Tag Archives: hyperthyroidism

Lipoprotein(a) Levels in Thyroid Disorders

DOI: 10.2478/amma-2013-0018

Objective: The aim of this study was to assess the serum levels of Lipoprotein(a) [Lp(a)] in subjects with thyroid disorders, as well as to investigate their relationship with lipid profile and the markers of thyroid function and autoimmunity, admitting that elevated Lp(a) levels and dyslipidemia caused by thyroid disorders synergistically increased the atherogenic process.
Methods: This study enrolled 38 subjects with hypothyroidism, 30 with hyperthyroidism and 55 with euthyroidism. The following parameters were measured: Lp(a), apolipoprotein AI (apo AI), apolipoprotein B (apo B), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), very-low-density lipoprotein (VLDL), thyroid stimulating hormone (TSH), free thyroxine (FT4), triiodothyronine (T3), thyroid-peroxidase antibody (TPO-Ab).
Results: Lp(a) was found with increased mean serum levels in hypothyroid subjects (483.28 ± 281.55 mg/L). Hyperthyroid subjects showed normal levels (253.13 ± 94.29 mg/L) of Lp(a), but significantly lower than those with hypothyroidism and slightly increased levels in the euthyroid subjects (305 ± 100.44 mg/L). In hypothyroidism a significant positive correlation between Lp(a) and TSH, apo B, TC, TG, TC/HDL, VLDL levels and a negative correlation with FT4, T3 and apo AI/B (p < 0.05) was observed. No correlations were found between serum Lp(a) levels, lipids profile and thyroid function parameters in hyperthyroid subjects, neither with TPO-Ab.
Conclusions: The association of hypothyroidism with increased levels of Lp(a) seems to increase the already high cardiovascular risk in the hypothyroid subjects, while increased levels of Lp(a) represents independently a relevant cardiovascular risk factor.

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The Incidence and Risk of Inducing Hyperthyroidism Following Amiodarone Treatment

DOI: 10.2478/amma-2013-0031

Introduction: Amiodarone, a frequently used antiarrhythmic drug in cardiology, is very efficient in the treatment of ventricular and supraventricular tachiarrithmyas. The iodine content of amiodarone is 39%. Its chemical structure is similar to tyrosine. It is estimated that 1–23% of patients treated with amiodarone can develop hyperthyroidism. The purpose of this study is to assess and monitor the incidence of hyperthyroidism induced by amiodarone in patients admitted for various types of cardiac dysrhythmias, considering that most of the patients included in the study came from an endemic goitre area.
Material and method: One-hundred patients chosen systematically (62 men, 38 women) from 560 patients treated with amiodarone in the January 1st, 2009 – December 31, 2009 period were assessed (clinically, laboratory findings and imaging studies); their mean age was 64 years (range 50–70 years). In order to identify and diagnose hyperthyroidism, a questionnaire (Newcastle index) was used, also urinary iodine dosage, hormonal dosages (T3, T4, TSH) and thyroid imaging (ultrasound, radioactive iodine uptake test) were used.
Results: The incidence of hyperthyroidism induced by amiodarone in this study was 8%. Hyperthyroidism was more frequent in women (6 women vs. 2 men).
Conclusions: Thyroid hormonal levels have to be determined and a clinical or thyroid ultrasound examination should be made prior to initiating a treatment with amiodarone. At the end of the study, 8 patients, most of them female, were diagnosed with hyperthyroidism.

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The Characteristics of Amiodarone-induced Thyrotoxicosis in a Moderate Iodine Deficit Area

DOI: 10.2478/amma-2013-0045

Introduction: Amiodarone (AMI), a class III anti-arrhythmic drug, is associated with a number of side effects, including thyroid dysfunction (both hypo- and hyperthyroidism), which is due to amiodarone’s high iodine content and its direct toxic effect on the thyroid.
Objective: To evaluate the incidence of Amiodarone induced thyrotoxicosis (AIT) (type, rate of occurrence) and to identify the risk factors involved in its occurrence.
Material and method: We examined patients treated with amiodarone, between January 2002 and December 2011, who presented to our Department of Endocrinology Târgu Mures for thyroid dysfunctions.
Results: The retrospective study included 87 patients with thyroid dysfunctions; 58 (66.7%) patients had AIT and 29 (33.3%) had Amiodarone induced hypothyroidism (AIH). In the AIT group: 35 were women (60.3%), 23 were men (39.7%); the average age was 61.60 ± 12.39 years. Risk factors identified for the AIT group were male gender (RR = OR = 3.8; Chi-squer = 5.7, p = 0.004) and pre-existing thyroid abnormalities (RR = 2.5, Chi-square = 4.1, p = 0.005). The thyroid dysfunction occurrence was heterogeneous (0.2–183 months). The patients with previous thyroid abnormalities developed earlier thyroid dysfunction compared to those with an apparently normal thyroid gland (22.25 ± 4.14 months versus 32.09 ± 7.69 months, p = 0.02, T test).
Conclusion: In the context of the specific iodine geoclimatic intake and the area of origin, amiodarone – induced thyroid dysfunction spectrum is dominated by thyrotoxicosis. Screening and monitoring of thyroid function for patiens under chronic amiodarone treatment is necessary.

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