Postoperative Hypocalcemia in Hyperthyroid Patients: The Parathyroids Aren't Always to Blame.

INTRODUCTION: Hypocalcemia is commonly reported after thyroidectomy and has multiple possible etiologies including: parathyroid devascularization, reactive hypoparathyroidism from relative hypercalcemia in thyrotoxicosis, and abrupt reversal of thyrotoxic osteodystrophy. In patients that are actively hyperthyroid and undergoing thyroidectomy, it is not known how many experience hypocalcemia from nonhypoparathyroidism etiologies. Therefore, our aim was to examine the relationship among thyrotoxicosis, hypocalcemia, and hypoparathyroidism. METHODS: A retrospective review was performed of prospectively-collected data from all patients undergoing thyroidectomy for hyperthyroidism by 4 surgeons from 2016 to 2020. All patients carried a diagnosis of Graves' disease or toxic multinodular goiter. Patient demographics, preoperative medications, laboratory reports, and postoperative medications were reviewed. Hypocalcemia within the first month of surgery despite a normal parathyroid hormone (PTH) level was the primary outcome of interest and was compared between patients with and without thyrotoxicosis. Secondary outcomes were duration of postoperative calcium use and the relationship between preoperative calcium supplementation and postoperative calcium supplementation. Descriptive statistics, Wilcoxon rank-sum, and chi-square tests were used for bivariate analysis, as appropriate. RESULTS: A total of 191 patients were identified, with mean age of 40.5 y (range 6-86). Most patients were female (80%) and had Graves' disease (80%). At the time of surgery, 116 (61%) had uncontrolled hyperthyroidism (thyrotoxic group, Free Thyroxine >1.64 ng/dL or Free Triiodothyronine > 4.4 ng/dL), with the remaining 75 (39%) considered euthyroid. Postoperative hypocalcemia (calcium < 8.4 mg/dL) developed in 27 (14%), while hypoparathyroidism (PTH < 12 pg/mL) was observed in 39 (26%). Thyrotoxic patients comprised a majority of those with hypocalcemia (n = 22, 81%, P = 0.01) and hypoparathyroidism immediately following surgery (n = 14, 77%, P = 0.04). However, a majority of initially hypocalcemic, thyrotoxic patients had normal PTH values within the first month after surgery (n = 17, 85%), pointing to a potential nonparathyroid etiology. On bivariate analysis, no significant relationship was found for thyrotoxic patients with initial postoperative hypocalcemia (18%) and hypoparathyroidism <1-month after surgery (29%, P = 0.29) or between 1 and 6 mo after surgery (2%, P = 0.24). Of the 19 patients in the nonhypoparathyroidism group, 17 (89%) were off all calcium supplements by 6 mo postop. CONCLUSIONS: In patients with hyperthyroidism, those in active thyrotoxicosis at time of surgery have a higher rate of postoperative hypocalcemia compared to euthyroid patients. When hypocalcemia lasts >1 mo postoperatively, data from this study suggest that hypoparathyroidism may not be the primary etiology in many of these patients, who typically require calcium supplementation no more than 6 mo postoperatively.

[Response to adjuvant therapy with potassium perchlorate in amiodarone-induced thyrotoxicosis: observations on three cases]. / A propósito de tres casos. Respuesta a la terapia adyuvante con perclorato potásico en la tirotoxicosis inducida por amiodarona.

INTRODUCTION: Amiodarone-induced thyrotoxicosis (AIT) is a common clinical disorder that may be life threatening and whose clinical manifestations and response to treatment may vary among patients. METHODS: We present three patients treated with amiodarone for atrial fibrillation who developed AIT at least 36 months after beginning the treatment. Thyrotoxicosis worsened the underlying cardiac disorders and was resistant to treatment based on the combination of dexamethasone 8-12 mg/day i.v., thioamides 45 mg/day p.o., beta blockers and potassium perchlorate at doses of 800 to 1000 mg per day p.o. Two of the patients attained sustained euthyroidism after 12 and 32 days of combined treatment, while the third required total thyroidectomy. CONCLUSION: The combination of thioamides with potassium perchlorate is an appropriate form of therapy for AIT in patients resistant to thioamides. The use of this combination should be evaluated in patients with mixed AIT or AIT of unclear etiology.

