The effect of thyroid hormones on the renin-angiotensin-aldosterone system has not been fully resolved. Highly specific immunoassays for measurement of renin, aldosterone, free T4 (fT4), free T3 (fT3) and ultrasensitive TSH enables a direct and more accurate measurement of these hormones. We investigated the relationship between plasma renin, aldosterone and thyroid hormones in the basal state and after intravenous frusemide. This is a cross-sectional study involving 37 patients with thyrotoxicosis, 42 rendered euthyroid with normal fT4, fT3 and TSH levels, 17 with euthyroid levels of fT4 and fT3 but suppressed TSH, and 11 with hypothyroidism. Basal plasma renin was significantly higher in thyrotoxicosis (63.4 +/- 9.8 microU/ml, mean +/- SEM) compared to euthyroid (32.7 +/- 4.4 microU/ml) and hypothyroid (26.7 +/- 9.8 microU/ml). Basal plasma renin for euthyroid with suppressed TSH (41.0 +/- 7.4 microU/ml) was significantly higher than hypothyroid (p = 0.02). Basal plasma aldosterones were not significantly different except for suppressed TSH (157.7 +/- 13 pg/ml), which was higher than normal (109.9 +/- 10.4 pg/ml; p = 0.04). Following frusemide, plasma renin and aldosterone were significantly increased in all groups. Plasma renin was highly correlated to fT3 (r = 0.405, p < 0.001), total T3 (r = 0.359, p < 0.001), fT4 (r = 0.331, p < 0.001) and TSH (r = 0.300, p < 0.001) in the basal state, but less to total T4 (r = 0.248, p < 0.01). Plasma renin correlated poorly to serum aldosterone (r = 0.212, p < 0.03). This study clearly showed that regulation of renin was mainly influenced by fT3, and that aldosterone response to frusemide was blunted in thyrotoxicosis despite normal electrolytes.
A group of patients with solitary nodules of the thyroid were treated at the University of Malaya by surgery under local anaesthesia. This was done in order to expedite exploration of a potentially malignant condition. This group comprised 43 patients, and four cancers were found. The standard technique used was satisfactory from the viewpoint of both the patient and the surgeon. The pattern of this condition in a Malaysian population is documented, the technique used is described, and thyroidectomy under local aneaesthesia is discussed.
Lithium is an integral drug used in the management of acute mania, unipolar and bipolar depression, and prophylaxis of bipolar disorders. Thyroid abnormalities have been associated with treatment with lithium. Zinc is an essential trace element that plays a role in several biological activities. Therefore, the present study was aimed at investigating the potential role of zinc in the thyroid gland following lithium administration to explore the role of zinc under such conditions. To achieve this goal, male Wistar rats (150-195 g) were divided into four groups: Group 1 animals were fed standard pellet feed and tap water ad lib; Group 2 rats were fed lithium in the form of lithium carbonate through diet at a concentration of 1.1 g/kg body weight; Group 3 animals received zinc treatment in the form of zinc sulfate (ZnSO4·7H2O) at a dose level of 227 mg/L mixed with drinking water of the animals; and Group 4 animals were given lithium and zinc in a similar manner as was given to the animals belonging to groups 2 and 4 respectively. The role of zinc on thyroid functions in lithium-treated rats was studied after 2, 4, and 8 weeks of different treatments. Zinc has been observed to have the capability to nearly normalize the altered 2-h uptake of 131I, biological and effective half-lives of 131I, and circulating T4 levels that were altered after lithium treatment. The present study concludes that zinc may be an effective agent in normalizing the adverse effects caused by lithium on thyroid functions.
Background: The resultant dysphonia and aspiration in unilateral vocal cord palsy can be overcome with
medialisation thyroplasty. With this background, we aim to determine the aetiology of the unilateral vocal
cord palsy and effectiveness of the phonosurgical procedure with Gore-Tex as a sole treatment. Methods:
Within a seven year period, 37 Gore-Tex medialisation thyroplasty were performed for unilateral vocal cord
palsy at our institution and medical records were retrospectively reviewed. Results: There were 18
males and 19 females with mean age of 48.7 years (range 19–81 years). The predominant aetiology was
thyroidectomy (43.2%) with benign thyroid disease predominates (n=13) over thyroid malignancy (n=3). Voice
outcome was evaluated subjectively using visual analogue scoring system, results indicating that Gore-Tex
medialisation thyroplasty was effective in addressing dysphonia in 62.5% (n=15) patients. However it alone
cannot address aspiration seen in those with high vagal nerve lesion. Airway compromise occurred in two
cases postoperatively (5.4%) presenting as acute stridor. Conclusion: In unilateral vocal cord palsy, Gore-Tex
medialisation thyroplasty can effectively improve the resultant dysphonia and often accompanying aspiration
which would otherwise be disabling for the patients.