Sotalol in hyperthyroidism

Ten hyperthyroid patients were studied before and after 2 weeks' beta-adrenoceptor blockade with sotalol. The following variables were measured: resting pulse rate, blood pressure, weight, thyroid hormone levels, plasma lipids, alkaline phosphatase, plasma glucose and insulin responses to oral glucose, bromsulphthalein retention and the 24-h urinary excretion of calcium, hydroxyproline, creatine and creatinine. Sotalol produced a significant fall in pulse and blood pressure. Weight loss continued during treatment. No metabolic changes of any consequence were found. It is concluded that sotalol should not be used as the sole treatment of a patient with hyperthyroidism.     

Neonatal hyperthyroidism caused by TSH receptor antibodies in maternal autoimmune hyperthyroidism

Between July 1993 and December 1994 five term infants of mothers with Graves' disease were hospitalised at the Frühgeburtenstation of the Univ.-Frauenklinik Graz. Four Mothers had elevated TSH-receptor-antibody (TRAb)--levels during pregnancy, one had normalised TRAb-titers. In one case hyperthyroidism was first diagnosed during pregnancy. Three newborns had elevated TRAb-titers; in one of them thyrotoxicosis was diagnosed clinically and biochemically at the second day of life, one newborn had mild hyperthyroidism with tachycardia at the end of the first week of life and one newborn was asymptomatic by immediately initiated therapy. The two other newborns had normal thyroid hormone and antibody levels and no symptoms or signs of hyperthyroidism. The cases are reported and discussed in detail and our overall approach to diagnosis and treatment of neonatal hyperthyroidism in case of maternal Graves' disease will be given.     

Central hyperthyroidism

Central hyperthyroidism is a rare condition in which thyrotoxicosis results from primary overproduction of TSH by the pituitary gland with subsequent thyroid enlargement and hyperfunction. The two known causes of central hyperthyroidism are TSH-producing pituitary tumors (TSHomas) and the syndrome of PRTH. Both of these entities are characterized by clinical thyrotoxicosis, diffuse goiters, elevated circulating levels of free T4 and T3, and a nonsuppressed serum TSH. It is critical to distinguish central hyperthyroidism from the much more common types of primary hyperthyroidism, all of which have undetectable TSH values. TSHomas and PRTH can usually be differentiated from one another by measuring the serum alpha-subunit and the TSH response to intravenous TRH or exogenous thyroid hormone, and by pituitary imaging studies. TSHomas are usually benign adenomas arising from the monoclonal expansion of neoplastic thyrotropes. Causative oncogenes have not yet been convincingly identified. PRTH is a nonneoplastic disorder caused by inherited mutations in the gene for the thyroid hormone receptor beta; it is a poorly understood variant of GRTH. For unclear reasons, in PRTH, the pituitary gland is resistant to the feedback inhibitory effects of circulating thyroid hormones while peripheral tissues respond normally, causing patients to experience the toxic peripheral effects of thyroid hormone excess. TSHomas are best treated by transphenoidal surgical removal. Radiotherapy is indicated for inoperable or incompletely resected tumors. Octreotide administration is a useful adjunct for preoperatively reducing tumor size and for the medical management of surgical treatment failures. PRTH is ideally treated by chronically suppressing TSH secretion with medications such as D-thyroxine, TRIAC, octreotide, or bromocriptine. If such therapy is ineffective or unavailable, thyroid ablation with radioiodine or surgery may be employed with subsequent close monitoring of both thyroid hormone status and pituitary gland size.     

Primary hyperthyroidism 1996

55 prospectively documented patients aged 20-84 (median 67) years (47 women, 8 males) underwent surgery for primary hyperparathyroidism (pHPT). The most frequent symptoms and associated conditions were nephrolithiasis (42%) and neuropsychiatric symptoms (39%). Only one case of asymptomatic and one case of "normocalcemic" pHPT were found in this series. 47 patients (89%) were cured following initial neck exploration, and 3 further patients (6%) were cured by a second operation. Reoperation also led to cure in 2 patients operated on elsewhere in the first instance. 6 patients (11%) had double adenoma (bilaterally) and 36% of the adenomas had an ectopic location, with an intrathyroidal adenoma in 2 cases. In 2 patients sternotomy was carried out. Persistent pHPT was observed in 3 patients (following initial exploration in 2 cases and reoperation in one). These patients had a supernumerary adenomatous gland with ectopic location in 2 cases and a double adenoma with ectopic position of one adenoma in a further case. One 80-year-old patient died post-operatively from intestinal ischemia. 2 patients had permanent postoperative hypoparathyroidism; in no case was a permanent recurrent laryngeal nerve palsy observed. Bilateral parathyroid exploration with thyroid mobilization by capsular dissection is the procedure of choice for pHPT. In 2 patients with the MEN 2A-syndrome and with medullary thyroid carcinoma thyroidectomy, lymphadenectomy and autotransplantation of normal parathyroids to the arm was performed, with normal parathyroid function in both cases.     