Concomitant hyperthyroidism in patients with thyroid carcinoma and the effects of iodine supplementation in an iodine-deficient area.

Objectives of this study were to investigate the occurrence and aggressiveness of differentiated thyroid carcinoma (DTC) in patients with hyperthyroidism and to explore the influence of the changes in dietary iodine intake on the association of hyperthyroidism and DTC. Clinical records of 1,800 patients with DTC were reviewed. The characteristics of DTC cases with and without thyrotoxicosis and their thyroid tumors were comparatively assessed.In the current series, 76 patients (4.2%) presented with hyperthyroidism before thyroid surgery. The most common type of goiter among 76 patients was toxic multinodular goiter. Presence of lymph node metastasis and recurrence was only observed in patients with toxic diffuse goiter. When DTC cases with and without thyrotoxicosis were compared irrespective of the type of goiter, aggressiveness of thyroid carcinoma was not higher in the thyrotoxic group. Hyperthyroidism and thyroid carcinoma coexisted in 3.3% and 4.7% in cases diagnosed before and after national iodine supplementation program, respectively (P = 0.04). Clinical course of the disease was not different in the diagnosis of these cases. As a result of no significant difference in complete remission ratio, we conclude that there is no need for a different DTC treatment protocol in cases with coexisting hyperthyroidism.

Combination of minimally invasive thyroid surgery and local anesthesia associated to iopanoic acid for patients with amiodarone-induced thyrotoxicosis and severe cardiac disorders: a pilot study.

BACKGROUND AND AIMS: Amiodarone-induced thyrotoxicosis is a life-threatening condition. A prompt control of thyrotoxicosis is obtained by thyroidectomy. Preparation with iopanoic acid proved to be very effective in reducing cardiovascular complications. Nevertheless, general anesthesia and extensive surgery may affect negatively patients also after adequate preparation. Safety and efficacy of minimally invasive video-assisted thyroidectomy performed under regional anesthesia (bilateral modified deep cervical block) in patients with amiodarone-induced thyrotoxicosis was evaluated. PATIENTS AND METHODS: Eight patients with amiodarone-induced thyrotoxicosis (three with type I and five with type II), mean age 66.2 years, were prepared with iopanoic acid. There were five men and three women. Three patients had dilatative cardiomyopathy, three had heart failure secondary to severe myocardial infarction, and two had refractory unstable rhythm disorders. RESULTS: Minimally invasive video-assisted thyroidectomy was performed under regional anesthesia. Mean operative time was 55.5 min. During surgery, lung and heart function remained well and no surgical complications occurred. After surgery, all patients remained on amiodarone therapy and two patients were subsequently removed from the checklist for heart transplantation. CONCLUSION: Minimally invasive video-assisted thyroidectomy under regional anesthesia can be proposed as resolution of amiodarone-induced thyrotoxicosis in high risk patients with severe cardiac disorders, after preparation with iopanoic acid.

Total thyroidectomy for amiodarone-associated thyrotoxicosis in patients with severe cardiac disease.

BACKGROUND: Surgical treatment of amiodarone-associated thyrotoxicosis (AAT) is effective although fewer than 100 cases have been reported world wide. MATERIALS AND METHODS: We reviewed 14 patients treated with total thyroidectomy by a single surgeon from 1998 to 2005. RESULTS: There were 11 male and 3 female patients who ranged in age from 26 to 82 years (average 50.5). Nine patients refractory to medical management and 5 in whom amiodarone needed to be continued were treated surgically. Ten patients developed thyrotoxicosis while being treated with amiodarone, but 4 became thyrotoxic after ceasing amiodarone 2, 2, 6 and 13 months previously. One patient recently had a cardiac transplant, and 4 were on the active cardiac transplant waiting list. Cardiac ejection fractions ranged from 15% to 50% (average 39%). Four patients had serious complications from medication used to control thyrotoxicosis, including one case of agranulocytosis from carbimazole. Total thyroidectomy was performed under general anaesthesia with no significant intraoperative complications and no deaths. There were no recurrent laryngeal nerve injuries. Two patients required short-term calcium supplementation. All patients had rapid resolution of their symptoms and were euthyroid on thyroxine postoperatively. Two patients had such improvement they were removed from the cardiac transplant list. CONCLUSIONS: Despite severe cardiac disease, total thyroidectomy can be performed successfully under general anaesthesia. Surgery should be considered early in the treatment plan. Surgery is particularly appropriate where it is considered necessary to continue amiodarone, when there are complications from the medications used to treat thyrotoxicosis and to facilitate fitness for or defer the need for cardiac transplantation.

