Prevention and management of hypothyroidism after thyroidectomy for thyrotoxicosis

Treatment of patients with toxic multinodular goiter

The medical records of 253 patients evaluated for toxic multinodular goiter from 1975 through 1993 were reviewed to determine treatment trends, success, and complications. Of the 235 (93%) treated, 174 (74%) received surgical treatment and 61 (26%) received radioiodine (131I) treatment. Three months after initial treatment, 82% of surgically treated patients became euthyroid or hypothyroid compared with 21% of the 131I group. Among the 131I-treated patients, 20% required a second treatment, whereas none needed further treatment in the surgical group. At 2 years, the estimated probability of success was similar. The probability of post-treatment hypothyroidism was significantly higher for surgically treated patients, which is expected.

Follow-up evaluation of patients with Graves' disease treated by subtotal thyroidectomy and risk factor analysis for post-operative thyroid dysfunction

Eight-year follow-up evaluation and analysis of factors related to postoperative thyroid dysfunction were made in 216 patients with Graves' disease treated by subtotal thyroidectomy. The postoperative status of thyroid function were as follows according to hypersensitive TSH level: 65 patients (30.1%) were euthyroid, 25 (11.5%) had overt hyperthyroidism requiring treatment, 14 (6.5%) had subclinical hyperthyroidism with normal thyroid hormone and suppressed TSH, 21 (9.8%) were overt hypothyroid requiring thyroid hormone replacement and 91 (41.1%) had latent hypothyroidism without hormone replacement. In order to know factors related to postoperative thyroid function, age, sex, preoperative levels of TSH receptor antibody (TRAb), thyroid antibody titers, degree of lymphocyte infiltration, duration of medical treatment, weight of the resected thyroid tissue and weight of the remnant thyroid tissue were determined. No factor except thyroid remnant and antimicrosomal antibody titer was related to postoperative thyroid function. The weight of remnant should be less than 6 g to avoid recurrent hyperthyroidism. As recurrence of hyperthyroidism was observed more than 5 yr after surgery, long follow-up is needed.

Retrospective analysis of prognostic factors affecting the thyroid functional status after subtotal thyroidectomy for Graves' disease

To determine the factors causing thyroid dysfunction after surgery for Graves' disease, we studied 321 patients who underwent subtotal thyroidectomy during the 7-year period from 1981 to 1987. Thyroid functional status was evaluated biochemically and the patients were divided into four categories: recurrent hyperthyroidism, euthyroidism, latent hypothyroidism, and hypothyroidism. The following factors were analyzed: sex, age at onset of the disease, indication for surgery, serum titer of antimicrosomal hemagglutination antibody (MCHA), weight of resected thyroid tissue, size of remnant thyroid relative to body surface area, pathological findings of lymphoid follicles, and lymphocytic infiltration in the thyroid tissue. Probabilities of failure (recurrent hyperthyroidism and hypothyroidism) were estimated by the Kaplan-Meier method. Prognostic factors for failure were identified by using Cox's proportional hazards model. The incidence of hyperthyroidism and hypothyroidism 5 years after subtotal thyroidectomy was 16.2% and 9.6%, respectively. Significant factors for hyperthyroidism were relatively large thyroid remnant, high serum titer of MCHA (greater than or equal to 1:3200), and age at onset of the disease less than 20 years. The significant factor for hypothyroidism was severe lymphocytic infiltration. The level of postoperative thyroid stimulating hormone (TSH)-binding inhibition immunoglobulins (TBII) in patients with recurrence was significantly higher than in patients in remission. It is reasonable to determine the amount of remnant thyroid tissue in relation to patient body surface area. Although subtotal thyroidectomy can induce immunological remission by reduction of antigen, if the remission disappears, that is if TBII increases, recurrence of hyperthyroidism may develop even in patients without the unfavorable factors.

Long-term follow-up of treatment of thyrotoxicosis by three different methods

In view of continuing debate regarding the best definitive therapy for thyrotoxicosis, we examined the long-term outcome of radioiodine (131I) or surgical treatment of 1918 thyrotoxic patients divided into three groups: those given 131I at a dose calculated from thyroid size, 131I uptake and effective half-life to administer a fixed radioactivity dose to the thyroid; those treated with a dose of 131I (110, 185 or 370 MBq) chosen empirically; and those treated by partial thyroidectomy. A minimum 10-year follow-up was achieved for 1119 patients treated with a calculated 131I dose; a single dose resulted in control of disease in 90.5%. At 5 years, 18% were hypothyroid, the prevalence rising to 42% at 20 years. Of 504 patients treated with an empirical 131I dose and followed for at least 5 years, thyrotoxicosis was controlled by a single dose in 89.7%. The rate of hypothyroidism at 5 years (38.5%) was higher than that found in the calculated dose group. A minimum 10-year follow-up was achieved for 295 surgically treated patients; thyrotoxicosis was controlled in 89.2%. The prevalence of hypothyroidism (2% at 5 years, 27.5% at 20 years) was lower than that found after 131I, whether given by calculated or empirical dose. Each of the treatments employed resulted in an acceptable rate of cure of thyrotoxicosis. If maintenance of euthyroidism is the major objective, our findings suggest that surgery represents the treatment of choice. Furthermore, calculated dose 131I administration has advantages in terms of risk of hypothyroidism over empirical dose treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Long term thyroid function after subtotal thyroidectomy for Graves' disease

