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From the Department of Anesthesia and Perioperative Medicine, St. Joseph’s Health Care, University of Western Ontario, London, Ontario, Canada.
Address correspondence to: Dr. John G. Fuller, Department of Anesthesia and Perioperative Medicine, St. Joseph’s Health Care, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada. Phone: 519-663-3283; Fax: 519-663-3079; E-mail: jfuller{at}uwo.ca
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Clinical features: A 32-yr-old previously healthy woman (gravida 4, para 2) presented to our tertiary care obstetrical hospital at 34 weeks five days gestation with a history of labile blood pressure and severe hypertension. A week prior to admission she began having episodes of severe headache, dizziness, sweating and nausea. On a routine obstetric visit she was noted to be severely hypertensive with a blood pressure of 200/120 mmHg. Biochemical investigations confirmed the diagnosis of pheochromocytoma and magnetic resonance imaging demonstrated a 3 cm x 3 cm right adrenal mass. The patient was invasively monitored in the intensive care unit and treated with alpha- followed by beta-blockade with phenoxybenzamine and metoprolol. A multidisciplinary conference was organized involving endocrinology, anesthesiology, general surgery and obstetrics to determine the most appropriate management of the patient. An uncomplicated laparoscopic adrenalectomy was performed following a period of recovery after an uneventful elective Cesarean delivery.
Conclusions: The primary goals in the management of pheochromocytoma in pregnancy are early diagnosis, avoidance of a hypertensive crisis during delivery and definitive surgical treatment. Timing of surgical resection will depend on the gestational age at which diagnosis is made. Cesarean section is the preferred mode of delivery when the tumour is still present. This case illustrates that with antenatal diagnosis, advanced methods of tumour localization, adequate preoperative adrenergic blockade and team planning, pheochromocytoma in pregnancy can be treated successfully.
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Case report |
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The patient had no history of diabetes, hypertension or cardiovascular disease. She was a non-smoker and non-drinker, was not on any regular medications and had no reported allergies. There was no history of illicit drug use. She had two prior uncomplicated pregnancies with term vaginal deliveries and one miscarriage at 12 weeks gestation for which she had a dilatation and curettage. Family history was negative for multiple endocrine neoplasia (MEN) syndromes and pheochromocytoma.
The patient was admitted directly to our intensive care unit (ICU) with the presumptive diagnosis of pheochromocytoma. Continuous fetal heart rate monitoring and maternal electrocardiogram (EKG) were unremarkable. An arterial line and pulmonary artery catheter (PAC) were inserted for hemodynamic monitoring. Pulmonary artery (PA) pressures were 20 to 25/8 to 10 mmHg, cardiac index was within normal limits at 3.5 to 4.0 L•min-1•m2 and pulmonary capillary wedge pressure was 8 to 12 mmHg. The patient was given iv fluids and BP was controlled with phentolamine iv followed by phenoxybenzamine 30 mg tid to keep systolic BP 140 to 160 mmHg and diastolic BP < 90 mmHg. Metoprolol 50 mg bid was used to control maternal tachycardia. The patient received a total of 14 days of alpha-adrenergic blockade with phenoxybenzamine and ten days of beta-blockade with metoprolol preoperatively. Biochemical investigations showed markedly elevated 24-hr urine norepinephrine (740 nmol•day-1), vanillylmandelic acid (63 µmol•day-1), metanephrine (695 µmol•day-1), and normetanephrine (8,878 µmol•day-1) levels as well as elevated plasma norepinephrine (7,719 pmol•L-1), confirming the diagnosis of pheochromocytoma. Subsequent MRI demonstrated a 3 cm x 3 cm right adrenal mass, normal left adrenal gland and no extra-adrenal tumours. A multidisciplinary conference involving endocrinology, anesthesiology, general surgery and obstetrics was held to determine the most appropriate management of this patient. As laparoscopic adrenalectomy would be technically difficult in the presence of a gravid uterus, it was decided that a Cesarean delivery would be performed first, followed by laparoscopic right adrenalectomy after a period of recovery. The patient was invasively monitored for seven days in the ICU until hemodynamically stable before being transferred to the antenatal unit until time of Cesarean delivery. The PAC and radial arterial line were removed upon discharge from the ICU.
