Endocrine Abstracts

A third of people over the age of 65 and half of those over 85 fall at least once a year. Aside from the human cost, the cost to the NHS is an estimated £2 billion/year and 4 million bed days (2014 figures). Hyponatraemia in the elderly is associated with falls, fractures, morbidity and mortality. Previous studies have demonstrated decreased activity of renin-angiotensin-aldosterone system with increasing age. More recent studies have suggested dysregulation of aldosterone secretion with advancing age, with high aldosterone levels as a potential cardiovascular disease risk factor. We investigated the status of the renin-angiotensin-aldosterone system in 20 elderly patients (7 males and 13 females) aged 66-92 (mean age 82) referred with hyponatraemia who had also experienced falls. All had supine and standing blood pressure measurement. Only 5 patients were receiving medications recognised to affect renin and aldosterone levels. The results suggested that dysregulated aldosterone secretion in the elderly can result in symptomatic hypoaldosteronism:

Plasma renin activity ranged between 0.1-8.6 nmol/l/h (mean 1.3) and aldosterone <50-289 pmol/l (mean 107). The postural drop in blood pressure provides a possible explanation of the association of hyponatraemia with falls. The suggestion is supported by the improvement of all abnormalities on treatment with fludrocortisone:

Our findings suggest an accelerated deterioration in the ability to secrete aldosterone in response to recognised stimuli (dysregulation) in extreme old age, with significant adverse consequences. The therapeutic effect of fludrocortisone provides an effective treatment for this difficult patient group.