Between 1973 and 1980, 93 patients with Graves' disease underwent subtotal thyroidectomy by the same surgeon (the size of thyroid remnant was 4 g per side). No case of operative mortality, no case of thyroid storm nor of surgical complications occurred. Three months after surgery 40% of patients were euthyroid, 25% had overt hypothyroidism, 35% had subclinical hypothyroidism. In the following yr important variations of thyroid function were observed. The number of patients with subclinical hypothyroidism decreased slowly (22% and 9% at 3 and 6 yr, respectively), and some became euthyroid, some hypothyroid, others relapsed. Seven patients had recurrent hyperthyroidism. In particular at 3 yr 45% of patients were euthyroid, 28% had overt hypothyroidism, 22% had subclinical hypothyroidism, 4% had recurrence; at 6 yr 56% were euthyroid, 32% had overt hypothyroidism, 9% had subclinical hypothyroidism, 3% had recurrence. Four out of the 8 patients operated under 20-yr-old became hypothyroid in comparison with only 2 out of the 15 patients over 50-yr-old. Relapses were present only in patients operated at less than 40-yr and only in females. No correlation was found between thyroid lymphocytic infiltration and thyroid function after surgery, nor between the presence of antithyroid antibodies and hypothyroidism. All cases who relapsed had high TMA titers both before and after operation. This study confirms the need for accurate follow-up after subtotal thyroidectomy for Graves' disease.

Operation for hyperthyroidism. Methods and rationale

Five hundred patients with hyperthyroidism underwent operation between 1970 and 1984. Sixty-nine percent had Graves' disease, 19 percent had toxic thyroid adenoma, and 12 percent had multinodular toxic goiter. Good results were achieved in the 275 patients most recently treated. These results may be attributed to the following: good personal contact between the surgeon and the patient at the first meeting, 1 month of preoperative management with carbimazole and propranolol without interruption of work, operation adapted to the type of goiter, and treatment of postoperative tachycardia by propranolol. The mean duration of hospital stay was 5 days. Sequelae were rare. In the patients with Graves' disease, results at 2 years were as follows: 74 percent of operated patients were euthyroid, 23 percent required substitutive treatment, and surgical treatment failed or early relapse occurred in 3 percent. There were no recurrences after operation in patients with solitary or multinodular toxic goiter, but 30 percent of the former and 98 percent of the latter had to be treated with L-thyroxine. Seventy-two percent of the patients who presented with atrial fibrillation had return of normal cardiac rhythm after operation.

[Surgical therapeutic concept of immune thyropathy]

73 patients with Graves' disease, surgically treated from 1975-1986, were investigated retrospectively. 43 patients, treated by subtotal thyroidectomy (Enderlen-Hotz) and a bilateral thyroid remnant of a total of about 8-12 g, were compared with 30 patients, treated by a modified subtotal thyroidectomy leaving a unilateral thyroid remnant of about 4-8 g, with respect to preoperative duration of disease, indications for surgical treatment, weight of resected specimens, operative complications and postoperative thyroid function. Surgical complications were similar in both groups. After subtotal thyroidectomy 14/43 patients (33%) displayed either recurrent hyperthyroidism (9/43, 21%) or local recurrence of Graves' goiter (3/43, 7%) or both (2/43, 5%). The modified subtotal resected group showed no recurrences of the disease. After subtotal thyroidectomy 11 patients were euthyroid without thyroid medication (26%) compared to only two patients (7%) after the modified procedure of subtotal thyroid resection. To prevent recurrences of goiter as well as hyperthyroidism and, on the other hand, to achieve euthyroid function postoperatively without need for thyroid replacement therapy, subtotal thyroidectomy with a small thyroid remnant of about 4-8 g is recommended for all patients with large goiter and a chronic recurrent course of the disease or with iodine induced thyrotoxicosis. Patients with non-recurrent Graves' disease but large goiter probably benefit from subtotal thyroidectomy with a larger thyroid remnant of about 8-12 g.

