Any hypertension with hypokaliemia or resistant to the therapeutic requires the investigation of a primary hyperaldosteronism. The first step is to eliminate the absorption of liquorice, alkaline compounds or diuretics. The next step is to verify that the therapeutics are compatible with hormonal measurements and that urinary sodium and potassium are normal. The diagnosis is confirmed by the elevation of plasma or urinary aldosterone and a low renin concentration. Conn adenoma is present in 2/3 of the cases and is treated by surgery, whereas bilateral adrenal hyperplasies require distal diuretics. The 2 aetiological forms are distinguished by CT scan and dynamic hormonal measurements.