Lingual thyroid and hypothyroidism. Report of a case in a middle aged woman.

There are approximately 400 reported cases of lingual thyroid (LT) with a clear cut prevalence in paediatric age. These glands are probably quantitatively deficient and function at marginal levels. Thyro-stimulating hormone (TSH) causes hypertrophy producing local symptoms and in younger patients may induce dangerous obstruction. The presumptive diagnosis is usually made by indirect laryngoscopy and thyroscintigraphy. The authors describe a case of LT in a middle aged patient in whom the anomaly remained undiscovered, being without local symptoms, and permitting a normal life. The discovery was made possible by the development in the last four years of a progressive, frank hypothyroidism, probably induced by silent thyroiditis into the ectopic gland.

[Primary empty sella syndrome. Report of 6 cases]. / La sindrome della sella vuota (empty sella sindrome) primitiva. Considerazioni a proposito di sei casi.

The extension of the suprasellar subarachnoid space through an incompetent diaphragma sellae into the sella turcica is defined as empty sella syndrome (ESS). The primary form arises in the absence of previous pituitary surgery or irradiation. Predominance of obese, middle aged, often multiparous women are generally observed; clinically headaches and slight endocrine alterations are frequent but not characteristic symptoms. Rarely liquor rhinorrhea or visual campimetric defects may occur. The authors report six cases observed in their Departments of Internal Medicine during the last two years; they discuss the aspecific symptoms of presentation and the associated pathologic conditions. Standard skull X rays were negative in half the cases showing the overall poor sensitivity of this examination in detecting ESS. According to the literature no evident abnormality of hypophyseal basal hormone levels was found. Diagnosis was done by high resolution TC or MR which now must be preferred to pneumoencephalography (PEG). Three patients had peculiar pathologic conditions associated with ESS: a very high suspicion of partial insipidus diabetes was made in a man with hypo-osmolar polyuria; one patient without related humoral symptoms had a duodenal carcinoid endoscopically removed and in another primary ESS was associated with Hashimoto thyroiditis. These last two pathologies were never related before associated to primary ESS. The authors conclude that primary ESS is most often a diagnosis made by serendipity, lacking specific signs and or symptoms, whenever an imaging technique (TC or MR) is employed for detecting an unrelated endocranic pathology or the content of an enlarged sella turcica.

Assays of TSH-receptor antibodies in 576 patients with various thyroid disorders: their incidence, significance and clinical usefulness.

UNLABELLED: The incidence and the significance of TSH-receptor antibodies in Graves' disease and in various thyroid disorders have been evaluated. TSH-binding inhibiting antibodies (TBIAb) and thyroid stimulating antibodies (TSAb) were detected in a large proportion of Graves' disease patients (TBIAb in 68.8% and TSAb in 77.8%), in a small number of patients with idiopathic myxoedema or Hashimoto's thyroiditis, and were not detected in patients with endemic euthyroid goitre, differentiated thyroid carcinoma and toxic adenoma. Furthermore, TSH-receptor antibodies were present in some patients with toxic multinodular goitre (TBIAb in 12.7% and TSAb in 15.9%). When TSH-receptor and other thyroid autoantibodies were compared, it was found that 13 of the 15 Graves' patients with negative tests for thyroglobulin and thyroid microsomal antibodies were positive for TSH-receptor antibodies. On the other hand, 9 of the 11 patients with toxic multinodular goitre who had positive TSH-receptor antibody tests, also had serum thyroglobulin and/or thyroid microsomal antibodies. No significant differences in the prevalence of TSH-receptor antibodies were found in Graves' patients irrespective of the presence of ophthalmopathy or pretibial myxoedema. Elevated TBIAb activity at the end of anti-thyroid drug treatment was found in 52.9% of Graves' patients who subsequently relapsed, while in Graves' patients in remission TBIAb was always negative. TSH-receptor antibody results were not predictive of the outcome of radioiodine treatment in Graves' disease. Finally no correlation could be found between TBIAb and TSAb in Graves' disease and Hashimoto's thyroiditis. IN CONCLUSION: the high incidence of TSH-receptor antibodies in Graves' disease confirms their pathogenetic role in the development of hyperthyroidism; TSH-receptor antibodies in Graves' disease are not significantly associated with the presence of ophthalmopathy or pretibial myxoedema; TSH-receptor antibody assays may be useful for the diagnosis of Graves' disease in the absence of other signs of autoimmunity. TBIAb seems to be a good predictor of relapse in Graves' patients treated with anti-thyroid drugs; a fraction of toxic multinodular goitre could be a nodular variant of Graves' disease.

Demonstration of blocking immunoglobulins G, having a heterogeneous behaviour, in sera of patients with Graves' disease: possible coexistence of different autoantibodies directed to the TSH receptor.

Previous studies by us and others have shown that Graves' immunoglobulins G (IgGs) behaved as agonists or even antagonists of TSH. In this paper we have looked for the existence of IgG preparations without any thyroid stimulatory activity but able to significantly block the action of TSH in 128 hyperthyroid Graves' patients. The presence of TSH-binding inhibiting antibodies (TBIAb) and that of thyroid stimulating antibodies (TSAb) was evaluated by a radioreceptor assay using solubilized thyroid plasma membranes and by assaying the adenylate cyclase (AC) function of thyroid plasma membranes, respectively. Seventeen IgGs were negative for TSAb but positive for TBIAb in the screening, using only one concentration of IgG. Three kinds of activity were investigated in these IgGs at different doses: (1) TSH-binding inhibiting activity; (2) thyroid AC stimulating activity; and (3) the inhibition of TSH-induced AC stimulation. The results showed that the level of activity was not always dose-dependent. A significant (greater than 20%) inhibition of the TSH-dependent AC stimulation was present in 15 of the 17 IgGs examined: this inhibition was more elevated at lower than at higher doses in two preparations. No significant correlation was found between the three activities. In short, we have been able to demonstrate the existence of 'blocking' antibodies, apparently without any stimulatory activity, in some patients with Graves' disease. The diphasic pattern of the dose-response curves of some IgGs and the lack of correlation between the different activities can be explained by the co-existence in the sera of Graves' patients of different autoantibodies varying in concentration, binding affinity constant and intrinsic biological activity.

Can the inhibition of prostaglandin synthesis affect the adenylate cyclase response to thyroid stimulating antibodies?

The majority of Graves' immunoglobulins have the capacity to stimulate thyroid adenylate cyclase (AC) activity in vitro. So far, the exact events leading to AC activity stimulation by thyroid stimulating antibody (TSAb) are not known. It has been suggested that TSAb activates thyroid AC through prostaglandin (PG) synthesis, implying the concept that TSH and TSAb stimulate AC in different ways. If this is so, the inhibition of PG synthesis should notably reduce the response of thyroid plasma membrane to TSAb. We have, therefore, investigated the effect of 2 inhibitors of PG synthesis on the TSAb-stimulated AC activity in a crude human thyroid plasma membrane preparation. Neither indomethacin, nor hydrocortisone, even at concentrations able to completely inhibit PG synthesis, had any significant effect on the thyroid plasma membrane response to TSAb. The results suggest, therefore, that, at least under our experimental conditions, PG does not mediate the AC activation by TSAb. Consequently, the aforementioned suggestion should not be used to claim that TSH and TSAb activate thyroid AC through different pathways. The data, however, do not exclude that TSAb may determine PG synthesis in thyroid cells through the phosphatidylinositol signal system (Pl system).