Adrenergic Crisis Due to Pheochromocytoma – Practical Aspects

153 Central European Journal of Urology REVIEW PAPER UROLOGICAL ONCOLOGY Adrenergic crisis due to pheochromocytoma – practical aspects. A short review Kajetan Juszczak1,2, Tomasz Drewa3,4 1Department of Urology, Rydygier Memorial Hospital, Cracow, Poland 2Department of Pathophysiology, Jagiellonian University, Medical College, Cracow, Poland 3Department of Regenerative Medicine, Medical College, Nicolaus Copernicus University, Toruń, Poland 4Department of Urology, Nicolaus Copernicus University, Toruń, Poland Article history Introduction The definitive therapy in case of pheochromocytoma is complete surgical resection. Submitted: Feb. 17, 2014 Improper preoperative assessment and medical management generally places the patient at risk for Accepted: March 21, 2014 complications, resulting from an adrenergic crisis. Therefore, it is crucial to adequately optimize these patients before surgery. Optimal preoperative medical management significantly decreases morbidity and mortality during the tumor resection. Material and methods This review addresses current knowledge in pre– and intraoperative assess- Correspondence ment of a patient with pheochromocytoma. Kajetan Juszczak Results Before surgery the patient is conventionally prepared with α–adrenergic blockade (over 10–14 Department of Pathophysiology days) and subsequently, additional β–adrenergic blockade is required to treat any associated tachyar- Jagiellonian University rhythmias. In preoperative assessment, it is obligatory to monitor arterial blood pressure, heart rate, Medical College and arrhythmias and to restore the blood volume to normal. 18, Czysta Street In conclusion, due to the pathophysiological complexity of a pheochromocytoma, the 31–121 Cracow, Poland Conclusions phone: +48 12 633 3947 strict cooperation between the cardiologist, endocrinologist, surgeon and the anaesthesiologist for an [email protected] uneventful outcome should be achieved in patients qualified for the surgical removal of such a tumor. Key Words: adrenergic crisis ‹› pheochromocytoma ‹› surgery Adrenergic crisis is not a rare phenomenon associ- tumor may induce adrenergic storm. Previously, the ated with pheochromocytoma. The factors trigger- pheochromocytoma crisis was also associated with ing an adrenergic storm are attributed to excessive contrast media. In pregnancy excessive uterine con- release of catecholamines from the pheochromocy- tractions, fetal movements, normal vaginal delivery toma tumor secondary to anxiety of the patient, or or Cesarean section may precipitate the adrenergic secondary to the induction of anesthesia and intu- crisis [1]. The perioperative pheochromocytoma cri- bation. Moreover, these hormones released may be sis may mimic other conditions such as a thyroid induced by drugs due to dopamine receptor blockade storm [2] or a malignant hyperthermia [3]. (e.g. droperidol), histamine release (e.g. morphine, Pheochromocytomas are rare, catecholamine–secret- atracurium), sympathetic stimulation (e.g. pancuro- ing (predominantly norepinephrine) tumors arising nium), anticholinergic drugs (e.g. atropine), or cat- from chromaffin cells of the adrenal medulla. Ad- echolamine–sensitizing anesthetics (e.g. halothane, ditionally, other substances are released by such a desflurane). Additionally, squeezing of the tumor tumor, such as: dopamine, VIP, adrenocorticotropic during straining, positioning of the patient, by scrub- hormones, and β–endorphins. Once the pheochromo- bing, by intraperitoneal carbon dioxide insufflations cytoma has been diagnosed, the mainstay of defini- during laparoscopy, or by direct manipulation of the tive therapy is complete surgical resection. Surgery Cent European J Urol 2014; 67: 153-155 10.5173/ceju.2014.02.art7 154 Central European Journal of Urology is not routinely advocated for the treatment of acute stopped the day before surgery as it has a long half hyperadrenergic crisis. Prior to surgery, the effects life and can cause postoperative hypotension [14]. of excess release of catecholamines must be mini- The tachycardia induced by α–receptor blockade can mized in order to avoid perioperative complications be suppressed by carefully introducing β–adrener- and improve outcomes [4, 5]. Surgical resection of gic blockers (e.g. atenolol: 100 mg, bisoprolol: 10–20 the pheochromocytoma tumor is the only curative mg). Moreover, β–receptor blockade should never procedure. Laparoscopic adrenalectomy (LA) is a be instituted until α–receptor blockade is fully es- well–approved operative technique. The indications tablished as unopposed α–stimulation may lead to for LA include primary hyperaldosteronism, pheo- severe hypertension [12]. Also, a calcium channel chromocytomas, and glucocorticoid secreting adrenal blocker (nifedipine: 