Endocrine Abstracts

Primary aldosteronism is the most common secondary cause of hypertension. Less than 50% of patients with the disorder have a solitary aldosterone producing adenoma. In the most common presentation, patients present with bilateral hyper-secretion of aldosterone. The aetiology of this is uncertain. Studies within our own group have suggested that there is an underlying genetic predisposition to develop hypertension with a raised aldosterone to renin ratio (ARR) associated with variation in the gene encoding aldosterone synthase (CYP11B2). More recent studies have suggested that the development of aldosterone excess is a digenic phenomenon with variations in CYP11B2 and in the neighbouring gene (CYP11B1) that encodes 11ß-hydroxylase. The combination of polymorphisms, which are inherited as a single haplotype block in Caucasian subjects, leads to reduced efficiency of 11ß hydroxylation and excess of aldosterone production. We have proposed that, over a lifetime, this may predispose subjects to develop hypertension with relative aldosterone excess.

Regardless of the aetiology, identification of Primary Aldosteronism depends on detection using a simple screening procedure such as measurement of the ARR. Confirmation of diagnosis is had, thereafter, by appropriate sodium loading manoeuvres followed by lateralisation using imaging and adrenal vein sampling.

Therapeutic strategies, including laparoscopic adrenalectomy, and medical approaches using specific mineralocorticoid receptor antagonists will be discussed.