocytes.

/pdf/effect-of-tryptophan-on-the-early-tri-iodothyronine-uptake-1xpd5gyr75.pdf

N Viceconti

Papers

Thyroxine in goiter, Helicobacter pylori infection, and chronic gastritis.

Age-related prevalence of platelet-associated immunoglobulins G in nonthrombocytopenic patients with autoimmune thyroid disease and autoimmune polyglandular syndrome

Chronic unexplained anaemia in isolated autoimmune thyroid disease or associated with autoimmune related disorders

Reversible increase of intraocular pressure in subclinical hypothyroid patients.

Effect of tryptophan on the early tri-iodothyronine uptake in mouse thymocytes