Pheochromocytoma is a catecholamine-secreting tumor of chromaffin cells and is a rare cause of hypertension [1-3]. Unsuspected pheochromocytoma greatly increases the perioperative mortality rate in patients undergoing even relatively minor surgical procedures [4,5]. However, most anesthesiologists are unfamiliar with pheochromocytoma of the urinary bladder. We report a case of unsuspected pheochromocytoma of the urinary bladder with severe hypertensive episodes during transurethral resection. Case Report A 69-yr-old, 72-kg, 169-cm male presented with visible hematuria. Physical examination was unremarkable, and results of routine laboratory examinations (blood cell counts, blood chemistry, coagulation studies, chest radiograph, and electrocardiogram) were within normal limits. The heart rate (HR) was 50-60 bpm, and the arterial pressure 110-140/60-80 mm Hg. The patient had no remarkable past medical history including hypertension and chronic preoperative medication. Cystoscopy under topical anesthesia disclosed a 2-cm solitary tumor in the right lateral wall of the bladder. Transurethral resection of the bladder tumor under epidural analgesia was planned. The patient was premedicated with oral diazepam (10 mg) 1 h before anesthesia. According to our routine for transurethral resection, the usual monitors were used in addition to an arterial cannula for monitoring arterial blood pressure and blood chemistry. A lumbar epidural catheter was placed at L4-5 and 15 mL of 2% lidocaine containing 1:200,000 epinephrine solution was injected. This was followed by continuous infusion of the solution at a rate of 10 mL/h. After epidural injection of the anesthetic solution, arterial pressure changed from 135/70 to 100/60 mm Hg, and the HR from 50 to 60 bpm in 5 min, and values were stabilized in that range. Twenty minutes after the initial epidural injection, complete analgesia was obtained from T4 to S5 determined by the pinprick method. Then, using a nerve stimulator as a guide, we performed a right obturator nerve block with 10 mL of 0.25% bupivacaine. The surgery was started 45 min after the initial epidural injection. During the first 15 min, arterial pressure and HR were stable (blood pressure, 100/60 mm Hg; HR, 60 bpm). Then the arterial pressure suddenly increased from 100/60 to 200/100 mm Hg together with a decrease in HR from 60 to 50 bpm with premature supraventricular contractions. The patient noticed a slightly oppressive sensation in the lower abdomen. We notified the surgeon of these changes. Outflow of the irrigating fluid caused the arterial pressure to return to 100/60 mm Hg within 5 min. Surgery was restarted. The time course was uneventful during the next 30 min. Then again, the arterial pressure increased suddenly from 120/60 to 220/110 mm Hg, with a decrease in HR from 60 to 40 bpm. The patient again noticed an oppressive sensation in the lower abdomen. We again requested the surgeon to stop the procedure and release the irrigating fluid. Arterial pressure gradually recovered, but it took 20 min this time. The postoperative course was uneventful. Histologic examination of the tumor disclosed typical findings of pheochromocytoma. Two months later, to eliminate the chance of local recurrence from residual tumor, partial cystectomy was performed under general anesthesia combined with epidural analgesia. The surgery was uneventful. Discussion Pheochromocytoma of the urinary bladder is rare, accounting for less than 0.06% of all bladder tumors [6-9]. Characteristic symptoms are sharp headache, hypertension, palpitation, sweating, and fainting immediately after voiding due to increased catecholamine release in association with bladder contraction during micturition [6-8,10-12]. However, approximately half of the patients, such as this case, lack these typical symptoms [8-10]. Therefore, anesthesiologists may give anesthesia without suspecting pheochromocytoma. A common cause of intraoperative hypertension is insufficient depth of anesthesia. The patient, in this case, noticed an oppressive sensation in the lower abdomen. The range of analgesia obtained was from T4 to S5. However, this was determined by the pinprick method. We could not deny the possibility of insufficiently dense or patchy neural block. Thus, we suspected overdistended bladder as the cause, and outflow of the irrigating fluid caused the arterial pressure to normalize during the first episode. During the second episode, however, the bladder was not overdistended. The range or density of analgesia was sufficient for surgery. We could not find appropriate reasons to explain the hypertensive crisis this time. We could only stop the procedure. We now believe that the cause of hypertension was pheochromocytoma of the urinary bladder. Catecholamine release may have been facilitated when the bladder was distended or when the tumor was cut. The cause of the hypertension would have been more convincing if catecholamine levels had been measured from the blood samples obtained during the episodes. In conclusion, we should be aware of the possibility of undiagnosed pheochromocytoma of the urinary bladder in case of a hypertensive crisis during transurethral resection of a bladder tumor.
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Mar 1, 2004
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