A 46-year-old man undergoes an elective inguinal hernia repair. After induction of general anesthesia, he is noted to be pale and tachycardic. The patient's medical history is significant for frequent headaches, hypertension, and an anxiety disorder. His outpatient medications include lisinopril, alprazolam, and as-needed naproxen. The patient regularly drinks a 6-pack of beer on weekends but does not use tobacco or illicit drugs. Family history is unremarkable. His temperature is 36.9 C (98.4 F), blood pressure is now 250/140 mm Hg (it was 144/90 mm Hg before induction), and pulse is 125/min. ECG shows sinus tachycardia with no ischemic changes. Which of the following is the most likely diagnosis?

Question

A 46-year-old man undergoes an elective inguinal hernia repair.  After induction of general anesthesia, he is noted to be pale and tachycardic.  The patient's medical history is significant for frequent headaches, hypertension, and an anxiety disorder.  His outpatient medications include lisinopril, alprazolam, and as-needed naproxen.  The patient regularly drinks a 6-pack of beer on weekends but does not use tobacco or illicit drugs.  Family history is unremarkable.  His temperature is 36.9 C (98.4 F), blood pressure is now 250/140 mm Hg (it was 144/90 mm Hg before induction), and pulse is 125/min.  ECG shows sinus tachycardia with no ischemic changes.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

In light of this patient's history of hypertension and frequent headaches, his presentation with severe hypertension, pallor, and sinus tachycardia is concerning for an occult pheochromocytoma with a catecholamine surge due to anesthesia. Pheochromocytomas and paraganglionomas are catecholamine-producing tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia, respectively. Hypertension in pheochromocytoma can be intermittent or sustained. Paroxysms of severe hypertension can be precipitated by increases in intra-abdominal pressure (eg, tumor palpation, positional changes), surgical procedures, and a number of medications, particularly anesthetic agents. In addition, nonselective beta blockers can cause a state of unopposed alpha adrenergic stimulation leading to vasoconstriction and paradoxical hypertension. For this reason, alpha adrenergic blockers (eg, phenoxybenzamine) should be administered prior to beta blockers in patients with pheochromocytoma. (Choices A, C, and F) Alcohol withdrawal and panic disorder can mimic pheochromocytoma paroxysms but are unlikely to manifest when the patient is under anesthesia. Thyroid storm can be precipitated by surgery in patients with preexisting thyrotoxicosis, but the presentation is usually less acute, and almost all patients will have pyrexia. Severely elevated blood pressure and pallor (from catecholamine-induced vasoconstriction) are more likely due to catecholamine surge from pheochromocytoma. (Choice B) Anaphylaxis is a severe type 1 hypersensitivity reaction to a drug, environmental agent, or food. Anaphylaxis typically causes hives, angioedema, respiratory compromise, and acute hypotension rather than hypertension. (Choice E) Serotonin syndrome is characterized by abnormal mental status, autonomic hyperactivity, and muscular rigidity with hyperreflexia. It is typically triggered by initiation or titration of selective serotonin reuptake inhibitors. Educational objective: Pheochromocytomas are catecholamine-producing tumors arising from chromaffin cells of the adrenal medulla. Paroxysms of severe hypertension in patients with pheochromocytoma can be precipitated by surgical procedures, induction of anesthesia, and a number of medications. References: Pheochromocytoma and paraganglioma: an endocrine society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/24893135)

A 46-Year-Old Man Undergoes an Elective Inguinal Hernia Repair