[Results of the surgical treatment of thyrotoxicosis].

OBJECTIVE: The aim of this study was to evaluate the results of the surgical treatment of patients with thyrotoxicosis in three surgical clinics in Plovdiv. PATIENTS AND MEDHOTS: We studied 90 patients, who underwent surgical treatment for thyrotoxicosis between 2000-2004. Of those 19 men (21%) and 71 women (79%); men:women = 1:3.74; mean age 38 +/- 8.3 years. The nosological distribution was as follows: Graves' disease--72 subjects (80.00%), solitary toxic adenoma--4 subjects (4.40%), toxic nodular goiter--14 subjects (15.60%). 77 subtotal thyroidectomies (85%) and 9 total thyroidectomies were performed. Patients with solitary toxic adenoma underwent lobectomy. RESULTS: Massive bleeding witch required revision and haemostasis was encountered in 1 patient. Transient laryngeal nerve injury occurred in 3 patients (3.33%), and temporary hypoparathyroidism in 6 subjects (6.67%), necessitating calcium supplementation. One year postoperatively, 49.35% (n = 38) of the patients who have undergone subtotal thyroidectomy were euthyroid, 45.45% (n = 35) developed hypothyroidism, and 5.2% (n = 4) relapsed. DISCUSSION: Our results indicate that surgery is safe and effective for patients with thyrotoxicosis referred for radical treatment. Because of the high rate of postoperative thyroid disfunction, assessment of the non-operative factors, witch influence the functional results, is recommended.

Thyroidectomy using local anesthesia in critically ill patients with amiodarone-induced thyrotoxicosis: a review and description of the technique.

Hyperthyroidism caused by amiodarone is a well-known and accepted side effect of therapy. This problem can frequently be treated by medical means if patients are stable. In some patients, particularly those who are critically ill with cardiac disease the addition of hyperthyroidism can be particularly detrimental. These patients present with an interesting paradox because they are frequently on amiodarone because of life-threatening arrhythmias not responsive to other regimens, yet the amiodarone can precipitate hyperthyroidism that can acutely worsen the progression of their disease and prevalence of arrhythmias. In these patients, prompt treatment of their hyperthyroidism by total thyroidectomy may be the best option. Unfortunately, this also raises another treatment paradox in that these patients are at particularly high risk for complications from general anesthesia. In this subset of patients, total thyroidectomy under local anesthesia may be the best treatment option. Herein, we present a review of amiodarone-induced hyperthyroidism and our technique and review of our experience in its management with total thyroidectomy performed under local anesthesia.

Thyrotoxicosis in children: thirty years' experience.

Optimal treatment for thyrotoxicosis remains controversial in adults, but more so in paediatric practice. We have conducted a retrospective review of the records of 76 paediatric patients seen between 1965 and 1995 to determine management practice and outcome of therapeutic interventions. Seventeen are currently on antithyroid drug (ATD) treatment, while four have had their care transferred. Of the remaining 55, 21 (38%) achieved long-term remission with ATD alone following a mean treatment duration of 3.3 y (range 0.5-7 y). Block-replacement (high dose of ATD with thyroxine replacement) was more convenient than the titration regimen (3.4+/-0.3 visits to hospital per year versus 6.1+/-0.4, p<0.001). Surgery (subtotal/total thyroidectomy) was carried out in 27 patients, of whom 24 subsequently became hypothyroid and were treated with thyroxine. I131 was used successfully in six patients, two following surgery. ATD should remain the first-line therapy; a block-replacement regimen is more convenient. Surgery in a specialized centre carries a low risk. Caution should still be exercised in the use of I131 in young children.

