Quitting smoking as a probable trigger for new-onset hypothyroidism after successful medical treatment of Graves' disease: case report.

Graves' disease (GD) is the most common cause of hyperthyroidism while Hashimoto or autoimmune thyroiditis is the most common cause of hypothyroidism. Spontaneous hypothyroidism may develop after successful medical treatment of GD in up to 20% of cases. This report presents a gentleman who is a known smoker and was diagnosed with GD at the age of 64 years. He was counseled about smoking cessation and started with medical treatment using carbimazole (CBZ). He was adequately controlled using medical treatment, yet he continued to smoke. After 2 years of medical treatment, CBZ was stopped due to developing hypothyroidism on the minimum dose of treatment. Celebrating the discontinuation of treatment, the patient decided to quit smoking. One month later, he was euthyroid; however, 4 months later, he developed overt hypothyroidism. He received levothyroxine replacement therapy and titrated to achieve euthyroidism and remained on levothyroxine for more than 5 years. The possibility that quitting smoking may have triggered the development of hypothyroidism was raised due to the coincidence of developing hypothyroidism only 4 months after quitting smoking. Current smoking is associated with a higher risk of developing both GD and Graves' orbitopathy. Quitting smoking is associated with a higher risk of developing new-onset thyroid autoimmunity. Quitting smoking is also associated with a sevenfold higher risk of autoimmune hypothyroidism especially in the first year of smoking cessation. Involved mechanisms may include a sudden increase in oxidative stress, a sudden increase in iodide delivery to thyroid follicles, or promoting T-helper 1-mediated autoimmune thyroiditis after quitting smoking. The present case suggests that quitting smoking may be a triggering factor for the development of hypothyroidism following successful medical treatment of GD, a phenomenon that may affect one-fifth of GD patients without previously reported triggers.

Quitting smoking may trigger hypothyroidism in previously treated Graves' disease patients Graves' disease is the commonest cause of hyperthyroidism. Medical treatment is the mainstay treatment, and about 5-20% of patients may develop hypothyroidism after successful medical treatment. The triggers to this conversion are not known. The present case, a 64 years old gentleman who is a smoker, after being diagnosed with graves' disease, receives medical treatment for 2 years. On the occasion of stopping medical treatment for graves' disease, he decides to quit smoking. One month later he is euthyroid off medications, but 4 months later, he develops severe hypothyroidism, for which he receives replacement therapy for the following five years. The possibility that quitting smoking may have triggered this conversion was raised. Smoking is associated with a 2-folds higher risk of having graves' disease. Quitting smoking on the other hand increases the risk of acquiring thyroid autoantibodies, and new onset autoimmune hypothyroidism. Quitting smoking is also associated with symptoms of weight gain, constipation, and depression, all of which may also occur in hypothyroidism. That is why, ordering thyroid function tests is recommended in recent quitters if they develop such symptoms. Thus, quitting smoking in the present case may have triggered this severe hypothyroidism. Underlying mechanisms may involve increased oxidative stress or autoimmune reactions favoring the occurrence of autoimmune thyroiditis.

Twice or thrice weekly levothyroxine provides similar rates of adherence and post-Ramadan euthyroidism compared to daily levothyroxine during Ramadan fasting.

BACKGROUND: Having to take levothyroxine (L-T4) on a daily basis, on an empty stomach is burdensome and may impair adherence, especially during Ramadan fasting. A long half-life and autoregulation of thyroid hormone levels allows for twice or thrice weekly administration of L-T4. This study aims to establish twice or thrice weekly L-T4 dosing as a convenient and effective practice during Ramadan fasting. METHODS: The study included 2 groups; twice or thrice weekly (TTW) group included patients assigned to take L-T4 twice or thrice a week, and standard daily dosing (SDT) group included patients assigned to take L-T4 daily. Patients freely chose between three L-T4 regimens: before Iftar, before Suhor, or before the next fast. Thyroid status was assessed before and within 6 weeks after Ramadan. Only euthyroid patients were included. RESULTS: TTW group included 57 patients, while SDT group included 91 patients. Pre-Ramadan TSH in TTW group (1.80 ± 0.88 µIU/L) was higher compared to SDT group (1.39 ± 0.72 µIU/L) [P = 0.003]. Similar adherence rates were observed in both groups, 96.5% in TTW group versus 89% in SDT group, [P = 0.13]. similar rates of post-Ramadan euthyroidism were also found in both groups, 91.2% in TTW group versus 94.5% in SDT group, [P = 0.509]. TTW group preferred regimen 1 (64.9%) significantly more than SDT group (35.2%) [P = 0.001]. CONCLUSION: Twice or thrice weekly levothyroxine results in similarly high rates of adherence (96.5%) and post-Ramadan euthyroidism (91.2%) compared to daily levothyroxine during Ramadan fasting.

