Does preoperative iodide treatment for thyrotoxicosis bring about involution?

It is generally believed that preoperative iodide decreases the hyperplasia of the toxic thyroid gland. Histometric studies of glands from thyrotoxic patients pretreated with propranolol alone compared with those from patients pretreated with propranolol and iodide failed to confirm this. Although histological appearances and volume percentage measurement of component tissues suggested that the glandular epithelium had involuted after iodine treatment, measurement of their absolute mass indicated that the mean mass of epithelium was the same in both groups and that involution had not occurred. We conclude that considerable confusion in the thyroid literature has arisen through incorrect use of the term involution.

Echocardiogram before and after subtotal thyroidectomy for hyperthyroidism

Myocardial contractility was estimated in 27 patients with hyperthyroidism (10 men and 17 women, aged from 16 to 38) by echocardiography. Echocardiographic examination was performed before and on the 7th day after the subtotal thyroidectomy. Thyroid functions (PBI, T3, and T4) decreased significantly after the operation (p less than 0.01). Heart rate and systolic blood pressure showed a slight decrease (N.S.), while diastolic blood pressure showed a slight increase (N.S.), while diastolic blood pressure showed a slight increase (N.S.). Mean AWVs decreased from 35.8 +/- 7.0 mm/sec to 27.6 +/- 5.7 mm/sec and correlated wtih T3 (r=0.4008, p less than 0.05). Mean PWV's also decreased from 53.2 +/- 12.2 mm/sec to 45.2 +/- 11.4 mm/aec and correlated with T3 (r=0.5237, p less than 0.02). DDR decreased from 108.0 +/- 36.8 mm/sec to 85.7 +/- 31.7 mm/sec and correlated wtih T3 (r=0.4008, p less than 0.05). Above results suggest that enhanced myocardial contractility and elevated rate of ventricular filling in hyperthyroidism are suppressed after the operation, and that echocardiography is useful for the evaluation of the clinical course after the operation.

Thyroid carcinoma and concurrent hyperthyroidism: a study of ten patients

Ten patients with thyroid carcinoma and co-existing thyrotoxicosis have been studied. In six patients thyroid carcinoma was suspected before thyroidectomy. In three of the four patients in whom neoplasia was not suspected before operation, the lesion was a small papillary carcinoma. In only one of the eight patients in whom serum long acting thyroid stimulator (LATS) and long acting thyroid stimulator protector (LATSP) were assayed was detectable activity found, a low incidence. The possible role of hyperthyroidism in initiating thyroid malignancy is discussed.

[Long-term critical evaluation of hypothyroidism after subtotal thyroidectomy for thyrotoxicosis]

A retrospective study was made of 66 cases in which subtotal thyroidectomy had been carried for hyperthyroid syndromes, mainly of Basedow type, with a view to establishing a more careful selection of thyrotoxicosis candidates for surgery or other management. The reasons for the different findings and post-operation evaluation of performance are analysed in the light of the time of follow-up, mostly within 5 to 15 yr of surgery. Clinical examination in the light of statistical diagnostic indices was supplemented by evaluation of RIA-T3, TSH and T4, and anti-thyroglobulin antibodies. Four different metabolic states were identified: 1) clinical euthyroidism with normal hormone profile (56.1%); 2) latent hypothyroidism, as shown by high TSH, low T4 and normal RIA-T3 (12.1%); 3) frank hypothyroidism, seen in one case only; 4) high TSH, observed as an isolated finding (30.3%). This last group is fully discussed from the prognostic standpoint. It is not considered as an expression of initial hypothyroidism within the present series and its follow-up range, but as indicative of hypersecretion of an abnormal TSH, or as evidence of an increased hypothalamus-hypophysis axis threshold for the retroactive action of circulating T4 and T3. Attention is drawn to differences between surgical and radio-iodiotherapeutic hypothyroidism. The former, in particular, is less frequent, earlier to appear, and less predictable, whereas the latter displays a gradually increasing pattern.