Surgical treatment of hyperthyroidism in children

During the past ten years, subtotal thyroidectomy for hyperthyroidism was performed upon 43 children at Childrens Hospital of Los Angeles. There were no deaths, no recurrent laryngeal nerve injuries and no permanent hypoparathyroidism. During the one to ten year follow-up period, one patient had recurrent hyperthyroidism develop and was treated with 131I. Twenty-five patients are hypothyroid and require thyroid supplement; 14 are euthyroid and receiv no medication. Postoperative thyroid function did not correlate well with gland remnant size, degree of fibrosis or the extent of lymphoid follicle formation. Lymphocytic infiltration was more severe in patients who had hypothyroidism develop postoperatively. Transient hypocalcemia developed in 22 patients. The effectiveness and safety of the surgical treatment for hyperthyroidism in children is reaffirmed, and it is advocated for consideration over 131I or prolonged medical therapy.     

Secretion of growth hormone in hyperthyroidism

The authors studied growth hormone (GH) secretion in a group of adult controls and another group of hyperthyroid patients after stimulation with intravenous insulin-induced (0,1 IU/kg) hypoglycemia, aiming to clear out the problem of discrepancies in literature concerning GH secretion in hyperthyroidism. They concluded that in this syndrome, GH levels are significantly higher than those of controls. The GH releasing response is normal, though it could be expected to be decreased due to decreased pituitary GH contents as a result of permanent somatotrophic cell stimulation.     

Elevated plasma adrenomedullin level in hyperthyroidism

Adrenomedullin is a recently discovered peptide that was first purified from phaeochromocytoma tissue and has marked vasodilatory activity, causing hypotension. In thyrotoxicosis, various haemodynamic changes are observed, including an increase in cardiac output and heart rate with a concomitant decrease in peripheral vascular resistance. To evaluate the mechanism underlying these haemodynamic changes in thyrotoxicosis, we measured the plasma adrenomedullin concentration in thyrotoxic patients with Graves' disease. The plasma concentration of adrenomedullin was elevated in hyperthyroid patients (14.7 +/- 5.7 pmol L-1) compared with euthyroid control subjects (5.6 +/- 1.3 pmol L-1) (P < 0.001). The correlation between the plasma adrenomedullin concentration and serum free thyroid hormone levels was marginally significant. The mean blood pressure was relatively low in the face of an elevated plasma adrenomedullin level. Adrenomedullin may therefore be responsible for the vasodilatation observed in thyrotoxicosis.     

Recurrent hyperthyroidism after thyroidectomy

For 53 patients with toxic recurrent goiter (TRG), the interval between thyroidectomy and recurrent hyperthyroidism range from six months to 50 years (average, 12.4 +/- 11.9 years). Recurrent hyperthyroidism may occur in older patients for whom cardiac decompensation may be the initial manifestation. Reports on surgically treated hyperthyroid patients may underestimate the incidence of TRG unless follow-up is extended for many years.     

Study of calcium homeostasis in feline hyperthyroidism

Thirty cats with untreated hyperthyroidism were blood sampled and their calcium homeostatic mechanisms and renal function assessed. The results were compared with those obtained from 38 age-matched control cats. The hyperthyroid group of cats were found to have significantly lower blood ionised calcium and plasma creatinine concentrations and significantly higher plasma phosphate and parathyroid hormone concentrations. Hyperparathyroidism occurred in 77 per cent of hyperthyroid cats, with parathyroid hormone concentrations reaching up to 19 times the upper limit of the normal range. The aetiology, significance and reversibility of hyperparathyroidism in feline hyperthyroidism remains to be established but could have important implications for both bone strength and renal function.     

Hypothyroidism and hyperthyroidism in major depression revisited

BACKGROUND: The aim of our study was to evaluate the prevalence of thyroid abnormalities among depressed outpatients and to examine the response to treatment of those subjects with relatively low or high thyroid hormone levels. METHOD: Outpatients (N = 200) 18 to 65 years of age who met DSM-III-R criteria for major depression were screened for the presence of thyroid abnormalities using a number of thyroid indices. Of these patients, 166 were then treated openly with the antidepressant fluoxetine for 12 weeks. We assessed whether patients with relatively low or high thyroid hormone levels had a different response to treatment compared with other patients. The 17-item Hamilton Rating Scale for Depression (HAM-D-17) was administered during the study to assess changes in depressive symptoms. Thyroid function was assessed by measuring T3, T4, free T4 index (FT4I), T3 uptake (T3U), and serum thyroid-stimulating hormone (TSH) levels. RESULTS: No clinical cases of hyperthyroidism or hypothyroidism were detected. Of the patients examined, 5 (2.6%) had slightly elevated TSH levels (range, 4.7-8.2); none of these had T4 or FT4I levels below the normal range. Subnormal levels of T4 or FT4I were found in 1 subject (0.5%). T3 and T3U levels were below the normal range in a larger number of patients (7.6% and 15.0% respectively), but only 1 of these patients had elevated TSH levels. None of the patients had levels of TSH below the normal range, and only 3 subjects (1.5%) had T4 levels above the normal range. No relationship was found between response rate (assessed as either change in HAM-D-17 score or as remission of depressive symptoms with a HAM-D-17 score < or = 7 for 3 consecutive weeks) and each of the thyroid tests, even after adjusting for baseline severity of depression. CONCLUSION: In depressed outpatients, it appears that hypothyroidism and hyperthyroidism are extremely uncommon and that the presence of subtle thyroid function abnormalities does not have an impact on treatment outcome.     