Cesarean delivery occurred at 37 weeks gestation under general anesthesia. Intraoperative monitoring included a #20 gauge radial arterial line, PAC, 5-lead EKG and other routine monitors. Prior to induction, nitroprusside (0.5 µg•kg-1•min-1) and remifentanil (0.1 µg•kg-1•min-1) infusions were started. Intermittent boluses of esmolol 10 mg iv (total 30 mg) were also used to control BP (systolic BP 165 mmHg reduced to 120 mmHg pre-induction). The patient was positioned with left uterine displacement. A 5-mg defasciculating dose of rocuronium was administered and following three minutes of pre-oxygenation, a rapid sequence induction with 100 mg lidocaine, 280 mg thiopental and 120 mg succinylcholine was performed under cricoid pressure. A 7.0-mm endotracheal tube was easily inserted. The nitroprusside infusion (0.5–1.0 µg•kg-1•min-1) was used to control BP intraoperatively which ranged from 120 to 140/70 to 80 mmHg. PA pressures were within normal limits (20–25/8–10 mmHg). Anesthesia was maintained with 50% nitrous oxide and 0.4 to 0.8% isoflurane in oxygen. Following an uncomplicated Cesarean delivery, the patient returned to the ICU in stable condition for 48 hr of monitoring before transfer to our step-down unit. Postoperative pain was controlled with fentanyl patient-controlled analgesia. The reduction in intra-abdominal pressure and presumed decrease in mechanical stress on the adrenal tumour following delivery of the fetus did not lead to a reduction in anti-adrenergic drug requirement postoperatively and she remained hemodynamically stable. The neonate was transiently hypotensive postdelivery and required temporary inotropic support in the neonatal ICU.
Following delivery, the patient had a meta-iodobenzylguanidine (MIBG) scan which was negative despite the presence of a right adrenal pheochromocytoma. Two weeks postpartum, the patient underwent uneventful laparoscopic right adrenalectomy with a similar anesthetic technique provided by the same anesthesiologist. Postoperatively she was observed for 48 hr in the ICU and her BP remained normal (110–120/70–80 mmHg) off all anti-hypertensive medications. Follow-up 24-hr urinary catecholamine levels were normal. Serum calcium, calcitonin and parathyroid hormone levels were measured one month postoperatively and within normal limits, excluding MEN (2A/2B) syndrome. Final pathology report confirmed the right adrenal tumour was indeed a pheochromocytoma. Unfortunately, there is no definitive pathological way to determine the malignant potential of pheochromocytomas.
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Unrecognized pheochromocytoma in pregnancy can result in potentially fatal hypertensive crises precipitated by general anesthesia, vaginal delivery or the mechanical effects of an enlarging uterus, uterine contractions or fetal movements.6,8 The primary goal in the management of pheochromocytoma is to avoid a hypertensive crisis which can lead to hemorrhage and infarction in vital organs, congestive heart failure, cardiac dysrhythmias and death. In pregnancy, such a crisis can lead to uteroplacental insufficiency with resultant IUGR, fetal hypoxia and death. Accurate diagnosis is imperative as delivery of the fetus will be beneficial in the treatment of pre-eclampsia but can be catastrophic in undiagnosed pheochromocytoma.7
Once a diagnosis has been confirmed biochemically, efforts should be made to localize the tumour. Ultrasonography and MRI are the safest modalities of tumour localization in pregnancy.3 Ultrasound had a reported sensitivity of 89 to 97% for adrenal masses and MRI avoids all radiation and allows sectional imaging to identify extra-adrenal tumours.3,6,9 MIBG scintigraphy can be used for tumour localization following delivery of the fetus but has a reported sensitivity of 77% resulting in a significant false negative rate.10
Timing of tumour excision will depend on the gestational age at which diagnosis is made, fetal development and the success of treatment of maternal symptoms.5 It is recommended that if diagnosis is confirmed prior to 24 weeks gestation, the tumour should be excised immediately, with termination or continuation of the pregnancy dependent on clinical circumstances.11 After 24 weeks, the uterine size precludes adequate surgical exploration and it is reasonable to allow the pregnancy to continue under adrenergic blockade until fetal maturity is reached, assuming mother and fetus are medically stable. Establishment of adequate alpha-adrenergic blockade generally requires 10 to 14 days of treatment. Persistence of tachycardia or the presence of cardiac dysrhythmias is an indication for beta blockade and usually responds following two to three days of treatment. Elective Cesarean section is the preferred mode of delivery when the tumour is still present.3,9,11 Mechanical pressure placed on the adrenal tumour from uterine contractions and maternal expulsive efforts during vaginal delivery can precipitate a potentially fatal hypertensive crisis.3,9 In a study by Shenker, it was found that vaginal delivery carried a higher maternal mortality (31%) than Cesarean delivery (19%).12
