Management of a Paraganglioma in a Fontan Patient: A Complex Case of Adrenergic Imbalance and Perioperative Care.

Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors that secrete catecholamines. They can induce severe hypertension and tachycardia; thus, complicating the health of patients with stabilized congenital heart disease. Chronic hypoxemia is a potential driver for tumor development as discovered by the role of hypoxia-inducible factors in tumorigenesis. This case report describes a 24-year-old woman with hypoplastic left heart syndrome and fenestrated Fontan palliation who developed an adrenergic crisis following adjustments to her medications. She was initially on metoprolol for ventricular ectopy and suspended it to initiate phenoxybenzamine, an alpha-blocker, in preparation for surgical removal of a hormonally active retroperitoneal paraganglioma. Six days after discontinuation of the metoprolol, she presented to the emergency department with severe abdominal pain, palpitations, and nausea. The evaluation revealed supraventricular tachycardia and elevated blood pressure, which did not respond to initial treatments. She was admitted to the cardiac intensive care unit where she experienced further deterioration, necessitating intubation and treatment with amiodarone for rhythm control of her identified ectopic atrial tachycardia. Following stabilization and successful extubation, the patient was discharged on a regimen including amiodarone, metoprolol, and doxazosin. She successfully had her surgery in the following months and was weaned off amiodarone and metoprolol while remaining free of arrhythmias. This case highlights the complexities of managing PPGLs in Fontan patients and emphasizes the importance of multidisciplinary care to prevent and manage adrenergic crises.