The treatment of low-renin (“primary”) hyperaldosteronism

Abstract

Sixty-four patients with low-renin (“primary”) hyperaldosteronism underwent adrenal surgery. A unilateral adrenocortical adenoma was found in 48; no tumor was identified in 14, the adrenal glands then usually showing hyperplasia of the zona glomerulosa. The adrenal lesion in two further patients was difficult to classify. There was a significant fall in systolic and diastolic blood pressure after operation in both the adenoma and hyperplasia groups, although the fall in diastolic pressure was significantly greater in the adenoma group. Blood pressure fell to an arbitrary normal level in 56 per cent of patients with adenoma and in 15 per cent of patients in the hyperplasia group. Ninety-five patients with primary hyperaldosteronism received spironolactone for a minimum period of four weeks. There was a significant fall in mean systolic and diastolic pressure during treatment in both the adenoma and hyperplasia groups. However, the fall in diastolic pressure was again significantly greater in the adenoma group. There was a significant positive correlation between the fall in blood pressure during spironolactone and following adrenal surgery. Eighteen patients also received amiloride preoperatively and again there was a significant fall in systolic and diastolic blood pressure, although levels were slightly higher than during spironolactone or after subsequent adrenal surgery. Nineteen patients received a two week course of dexamethasone, without effect on blood pressure or the electrolyte abnormalities. It is suggested that removal of the tumor-bearing gland is usually the treatment of choice for patients with an aldosterone producing adenoma, provided preoperative spironolactone has reduced blood pressure to normal or near normal. However, long-term spironolactone is an acceptable alternative. For patients in the hyperplasia group, long-term spironolactone is usually the treatment of choice. If this drug is not tolerated, amiloride may be substituted. If preoperative spironolactone does not produce a satisfactory hypotensive response, adrenal surgery is unlikely to do so and hypertension should be controlled with other conventional hypotensive drugs. All patients with primary hyperaldosteronism in whom an adrenocortical adenoma is not identified preoperatively should be screened for the rare glucocorticoid-remediable variant. Dexamethasone 1 to 2 mg. daily for two to four weeks will reverse the biochemical abnormalities and reduce blood pressure. When an adrenocortical carcinoma is suspected, prompt surgical excision is required.