Thyrotoxicosis in Zaria, Nigeria: an update.

The total number of operations performed for thyroid diseases at the ABU Teaching Hospital, Zaria from January 1986 to December 1995 has reduced. Those performed for thyrotoxicosis have tripled (18.5% of all thyroid operations compared to 5.7% ten years ago). Younger patients (mean age 27.7 years, range 13-15 years) with thyrotoxicosis are being seen but the clinical features of the disease and its management at the centre have not changed. It is suggested that the apparent increase in incidence and earlier onset of thyrotoxicosis in this environment may be due to the increasing use of iodised salt to combat endemic goitre.

Endemic goiter and endemic thyroid disorders.

The primary role of iodine deficiency in goitrogenesis and the prevention and treatment of endemic goiter by iodine supplementation is firmly established. Unfortunately, implementation of iodine prophylaxis programs has met with considerable technical and socioeconomic difficulties. Besides, lack of knowledge concerning some of the other causative factors of endemic goiter has prevented development of appropriate measures for its complete eradication in those areas where goiter persists in spite of prolonged and adequate iodine supplementation. At present, no less than 5% of the world's population have goiters and associated disorders, resulting in a public health and socioeconomic problem of major proportions. Seventy-five percent of people with goiter live in less developed countries where iodine deficiency is prevalent. Goiter prevalence rates of more than 50% and the highest frequency of severe cases of iodine deficiency disorders, namely, cretinism, congenital hypothyroidism, and various degrees of impairment of growth and mental development are found in endemic areas with extreme iodine deficiency. Goiters are usually multinodular and of very large size, producing, on occasion, signs of compression that require surgery. Recurrence rates are as high as 25-30% and second surgery accounts for 16% of all thyroidectomies. Unfortunately, most of these goiters occur in areas with highly restricted medical and surgical facilities. Twenty-five percent of people with goiters live in more developed countries where goiter continues to occur in certain areas despite iodine prophylaxis. Iodine-sufficient goiters are associated with autoimmune thyroiditis, hypothyroidism, hyperthyroidism, and thyroid carcinoma. Goiter is of considerable surgical significance in iodine-sufficient endemic areas and, to a lesser degree, in nonendemic areas where it is called "sporadic" goiter. Recurrence rates of iodine-sufficient goiter are 10-19% following thyroidectomy. Since most of these goiters grow by mechanisms other than increased thyrotropin (TSH) stimulation, treatment with suppressive doses of L-thyroxine is inefficient and, because of possible complications, not recommended. Although Graves' hyperthyroidism is not directly related to endemic goiter, it does relate adversely with ingestion or administration of iodine. At present, Graves' disease is treated with 131I or antithyroid drugs in more than 90% of the cases. The incidence rates of papillary, follicular, and anaplastic thyroid carcinomas appear to be related to endemic goiter and iodine supplementation, with surgery being required in essentially all of these cases.

The management of hyperthyroidism. A surgeon's perspective.

Surgery for the treatment of hyperthyroidism is rapid and permanent, highly safe, and highly successful and has an important and complementary role with medical therapy and 131I. In Grave's disease cases total thyroidectomy, performed only if parathyroid glands are preserved, prevents recurrent hyperthyroidism. Bilateral subtotal thyroidectomy or total lobectomy with contralateral subtotal lobectomy are done if at least one parathyroid cannot be preserved on each side. In terms of recurrent laryngeal nerve preservation, all three operations are equally safe if the nerve is positively identified and traced throughout its course.

[Preoperative preparation of patients with thyrotoxicosis]. / Predoperatsionnaia podgotovka bol'nykh s tireotoksikozom.

Transfusion of UV-irradiated autoblood in the complex preoperative preparation of patients with different degrees of thyrotoxicosis facilitates normalization of the protein-forming function of the liver, decreases concentration of thyroid hormones, stimulates erythropoiesis and is an effective means of preoperative preparation and complex treatment of patients with thyrotoxicosis.