Propranolol in the treatment of thyrotoxicosis by subtotal thyroidectomy

Subtotal thyroidectomy was performed in 40 patients with thyrotoxicosis in whom propranolol alone was used as preparation for surgery. Propranolol was given orally in a dose of 40 mg every 6 h for a mean preoperative period of 17 days (range 4-60 days) and continued for seven days after operation. The mean +/- SE blood loss at operation was only 160 +/- 20 ml. The period of follow-up was from three to nine months. Recurrent thyrotoxicosis has not occurred in any patient. Low levels of total serum triiodothyronine (T3) and total serum thyroxine (T4) were observed in the early postoperative weeks in some patients and were associated with symptoms of mild hypothyroidism, but by six months in the presence of a raised serum thyrotropin (TSH) the thyroid hormone levels returned to normal. Permanent hypothyroidism developed in only two patients. Despite normal or low total serum T3 and T4 levels, the TSH response to thyrotropin-releasing hormone (TRH) was absent in all patients one week after operation. At four weeks and at eight weeks, the response was absent or sub-normal in 70% and 20% of the patients respectively, indicating a delay in the recovery of the hypothalamo-pituitary axis previously exposed to high levels of T3 and T4. It is considered that subtotal thyroidectomy for thyrotoxicosis in patients prepared with propranolol is an acceptable procedure which has some advantages over the conventional preparation with carbimazole and potassium iodide, not the least of which are the potential reduction in preparation time, the more flexible timing of operation, and the reduced operative blood loss.

Temporary hypothyroidism after surgical treatment of thyrotoxicosis

Mild clinical hypothyroidism associated with low levels of serum total thyroxine (T4) and tri-iodothyronine (T3) and raised levels of serum thyroid-stimulating hormone (T.S.H.) has been observed in 14 of 40 patients (35%) in the early months after a subtotal thyroidectomy for thyrotoxicosis under cover of propranolol. In 10 of the patients, however, the hypothyroidism was temporary and at 6 months after operation the thyroid hormone levels were normal and the serum T.S.H. levels had fallen. In 4 of the patients in whom clinical and biochemical evidence of hypothyroidism persisted 6 months postoperatively, long-term T4 replacement therapy was instituted. It is concluded that the diagnosis of permanent hypothyroidism should not be made with confidence before 6 months have elapsed after operation and that the incidence of hypothyroidism following the surgical treatment of thyrotoxicosis may have been overestimated in the past.

Malignant cold thyroid nodules in hyperthyroidism

In 65 hyperthyroid patients with a cold nodule a carcinoma was found at operation in 14 cases, i.e. a malignancy incidence of 21-5 per cent. In 859 euthyroid cases with a cold thyroid nodule 104 malignant lesions (12-1 per cent) were found. The difference is statistically significant. Surgery in cases with a cold thyroid nodule is strongly indicated if this occurs in a hyperthyroid gland.

[Preoperative care and anesthesia in surgical treatment of thyrotoxicosis]

The authors made an analysis of clinical materials pertaining to 1234 patients with thyrotoxicosis, who were given different preoperative management and operated upon under local and general anesthesia. It is noted, that there is less number of postoperative thyrotoxic crises after mercosolyl administration in combination with reserpine and nonspecific drugs than after Plummer preoperative preparation (0.1% versus 1.2%).

[Hyperthyroidism with hypercalcaemia (author's transl)]

Anorexia, constipation, vomiting and somnolence in a 39-year-old woman were at first misinterpreted as being of psychological and autonomic nervous system origin. Further clinical and biochemical tests revealed hyperthyroidism associated with hypercalcaemia and hypercalciuria. Thyrostatic treatment for 12 days caused regression of the hypercalcaemia and, after subtotal resection, serum calcium levels and urinary calcium excretion returned to normal for good. The hypercalcaemia syndrome must therefore be assumed to have been the direct result of the hyperthyroidism.