Objective: We have aimed to study the relation between Hashimoto's thyroiditis (HT) and thyroid autoantibodies and oxidative stress parameters in euthyroid, subclinical and overt hypothyroid stages. Design and methods: A total of 124 patients were included in the study; 93 of whom were newly diagnosed with HT (31 patients in each of the euthyroid, subclinical hypothyroid and overt hypothyroid subgroups), aged over 18 and had not received any prior treatment and 31 of whom were healthy volunteers. Results: Total oxidant status (TOS) and oxidative stress index (OSI) levels were higher, and total antioxidant status (TAS) and total thiol and arylesterase levels were lower in the overt hypothyroid group compared to other groups. TOS and OSI levels increased, and TAS levels decreased significantly in each phase from euthyroid, subclinical hypothyroid, to overt hypothyroid subgroups among HT patients. There was a negative correlation between TAS, log (paraoxonase1) and paraoxonase1/HDL and anti-thyroid peroxidase and a negative correlation between anti-thyroglobulin and total thiol. It was also determined that overt hypothroidism was an individual predictor that effects all of the oxidative stress parameters, but not total thiol, levels. Conclusion: Our results suggest that oxidative stress increases continuously during the development of subclinical hypothyroidism and overt hypothyroidism in patients with HT. To determine whether this is a cause or result, randomized, controlled trials that study the effect of antioxidant treatment on the development of overt hypothyroidism and its consequences, e.g., increase in total cholesterol levels, may be performed in euthyroid and/or subclinical hypothyroid patients with HT.

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Objective: Our objective in this study was to determine the relationship between irisin hormone, which has a similar effect with thyroid hormones on adipose tissue and the metabolism, and the thyroid functions and the obesity secondary to thyroid disease. Subjects and methods: Seventy--four patients were included in the study, of the patients, 37 were newly diagnosed with Hashimoto's thyroiditis related hypothyroidism but not started on a treatment yet, and the remaining 37 were healthy volunteers without a known disease. Serum thyroid stimulating hormone (TSH), free thyroxin (fT4), anti-thyroglobulin and anti-thyroid peroxidase were measured and thyroid ultrasonography was performed in both groups. Serum irisin levels were measured using the commercially available ELISA kit. Results: The hypothyroidism group had higher levels of irisin compared to the control group (2.77 ng/mL vs. 2.15 ng/mL respectively; p = 0.017). The hypothyroidism group had higher median levels of irisin in the obese patients than those in the control group (3.10 ng/mL vs. 2.10 ng/mL respectively; p = 0.013). Irisin level was negatively correlated with age in the whole population and patients with hypothyroidism (r = -0.255, p = 0.028; r = -0.346, p = 0.036 respectively). Irisin level was positively correlated with TSH (r = 0.247, p = 0.034) but negatively correlated with the fT4 (r = -0.316, p = 0.006) in the whole population. Obesity, fT4 and irisin levels were identified to be independent predictors in the diagnosis of hypothyroidism in the multivariable logistic regression analysis. Conclusion: To the best of our knowledge, this study is the first in literature to identify that obesity, irisin level and fT4 level are independent risk factors for hypothyroidism. Arch Endocrinol Metab. 2016;60(2):95-100

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The RNFL thickness in CRF without DM, which was measured by OCT-3, was found to be significantly decreased. The presence of CRF can be a source of false positive results and lead to overestimation of glaucomatous optic neuropathy.

