[When should secondary hypertension be suspected?].

Secondary hypertension is diagnosed in 5 to 10% of hypertensive patients. The probability of secondary hypertension increases, if the screening is focused on patients in which even a combination of three medicaments fails to attain the therapeutic objective, i.e. the so-called treatment-resistant hypertensives. Exclusion of secondary hypertension is part of the analysis of treatment-resistant hypertension. The most common causes of secondary hypertension are renal diseases, renal artery stenosis and primary hyperaldosteronism.