REN and hematocrit: Around 15 endocrine disorders may initially present with HT.4 Amongst these, primary hyperaldosteronism is the most common cause and therefore should be considered in patients as an underlying cause of secondary HT.12 Primary hyperaldosteronism is excess production of aldosterone, independent of the renin–angiotensin system and may be caused by an adrenal adenoma, unilateral or bilateral adrenal hyperplasia or adrenocortical carcinoma.4