The cornerstone of managing pheochromocytoma in pregnancy is stabilizing the cardiovascular system before delivery. Preoperative management starts with alpha-adrenergic blockade for at least 10 to 14 days before surgery or delivery, using either phenoxybenzamine (a non-selective, irreversible blocker, started at 10 mg twice daily and titrated toward about 1 mg/kg/day) or a selective alpha-1 blocker such as doxazosin (2 to 16 mg daily) or prazosin. Phenoxybenzamine crosses the placenta and can cause neonatal hypotension and respiratory depression for a few days after birth, so the neonatal team must be told; doxazosin produces less reflex tachycardia and less post-resection hypotension and is preferred by many centers in pregnancy. A liberal salt and fluid intake accompanies the blockade to re-expand the contracted intravascular volume. This alpha-blockade is crucial to controlling hypertension and preventing hypertensive crises during labor or cesarean delivery. Adequacy of blockade is judged by the Roizen criteria: no blood pressure above 160/90 mmHg for the 24 hours before surgery; some orthostatic hypotension, but a standing pressure no lower than 80/45 mmHg; no ST-T changes on the ECG for a week; and no more than one premature ventricular contraction every 5 minutes. The Endocrine Society aims lower, for a seated pressure below 130/80 mmHg with a standing systolic above 90 mmHg; in pregnancy, symptomatic hypotension is avoided because uteroplacental flow depends on maternal pressure.
After establishing alpha-blockade (usually 2 to 3 days later), a cardioselective beta-blocker such as metoprolol is introduced to control reflex tachycardia; labetalol alone is inadequate because its beta-blockade outweighs its alpha-blockade. Beta-blockers should always be administered after alpha-blockade to avoid unopposed alpha-adrenergic stimulation, which could lead to dangerous hypertensive episodes. Fluid resuscitation is also essential to address the hypovolemia often seen in pheochromocytoma patients due to chronic vasoconstriction, ensuring adequate intravascular volume before surgery.
Timing of Tumor Removal and Delivery
Gestational age at diagnosis decides the plan. Before about 24 weeks, laparoscopic adrenalectomy in the second trimester after adequate blockade is usually recommended, when organogenesis is complete and the uterus is still small enough for access. After 24 weeks, medical management continues until fetal maturity, and the tumor is removed either at the time of cesarean delivery or electively a few weeks postpartum after re-blockade. Cesarean delivery under a carefully conducted anesthetic is generally preferred over vaginal delivery, since labor and pushing provoke catecholamine release, although successful vaginal deliveries have been reported in fully blocked patients. Modern data show that it is recognition and alpha-blockade, not the timing of surgery, that improves outcomes.
Choice of Anesthesia
The decision between regional and general anesthesia depends on the patient's condition and the degree of preoperative preparation. Epidural anesthesia is often preferred for cesarean sections or vaginal deliveries because of its gradual onset of sympathetic blockade, reducing the risk of hypotension. Combined spinal-epidural anesthesia can also offer better hemodynamic control and help mitigate hypertensive surges.
For cases requiring general anesthesia, careful management is crucial to prevent adrenergic responses during intubation, extubation, and surgical stimulation. The pressor response to laryngoscopy is blunted with a deep plane, a generous opioid dose (remifentanil or fentanyl), intravenous lidocaine, and magnesium sulfate, with esmolol, nicardipine, or phentolamine drawn up for surges. Sodium nitroprusside works but is limited in pregnancy because its cyanide metabolite crosses the placenta: keep it to brief, low-dose use (under about 2 mcg/kg/min) and prefer nicardipine, nitroglycerin, or phentolamine when possible. Drugs that provoke catecholamine release or a sympathetic surge are avoided: ketamine, ephedrine and other indirect sympathomimetics, pancuronium and atropine, metoclopramide, droperidol, succinylcholine (fasciculations can squeeze the tumor; rocuronium is preferred for rapid sequence induction), histamine-releasing agents such as morphine and atracurium, and desflurane in high concentrations.
