Inhibitor of Tyrosine Hydroxylase and Catecholamine-induced Cardiomyopathy in Pheochromocytoma

Abstract

Usual clinical presentation of secreting pheochromocytoma is headache, palpitations, sweating and paroxysmal hypertension but emergency situations are also described. We herein reported a case of pheochromocytoma revealed by cardiogenic shock on dilated cardiomyopathy with improvement of left ventricular ejection fraction (LVEF) after the introduction of an inhibitor of tyrosine hydroxylase. A 41-year-old patient was admitted in the ICU for cardiogenic shock with initially hypertension emergency and tachycardia. Transthoracic echocardiography revealed a dilated cardiomyopathy with estimated 2-dimensional LVEF at 15 %. A computed tomography angiography was performed to rule out a pulmonary embolism and led to discover bilateral adrenal tumors measured at 3 cm and 2 cm respectively on the left and right sides. Plasmatic noradrenaline was increased 5.5 μg/L ( N < 0.60). 123I-metaiodobenzylguanidine scintigraphy, 18F-fluorodeoxyglucose and FDOPA positron emission tomography showed uptake of the 2 lesions. Despite an optimized heart failure treatment including an angiotensin-converting-enzyme inhibitor, a diuretic, an inhibitor of aldosterone and increasing doses of beta-blocker in addition to a calcic-blocker and alpha-blocker for hypertension, a stagnation of LVEF around 20 % was still observed ten weeks after diagnosis, contraindicating the patient for adrenal surgery. The addition of an inhibitor of tyrosine hydroxylase (metyrosine, 1500 mg/day) led to a dramatic decrease of blood metanephrines (0.21 versus 1.42 μg/L before the introduction), even if results must be interpreted with caution regarding possible interference with this different medicine. Moreover, LVEF improved up to 40 % within 22 weeks allowing the bilateral adrenelactomy. Pathology results confirmed the diagnosis of benign bilateral pheochromocytomas. Genetic analysis showed a MAX mutation (c.145T > C, p.S49P). Congestive heart failure has a poor prognosis unless a correctable cause is identified. For the treatment of pheochromocytoma, surgical removal of tumor is the first choice but in particular cases, using an inhibitor of tyrosine hydroxylase could be a short-term alternative in preparation to surgery.