[Premedication in pheochromocytoma]

Abstract

Pheochromocytomas are active, catecholamine-producing tumours derived from chromaffine tissue, causing arterial hypertension. The therapeutical aim is the surgical removal of the tumour. Blockade of the alpha-adrenergic receptors during the preoperative phase is necessary to prevent cardiovascular complications. Phenoxybenzamine is the commonly used alpha-adrenergic blocking agent. Therapy begins with low doses and is increased stepwise up to 250 mg daily. The optimal duration of preoperative therapy is 10 to 14 days. Efficiency of therapy should be judged by reduction of symptoms, a stabilisation of arterial blood pressure, and the presence of light orthostatic hypotension. Swelling of nasal mucosa indicates a successful blockade of the alpha-adrenergic receptors. Persistent tachyarrhythmia is an indication to apply beta-adrenal receptor blockers, but only after alpha-blockade. Reexpansion of blood volume has to be adjusted according to hemodynamic monitoring data. With an adequate preoperative management, mortality of patients with pheochromocytomas has been reduced to less than 1 percent. Postoperatively, most patients become normotensive and other symptoms of excessive catecholamine-production disappear. In cases of long persisting and fixed hypertension paroxysmal crises of high blood pressure can be avoided.