APPROXIMATELY 10% ARE INHERITED & ARE FREQUENTLY ASSOCIATED WITH FAMILIAL SYNDROMES.RISK FACTORS: Multiple endocrine neoplasia types II A and B
β’ Neurofibromatosis, type 1, Von Hippel-Lindau syndrome, Familial paraganglioma
SURGICAL resection of the tumor is the treatment of choice and usually results in cure of the hypertension. Careful treatment with alpha- and beta-blockers is required preoperatively to control blood pressure and prevent intraoperative hypertensive crises.
Start alpha blockade with phenoxybenzamine 7-10 days preoperatively to allow for expansion of blood volume.
The patient should undergo volume expansion with isotonic sodium chloride solution. Encourage liberal salt intake.
Initiate a beta-blocker only after adequate alpha blockade. If beta blockade is started prematurely, unopposed alpha stimulation could precipitate a hypertensive crisis.
Administer the last doses of oral alpha- and beta-blockers on the morning of surgery.
Surgical Care
Both an experienced anesthesiologist and an experienced surgeon are crucial to the success of the operation. Surgical mortality rates are less than 2-3% with an experienced anesthesiologist and surgeon.
Use an arterial line, cardiac monitor, and Swan-Ganz catheter. Administer stress-dose steroids if bilateral resection is planned.
An anterior midline abdominal approach was used in the past; however, in current practice, laparoscopic adrenalectomy is the preferred procedure for lesions smaller than 8 cm. If the pheochromocytoma is intra-adrenal, remove the entire adrenal gland. In the case of a malignant pheochromocytoma, resect as much of the tumor as possible.
PREGNANCY CONSIDERATIONS : VAGINAL DELIVERY IS EXTREMELY DANGEROUS.
MAGNESIUM SULPHATE MAY BE USED TO CONTROL HYPERTENSIVE EMERGENCIES DURING LABOR & DURING OPERATION OF THE TUMOR IN A PREGNANT PATIENT.
- 1 ST & 2 ND TRIMESTER : TUMOR SHOULD BE EXCISED AS SOON AS PATIENT HAS BEEN ADEQUATELY PRETREATED WITH ALPHA BLOCKERS
- 3 RD TRIMESTER : PT SHOULD BE TREATED WITH ALPHA BLOCKERS UNTIL THE FETUS IS VIABLE , AT WHICH TIME BABY SHOULD BE DELIVERED BY CESAREAN SECTION. THE TUMOR MAY BE RESECTED IN THE SAME OPERATION.
DRUG TREATMENT :
- * PT CAN BE HYPOVOLEMIC, SODIUM INTAKE MUST BE ADEQUATE TO PREVENT PROFOUND POSTURAL HYPOTENSION, SO GIVE NORMAL SALINE INFUSION.
- * BETA BLOCKERS SHOULD BE GIVEN ONLY AFTER PRIOR ADEQUATE ALPHA BLOCKERS TO AVOID HYPERTENSIVE CRISIS.
1. PHENOXYBENZAMINE
2. PRAZOSIN, TERAZOSIN & DOXAAZOSIN ( SPECIFIC ALPHA-1 ADRENERGIC BLOCKER )
3. LABETALOL ( ALPHA & BETA ANTAGONIST )
4. METYROSINE ( COMPETITIVE INHIBITOR OF TYROSINE HYDROXYLASE, THE RATE LIMITING STEP IN CATECHOLAMINE BIOSYNTHESIS )
5. CALCIUM CHANNEL BLOCKERS
6. VARIOUS CHEMOTHERAPEUTIC COMBINATIONS WITH OR WITHOUT RADIATION THERAPY TO TREAT MALIGNANT PHEOCHROMOCYTOMA. ( AFTER AGGRESSIVE SURGICAL RESECTION ).
ALTERNATIVE DRUGS:
β’ Alpha-adrenergic blocking agents - prazosin (Minipress), terazosin (Hytrin), doxazosin (Cardura)
β’ Beta-adrenergic blocking agents - nadolol (Corgard), atenolol (Tenormin), metoprolol (Lopressor)
β’ Combined beta- and alpha-adrenergic blocker - labetalol (Normodyne, TranDate)
β’ Catecholamine synthesis inhibitor - metyrosine (Demser)
PATIENT MONITORING
β’ Daily blood pressure monitoring prior to surgery
β’ Intra-operative hemodynamic monitoring
β’ Two weeks postoperatively - 24-h urine for measurement of catecholamines and metanephrines; if normal,
re-check annually, indefinitely
POSSIBLE COMPLICATIONS
β’ Postural hypotension with alpha-adrenergic blockade
β’ Pulmonary edema with beta-adrenergic blockade
β’ Intra-operative hypertensive crisis
EXPECTED COURSE/PROGNOSIS
β’ The survival rate after removal of a benign pheochromocytoma is nearly that of age- and sex-matched
controls
β’ For malignant pheochromocytoma, the 5-year survival rate is less than 50%
First and second trimester - surgical resection. Third trimester - cesarean section and removal of the
pheochromocytoma in the same operation