Surgery for thyroid disease

Thyroidectomy is the keystone of management in most patients with thyroid cancer, and has unique advantages in many cases of hyperthyroidism. The role of thyroidectomy in these two conditions is considered, with specific discussion of indications, extent of operation, complications, and technique.

Long-term follow-up study of compensated low-dose 131I therapy for Graves' disease

We treated 187 patients who had Graves' disease with low-dose radioactive iodide (131I), using a protocol that included a compensation for thyroid size. The incidence of early hypothyroidism (12 per cent) was acceptably low in the first year after 131I treatment, but we found a cumulative high incidence (up to 76 per cent) at the end of the 11th year. In contrast, the incidence of permanent hypothyroidism was relatively stable in 166 surgically treated patients, increasing from 19 to 27 per cent at the end of 11 years. Among 122 medically treated patients, only 40 per cent entered remission, and hypothyroidism developed in 2 per cent during the same period of follow-up. The long-term incidence of hypothyroidism in our patients treated with low-dose 131I therapy was much higher than that found in earlier studies using a comparable dose. Our study suggests that it will be difficult to modify therapy with 131I alone to produce both early control of thyrotoxicosis and a low incidence of hypothyroidism.

Surgery for thyrotoxicosis

Recent reports have suggested the use of radio-iodine for the treatment of all cases of thyrotoxicosis. This paper evaluates the results of 627 patients undergoing subtotal thyroidectomy with a mean follow-up of 5 X 8 years. The most common complications were hypothyroidism (26 X 6 per cent) and recurrent thyrotoxicosis (2 X 6 per cent). Permanent hypocalcaemia occurred in 8 cases (1 X 4 per cent) and one patient developed a permanent, though asymptomatic, unilateral cord palsy (0 X 2 per cent). Ultimately all patients receiving radio-iodine appear to become hypothyroid and there is continued worry about possible thyroid malignancy. Almost 70 per cent of our cases were free of complications and euthyroid and we therefore believe that surgery remains the treatment of choice for thyrotoxicosis. We also discuss the difference in results between Graves disease and toxic multinodular goitre.

Hypothyroidism after thyroidectomy for Graves' disease

In 100 patients who underwent subtotal thyroidectomy for Graves' disease in 1970 through 1975, postoperative hypothyroidism developed in 75 patients an average of 4.6 months after operation. One patient had permanent hypocalcemia. Unilateral vocal cord function was abnormal postoperatively in three patients. Thyroidectomy for Graves' disease is used at our institution much less frequently than in the past and its use is being restricted to a younger population. The low recurrence rates of thyrotoxicosis (1 percent) was obtained at the expense of a high rate of postoperative hypothyroidism.

Results following surgical treatment of hyperthyroidism

In the years 1965-1978 1,222 patients with different types of thyrotoxicosis underwent surgical treatment at the 1st Department of Surgery, University of Vienna. Wherever possible a sparing selective surgical approach was considered preferable: autonomous adenoma (45%) enucleation resection or subtotal uni-lateral resection; multinodular toxic goiter (36%) and Graves disease (5%) uni- or bilateral subtotal resection. The remaining 5% were rather rare types of goiter (recurrent goiter, thyroiditis, adenocarcinoma). Overall mortality due was 0.7%. One-hundred and seven patients (8.76%) were over 70 years old at the time of the operation. Post-operative death occurred in the group of patients with toxic adenomas (2.7%). Four-hundred and ninety-five patients were followed up from 3-13 years postoperatively: the rate of recurrent thyrotoxicosis was 4.4%, 4.8% of the patients with hypothyroidism. In this paper the significance of the rapid effect of surgery in cases of hyperthyroidism is discussed and the results are compared with findings in other studies.

Thyroid morphology and function after subtotal resection for hyperthyroidism

Two main patterns of hyperplasia of the thyroid epithelium are seen in hyperthyroidism--toxic diffuse hyperplasia and toxic nodular hyperplasia. Toxic diffuse hyperplasia may affect the entire gland or it may arise in the extranodular tissue in a gland with nodular lesions. A series of patients treated by subtotal thyroidectomy for hyperthyroidism were classified into three morphological groups of goitre: 98 had a toxic diffuse goitre (TDG), 58 toxic nodular goiter with diffuse hyperplasia (TNGDH), and 105 toxic nodular goitre with nodular hyperplasia (TNGNH). The type of goitre was correlated to the development of disturbed thyroid function 1-6 years after surgery. Twenty-two patients with TDG and 18 (31 per cent) with TNGDH developed hypothyroidism; only 3 (3 per cent) with TNGNH showed hypofunction. Six patients with recurrent hyperthyroidism were found; all showed diffuse hyperplasia of the gland. It is concluded that the development of disturbed thyroid function after surgery is closely related to the histopathological type of goitre.