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Biomedical subjects

H Gharib

Publications and source records attributed to H Gharib.

At least 73 records · Page 4Linked to original sources

Hyperthyroidism following hypothyroidism. Data on six cases.

Hypothyroidism complicated by spontaneous hyperthyroidism is an interesting but rare occurrence in the spectrum of autoimmune thyroid disorders. We report data on six patients who had hyperthyroidism two to 20 years (mean, eight years) after the diagnosis of hypothyroidism. In three patients, triiodothyronine toxicosis accounted for the hyperthyroid symptoms. The presence of thyroid antibodies and lymphocytic infiltration in the thyroid gland points to an autoimmune mechanism. It is believed that this phenomenon occurs more often than is recognized.

Adult↗

Suppressive therapy with levothyroxine for solitary thyroid nodules. A double-blind controlled clinical study.

Thyroid nodules are present in up to 50 percent of adults in the fifth decade of life. Patients are often treated with thyroxine in order to reduce the size of the nodule, but the efficacy of thyrotropin-suppressive therapy with thyroxine remains uncertain. In this study, 53 patients with a colloid solitary thyroid nodule confirmed by biopsy were randomly assigned in a double-blind manner to receive placebo (n = 25) or levothyroxine (n = 28) for six months. Before treatment, pertechnetate-99m thyroid scanning showed that 22 percent of the nodules were functional, 25 percent hypofunctional, and 53 percent nonfunctional. High-resolution (10-MHz) sonography was used to measure the size of the nodules before and after treatment. Suppression of thyrotropin release was confirmed in the levothyroxine-treated group by the administration of thyrotropin-releasing hormone; thyrotropin release was normal in the placebo group. Six months of therapy did not significantly decrease the diameter or volume of the nodules in the levothyroxine group as compared with the placebo group. We conclude that the efficacy of levothyroxine therapy in reducing the size of colloid thyroid nodules is not apparent within six months, despite effective suppression of thyrotropin.

Adult↗

Fine-needle aspiration. Usefulness for diagnosis and management of metastatic carcinoma to the thyroid.

The usefulness of fine-needle aspiration (FNA) for the diagnosis and management of metastatic carcinoma to the thyroid was determined by reviewing the records of 19 patients identified during a six-year period. Fine-needle aspiration was able to document metastatic cancer to the thyroid in 14 patients with, and five patients without a history of prior nonthyroidal cancer. Breast, kidney, and lung were the most frequent carcinomas metastatic to the thyroid. Age range and time from diagnosis of the primary carcinoma to documentation of metastasis were similar to those in prior surgical series from this institution. The finding of metastatic disease on FNA was totally unexpected in four patients. The possibility of metastasis was not mentioned before FNA in six patients with a known history of nonthyroidal cancer. Only six patients underwent a thyroid operation after FNA. Fine-needle aspiration was able to direct appropriate surgical or conservative management without adversely affecting survival among patients.

Biopsy, Needle↗

Primary idiopathic hypothalamic hypothyroidism. Report of four cases.

One man and three women with hypothalamic hypothyroidism are described; they had isolated thyrotropin-releasing hormone deficiency, otherwise normal pituitary function, and no identifiable central nervous system anatomic abnormality. Serum thyrotropin levels were low and thyrotropic response to thyrotropin-releasing hormone was uniformly present, consistent with a hypothalamic cause of hypothyroidism. In two patients, hypothyroidism was transient and spontaneously resolved; in one of them, it was recurrent. Because hypothalamic hypothyroidism is mild and potentially reversible, it is suggested that such patients have follow-up evaluation before therapy is initiated in order to avoid unnecessary treatment.

Adult↗

Determination of silica-purified plasma calcitonin for the detection and management of medullary thyroid carcinoma: comparison of two provocative tests.

Radioimmunoassays for human calcitonin in whole plasma are limited in sensitivity and specificity; basal values of calcitonin are often undetectable in normal plasma, and nonspecific increases are occasionally found in seemingly healthy persons. We avoided these problems by applying a silica-cartridge extraction-concentration technique for calcitonin assay, and the effectiveness of two calcitonin stimulation tests in healthy volunteers and patients with medullary thyroid carcinoma was compared. The radioimmunoassay was improved by using a new antiserum and a sequential incubation procedure that reduced the previously used sample-volume requirement and incubation period substantially. This method was used to measure mean basal plasma levels of calcitonin (+/-SD) in 45 normal men (8.2 +/- 5 pg/ml) and 47 normal women (4.8 +/- 4 pg/ml) (P less than 0.001). Calcium infusions (2 mg/kg over 5 minutes) in 18 normal men and 37 normal women yielded a significantly greater secretory response than did pentagastrin (0.5 micrograms/kg as a bolus). Among 12 patients with medullary thyroid carcinoma, pentagastrin seemed to be a better secretagogue than calcium (P less than 0.001). We recommend routine measurement of plasma silica-extractable calcitonin and pentagastrin injection as the provocative test of choice for the detection and management of medullary thyroid carcinoma. The short calcium-infusion test is a good alternative.

