FRI231 Pheochromocytoma - A Silent Killer

Disclosure: K. Le: None. H. Shakeel: None. M.T. Sheehan: None. S. Sen: None. E. Paal: None. Background: Pheochromocytoma, a neuroendocrine tumor that develops in the adrenal medulla, can be fatal to patients who have to undergo surgery if left undiagnosed. It often presents with episodic headache, palpitations, sweating and paroxysmal hypertension (HTN). However, some patients can be asymptomatic, making the diagnosis challenging in an acute setting. Clinical Case: A 59-year-old male with a past medical history of previously well-controlled Type 2 Diabetes Mellitus, HTN, and hyperlipidemia was referred to the emergency department by his primary care physician due to an elevated blood glucose level associated with symptoms of polyuria, polydipsia, and increased fatigue. Upon arrival, blood glucose level was 603 mg/dl with an elevated beta-hydroxybutyrate (a ketone body) of 1.35 mmol/L (reference 0.00-0.24), but a normal anion gap and acidic pH. He was admitted for further glycemic control with IV fluids and subcutaneous insulin. Hemoglobin A1C was 15.5% on admission, which had markedly increased from 6.9% six months prior when patient was on metformin alone. The patient attributed his worsening glycemic control to dietary indiscretion. Given the rapid increase in A1C and uncontrolled glucose level, a CT abdomen/pelvis was done to rule out a pancreatic tumor. No pancreatic tumor noted, but a 4.7 x 5.2 x 5.3 cm right adrenal mass was seen (CT abdomen showed a large right adrenal mass with peripheral enhancement and necrotic center characteristics). Further testing revealed markedly elevated normetanephrine levels of 2583 pg/ml (normal < 148) with a slight increase in metanephrines 73 pg/mL (normal <57). Levels of aldosterone, plasma renin activity, DHEAS and midnight cortisol were within normal limits. Interestingly, prior to admission, patient’s BP was not controlled (ranges 140s-170s/60s-90s) even on three antihypertensives (Hydrochlorothiazide (HCTZ), Valsartan, & Amlodipine). HCTZ was discontinued and Prazosin was initiated prior to surgery to control intra-operative hypertension. The patient underwent right adrenalectomy without complications. On discharge he was maintained on Prazosin, valsartan, and amlodipine for hypertension and Lantus 28-unit qAM along with Aspart 4-unit premeal for diabetes. Four months post-operatively, normetanephrine (121 pg/ml) and metanephrine (25 pg/ml) levels were within normal limits. In addition, A1c went down to 6.2% on a much lesser regimen of hypoglycemic agents (Lantus 15 units qAM & Metformin only) and antihypertensive regimen went down to amlodipine with BP well controlled, ranging from 130s-140s/60s-80s. Conclusion: This case highlights the importance of familiarity with the different presentations of pheochromocytoma (i.e. uncontrolled and challenging hyperglycemia, persistent uncontrolled hypertension, without any obvious physical signs) to healthcare providers as it can be mistreated if left undiagnosed. Presentation: Friday, June 16, 2023