A 52-year-old woman is undergoing screening colonoscopy and receives midazolam for sedation. Shortly after the procedure is started, she becomes tachycardic and hypertensive. Blood pressure is 240/140 mm Hg, pulse is 180/min, and respirations are 22/min. Oxygen saturation is 92% on 4 L by nasal cannula. ECG shows atrial fibrillation with rapid ventricular response. Fine crackles are heard at the lung bases.
The procedure is aborted and the patient is admitted to the cardiac care unit for further management. Medical history is significant for chronic lower back pain, anxiety disorder, and chronic headaches. Medications include acetaminophen as needed for pain. She has had no previous surgeries.
The following day, she feels fine and wishes to go home. Blood pressure is 112/70 mm Hg, and pulse is 78/min and regular. ECG shows normal sinus rhythm with nonspecific ST-segment and T-wave changes. Complete blood count, serum chemistries, and TSH are unremarkable. Transthoracic echocardiogram shows mild left atrial enlargement and mild mitral regurgitation. Left ventricular systolic function is normal.
Which of the following is the best next step in management of this patient?

Question

A 52-year-old woman is undergoing screening colonoscopy and receives midazolam for sedation.  Shortly after the procedure is started, she becomes tachycardic and hypertensive.  Blood pressure is 240/140 mm Hg, pulse is 180/min, and respirations are 22/min.  Oxygen saturation is 92% on 4 L by nasal cannula.  ECG shows atrial fibrillation with rapid ventricular response.  Fine crackles are heard at the lung bases.
The procedure is aborted and the patient is admitted to the cardiac care unit for further management.  Medical history is significant for chronic lower back pain, anxiety disorder, and chronic headaches.  Medications include acetaminophen as needed for pain.  She has had no previous surgeries.
The following day, she feels fine and wishes to go home.  Blood pressure is 112/70 mm Hg, and pulse is 78/min and regular.  ECG shows normal sinus rhythm with nonspecific ST-segment and T-wave changes.  Complete blood count, serum chemistries, and TSH are unremarkable.  Transthoracic echocardiogram shows mild left atrial enlargement and mild mitral regurgitation.  Left ventricular systolic function is normal.
Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_96bb_08f2_853d_f98eef5233db_MD0002_00 This patient with a history of headaches and anxiety developed hypertensive crisis, flash pulmonary edema, and atrial fibrillation (AF) with rapid ventricular response following anesthesia induction. This presentation suggests catecholamine surge due to pheochromocytoma. Patients are most commonly diagnosed in their 40s after an adrenal mass is incidentally discovered on imaging or symptoms are unmasked by a precipitating factor (eg, anesthesia induction, pregnancy, excessive physical activity). The classic triad of headache, diaphoresis, and palpitations is uncommon; ~50% of patients have paroxysmal hypertension. Nearly 95% of tumors are located in the abdomen, and 85% of these are in the adrenals. Most are benign but nearly 10% have malignant potential. In patients with high pretest probability, both urine and plasma metanephrines should be checked; in patients with low pretest probability, negative urine catecholamines alone rule out the condition. Positive results should be followed by abdominal imaging (eg, CT scan or MRI); patients with unremarkable imaging may need additional testing (eg, radiolabeled metaiodobenzylguanidine [MIBG] scan) to locate the tumor. Treatment includes initial preoperative alpha blockade (eg, phenoxybenzamine) followed by low-dose beta blocker (eg, propranolol) (titrated to heart rate) and surgical resection/adrenalectomy (not always curative). high pretest probability (Choice A) Anticoagulation is indicated to reduce the risk of embolic stroke in many patients with paroxysmal or permanent AF. However, this patient's isolated episode of AF, likely precipitated by pheochromocytoma, is not an indication for anticoagulation. (Choice B) An electrophysiology study can locate the accessory pathway in patients with AF due to Wolff-Parkinson-White syndrome. However, these patients do not typically have hypertensive crisis during episodes of supraventricular tachycardia. (Choice C) Opioid withdrawal typically causes gastrointestinal symptoms (eg, vomiting, diarrhea) and mydriasis (pupillary dilation) and does not lead to the degree of severe hypertension and tachycardia seen in this patient. (Choice E) Flecainide is a class 1c antiarrhythmic agent used to maintain sinus rhythm in patients with paroxysmal AF without underlying structural cardiac disease. This patient had a single episode of AF lasting for a few hours, which does not warrant treatment with flecainide. Educational objective: Pheochromocytoma may be clinically silent in many patients until symptoms are unmasked by a precipitating factor (eg, anesthesia induction). For initial diagnostic testing, plasma and urine metanephrines should be measured. If these are elevated, CT scan or MRI should be performed to check for an adrenal mass. __________ References: Pheochromocytoma. (http://www.ncbi.nlm.nih.gov/pubmed/16112304) The North American Neuroendocrine Tumor Society consensus guideline for the diagnosis and management of neuroendocrine tumors: pheochromocytoma, paraganglioma and medullary thyroid cancer. (http://www.ncbi.nlm.nih.gov/pubmed/20664475)

A 52-Year-Old Woman Is Undergoing Screening Colonoscopy and Receives Midazolam