Following preoperative optimization, definitive treatment of pheochromocytoma is surgical removal.1,3,5,9,10,13 A patient undergoing surgical excision of a pheochromocytoma is at greatest risk of hemodynamic instability during intubation of the trachea, tumour manipulation and following ligation of the tumour’s venous drainage. The goal of anesthetic management is the avoidance of drugs or events that will result in stimulation of the sympathetic nervous system (SNS). Intraoperative monitoring is geared toward early detection of catecholamine-induced changes in cardiovascular performance and includes invasive arterial BP monitoring and PA catheterization. Use of transesophageal echocardiography to monitor myocardial performance and volume status has also been reported. Laryngoscopy and tracheal intubation can trigger abrupt catecholamine release and an acute hypertensive crisis resulting in uteroplacental insufficiency and fetal hypoxia.5 To minimize this, a surgical depth of anesthesia should be achieved (1.3 MAC) prior to any attempt at laryngoscopy and intubation.7 Administration of a bolus of iv lidocaine (1–2 mg•kg-1) prior to intubation can attenuate catecholamine-induced responses including cardiac dysrhythmias. An iv opioid and short-acting vasodilator such as remifentanil and nitroprusside respectively are useful adjuncts and were employed in our patient. All iv induction agents are reported to be safe except for ketamine which results in SNS stimulation. Intraoperative infusions of magnesium sulphate have been used successfully in the management of pheochromocytoma in pregnancy provided therapeutic drug levels are attained.14 Its ability to inhibit catecholamine release from both the adrenal medulla and peripheral adrenergic nerve terminals, reduce the sensitivity of postsynaptic alpha-adrenergic receptors to catecholamines and act as a direct peripheral vasodilator make it an ideal agent. Non-depolarizing muscle relaxants with vagolytic or histamine-releasing properties are best avoided. Maintenance of anesthesia is most often achieved with the administration of a volatile anesthetic in combination with nitrous oxide and an opioid. Halothane is not recommended as it sensitizes the myocardium to circulating catecholamines. Desflurane should be avoided owing to catecholamine release associated with rapid administration of high concentrations. Isoflurane is the preferred agent because it does not sensitize the myocardium to catecholamines, is a vasodilator and provides good analgesia.15 Sevoflurane has also been used successfully. Following discussion of anesthetic options, a general anesthetic was administered for Cesarean delivery in keeping with both anesthesiologist and patient preference. Successful use of epidural anesthesia in patients antenatally diagnosed with pheochromocytoma has been reported.16
The transient hypotension seen in the neonate following Cesarean delivery may have resulted from placental transfer of phenoxybenzamine used to treat maternal hypertension. Santeiro et al.17 confirmed that placental transfer of phenoxybenzamine does occur in the third trimester of pregnancy and can accumulate in the fetal blood leading to perinatal depression and transient hypotension following Cesarean delivery. Placental transfer of remifentanil does occur but has minimal neonatal effects secondary to rapid metabolism and redistribution.18
Laparoscopic adrenalectomy can be performed safely for excision of pheochromocytomas less than 7 cm in size.19 Previous concerns surrounding laparoscopy included the potential adverse hemodynamic effects associated with pneumoperitoneum. In a recent study, it was found that creation of a pneumoperitoneum for laparoscopic adrenalectomy did not have any significant effect on cardiac index or left ventricular work index when compared to a control group of patients undergoing open adrenalectomy for pheochromocytoma.19 Furthermore, serum catecholamine concentrations increased to a lesser extent with laparoscopic than with open adrenalectomy during tumour manipulation.10 Clinically, this translates into a lower incidence cardiovascular instability among patients undergoing laparoscopic tumour excision. Laparoscopy being a less invasive procedure also resulted in less postoperative pain and shorter hospital stays.20 Considering these benefits and the expertise of our consulting surgeon in laparoscopic surgery, it was the favoured technique.
