SAT-181 Pheochromocytoma Masquerading as Acute Coronary Syndrome. To Cath or Not to Cath?

Background Pheochromocytoma had been known as the “Great Mimic” as it can present with signs and symptoms consistent with numerous differentials [1]. Cardiac ischemia is one in particular which creates a diagnostic dilemma and poses significant risk for misdiagnosis. Clinical Case 62-year-old female with recent onset hypertension and type II diabetes(HbA1C of 6.9%) presented to the ER with new episodes of nausea, vomiting, and substernal chest pain. During the preceding four months she also experienced episodic headaches, palpitations, and flushing. Initial vital signs were significant for blood pressure 157/81 mm Hg. Physical exam was unremarkable. An Electrocardiogram showed normal sinus rhythm with right axis deviation and ST segment depressions in the inferior leads II, III and aVF. Labs revealed a troponin peak at 2.95 (<0.04 ng/mL) and d-dimer of 403 (<400 ng/mL). Serum chemistry, TSH, and complete blood count were within normal limits. A CT Chest with angiography was negative for pulmonary emboli. However, it did note a heterogenous 7.6 cm right adrenal mass. At this juncture there was clinical concern for pheochromocytoma and serum free metanephrines was ordered. Prior to receiving medical treatment for her pheochromocytoma, she underwent cardiac catheterization which showed no evidence of coronary artery disease. The procedure was uncomplicated. However, post-procedurally she did develop worsening paroxysms and severe hypertensive episodes with heart rate up to 140 beats per minute and systolic blood pressure up to 220 mm Hg. She was subsequently started on alpha blockage with phenoxybenzamine 10mg twice daily to which she responded favorably. Her initial serum free metanephrine was 6087(< 57 pg/mL) and free normetanephrine 2489 (<148 pg/mL). Conclusions This case highlights the importance of maintaining a high index of suspicion for pheochromocytoma for all patients with acute chest pain and hypertension. Her untreated pheochromocytoma could have been fatal during or immediately after the cardiac catheterization. Given the suspicion for pheochromocytoma in this case, it would have been most appropriate to have begun alpha blockade after blood was drawn for metanephrines and before attempting any invasive procedures. Pheochromocytoma should be included in the differential diagnosis of acute coronary syndrome because it can mimic an ischemic episode. References: 1. Soltani A, Pourian M, Davani BM. Does this patient have Pheochromocytoma? a systematic review of clinical signs and symptoms. J Diabetes Metab Disord. 2016 Mar 17;15:6. doi: 10.1186/s40200-016-0226-x. Erratum in: J Diabetes Metab Disord. 2017 Oct 16;16:42. PMID: 26998444; PMCID: PMC4797176.