Adult↗

Medullary thyroid carcinoma: role of high-resolution US.

Medullary thyroid carcinoma accounts for 10% of thyroid malignancies. Accurate determination of the extent of disease is important because surgery is required for initial treatment and recurrence. High-resolution (10-MHz) ultrasonography (US) of the neck was used to study 15 patients with medullary thyroid carcinoma; nine of the 15 had undergone thyroidectomy but had biochemical evidence of tumor recurrence. Metastatic cervical lymph nodes were detected with US in all 12 patients who had metastatic nodes at surgery, although these nodes were palpable in only four. Punctate bright echogenic foci were seen within some of the nodes in nine of the 12 patients (75%). Similar bright echogenic foci were seen within the primary intrathyroid tumor in five of the six patients who had not yet undergone thyroidectomy (83%). Pathologically, these foci correlated with deposits of calcium surrounded by amyloid, which is characteristic of medullary thyroid carcinoma. US is useful for the detection of nonpalpable recurrence of cervical metastatic lymph nodes, and because it is noninvasive and relatively inexpensive, it should be the first imaging investigation performed after thyroidectomy.

Adult↗

Atrial natriuretic peptide in hypothyroidism.

The effect of hypothyroidism on circulating levels of atrial natriuretic peptide (ANP) was studied in 11 hypothyroid patients (aged 11-65 yr; mean, 31 yr) and 13 normal subjects (aged 28-39 yr; mean, 32 yr). Plasma ANP was 32 +/- 9 (+/- SD) pg/ml in normal subjects and 20 +/- 5 pg/ml in the hypothyroid patients (P less than 0.005). In 7 hypothyroid patients, plasma ANP levels were measured after 10-14 weeks of L-T4 therapy. ANP increased from 22 +/- 5 to 46 +/- 18 pg/ml (P less than 0.02), along with an increase in mean serum T4 from 0.6 +/- 0.5 to 8.1 +/- 2.5 micrograms/dl (P less than 0.001). Thus, hypothyroidism is characterized by decreased circulating levels of ANP which are reversed by L-T4 therapy.

Adolescent↗

Nonidentical expressions of multiple endocrine neoplasia, type I, in identical twins.

We studied 25-year-old HLA- and blood group-identical male twins who had multiple endocrine neoplasia, type I (MEN I). At the time of initial examination, one twin (case 1) had epigastric pain and diarrhea; he was cushingoid in appearance. Further evaluation revealed primary hyperparathyroidism, Zollinger-Ellison syndrome, Cushing's disease, and hyperprolactinemia. Immunostaining of a resected pituitary specimen demonstrated both prolactin and, to a lesser extent, growth hormone reactivity. The nontumorous adenohypophysis showed corticotropic hyperplasia. In contrast, the other twin (case 2) was asymptomatic. He had only primary hyperparathyroidism and hyperprolactinemia. An invasive pituitary adenoma was resected and showed similar proportions of cells with immunoreactive prolactin and those with growth hormone; no nontumorous gland was available for study. Apparently, factors other than heredity may play a role in the expression of MEN I.

Adenoma↗

Hashimoto's thyroiditis. An uncommon cause of painful thyroid unresponsive to corticosteroid therapy.

The records of eight patients with thyroid tenderness secondary to Hashimoto's thyroiditis were reviewed. The pathologic characteristics of thyroid tissue sections from these patients were compared with those from patients with nontender Hashimoto's thyroiditis, and no difference was identified. Laboratory features helpful in distinguishing tender Hashimoto's thyroiditis from subacute (de Quervain's) thyroiditis include normal erythrocyte sedimentation rate, significant 131I uptake, and significant antithyroid antibody titer. Diagnosis should be confirmed by fine-needle aspiration biopsy. Corticosteroid therapy was unsuccessful in treating these patients; L-thyroxine and aspirin were successful more often. Two patients required thyroidectomy to control pain.

Adrenal Cortex Hormones↗

Follicular carcinoma of the thyroid presenting with hematuria: a case report.

A 59-year-old woman presented with hematuria in which a subsequent workup showed follicular carcinoma of the thyroid metastatic to the urinary bladder. Soft tissue metastasis from such a carcinoma is seen most commonly in the lungs and occasionally in the liver and kidneys. This case illustrates that follicular carcinoma of the thyroid may have a variable presentation, including hematuria.

Adenocarcinoma↗

Use of 131I-MIBG scintigraphy in the evaluation of suspected pheochromocytoma.