This case report illustrates that with antenatal diagnosis, appropriate preoperative alpha-adrenergic blockade, multidisciplinary team planning, and administration of a carefully tailored anesthetic, patients with pheochromocytoma diagnosed in the third trimester of pregnancy can have a promising outcome.
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Footnotes |
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2 Lau P, Permezel M, Dawson P, Chester S, Collier N, Forbes I. Phaeochromocytoma in pregnancy. Aust NZ J Obstet Gynaecol 1996; 36: 472–6.[Medline]
3 Freier DT, Thompson NW. Pheochromocytoma and pregnancy: the epitome of high risk. Surgery 1993; 114: 1148–52.[Medline]
4 Mastrogiannis DS, Whiteman VE, Mamopoulos M, Salameh WA. Acute endocrinopathies during pregnancy. Clin Obstet Gynecol 1994; 37: 78–92.[Medline]
5 Harrington JL, Farley DR, van Heerden JA, Ramin KD. Adrenal tumors and pregnancy. World J Surg 1999; 23: 182–6.[Medline]
6 Harper MA, Murnaghan GA, Kennedy L, Hadden DR, Atkinson AB. Phaeochromocytoma in pregnancy. Five cases and a review of the literature. Br J Obstet Gynaecol 1989; 96: 594–606.[Medline]
7 Stoelting RK, Dierdorf SF. Anesthesia and Co-Existing Disease, 4th ed. New York: Churchill Livingstone Inc.; 2002: 430–4.
8 Bullough AS, Karadia S, Watters M. Phaeochromocytoma: an unusual cause of hypertension in pregnancy. Anaesthesia 2001; 56: 43–6.[Medline]
9 Almog B, Kupferminc MJ, Many A, Lessing JB. Pheochromocytoma in pregnancy – a case report and review of the literature. Acta Obstet Gynecol Scand 2000; 79: 709–11.[Medline]
10 Inabnet WB, Pitre J, Bernard D, Chapuis Y. Comparison of the hemodynamic parameters of open and laparoscopic adrenalectomy for pheochromocytoma. World J Surg 2000; 24: 574–8.[Medline]
11 Gagner M, Lacroix A, Prinz RA, et al. Early experience with laparoscopic approach for adrenalectomy. Surgery 1993; 114: 1120–5.[Medline]
12 Schenker JG, Granat M. Phaeochromocytoma and pregnancy–an updated appraisal. Aust NZ J Obstet Gynaecol 1982; 22: 1–10.
13 O’Riordan JA. Pheochromocytomas and anesthesia. Int Anesthesiol Clin 1997; 35: 99–127.
14 James MF, Huddle KR, Owen AD, van der Veen BW. Use of magnesium sulphate in the anaesthetic management of phaeochromocytoma in pregnancy. Can J Anaesth 1988; 35: 178–82.
15 Pullerits J, Ein S, Balfe JW. Anaesthesia for phaeochromocytoma. Can J Anaesth 1988; 35: 526–34.
16 Stonham J, Wakefield C. Phaeochromocytoma in pregnancy. Caesarean section under epidural analgesia. Anaesthesia 1983; 38: 654–8.[Medline]
17 Santeiro ML, Stromquist C, Wyble L. Phenoxybenzamine placental transfer during the third trimester. Ann Pharmacother 1996; 30: 1249–51.[Abstract]
18 Kan RE, Hughes SC, Rosen MA, Kessin C, Preston PG, Lobo EP. Intravenous remifentanil. Placental transfer, maternal and neonatal effects. Anesthesiology 1998; 88: 1467–74.[Medline]
19 Janetschek G, Neumann HP. Laparoscopic surgery for pheochromocytoma. Urol Clin North Am 2001; 28: 97–105.[Medline]
20 Fernandez-Cruz L, Taura P, Saenz A, Benarroch G, Sabater L. Laparoscopic approach to pheochromocytoma: hemodynamic changes and catecholamine secretion. World J Surg 1996; 20: 762–8.[Medline]
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