Plasma insulin disturbances in primary hyperparathyroidism.

Plasma insulin dynamics were evaluated in 10 patients with primary hyperparathyroidism before and after parathyroidectomy and correction of hypercalcemia. Before surgery fasting plasma insulin concentrations and insulin responses to administered glucose, tolbutamide, and glucagon were significantly greater than postoperative values. Hyperinsulinemia was not associated with altered glucose curves during glucose or glucagon tolerance tests, but a relatively greater insulin response to tolbutamide resulted in an increased hypoglycemic effect following its administration. The glucose-lowering action of intravenous insulin was slightly impaired before treatment. Intramuscular injections of parathormone to six normal men for 8 days induced mild hypercalcemia and hypophosphatemia and reproduced augmented plasma insulin responses to oral glucose and intravenous tolbutamide. 4-hr intravenous infusions of calcium to another group of six normal men raised serum calcium concentrations above 11 mg/100 ml. This did not alter glucose or insulin curves during oral glucose tolerance but markedly accentuated insulin responses to tolbutamide and potentiated its hypoglycemic effect. When highly purified parathormone was incubated with isolated pancreatic islets of male rats, glucose-stimulated insulin secretion was unaffected. These findings suggest that chronic hypercalcemia of hyperparathyroidism sustains a form of endogenous insulin resistance that necessitates augmented insulin secretion to maintain plasma glucose homeostasis. This state is insufficient to oppose tolbutamide-induced hypoglycemia because of an additional direct, selective enhancement of hypercalcemia on pancreatic beta cell responsiveness to the sulfonylurea. The possible direct role of parathormone in these events has not been established.

Spontaneous regression of a postpartum pituitary mass demonstrated by computed tomography.

An 18-year-old woman had postpartum thyrotoxicosis, hypercalcemia, and secondary adrenocortical insufficiency. A pituitary mass with suprasellar extension was demonstrated on computed axial tomography (CT). The patient subsequently became hypothyroid and normocalcemic, and repeated CT scanning showed that the pituitary mass had undergone a spontaneous regression in size. Computed axial tomographic scanning is an important modality for the evaluation of postpartum pituitary masses and their natural history. This case suggests that some patients with postpartum hypopituitarism and a pituitary mass need not have early surgical intervention but may be closely observed and treated by hormone replacement alone.

DNA content in radiation-associated thyroid cancer.

DNA content has been reported to be of prognostic significance in differentiated thyroid carcinoma. Since malignant tumors with irradiation as an initiator often contain DNA aberrations, the DNA content of well-differentiated thyroid carcinoma in patients with a prior history of low-dose head and neck irradiation was determined and compared with similar nonradiation-associated lesions. The DNA content of thyroid cancers from 53 patients was determined with use of flow cytometry. Sixteen radiation-associated thyroid carcinomas (11 papillary, 3 follicular, and 2 medullary) all were diploid. In a group of 37 nonradiation-associated tumors, 10 were aneuploid (10 of 29 papillary carcinomas and 0 of 2 follicular or 6 medullary carcinomas). This difference in DNA content is significant (p less than 0.02, Fisher's exact test). These findings were unexpected and suggest that if the initiating irradiation causes a DNA aberration, this aberration is not reflected in DNA content as measured by means of flow cytometry.

Total or near total thyroidectomy versus limited resection for radiation-associated thyroid nodules: a twelve-year follow-up of patients in a thyroid screening program.

Controversy continues regarding the extent of thyroidectomy appropriate for patients with radiation-associated thyroid nodules. The incidence of cancer in this group of patients is more than 50% when near total or total thyroidectomy is done and all thyroid tissue is serially sectioned and examined. Tumor multicentricity is common. Is total or near total thyroidectomy warranted in all of these patients? A prospective study and follow-up program of 2118 patients with prior low-dose head and neck irradiation who entered into a thyroid screening program allowed us to examine how the extent of thyroidectomy influenced the clinical course of these patients. Near total or total thyroidectomy was performed in 59 patients (36 had cancer), and limited thyroid resection, that is, lobectomy or less, was done in 78 patients (four of whom had cancer). During follow-up, only three patients have developed recurrent cancer; two had near total thyroidectomy and one had total thyroidectomy at first operation. Two patients with limited thyroid resection have had reoperation for new thyroid nodules, both of whom had benign nodules. We conclude that although limited thyroid resection may leave occult malignancies in unresected thyroid tissue, there is no significant difference in outcome between patients with limited resection and those with near total or total thyroidectomy after a 12-year follow-up of the program. Significant differences in cancer recurrence rats may occur with longer follow-up.

