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Biomedical subjects

A Gunn

Publications and source records attributed to A Gunn.

At least 91 records · Page 5Linked to original sources
PubMed1980

Propranolol dosage in thyrotoxicosis.

Eighteen thyrotoxic patients receiving chronic treatment with propranolol (160 mg/day) were studied to determine the relationship between plasma propranolol concentration and drug effect. There was a considerable interindividual variability in both the plasma propranolol steady state concentration and the degree of beta-adrenergic blockade. The plasma propranolol steady state concentration correlated significantly with both beta-adrenergic blockage and weight change but not with the degree of subjective improvement. In a group of 40 patients, including 10 severely thyrotoxic patients, who had the dosage of propranolol titrated objectively preoperatively to bring about a greater than 25% reduction in exercise heart rate at the end of a dosage interval, no case of thyroid storm was encountered. Many patients, the younger and severely thyrotoxic in particular, require doses in excess of 160 mg/day to achieve this degree of beta-adrenergic blockade.

Adolescent↗
PubMed1979

Short-term triiodothyronine in prevention of temporary hypothyroidism after subtotal thyroidectomy for Graves' disease.

To determine whether short-term thyroid hormone replacement prevents or merely delays temporary hypothyroidism after surgery for Graves' disease, serum T3, thyroid-stimulating hormone, and T4 were measured every 2 months for 18 months in two groups of Graves' disease patients who had had subtotal thyroidectomy. Group I (18 patients) were given T3 20 microgram four times daily from surgery through the twelfth postoperative month. Group II (18 patients) received no treatment. Hypothyroidism occurred at some time during the 18-month period in 10 group-II patients, but was temporary in 7. Temporary hypothyroidism did not occur in group-I patients, whose mean T4 level rose to that in group II within 2 months of T3 withdrawal. Short-term T3 replacement after surgery for Graves' disease thus prevents (and does not simply delay) temporary postoperative hypothyroidism without increasing the frequency of permanent hypothyroidism.

Adult↗
PubMed1979

The behaviour of the thyroidal iodide trap after subtotal thyroidectomy for thyrotoxicosis and its implication for the T3-suppression test.

It is important to distinguish between symptomatic response and immunological cure in thyrotoxicosis because it has been suggested that surgery, in addition to providing a rapid symptomatic response, may also cause the disappearance of thyroid-stimulating antibodies. The evidence, however, is based largely on suppression tests which we argue may not be valid in the post-operative period. Seventy thyrotoxicosis patients were treated for 6 months with a standard course of carbimazole and T3, at the end of which each patient was classified as suppressor (S) or non-suppressor (NS) according to the fall in radioiodine uptake. Group I (18 patients) and group II (18 patients) were then randomly selected for immediate surgery while group III (34 patients) continued on antithyroid drugs. All groups were reviewed every two months from the 6th month for 12 months, during which time group I was drug-free and groups II and III received T3. Twenty-min iodide uptakes were performed in all patients at each visit to compare the serial changes in mean iodide trapping capacity between treatment groups. Despite 10-fold differences in TSH levels between groups I and II, and irrespective of suppressibility before surgery, the mean uptakes in both these groups remained basal (less than 4%) throughout the period of study, while the serial mean uptakes in group III S (no TSH, by implication no TSAB, but intact iodide trap) were consistently higher than those of group I NS (high TSH, by implication TSAB as well, but reduced iodide trap size). The data points to an absence of dose-responsiveness between TSH and the surgical-remnant's iodide trap, implying that post-thyroidectomy suppression tests (at least during the first year) cannot measure changes in iodide trapping, and therefore do not measure the same phenomenon after subtotal thyroidectomy as they do before operation when the thyroid is intact. We therefore question the validity of comparing suppressibility before and after surgery and basing the frequency of surgical cure on the result.

Adult↗