Elif ÖZDEMİR, Nahide BELGİT DELAY, Şefika Burçak POLAT

Do Patients with Differentiated Thyroid Cancer Face the Risk of Hyponatremia at the Expense of Preparation for Radioactive Iodine Treatment?

Objective: Differentiated thyroid cancer (DTC) is the most common endocrine cancer. The main therapeutic strategies are surgeryand radioactive iodine (RAI) treatment in selected intermediate- and high-risk patients. Hyponatremia is the most frequent formof electrolyte imbalance and few studies have assessed the frequency and clinical impact of hyponatremia in patients with thyroid cancer. In this study, we aimed to determine the prevalence and severity of hypo¬natremia among hypothyroid patients inthe peri-ablation period. The secondary objective was to assess the correlation between Sodium (Na) level and hypothyroidismseverity, age, and RAI dosage.Methods: A total of 51 patients with DTC who were referred to our Nuclear Medicine Department for RAI ablation/treatment wereenrolled. Serum Na, thyroid-stimulating hormone (TSH), and free triiodothyronine and thyroxine levels were measured three timesduring the study (under LT4 suppression, when the patient was hypothyroid before and after receiving RAI). Baseline, pre-, and postRAI mean serum Na and other hormonal parameters were compared. The number of patients with hyponatremia and possible relatedsymptoms were noted. Correlation of serum Na levels with age, RAI dosage, and hypothyroidism severity was determined.Results: The number of patients with hyponatremia did not differ significantly in the baseline, pre-, and post-RAI periods. None ofthe patients experienced moderate-to-severe hyponatremia. There was no significant correlation between serum Na levels andage, serum TSH, or the hormone levels.Conclusion: In conclusion, preparation for RAI treatment with LT4 withdrawal and or a low-iodine diet is not a common etiologicalfactor for the development of hyponatremia in patients with DTC.

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1. Kitahara CM, Sosa JA. The changing incidence of thyroid cancer. Nat Rev Endocrinol 2016; 12: 646-53. [Crossref]
2. Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid 2016; 26: 1-133. [Crossref]
3. Orosco RK, Hussain T, Noel JE, Chang DC, Dosiou C, Mittra E, et al. Radioactive iodine in differentiated thyroid cancer: a national database perspective. Endocr Relat Cancer 2019; 26: 795-802. [Crossref]
4. Twining CL, Lupo MA, Tuttle RM. Implementing Key Changes in the American Thyroid Association 2015 Thyroid Nodules/Differentiated Thyroid Cancer Guidelines Across Practice Types. Endocr Pract 2018; 24: 833-40. [Crossref]
5. Niri T, Horie I, Ando T, Kawahara H, Ueda M, Eto M, et al. Renal Function and Plasma Renin Activity as Potential Factors Causing Hyperkalemia in Patients with Thyroid Carcinoma Undergoing Thyroid Hormone Withdrawal for Radioactive Iodine Therapy. Endocr Pract 2020; 26: 197-206. [Crossref]
6. Vannucci L, Parenti G, Simontacchi G, Rastrelli G, Giuliani C, Ognibene A, et al. Hypothyroidism and hyponatremia: data from a series of patients with iatrogenic acute hypothyroidism undergoing radioactive iodine therapy after total thyroidectomy for thyroid cancer. J Endocrinol Invest 2017; 40: 49-54. [Crossref]
7. Nozu T, Yoshida Y, Ohira M, Okumura T. Severe hyponatremia in association with I(131) therapy in a patient with metastatic thyroid cancer. Intern Med 2011; 50: 2169-74. [Crossref]
8. Kim J, Cho SG, Kang SR, Kwon SY, Cho DH, Cho JS, et al. Preparation for radioactive iodine therapy is not a risk factor for the development of hyponatremia in thyroid cancer patients. Medicine (Baltimore) 2017; 96: e6004. [Crossref]
9. Tuttle RM, Ahuja S, Avram AM, Bernet VJ, Bourguet P, Daniels GH, et al. Controversies, Consensus, and Collaboration in the Use of (131) I Therapy in Differentiated Thyroid Cancer: A Joint Statement from the American Thyroid Association, the European Association of Nuclear Medicine, the Society of Nuclear Medicine and Molecular Imaging, and the European Thyroid Association. Thyroid 2019; 29: 461-70. [Crossref]
10. Tang CYL, Thang SP, Zaheer S, Kwan CK, Ng DC. Recombinant human thyrotropin versus thyroid hormone withdrawal in an Asian population. Endocrine 2020; 69: 126-32. [Crossref]
11. Silva MC, Furlanetto TW. Another possible contributor to hyponatremia after radioactive iodine. Thyroid 2014; 24: 923. [Crossref]
12. Ota K, Kimura T, Sakurada T, Shoji M, Inoue M, Sato K, et al. Effects of an acute water load on plasma ANP and AVP, and renal water handling in hypothyroidism: comparison of before and after L-thyroxine treatment. Endocr J 1994; 41: 99-105. [Crossref]
13. Doshi SM, Shah P, Lei X, Lahoti A, Salahudeen AK. Hyponatremia in hospitalized cancer patients and its impact on clinical outcomes. Am J Kidney Dis 2012; 59: 222-8. [Crossref]
14. Shakir MK, Krook LS, Schraml FV, Hays JH, Clyde PW. Symptomatic hyponatremia in association with a low-iodine diet and levothyroxine withdrawal prior to I131 in patients with metastatic thyroid carcinoma. Thyroid 2008; 18: 787-92. [Crossref]
15. Baajafer FS, Hammami MM, Mohamed GE. Prevalence and severity of hyponatremia and hypercreatininemia in short-term uncomplicated hypothyroidism. J Endocrinol Invest 1999; 22: 35-9. [Crossref]
16. Dayrit JC, Cunanan EC, Kho SA. Prevalence of Hyponatremia in Hypothyroid Patients during Radioactive 131I Ablation for Differentiated Thyroid Cancer: Single Institution Experience. Endocrinol Metab (Seoul) 2016; 31: 410-5. [Crossref]
17. Hammami MM, Almogbel F, Hammami S, Faifi J, Alqahtani A, Hashem W. Acute severe hypothyroidism is not associated with hyponatremia even with increased water intake: a prospective study in thyroid cancer patients. BMC Endocr Disord 2013; 13: 27. [Crossref]
18. Tyack PL, Calambokidis J, Friedlaender A, Goldbogen J, Southall B. Formal Comment on Schorr GS, Falcone EA, Moretti DJ, Andrews RD. First Long-Term Behavioral Records from Cuvier's Beaked Whales (Ziphius cavirostris) Reveal Record-Breaking Dives. PLoS ONE 2014; 9: e92633. [Crossref]
19. Al Nozha OM, Vautour L, How J. Life-threatening hyponatremia following a low-iodine diet: a case report and review of all reported cases. Endocr Pract 2011; 17: e113-7. [Crossref]