The definitive treatment of pheochromocytoma is surgical excision of the tumor. Laparoscopic surgery is now the technique of first choice for resection adrenal and extra-adrenal pheochromocytomas. Preparation of the patient for surgery requires adequate preoperative medical treatment to minimize operative and postoperative complications . Exposure to high levels of circulating catecholamines during surgery may cause hypertensive crises and arrhythmias, which can occur even when patients are preoperatively normotensive and asymptomatic. All patients with pheochromocytoma should therefore receive appropriate preoperative medical management to block the effects of released catecholamines.

Phenoxybenzamine (Dibenzyline), an a-adrenoceptor blocker, is most commonly used for preoperative control of blood pressure. The drug is administered orally at a dose of 10-20 mg twice daily for 2 weeks before surgery. At some centers, a supplemental dose (0.5-1.0 mg/kg) is administered at midnight before surgery, in which case appropriate safeguards are required to avoid orthostatic hypotension. Intravenous fluids may be administered if there is concern that blood volume has not been adequately replaced. Alternatives to phenoxybenzamine for preoperative blockade of catecholamine-induced vasoconstriction include calcium channel blockers and selective a1-adrenoceptor blocking agents, such as terazosin (Hytrin) and doxazosin (Cardura).

A b-adrenoceptor blocker may be used for preoperative control of arrhythmias, tachycardia or angina. However, loss of b-adrenoceptor-mediated vasodilatation in a patient with unopposed catecholamine-induced vasoconstriction can result in dangerous increases in blood pressure (sometimes hypertensive crisis). Therefore, b-adrenoceptor blockers should never be employed without first blocking a-adrenoceptor mediated vasoconstriction.

In some patients blood pressure can reach very high values and such a situation is termed a hypertensive crisis when it is life-threatening or compromises vital organ function . The hypertensive crises are the result of a rapid and marked release of catecholamines from the tumor. Patients may experience hypertensive crises in different ways. Some report severe headaches or diaphoresis, while others have visual disturbances, palpitations, encephalopathy, acute myocardial infarction, congestive heart failure, or cerebrovascular accidents. Therefore, it is crucial to start proper antihypertensive therapy immediately. Treatment of a hypertensive crisis due to pheochromocytoma should be based on administration of phentolamine. It is usually given as an i.v. bolus of 2.5 mg to 5 mg at 1 mg/min. If necessary, phentolamine’s short half-time allows this dose to be repeated every 5 minutes until hypertension is adequately controlled. Phentolamine can also be given as a continuous infusion (100 mg of phentolamine in 500 mL of 5% dextrose in water) with an infusion rate adjusted to the patient’s blood pressure during continuous blood pressure monitoring. Alternatively, control of blood pressure may be achieved by a continuous infusion of sodium nitroprusside (preparation similar to phentolamine) at 0.5 to 10.0 µg/kg per minute (stop if no results are seen after 10 minutes) .

In all patients before surgery and in some patients on whom elevated blood pressure and arrhythmia cannot be controlled by using a and ß blockade, a-methyl-para-tyrosine (metyrosine, Demser™), a competitive inhibitor of tyrosine hydroxylase, is used (the starting dose is usually 250 mg twice to fourth time a day). As reviewed in detail by Bravo and Gifford to ensure adequate preoperative preparation, several criteria should be fulfilled: (a) blood pressure not greater than 160/90 mm Hg; (b) orthostatic hypotension not exceeding 80/45 mm Hg; and (c) no more than one ventricular extrasystole every 5 minutes and EKG without nonspecific ST segment elevations or depression and T wave inversions .

Although a few patients remain hypertensive in the immediate post-operative period, most require treatment for hypotension, which is best remedied by administration of fluids. Hypoglycemia in the period immediately after tumor removal is another problem that is best prevented by infusion of 5% dextrose started immediately after tumor removal and continuing for several hours thereafter. Post-operative hypoglycemia is transient, whereas low blood pressure and orthostatic hypotension may persist for up to a day or more after surgery and require care with assumption of sitting or upright posture.

The longterm prognosis of patients after operation for pheochromocytoma is excellent, although nearly 50% may remain hypertensive after surgery. Biochemical testing should be repeated after about 14-28 days from surgery in order to check for remaining disease. Importantly, however, normal postoperative biochemical test results do not exclude remaining microscopic disease so that patients should not be misinformed that they are cured and that no further follow-up is necessary. On longterm follow-up about 17% of tumors recur, with about 50% of these showing signs of malignancy. Although follow-up is especially important for patients identified with mutations of disease-causing genes, there is currently no method based on pathological examination of a resected tumor to rule out potential for malignancy or recurrence. Thus, long-term periodic follow-up remains recommended for all cases of pheochromocytoma.