Hypovitaminosis D masking hypercalcemia in primary hyperparathyroidism: case report.

Hyperparathyroidism (HPTH) is the third most common endocrine disorder. Hypovitaminosis D affects up to 40% of the general population and about a third of hyperparathyroid patients. Such a combination may alter the classic presentation of HPTH. This report presents a premenopausal female with long history of osteoporosis, normocalcemia, and hypovitaminosis D who was initially diagnosed as secondary HPTH. After restoring vitamin D to normal using parenteral loading doses, the patient developed persistent mild to moderate hypercalcemia with persistent parathormone elevation consistent with primary HPTH associated with hypercalciuria and complicated with nephrocalcinosis. Imaging confirmed a left upper parathyroid adenoma and fulfilling several indications for surgery, the patient was operated restoring normocalcemia that was maintained for several years of follow-up. Hypovitaminosis D is common and may mask expected hypercalcemia in patients with primary HPTH, thus delaying diagnosis and proper intervention. Reevaluating patients initially diagnosed as hypovitaminosis D and secondary HPTH may reveal a masked diagnosis of primary hyperparathyroidism.

Impact of fasting on thyrotropin and thyroid status during Ramadan in 292 previously well controlled hypothyroid patients. IFTAR study.

PURPOSE: Fasting during Ramadan affects thyrotropin both in healthy subjects and hypothyroid patients on adequate levothyroxine replacement. Few studies have addressed this effect in hypothyroid patients with pre-Ramadan euthyroidism. This study aims to report the impact of fasting in a relatively large cohort. METHODS: This was a prospective study including hypothyroid patients who fasted Ramadan during the years 2018, 2019, and 2020 in Alexandria, Egypt. All patients were euthyroid. Patients chosen one of three levothyroxine regimens during Ramadan, regimen 1: 60 min before Iftar, regimen 2: 3-4 h after Iftar, 60 min before Suhor, regimen 3: before the start of next fast, 3-4 h after an early Suhor. Thyroid status was assessed in pre-Ramadan visit and reassessed in post-Ramadan visit within 6 weeks from the end of Ramadan. RESULTS: The study included 292 hypothyroid patients. Most patients were adherent, 249 patients (85.3%), one sixth of patients were non-adherent, 43 patients (14.7%). Post-Ramadan TSH was 2.13 ± 1.88 mIU/L versus 1.60 ± 0.96 mIU/L pre-Ramadan [P = 0.001]. Most patients were still euthyroid post-Ramadan, 233 patients (79.8%), while 59 patients (20.2%) were dysthyroid. Post-Ramadan TSH significantly correlated to pre-Ramadan TSH [P < 0.001]. Post-Ramadan TSH was significantly higher in non-adherent patients, 3.57 ± 3.11 mIU/L compared to adherent patients, 1.88 ± 1.44 mIU/L [P < 0.001]. CONCLUSION: Fasting Ramadan in well controlled hypothyroid patients resulted in a significant increase in post-Ramadan TSH, yet 80% the patients remain euthyroid after Ramadan. Post-Ramadan TSH and euthyroidism are related to adherence and pre-Ramadan TSH.

Twice or Thrice Weekly versus Daily Thyroxine in Hypothyroid Fasting Ramadan: A Pilot Study.

Context: Hypothyroid patients require to take levothyroxine (L-T4) on an empty stomach, 60 min before next meal which is difficult to achieve while fasting Ramadan, on a daily basis. This pilot study aimed to assess the effect of twice or thrice weekly versus standard daily L-T4 dosing during Ramadan on adherence, post-Ramadan TSH, and thyroid status. Methods and Materials: The study included 2 groups; group 1 included 11 patients assigned to take L-T4 twice or thrice a week, and group 2 included 113 patients assigned to take L-T4 daily. Patients chose between three L-T4 regimens: regimen 1 - 60 min before Iftar; regimen 2 - 60 min before Suhor, on empty stomach for 3-4 h; regimen 3 - before the next fast, on empty stomach for 3-4 h. Thyroid status was assessed before and within 6 weeks after Ramadan. Only euthyroid patients were included. Results: No significant differences between the two groups regarding adherence, post-Ramadan TSH, or post-Ramadan thyroid status. 90.9% in group 1 and 88.5% in group 2 were adherent [p = 1.000]. Post-Ramadan TSH in group 1 was 1.9 ± 1.5 mIU/L, in group 2 was 2 ± 1.6 mIU/L [p = 0.809]. 81.8% in group 1 and 82.3% in group 2 were euthyroid post-Ramadan [p = 0.209]. Conclusions: In this pilot study, taking L-T4 twice or thrice weekly during Ramadan achieved similar adherence and metabolic control to standard daily L-T4, making it an easier option for hypothyroid patients wishing to fast Ramadan.