Search

In a large, mainly outpatient, series of hyperthyroid patients who attended a district general hospital the serum concentrations of calcium and albumin were measured before and in many cases after treatment. The calcium level (mean +/- SD) before treatment (2.41 +/- 0.21 mmol/l, n = 437) was significantly higher (P less than 0.01) than afterwards (2.36 +/- 0.15 mmol/l, n = 232) and the albumin level rose when the patients became euthyroid (from 40.5 +/- 3.1 g/l to 44.0 +/- 2.4 g/l; P less than 0.01). After treatment neither value differed from those of an unselected group of out-patients. The usual relation between the serum concentrations of calcium and albumin did not hold in the hyperthyroid subjects but reverted to normal on treatment; the variation, probably due to an increase in ionized calcium, leads to an overestimate of the 'corrected calcium' when conventional methods are used to calculate this figure. Thus, using a conventional formula 8.5% of our hyperthyroid patients would appear to have a calcium greater than 2.65 mmol/l (normal mean plus 2 standard deviations) whereas using a correction factor specific for the hyperthyroid situation the figure is reduced to 5.7% which is only twice the expected proportion. The calcium level was significantly greater (P less than 0.001) in those patients in whom initial T3 concentration was high (greater than 7.2 nmol/l). There was no effect of T4 upon serum calcium which could not be accounted for by the action of T3. In this series of 437 patients there was no case of symptomatic hypercalcaemia. The maximum value was 2.80 mmol/l in a patient with coincident primary hyperparathyroidism. Significant hypercalcaemia is rare in hyperthyroidism.

A retrospective analysis of 594 unselected cases of hyperthyroidism from one district was made to determine whether the thyroid gland had been palpable on presentation. The thyroid had been diffusely palpable in 374 patients (63%), nodular in 110 (19%) and impalpable in 96 (16%); there was no clinical record in 14 (2%) cases. Under 40 years of age a diffuse gland was usual, being present in 86% of cases. The proportion of nodular and impalpable glands both increased progressively with age comprising 30% and 48% respectively in patients older than 70 years. Grave's ophthalmopathy was present in 13% of hyperthyroid patients with diffuse glands, in 12% of those with impalpable glands, but in only 1.5% of those with nodular thyroids. Thyroid autoantibodies were found with a similar frequency in all three groups. There was a very good correspondence between clinical assessment of shape and nodularity of thyroid and the results of isotope scanning; the majority of patients with impalpable glands (86%) had a diffuse uptake of isotope. In the elderly hyperthyroid patient an impalpable thyroid gland is common and is not a factor to weight against the diagnosis.

Two female patients with functioning adrenocortical carcinomas had plasma ACTH detectable by RIA at presentation. In both patients there was evidence for biological activity of ACTH. There was no evidence for an ectopic source of ACTH, nor for a pituitary tumour. Urinary steroid analysis showed patterns of multiple hormone secretion characteristic of adrenocortical carcinomas. The finding of detectable ACTH concentrations in a patient with Cushing's syndrome does not exclude the presence of an adrenocortical tumour.