1/178. Familial occurrence of congenital hypothyroidism due to lingual thyroid gland.Two sisters who presented with midline neck masses proved to be biochemically hypothyroid. Thyroid scintigraphy supplemented with perchlorate discharge testing showed lingual thyroid glands and ruled out the expected autosomal recessive organification defect. The related literature is reviewed.- - - - - - - - - - ranking = 1keywords = gland (Clic here for more details about this article) |
2/178. A premature stopcodon in thyroglobulin messenger rna results in familial goiter and moderate hypothyroidism.Impaired thyroglobulin (Tg) synthesis is one of the putative causes for dyshormonogenesis of the thyroid gland. This type of hypothyroidism is characterized by intact iodide trapping, normal organification of iodide, and usually low serum Tg levels in relation to high TSH, and when untreated the patients develop goiter. In thyroid tissue from a 13-yr-old patient suspected of a thyroglobulin synthesis defect, the Tg mRNA was studied. The complete coding region of 8307 bp was directly sequenced and revealed a homozygous point mutation: a C886T transition in exon 7. Upon translation this mutation would result in a stopcodon at amino acid position 277, replacing the arginine residue. A Tg cDNA construct containing the mutation was expressed in rabbit reticulocyte lysate resulting in a truncated protein of 30 kDa. Expression in the presence of microsomal membranes resulted in a gel shift of this Tg molecule, indicating glycosylation ability. Two other siblings had a clinical presentation like the index patient, while their parents were unaffected. Additional restriction fragment length polymorphism analysis of the pedigree verified that the homozygous nonsense mutation cosegregated with the clinical phenotype. Clinically, hypothyroidism was not severe in the affected siblings because the truncated Tg glycoprotein was still capable of thyroid hormonogenesis.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
3/178. Thyroid hemiagenesis and elevated thyrotropin levels in a child with williams syndrome.A girl with williams syndrome (WS) presented with elevated thyrotropin (TSH) levels (7.0 microU/ml), normal free thyroid hormone concentrations, and absent antithyroid autoantibodies. Thyroid ultrasonography and scintigraphy showed hemiagenesis of the left lobe and no evidence of ectopic tissue. TSH response to thyrotropin-releasing hormone (TRH) injection (200 microg/mq, i.v.) was exaggerated and prolonged, suggesting subclinical hypothyroidism. The biological activity of circulating TSH was slightly below the normal range [TSH bioactivity (B) to immunoreactivity (I) ratio (TSH B/I) = 0.4, normal: 0.6-2.2]. These abnormalities are similar to those seen in patients with hypothalamic hypothyroidism. Thyroid function is not a recognized manifestation of WS and is not routinely investigated. However, abnormalities of the hypothalamic-pituitary-thyroid (HPT) axis and thyroid dysgenesis have been found in other WS cases. Genes mapping at 7q11.23, contiguous to the chromosomal region deleted in most WS patients, may be involved in the development of the thyroid gland, contributing to the complex phenotype of WS.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
4/178. Severe hypothyroidism in patients dependent on prolonged thyroxine infusion through a jejunostomy.BACKGROUND AND AIMS: Enteral absorption of thyroxine (T4) is variable; the duodenum and jejunum appear to be the most important sites of absorption. Our objective is to demonstrate that T4 infused via a standard jejunostomy may occasionally be poorly absorbed. methods: Two patients underwent esophagolaryngeal resection for carcinoma of the cervical esophagus. The procedure was accompanied by complete removal of the thyroid and parathyroid glands. A neck fistula at the gastropharyngeal anastomosis led to a restriction of oral intake; daily requirements of T4 and nutrients were given via the jejunostomy. T4 plasma levels deteriorated and thyroid-stimulating hormone (TSH) levels increased and in the third postoperative week, T4 (300 microg) was administered via a nasogastric tube. RESULTS: Although given a high dose (300 microg) of T4, both patients developed severe hypothyroidism. Infusion of T4 through the nasogastric tube precipitated the normalization of T4 and TSH plasma levels. Both patients (cases 1 and 2) resumed oral intake during the fifth and sixth postoperative weeks respectively. CONCLUSION: T4 malabsorption may occur in patients dependent on prolonged T4 infusion via a standard jejunostomy.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
5/178. congenital hypothyroidism with impaired thyroid response to thyrotropin (TSH) and absent circulating thyroglobulin: evidence for a new inactivating mutation of the TSH receptor gene.congenital hypothyroidism due to impaired thyroid response to TSH was originally described by Stanbury. A diagnosis of congenital hypothyroidism with thyroid unresponsiveness to TSH is accepted if the patient has congenital hypothyroidism, the thyroid gland is in the normal position in the neck, the size of the thyroid is either normal or atrophic, the serum TSH level is increased, the bioactivity of TSH is intact, and the response of the thyroid gland to TSH stimulation is decreased. In all originally described cases serum thyroglobulin was undetectable. We describe a 22-yr-old female patient who was severely hypothyroid and mentally retarded. serum T4 and T3 concentrations were below the sensitivity of the methods, with elevated serum TSH levels. serum thyroglobulin was undetectable. A normally shaped hypoplastic gland located in the appropriate anatomical position in the neck was found at scintiscan. The gland did not respond after administration of bovine TSH in terms of 131I uptake, serum thyroid hormones, and thyroglobulin secretion. A diagnosis of congenital hypothyroidism due to TSH unresponsiveness was formulated. Genetic analysis in the propositus showed a homozygous inactivating mutation of the TSH receptor that had not been previously described. The mutation consisted of the substitution of an isoleucine in place of a highly conserved threonine at position 477 in the first extracellular loop of the receptor (T477I). The brother, one sister of the father (whose dna was not available), the mother of the propositus, one sister, and the brother were heterozygous for T477I. All the heterozygous persons were unaffected. After transfection in COS-7 cells, the mutant receptor displayed an extremely low expression at cell surface. At variance with cells transfected with the wild-type TSH receptor, cells transfected with the mutant T477I did not show constitutive activity for the adenylyl cyclase pathway. A dramatic reduction in the amount of cAMP accumulation after bovine TSH challenge was observed in cells transfected with the mutant T477I receptor. A structural defect in the mutant TSH receptor protein was probably responsible for the poor routing of the receptor to the cell membrane. This is the first time that a loss of function mutation of the TSH receptor is described in a patient with severe congenital hypothyroidism and absent circulating thyroglobulin due to TSH unresponsiveness and the first time that an inactivating mutation of the TSH receptor is described in the first extracellular loop.- - - - - - - - - - ranking = 0.8keywords = gland (Clic here for more details about this article) |
6/178. Diabetic nephropathy accompanied by iodine-induced non-autoimmune primary hypothyroidism: two case reports.We reported 2 diabetic patients with nephrotic syndrome due to advanced diabetic nephropathy complicated by non-autoimmune primary hypothyroidism. Hypothyroidism developed along with the anasarcous status. Histological examinations of the thyroid gland revealed almost normal thyroid follicles without lymphocytic infiltration. The amounts of thyroid hormone lost into the extravascular space such as in urine and ascites were not sufficient to cause hypothyroidism alone. serum total iodine levels measured during the hypothyroidal state in both cases were definitely elevated, and the perchlorate discharge test of both cases showed positive discharge (24 and 34%, respectively). The thyroid functions normalized after iodine restriction in the first case and initiating hemodialysis in the second case, in parallel with normalization of serum total iodine levels. These findings suggest that impaired renal handling of iodine resulting in elevation of serum iodine levels, rather than an autoimmune mechanism or extravascular hormone loss, played a principal role in the development of primary hypothyroidism found in these 2 patients, probably through a prolonged Wolff-Chaikoff effect.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
7/178. Galactorrhoea and pituitary mass: a typical prolactinoma?A 21 year old woman presenting with galactorrhoea, hyperprolactinaemia, and a pituitary mass on magnetic resonance imaging (MRI) is described who was referred to us before planned pituitary surgery. Although a thorough history did not suggest hypothyroidism, laboratory studies revealed profound primary hypothyroidism. At that time, pituitary MRI showed homogeneous enlargement of the pituitary gland consistent with pituitary hyperplasia due to primary hypothyroidism. With thyroid hormone replacement therapy the galactorrhoea resolved, concentrations of prolactin and thyroid hormones returned to normal, and the pituitary shrunk to normal size within two months. This case illustrates that primary hypothyroidism can present only with galactorrhoea and pituitary mass, and should therefore be considered in the differential diagnosis of hyperprolactinaemia and pituitary enlargement.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
8/178. Primary hypothyroidism presenting as a pituitary mass.Pituitary enlargement secondary to primary hypothyroidism is a known but uncommon occurrence, which can be difficult to distinguish on computerized tomography (CT) and magnetic resonance imaging (MRI) from primary pituitary tumors. We describe a 33 year old female who was referred to a neurosurgeon for removal of a pituitary mass. The markedly elevated thyrotrophin stimulating hormone (TSH), absence of clinical features of hyperthyroidism, and low thyroid hormone values led to a diagnosis of pituitary enlargement secondary to primary hypothyroidism. The pituitary gland returned to normal size with thyroxine replacement therapy. Surgery was not indicated.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
9/178. Diagnosing and treating hypothyroidism.Hypothyroidism is a common endocrine disorder affecting 1.4% to 2.0% of women and 0.1% to 0.2% of men. The prevalence of both overt and subclinical hypothyroidism increases with age, affecting 5% to 10% of women over age 50 and 1.25% of men over age 60, with an increasing incidence in women ages 40 to 50. Typical symptoms are consistent with declining metabolic functions and range from vague complaints of fatigue in subclinical deficiency to overt clinical symptoms involving changes in mentation and memory, lethargy, weight gain, cold intolerance, constipation, and goitrous enlargement of the thyroid gland. Atypical presentations such as weight loss, hearing impairment, tinnitus, and carpal tunnel syndrome may occur, especially in the elderly. This case report reviews the presenting symptomatology of an otherwise healthy 43-year-old woman who exhibited typical and atypical symptoms of underlying thyroid deficiency.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
10/178. Combined pituitary hormone deficiency and pituitary hypoplasia due to a mutation of the Pit-1 gene.Several mutations of the pituitary-specific transcription factor pit-1 have been identified. We describe a girl with a mutation of the Pit-1 gene leading to a complete lack of GH, TSH and prolactin and a marked hypoplasia of the anterior pituitary gland. The patient had a homozygous nonsense-mutation at position 172 (CGA to TGA), converting arginine into a stop codon, leading to an early termination of protein translation. During the infancy period the girl had very conspicuous symptoms of hypothyroidism and the diagnosis of thyroid insufficiency preceded the diagnosis of GH-deficiency by 1.5 years. Treatment with thyroxine and GH resulted in excellent catch-up growth.- - - - - - - - - - ranking = 0.2keywords = gland (Clic here for more details about this article) |
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