1,721,381 research outputs found
Central hypothyroidism : pathogenic, diagnostic, and therapeutic challenges
No full textContext: Central hypothyroidism (CH) is a particular hypothyroid condition due to an insufficient stimulation by TSH of an otherwise normal thyroid gland. This condition raises several challenges for clinicians; therefore, a review of the most relevant findings on CH epidemiology, pathogenesis, and clinical management has been performed. Methodology: The relevant papers were selected by a PubMed search using appropriate key words. Main Findings: CH can be the consequence of various disorders affecting either the pituitary gland or the hypothalamus, but
most frequently affecting both of them. CH is about 1000-fold rarer than primary hypothyroidism. Except for the neonatal CH due to biallelic TSHβ mutations, the thyroid hormone defect is rarely as profound as can be observed in some primary forms. In contrast with primary hypothyroidism, CH is most frequently characterized by low/normal TSH levels, and adequate thyroid hormone replacement is associated with the suppression of residual TSH secretion. Thus, CH often
represents a clinical challenge because physicians cannot rely on the systematic use of the "reflex TSH strategy." The clinical management of CH is further complicated by the frequent combination with other pituitary deficiencies and their substitution
Elastographic techniques of thyroid gland : current status
No full textThyroid nodules are very common with malignancies accounting for about 5 %. Fine-needle biopsy is the most accurate test for thyroid cancer diagnosis. Elastography, a new technology directly evaluating the elastic property of the tissue, has been recently added to the diagnostic armamentarium of the endocrinologists as noninvasive predictor of thyroid malignancy. In this paper, we critically reviewed characteristics and applications of elastographic methods in thyroid gland. Elastographic techniques can be classified on the basis of the following: source-of-tissue compression (free-hand, carotid vibration, ultrasound pulses), processing time (real-time, off-line), stiffness expression (qualitative, semi-quantitative, or quantitative). Acoustic radiation force impulse and aixplorer shear wave are the newest and most promising quantitative elastographic methods. Primary application of elastography is the detection of nodular lesions suspicious for malignancy. Published data show a high sensitivity and negative predictive value of the technique. Insufficient data are available on the possible application of elastography in the differential diagnosis of indeterminate lesions and in thyroiditis. Elastography represents a noninvasive tool able to increase the performance of ultrasound in the selection of thyroid nodules at higher risk of malignancy. Some technical improvements and definition of more robust quantitative diagnostic criteria are required for assigning a definite role in the management of thyroid nodules and thyroiditis to elastography
Elastographic presentation of synchronous renal cell carcinoma metastasis to the thyroid gland
No full textSynchronous metastasis of renal cell carcinoma (RCC) are extremely uncommon with only few sporadic cases published in the literature and data on their elastographic appearance are lacking. Here we described a case of woman with multinodular goiter bearing a RCC metastasis, in which exhaustive ultrasonographic and qualitative elastographic evaluation were performed. The metastatic lesion presented some suspicious ultrasonographic features but was mainly "soft" at qualitative elastographic evaluation, suggesting that RCC metastasis may represent a possible pitfall for the qualitative elastographic evaluation of thyroid nodules
Medical management of thyrotropin-secreting pituitary adenomas
No full textThyrotropin-secreting pituitary tumors (TSH-omas) are a rare cause of hyperthyroidism and account for less than 1% of all pituitary adenomas. It is however noteworthy that the number of reported cases tripled in the last years as a consequence of the routine use of ultrasensitive immunometric assays for measuring TSH levels. Contrary to previous RIAs, ultrasensitive TSH assays allow a clear distinction between patients with suppressed and those with non-suppressed circulating TSH concentrations, i.e. between patients with primary hyperthyroidism (Graves' disease or toxic nodular goiter) and those with central hyperthyroidism (TSH-oma or pituitary resistance to thyroid hormone action). Failure to recognize the presence of a TSH-oma may result in dramatic consequences, such as improper thyroid ablation that may cause the pituitary tumor volume to further expand. The medical treatment of TSH-omas mainly rests on the administration of somatostatin analogs, such as octreotide and lanreotide. In fact, administration of dopamine agonists failed to persistently block TSH secretion in almost all patients and caused tumor shrinkage only in those with combined hypersecretion of TSH and PRL. On the contrary, somatostatin analogs were effective in reducing TSH and α-subunit secretion in more than 90% of cases with consequent normalization, of FT4 and FT3 levels and restoration of the euthyroid state in the majority of them. In about one third of patients, a clear shrinkage of tumor mass and vision improvement could be demonstrated. Tachyphylaxis, cholelithiasis and carbohydrate intolerance occurred in a minority of treated patients. Whether somatostatin analog treatment may be an alternative to surgery and/or irradiation in patients with TSH-oma remains to be established. Nonetheless, the long-acting somatostatin preparations represent a useful tool for long-term treatment of such a rare pituitary tumors
Thyrotropinomas
No full textThyrotropinomas are easily recognized, owing to the availability of ultrasensitive thyropin immunometric assays. These methods allow a clear distinction between patients who have suppressed and those who have nonsuppressed circulating thyrotropin concentrations. In the latter, it is mandatory to perform a differential diagnosis, as the management of the two disorders is completely different, and failure to recognize the presence of a thyrotropinoma may result in dramatic consequences. Adenomectomy is the firstline treatment of thyrotropinomas, followed by irradiation in the case of surgical failure. Medical treatment with somatostatin analogs is effective in reducing thyrotropin secretion in more than 90% of cases
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