Reduced cholinergic sinus node restraint in hyperthyroidism

The role of the cholinergic nervous system in the tachycardia of hyperthyroidism was investigated in this study of dogs made severely thyrotoxic by the administration of Na-L-thyroxine over a six to nine month period. Differences in heart rate between control and thyrotoxic unanesthetized dogs could be abolished by cumulative doses of intravenous atropine both before and after beta-adrenergic blockade with propranolol, and at submaximal as well as maximal heart rates. There were no differences in the heart rate response of control and thyrotoxic anesthetized dogs to vagal stimulation or to the selective injection of hypertonic saline or acetylcholine into the perfused sinus node artery. The results indicate that in addition to the direct effects of thyroid hormone on sinus node automaticity there is an abnormality in parasympathetic control of heart rate in hyperthyroidism. The data suggest that this abnormality is not due to a decreased responsiveness of the sinus node or an impaired release of the cholinergic neurotransmitter, but may reflect a reduction in cholinergic efferent activity in the thyrotoxic state.     

A phonomecanographic test of hyperthyroidism

Systolic intervals may be studied by phonomechanography. This provides data regarding the function of the left ventricle. In the absence of any problem of intraventricular conduction or valvular lesion, such information is particularly valuable. Thyroxine impregnation, whetHer active directly and/or by catecholamine hypersecretion, results in cardiac hyperkinesia which is reflected not only by tachycardia but also a shortening penetration time and contraction of the ventricular muscle. This shows itself within systole as a change in the relation between the duration of the pre-ejection phase (PPE) and the ejection phase. The first decreases whilst the second remains normal and their ratio changes, PPE/E changes from a normal value of 0.34 +/- 0.04 to 0.25 +/- 0.03. These tests are not only of value in diagnosis but also make it possible to observe the effects of treatment. It is certain that a true phonomechanographic syndrome of cardiac hyperkinesia may be described. The commonest, though not the only, aetiology is hyperthyroidism.     

Dose-response relationship in radioiodine therapy of hyperthyroidism]

The course of HOCM is characterized by a slow progression. Symptoms can often be influenced favourably by medical treatment. Altogether there is some difference between the course of untreated and the propranolol-treated patient groups which is, however, not statistically significant. Furthermore, the rate of sudden death is uninfluenced. Comparing clinical and haemodynamic results in medicically treated patients we find a reduction of the outflow tract obstruction in case with clinical improvement but not a reduction of the enddiastolic pressure. Independent on the clinical course there was a significant increase of the enddiastolic pressure after 5.5 years. We may conclude that there is a progredient process of hypertrophy which is uninfluenced by the obstruction and by conservative management. The best results are obtained in the operated group. According to our results a surgical intervention should possibly be considereed more generously.     

Risk of hyperthyroidism in examinations with contrast media

Nanoliter volumes of human tear fluid were collected by means of a capillary tube without inducing tearing and were analyzed for glucose content. The tear fluid was subjected to two enzymatic reactions to generate a fluorescent compound that is proportional to the concentration of glucose in the sample. CE with laser-induced fluorescence (LIF) detection was used to monitor the fluorescent species generated, hence glucose in the tear samples. The reproducibility of the method for six different preparations was < 9% relative standard deviation (RSD). The procedure was compared with the glucose dehydrogenase method for the determination of glucose in blood before using it to determine glucose in tear fluid. Blood and tear samples were collected from six healthy human subjects. The results showed that the higher glucose content in tear samples is consistent with the higher glucose content in blood samples. The glucose concentration of the tear samples analyzed ranged from 128 to 166 microM, and that of blood ranged from 3.3 to 4.3 mM.     

Subcorneal pustular dermatosis in a patient with hyperthyroidism

OBJECTIVES: Gastric carcinoma is the world's second most common cancer. Recent studies suggest an association between Helicobacter pylori and gastric carcinoma. The aim of this study was to address the effects of H. pylori infection on gastric antrum mucosal cell proliferation. METHODS: Forty patients undergoing upper endoscopy for standard indications were included in the study. A rapid urease test was used to determine the presence of H. pylori. Epithelial cell proliferation was determined by immunohistochemical techniques utilizing monoclonal antibody to bromodeoxyuridine. RESULTS: There were no significant differences in the number of labeled cells and in the proliferation fraction (p > 0.1) when patients with H. pylori were compared with those without, and when those over the age of 50 were compared to those under 50. The presence of ulcers similarly had no effect (p > 0.1). CONCLUSION: Helicobacter pylori infection does not increase gastric antrum mucosal cell proliferation.