Hypothyroidism is a wide clinical spectrum disorder and only a few cases in literature show this. Rhabdomyolysis and acute renal impairment can be seen concurrently in a hypothyroid state. We report a case of severe hypothyroidism with poor drug compliance leading to rhabdomyolysis and acute kidney injury. • Hypothyroidism is a rare cause of acute kidney injury. • In this case report, we studied a rare occurrence of acute renal impairment due to hypothyroidism with poor drug compliance, which induced rhabdomyolysis. • Our report emphasized that thyroid status should be evaluated in patients with unexplained acute renal impairment or presenting with the symptoms of muscle involvement. Case presentation A 53-year-old male was admitted to a hospital with 15 days history of dyspnoea, weakness and oliguria, and muscle pain. His medical history included pulmonary thromboembolic, hypertension and cardiac arrhythmia. He had undergone total thyroidectomy for papillary thyroid cancer two years ago. His medication consisted of metoprolol, enoxaparin and l-thyroxine with no use in the past 4 weeks. Physical examination revealed dry and pale skin and slow speech. His pulse rate was 55 beats/minute and blood pressure was 130/90 mm Hg. Electrocardiography has shown bigemine ventricular extra systole. Laboratory investigations showed the following values: creatine phosphokinase, 1560 U/L (reference range, 52-336 U/L); creatinine, 2.1 mg/dL (0.2-1.0 mg/dL); potassium, 5.3 mEq/L (3.5-5.0 mEq/L); thyroid-stimulating hormone (TSH) 43.2 µIU/mL (0.4-4.8 uIU/mL), free thyroxine (fT4) <0.3 ng/dL (1.71-2.8 ng/dL) and free triiodothyronine (fT3) 0.48 pg/mL (1.57-4.71 pg/ mL). Haematological tests showed haemoglobin 9.4 g/dL (12-16), white cell count 9000 µL and platelet counts were in normal range. His urine was bloody in appearance and urine analysis showed blood reaction with dipstick test, but no erythrocytes were found on microscopic examination. Fraction excretion of Na and urinary Na were high (2.6% and 46 mEq/L, respectively). Renal tract ultrasonography was normal. No signs suggested the presence of an associated infectious or systemic inflammatory disease. In addition, other causes resulting in rhabdomyolysis such as muscular trauma, drugs and toxins were excluded with history and laboratory investigations. His condition was diagnosed as acute kidney injury secondary to hypothyroidism-induced rhabdomyolysis. This case was also consulted with the department of cardiology physicians who started him on metoprolol 25 mg before beginning thyroid replacement therapy. Cardiac status remained stable: l-thyroxine 25 microgram/day was prescribed, then 2 weeks later it was continued with l-thyroxine 50 microgram/day. His fluid deficiency was treated aggressively. His symptoms resolved over the following 3 weeks.

Objective: Although several studies reported increased oxidative stress in Hashimoto's thyroiditis (HT), the effect of levothyroxine treatment on oxidative status is not studied extensively. Therefore, we conducted this study to investigate the effects of levothyroxine replacement on oxidative stress in HT. Design and methods: Thirty-six patients recently diagnosed with HT-related hypothyroidism and 36 healthy controls were included in the study. Levothyroxine replacement was started to patients with hypothyroidism, and had been followed-up for 6 months. Results: Mean basal serum total antioxidant status (TAS), total thiol, arylesterase, and paraoxonase 1 (PON1) levels were significantly lower, and serum total oxidant status (TOS) and oxidative stress index (OSI) were significantly higher in the patients with hypothyroid than the controls. In the hypothyroid group serum TAS, total thiol, arylesterase, and PON1 levels increased and serum TOS and OSI levels decreased significantly after levothyroxine treatment. Pretreatment serum TAS, total thiol, PON1, and arylesterase levels were positively correlated with free levothyroxine (fT 4 ) and negatively correlated with thyroid-stimulating hormone (TSH), antithyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG) levels. Also, pretreatment serum TOS and OSI levels were negatively correlated with fT 4 levels and positively correlated with TSH, anti-TPO, and anti-TG. We have also found that the fT 4 and anti-TPO levels are independent predictors of the oxidative stress parameters in stepwise multivariable linear regression analysis. Conclusion: This study suggests that levothyroxine replacement decreases oxidant status and increases antioxidant status following the 6 months of levothyroxine replacement in hypothyroidism that develops in accordance with the HT.

Oxidative stress may be an effective risk factor in the development of overt hypothyroidism in HT.