1Department of Anaesthesia, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK 2Present address: Department of Anaesthesia, Barnsley District General Hospital, Gawber Road, Barnsley S75 2EP, UK
Accepted for publication: May 9, 2000
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Abstract |
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Br J Anaesth 2000; 85: 6357
Keywords: complications, phaeochromocytoma; pregnancy
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Case history |
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The woman was admitted for induction of labour. Prostin gel 1 mg was administered per vaginum. The following morning, an infusion of 10% dextrose and potassium (10 mmol per 500 ml dextrose) was commenced with an i.v. insulin infusion started at 2 units h1. Artificial rupture of membranes was performed at 2 cm cervical dilation. An epidural catheter was then sited uneventfully at L3/4 and 10 ml of 0.25% bupivacaine was given. The first epidural top-up was requested 2.5 h later. An anaesthetist was called to check the epidural, because blood-stained aspirate was noted in the catheter. During examination of the catheter, the mother coincidentally became grey and clammy, and complained of a severe throbbing frontal headache. Her arterial pressure, measured non-invasively, was then 220/140 mm Hg. Within 10 min, the patient had recovered and her arterial pressure had returned to normal. She stated that similar headaches had occurred during the previous 3 months, that they lasted 5120 min and occasionally only stopped after vomiting. Her arterial pressure had never been measured during one of these episodes.
The presence of sudden, severe hypertension and abnormal glucose tolerance led us to a presumptive diagnosis of phaeochromocytoma. The epidural was topped up to T5 using 10 ml of 0.375% bupivacaine. Phentolamine was prepared as a rescue hypotensive agent. With this epidural management, the patients arterial pressure remained normal, even during contractions, and she had no further symptoms. The cardiotocograph (CTG) also remained normal. After discussion between the obstetricians, anaesthetists and the patient, it was decided to allow a trial of vaginal delivery with a short active second stage of labour. The epidural was topped up every 2 h to maintain good analgesia and sympathetic blockade. The patient began active pushing 4.5 h after the presumptive diagnosis, 1 h after full cervical dilation had been noted. After 10 min of pushing, she became breathless and felt unwell. Her arterial pressure peaked at 240/144 mm Hg but returned to normal when she stopped pushing. The obstetricians performed a ventouse delivery of the baby followed by manual removal of the placenta. A healthy 3.3 kg boy was delivered. The attendant anaesthetist administered intravenous boluses of phentolamine (3 mg total) during delivery, which kept the arterial pressure within normal limits (124/74 to 134/58 mm Hg). After delivery, the mothers arterial pressure remained labile, requiring further boluses of phentolamine (4 mg total). She was transferred to the high dependency unit; invasive monitoring of arterial pressure was initiated and a phentolamine infusion started at 4 mg h1. After medical review, oral phenoxybenzamine 10 mg tds was commenced.
Investigations 24 h after delivery revealed an increased serum epinephrine concentration of 413 nmol litre1 (normal range 1093 nmol litre1), which is diagnostic of a phaeochromocytoma. Norepinephrine and dopamine serum concentrations were within the normal range. On days 1, 2 and 3 post partum, urine tests showed normetanephrine concentrations of 29.4, 52.5 and 35.5 µmol litre1, respectively (normal range 03 µmol litre1), and metanephrine concentrations of 2908, 2231 and 3043 µmol litre1, respectively (normal range 02 µmol litre1). A magnetic resonance imaging (MRI) scan 3 weeks post partum revealed a 12 cm cystic mass arising from the right adrenal gland (Fig. 1). The phenoxybenzamine was gradually increased to 10 mg tds and the patient underwent uneventful laparotomy 8 weeks later. A 13x12x9 cm tumour was resected. Histology revealed a cystic lesion with a blood-stained centre and a peripheral adrenal paraganglioma consistent with a phaeochromocytoma. The patient made an uneventful recovery. Complete resection of the tumour was confirmed biochemically.
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Discussion |
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Once the presence of a phaeochromocytoma was suspected, it was decided to maintain epidural analgesia using 0.375% bupivacaine to produce extensive and dense sympathetic blockade without excessive weakness of the legs. The adrenal gland is innervated by sympathetic nerves from T5 to T12. Thus epidural sympathetic blockade across these levels would obtund the neurogenic stimulation of a possible adrenal tumour. An epidural would also provide optimal analgesia, thus reducing catecholamine concentrations further. Deafferentation would ensure optimal placental perfusion, which is particularly important in the presence of a rarer, extra-adrenal tumour. With this management, arterial pressure remained normal in this patient throughout the first stage of labour. Hypertension in response to placement in the lithotomy position has been noted in a patient with an extra-adrenal tumour who received antenatal and ß blockade and an epidural catheter with bolus doses of 0.25% bupivacaine during labour.4 No comment was made about the height of the epidural block during this case. Our patient had no such problems. The labour progressed uneventfully; invasive monitoring of arterial pressure was deferred as the patients arterial pressure was controlled and she remained asymptomatic.
There are no previous reports of phaeochromocytoma being diagnosed in labour (from Medline search and follow-up of references), so there is no clear guidance in the literature about the preferred mode of delivery in such patients. The majority of cases not diagnosed antenatally required Caesarean section for fetal distress. Between 1980 and 1987, there were 17 cases reported of women undiagnosed antenatally who survived to delivery.2 Twelve had Caesarean sections, with eight mothers and 10 babies surviving. Five were delivered vaginally, with four of the mothers and four of the babies surviving. There is thus no suggestion that one mode of delivery is less hazardous than another in this situation. Epidural analgesia allowed the option of vaginal delivery or topping up for Caesarean section.57 In our case, the obstetricians had not anticipated any problems with vaginal delivery. We decided to pursue a vaginal delivery unless hypertension or an abnormal CTG suggested the need for Caesarean section. Phentolamine controlled the patients arterial pressure during instrumental delivery. We chose this blocker because of its rapid, titratable effect when given intravenously. It can be given peripherally as a bolus or as an infusion. Phenoxybenzamine and labetolol were other options. Phenoxybenzamine takes up to 1 h to take effect after intravenous administration and needs to be given slowly over 2 h. Labetolol has a longer, less predictable onset time than phentolamine and we preferred to use a pure
blocker, as tachycardia was not a problem in this patient. Both the alternative drugs thus have an unacceptable onset time. The effectiveness of the epidural meant that manual removal of the placenta was uneventful, with no arterial pressure problems.
In summary, we have described the successful management of a multigravida patient with a phaeochromocytoma diagnosed during labour. Optimal management of a pregnant woman with a phaeochromocytoma should include antenatal diagnosis and and ß blockade. Unfortunately, some patients will not be diagnosed before delivery. With extended epidural sympathetic blockade, intravenous
blockade, limitation of pushing during the second stage of labour and close monitoring of arterial pressure, successful vaginal delivery was achieved.
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Footnotes |
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References |
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2 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: 594606[ISI][Medline]
3 Department of Health. Why Mothers Die. The Report on Confidential Enquiries into Maternal Deaths in the United Kingdom 19946. London: Department of Health, 1998
4 Davies AE, Navaratnarajah M. Vaginal delivery in a patient with a phaeochromocytoma. Br J Anaesth 1984; 56: 9136[Abstract]
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7 Botchan A, Hauser R, Kupfermine M, Grisaru, Peyser MR, Lessing JB. Phaeochromocytoma in pregnancy: case report and review of the literature. Obstet Gynecol Surv 1995; 50: 3217[Medline]