Thyroid gland morphology in young adults: normal subjects versus those with prior low-dose neck irradiation in childhood.

Thyroid glands obtained at autopsy from young adults were studied to establish more accurately the "normal" morphology in the groups 20 to 40 years of age. A total of 56 autopsy specimens (many obtained from trauma victims) were examined in detail by totally embedding and sectioning the thyroid glands. The morphology of these thyroid glands also was compared to that of surgically removed thyroid glands from 47 young adult patients with prior low-dose neck irradiation. The "normal" thyroid specimens frequently showed morphologic features, such as thyroid tissue outside the recognizable capsule of the gland (40 of 56 patients) and in the strap muscles of the neck (six of 56 patients), which are conditions commonly considered as evidence for invasive thyroid carcinoma. The thyroid glands from the "normal" young adult population were significantly different from those thyroid glands surgically removed from patients who had received irradiation. The irradiated thyroid glands invariably showed multiple nodules of a wide variety of histologic types, extensive lymphocytic infiltrates, and distorting fibrosis as well as a high incidence of malignancy (27 of 47 patients). A single 0.1 cm focus of papillary carcinoma was found in one specimen in the nonirradiated thyroid group. This study suggests that "occult" thyroid carcinomas in the group 20 to 40 years of age are rare and are significantly fewer in number than in the older population (P less than 0.02).

Radiation-related thyroid carcinoma.

Of 1,825 subjects with a history of head or neck irradiation, 358 (19.6%) were found to have thyroid abnormalities. One hundred sixty-five (9%) had either single or multiple nodules 153 (8.4%) had diffuse thyromegaly, and 40 (2.2%) had had thyroid surgery. Surgery was performed on 113 subjects with nodules; carcinoma was found in 34 (30.1%). Clinical examination of the neck was the most valuable method of detecting abnormalities. Detection of nodules was not significantly enhanced by routine use of thyroid imaging studies. Measurements of levels of serum thyroid-stimulating hormone, thyroxine, triidothyronine resin uptake, and thyroid antibodies were not useful in screening for nodules or carcinoma.

Elevated calcium level in parathyroid cyst fluid.

Parathyroid cysts are uncommon neck masses. The diagnosis is generally established when the parathormone level is found to be elevated in the typically clear cyst fluid obtained by fine needle aspiration. We present a case where the serum and cyst fluid intact parathormone levels were normal yet the diagnosis was established by demonstrating an elevated fluid calcium level. The cyst recurred after two attempts at aspiration, so the patient underwent a curative operative excision.

Results of a community thyroid screening program: who will benefit?

OBJECTIVE: To describe the results of a community-based thyroid screening program. METHODS: We review the recruitment process, the screening questionnaire, the laboratory procedure, and the data analysis. RESULTS: News media advertisements and facility-sponsored communications were used to recruit 1,176 participants, each of whom completed a health questionnaire and had blood withdrawn for a thyroid-stimulating hormone (TSH) assay. Most participants were female (78%), Caucasian (92%), and age 50 years or older (61%). Data from 1,139 participants were analyzed. Abnormal TSH values were found in 107 participants: TSH was low in 21 (2%) and elevated in 86 (8%). Elevated TSH values occurred in 8% of females, 7% of males, 8% of Caucasians, and 7% of Hispanics. Although the percentage of elevated TSH values tended to increase with advancing age, primarily in females, 5% of participants younger than 50 years of age had an elevated TSH. No associations were apparent between abnormal TSH values and health maintenance organization membership, self-rating of overall health, or presence of thyroid-related symptoms. Participants who rated their overall health as "excellent" or "very good" accounted for 48% of the TSH values >12 microIU/mL. CONCLUSION: Experience gained from the conduct of this screening program may help shape the expectations of future screening programs that use disease awareness and self-motivation and provide insights into program design that may maximize participation by the desired target audiences.

