Primary hyperaldosteronism was first described by Conn in 1955 and is commonly called Conn's syndrome. The syndrome results from an abnormally large amount of aldosterone being produced from the adrenal cortex. The excess production of aldosterone will result in the retention of sodium, and hence increase water retention. The main clinical finding in Conn's is hypertension (high blood pressure).
Secondary hyperaldosteronism occurs when abnormally large amounts of aldosterone are produced by the adrenals due to increased renin activity (e.g. in pregnancy or chronic heart failure).
Primary hyperaldosteronism occurs in 1% of people diagnosed with hypertension (high blood pressure). It is more common in men than women by a ratio of 2:1 and its incidence is highest in persons between the ages of 30 and 50 years.