Studies at the University of Michigan have shown that 131I-metaiodobenzylguanidine (131I-MIBG) is an effective agent for the diagnosis and localization of pheochromocytomas and paragangliomas. We conducted a study that confirmed and expanded that finding. From January 1983 to March 1984, 48 patients at our institution had 51 131I-MIBG scans during the workup of suspected sporadic or metastatic pheochromocytoma. Scintigrams were obtained after 500 microCI of 131I-MIBG had been administered intravenously. The final diagnosis (true-positive, false-negative, or false-positive result) was made at operation and pathologic examination. A true-negative diagnosis was confirmed by normal plasma and fractionated urinary levels of catecholamines and metabolites and, in most patients, computed tomography (CT). There were 20 true-positive studies (6 pheochromocytomas, 4 paragangliomas, and 10 metastatic or recurrent pheochromocytomas) and 24 true-negative studies. One patient with a suspected recurrent paraganglioma near the bladder had a false-positive 131I-MIBG scan (and also a false-positive (CT). Among six patients with false-negative scintigrams (three pheochromocytomas, one paraganglioma, and two metastatic lesions), one also had a false-negative CT. The overall sensitivity of 131I-MIBG scanning was 77%, specificity was 96%, and accuracy was 86%. This test is fairly sensitive in the workup of patients with known or suspected recurrent or metastatic pheochromocytoma. It may also be helpful in the evaluation of suspected sporadic pheochromocytoma when CT findings are normal.

3-Iodobenzylguanidine↗

Familial euthyroid hyperthyroxinemia secondary to pituitary and peripheral resistance to thyroid hormones.

Among 18 family members, representing four generations studied, a familial form of euthyroid hyperthyroxinemia was found in 6. The increased serum total thyroxine value in all hyperthyroxinemic subjects could not be explained by abnormalities in binding proteins. Five of the six patients had a goiter, and all had increased concentrations of triiodothyronine and free thyroxine without symptoms or signs of hyperthyroidism. Basal serum levels of thyroid-stimulating hormone (thyrotropin) were normal in all six; in the four who were tested, these levels responded normally to thyrotropin-releasing hormone (TRH). The normal suppression of basal and TRH-stimulated thyrotropin increase after administration of triiodothyronine did not occur. These patients seem to have resistance of peripheral and pituitary tissues to the actions of thyroid hormones. Family studies revealed that the disorder appeared as a new sporadic mutation and was consistent with an autosomal-dominant mode of inheritance. This disorder, an important example of euthyroid hyperthyroxinemia, should not be confused with Graves' disease.

Adolescent↗

Anaplastic carcinoma of the thyroid: a clinicopathologic study of 82 cases.

Anaplastic carcinoma of the thyroid accounts for about 10% to 15% of all thyroid carcinomas in the United States. Its lethality is evidenced by a 5-year survival rate of 3.6% and a median survival of 4 months. Rapid growth of a thyroid mass, frequently in a preexisting goiter, is the most common manifestation; the diagnosis should be considered and expeditiously pursued in all patients who present with this finding. Relatively favorable prognostic features seem to be unilateral tumors, a tumor diameter of less than 5 cm, no invasion of adjacent tissue, and absence of nodal involvement. For resectable lesions, thyroid lobectomy with wide margins of adjacent soft tissue on the side of the tumor seems to constitute a safe, appropriately aggressive surgical approach. Total thyroidectomy and radical neck dissection results in an increased complication rate and has no advantage over a more conservative approach. Radiotherapy, chemotherapy, immunotherapy, and combination radiotherapy and chemotherapy need further evaluation.

Adult↗

"Fish-eye sign" in scintigraphy of benign thyroid nodule.

An unusual scintigraphic appearance of a benign adenomatous nodule in the thyroid is described which showed a central core of functional tissue surrounded by a rim of nonfunctioning tissue and degenerative changes. The descriptive term "fish-eye sign" is proposed. The characterization of tissue by scintigraphy prior to fine needle aspiration may be helpful in its interpretation.

Adult↗

Pituitary thyrotropic adenoma associated with congenital hypothyroidism. Report of two cases.

Two patients with congenital hypothyroidism and thyroid-stimulating hormone-secreting pituitary adenomas are described. Both patients had a history of long-standing, inadequately treated hypothyroidism accompanied by markedly elevated levels of serum thyroid-stimulating hormone. Pituitary tissue, obtained at autopsy in the first patient and at surgery in the second, disclosed a thyrotropic adenoma. Immunocytochemical studies with anti-thyroid-stimulating hormone antisera showed both tumors to be strongly immunoreactive. Such thyrotropic adenomas of the pituitary gland are presumed to occur as the result of protracted pituitary stimulation secondary to long-standing thyroid deficiency.

Adenoma↗

Normal serum thyroxine values in patients with acute psychiatric illness.

The medical records of 278 consecutive patients with acute psychiatric illness admitted to a closed psychiatric unit after admission from the emergency room were reviewed. Serum thyroxine levels had been determined within 72 hours of admission in 106 patients (38 percent); in 74 of these patients (70 percent), the determination had been made within 24 hours. Ten patients (9 percent) were hypothyroxinemic, but further thyroid testing revealed that they were functionally euthyroid. Only one patient had hyperthyroxinemia, which was considered secondary to her postpartum state. The prevalence of hypothyroxinemia in the population studied is consistent with that in previous reports. However, the striking absence of hyperthyroxinemia in these patients is contrary to findings in several recent reports. Further prospective studies should clarify this issue.

Adolescent↗