Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Successful extracorporeal membrane oxygenation resuscitation of patient with cardiogenic shock induced by phaeochromocytoma crisis mimicking hyperthyroidism: A case report

A 29-year-old woman presented to the emergency department with the acute onset of palpitations, shortness of breath, and haemoptysis. She reported having an abortion (56 days of pregnancy) 1 week before admission because of hyperthyroidism diagnosis during pregnancy. The first diagnoses considered were cardiomyopathy associated with hyperthyroidism, acute left ventricular failure, and hyperthyroidism crisis. The young woman’s cardiocirculatory system collapsed within several hours. Hence, venoarterial extracorporeal membrane oxygenation (VA ECMO) was performed for this patient. Over the next 3 days after ECMO was established, repeat transthoracic echocardiography showed gradual improvements in biventricular function, and later the patient recovered almost completely. The patient’s blood pressure increased to 230/130 mm Hg when the ECMO catheter was removed, and then the diagnosis of phaeochromocytoma was suspected. Computed tomography showed a left suprarenal tumour. The tumour size was 5.8 cm × 5.7 cm with central necrosis. The vanillylmandelic acid concentration was 63.15 mg/24 h. Post-operation, pathology confirmed phaeochromocytoma. To our knowledge, this is the first case report of a patient with cardiogenic shock induced by phaeochromocytoma crisis mimicking hyperthyroidism which was successfully resuscitated by VA ECMO.