30–90 mg) has been employed tumors. Szydelko et al. reported 16 pheochromocyto- in the hemodynamic control [14]. Many data suggest mas among the group of 80 patients who had under- a growing evidence about the effectiveness of these gone LA [6]. blockers as first line agents. Walz et al. [15] routine- Surgical resection of pheochromocytoma without ly used high–dosage alpha–blockade with phenoxy- preoperative medical preparation and intraoperative benzamine in 126 patients, with pheochromocytoma support places the patient at higher risk for compli- and retroperitoneal paragangliomas, who qualified cations from hemodynamic instability and hyper- for surgery. Moreover, it is worth to note that ran- tensive crises. Therefore, it is crucial to adequately domized clinical trials showed that in the case of optimize the patient with pheochromocytoma before 73 patients without an α–receptor blockade before surgery. Optimal preoperative medical management the resections of a catecholamine–producing tumor, significantly decreases morbidity and mortality there were no significant differences in the maxi- during the surgery [7]. Emerson et al. reported the mum systolic blood pressure or in the incidence of decrement in mortality rate due to pheochromocy- hypertensive episodes during surgery [16]. Preoper- toma resection from 40–60% to 0–6% over the last ative sedation and anxiolysis using benzodiazepines 50 years [8]. In preoperative assessment it is oblig- provides the reduction of anxiety and prevents sig- atory to monitor arterial blood pressure, heart rate nificant hemodynamic fluctuation during the induc- and arrhythmias and to restore the blood volume to tion of anesthesia [9]. Close communication between normal. Additionally, anesthesiologists are obliged the surgeon and the anesthesiologist is absolutely to assess the severity of hypertension and look for crucial to the success of intraoperative management any end–organ damage, especially catecholamine in- of patients undergoing resection of a pheochromocy- duced cardiomyopathy [9, 10]. toma [17]. In general a mid to low thoracic epidural Before surgery, the patient is conventionally pre- anesthesia combined with adequate general anes- pared with α–adrenergic blockade (over 10–14 days) thesia and selective adrenergic antagonists is suf- and subsequently, additional β–adrenergic blockade ficient for proper control of hemodynamic surges in is required to treat any associated tachyarrhythmias response to tumor manipulation and catecholamine [9, 11]. A non–competitive, non–selective α–adren- release [18]. It should be taken into careful consid- ergic blocker (phenoxybenzamine) is commonly used eration during surgery that a sudden decrease in for α–receptor blocking. The treatment is typically the circulating catecholamines may occur after the started 7–21 days prior to surgery at 10 mg once or adrenal vessels ligation, leading to hypotension. twice daily and increased by 10–20 mg every 2–3 days Thus, the vasodilatatory agents should be discontin- for optimal blood pressure and symptom control. If ued and a modest fluid bolus should be given. Also, the side effects of phenoxybenzamine (e.g. orthostatic an infusion of a vasoconstrictor agents (e.g. norepi- hypotension, fatigue, nasal congestion, nausea, etc.) nephrine, phenylephrine) may be required tempo- become intolerable, alternative drugs may be consid- rarily [17]. Several factors associated with increased ered (e.g. doxazosin, terazosin, etc.) [4]. In addition, risk of intraoperative hemodynamic instability were selective competitive α1–adrenergic antagonists are described, as follows: 1) higher norepinephrine plas- preferably used in some cases because such drugs ma level, 2) tumor size larger than 4 cm, 3) postural do not induce reflex tachycardia and can be adjust- hypotension following blockade of α–receptors [19]. ed rapidly before surgery due to a shorter duration Thus, strict intraoperative monitoring is crucial due of action [12]. Kinney et al. [13] observed significant to the higher risk of complications associated with increases in arterial blood pressure especially during the resection of catecholamine secreting tumors. Se- tumor manipulation, despite preoperative α–adren- vere arterial hypertension should be treated with ergic blockade. Thus, α– and β–blockade should be intravenous administration of sodium nitroprusside continued until the day of the pheochromocytoma re- (SM) and phentolamine (short acting α–blocker). SM section except for phenoxybenzamine, which may be is preferred due to the rapid vasodilatory properties 155 Central European Journal of Urology and shorter duration of action. It should be started conservative therapy (e.g. intravenous fluid replace- at 0.5–5.0 mcg/kg of body weight per

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