[Rational diagnosis of endocrine forms of hypertension]

Primary aldosteronism, Cushing's syndrome and pheochromocytoma are the most frequent endocrine hypertensive disorders. Following biochemical confirmation of the clinical diagnosis, mainly non-invasive imaging techniques are necessary to determine the cause of the hormone excess. Diagnosis of primary aldosteronism is confirmed by analysis of aldosterone and renin in peripheral venous blood. Differentiation between adenoma and idiopathic adrenal hyperplasia usually is achieved by computed tomography and isotope scan. A reliable test for the biochemical confirmation of Cushing's syndrome is the determination of urine-free cortisol. In patients with equivocal results the dexamethasone suppression test is performed. Differential diagnosis between ACTH-dependent Cushing's syndrome (pituitary or ectopic) and primary adrenal disorders can be made by determination of plasma-ACTH and -cortisol. Non-invasive localization procedures include computed tomography of the abdomen, computed tomography or magnetic resonance imaging of the pituitary gland, sonography and isotope scan. Diagnosis of pheochromocytoma is based on elevated catecholamine levels in urine or plasma. The tumor is localized by ultrasound, computed tomography or isotope scan.