The radioactive handkerchief sign. A contamination artifact in I-131 imaging for metastatic thyroid carcinoma.

False-positive findings suggestive of metastatic functioning thyroid carcinoma have been well documented in I-131 whole-body imaging. These artifacts are often associated with contamination from radioiodine-containing body secretions. Recently, a contaminated handkerchief on an iodine-131 whole-body scan was reported. In the following study, two additional cases involving the sequestration of I-131 contaminated handkerchiefs in patients' pockets are presented, and the literature regarding these false-positive findings is reviewed. Although rare, this "radioactive handkerchief sign" may cause serious misinterpretation of a focal radioiodine accumulation.

Hyperthyroidism due to functioning metastatic thyroid carcinoma. Precipitation of thyroid storm with therapeutic radioactive iodine.

Two patients had hyperthyroidism secondary to functioning metastatic follicular thyroid carcinoma. Failure to control the thyrotoxic state with antithyroid drugs in one patient prior to treatment with radioactive iodine led to exacerbation of the thyrotoxicosis with thyroid storm and death. A second patient, in whom a euthyroid state was induced before radioactive iodine therapy, had a benign posttreatment course. Radioactive iodine therapy of functioning metastatic thyroid carcinoma should be administered with caution and only after adequate preparation of the elderly patient with cardiovascular disease.

Pregnancy in lymphocytic hypophysitis: case report and review.

Lymphocytic hypophysitis has reported in 22 cases, all but one in women. More than 80% of the cases in women occurred during pregnancy or in the postpartum period. We describe a girl with partial hypopituitarism secondary to lymphocytic hypophysitis who, five years after the diagnosis, successfully delivered a healthy infant at term. Of the previously reported cases, most patients remain amenorrheic after the diagnosis. From the present case report and review of the literature, it would appear that a diagnosis of lymphocytic hypophysitis does not necessarily preclude the patient's ability to conceive and successfully carry the pregnancy. Pituitary hormone deficiency in this disease, therefore, does not always include the gonadotropins.

Use of psychoactive substances in three medical specialties: anaesthesia, medicine and surgery.

In order to determine the prevalence of psychoactive substance use in three specialty groupings, 1,624 questionnaires were sent to physicians in medicine, surgery and anaesthesia; all had trained at the same academic institution. A response rate of 57.8% was achieved. Comparison of prevalence of impairment rates showed no differences between Surgery (14.4%), Medicine (19.9%) and Anaesthesia (16.8%). Substance abuse was clearly associated with a family history of abuse; 32.1% of the abusers had a family history of such abuse compared with 11.7% of the non-abusers. Increased stress at various career stages did not appear to increase substance abuse; problem areas during medical life times were similar for each specialty. Substances most frequently used were marijuana (54.7%), amphetamines (32.9%); and benzodiazepines (25.1%). Seventy-three used psychoactive drugs which were non-prescribed. Drug counselling programmes were judged inadequate by most. Use of alcohol and drugs by faculty members was reported by a number of respondents.

Ketoconazole reduces elevated serum levels of 1,25-dihydroxyvitamin D in hypercalcemic sarcoidosis.

The antifungal drug ketoconazole, a cytochrome P450 inhibitor, has been shown to inhibit renal 1,25-dihydroxyvitamin D production in vitro and to lower serum 1,25-dihydroxyvitamin D levels in normal subjects and in patients with primary hyperparathyroidism. To assess the usefulness of this drug in the hypercalcemia of sarcoidosis, a condition thought to result from overproduction of 1,25-dihydroxyvitamin D by sarcoid-involved tissues, two men with sarcoidosis, hypercalcemia, and elevated serum levels of 1,25-dihydroxy-vitamin D were given ketoconazole, 600-800 mg per day, for four to six days. Serum 1,25-dihydroxyvitamin D levels were markedly reduced (by approximately 40%) in both patients during ketoconazole administration, but serum calcium was not affected. In both patients, renal function deteriorated during ketoconazole treatment. We conclude that ketoconazole administration can lower the elevated serum 1,25-dihydroxyvitamin D levels in sarcoidosis. However, deterioration of renal function during ketoconazole administration as well as failure of hypercalcemia to be affected during short-term ketoconazole treatment suggest that this drug might not be appropriate for acute treatment of hypercalcemic sarcoidosis.