Endocrine Abstracts

Introduction: Pheochromocytoma is a rare catecholamine-secreting neuroendocrine tumour. A catecholamine crisis may be precipitated by certain drugs including β-blockers, steroids, anaesthetic agents, and nitrates. Reports of glyceryl trinitrate (GTN)-induced pheochromocytoma crisis are exceptionally rare, but recognition is critical to prevent catastrophic outcomes.

Case: A 50-year-old previously healthy male presented with a 4-year history of recurrent palpitations, tachycardia, sweating, anxiety, and episodic hypertension. Despite multiple attendances to the Emergency Department and outpatient cardiology assessments, no definitive diagnosis was made. During further evaluation, GTN spray was administered, precipitating a severe catecholamine crisis with haemodynamic collapse requiring intensive care. Urinary catecholamines were found to be elevated, with normetanephrines nine times the upper limit of normal MRI abdomen revealed a 49 × 44 × 47 mm T2-hyperintense left adrenal mass. A 68Ga-DOTATATE PET/CT confirmed no extra-adrenal disease. The patient underwent laparoscopic left adrenalectomy in 2025. Postoperatively, his symptoms resolved, and plasma metanephrines and urinary catecholamine metabolites normalised. MEN screening (calcitonin, calcium, 5-HIAA, chromogranin A and B) was unremarkable.

Discussion: This case demonstrates both the diagnostic delay common in pheochromocytoma and the risk of pharmacologically induced crisis. GTN can provoke abrupt catecholamine release through vasodilatation and reflex sympathetic activation, precipitating life-threatening haemodynamic instability.

Conclusion: GTN should be avoided in suspected or confirmed pheochromocytoma due to the risk of precipitating crisis. Early recognition, appropriate biochemical testing, and awareness of drug triggers are vital in order to prevent a potentially avoidable crisis being provoked.

References: 1. Giraud R, et al. J Clin Med. 2025;14(6):1907. 2. Lichter Y, et al. J Emerg Crit Care Med. 2022;6:45. 3. Lenders JWM, et al. J Clin Endocrinol Metab. 2014;99(6):1915–1942. 4.  Bechmann N, et al. Preoperative management of catecholamine-producing tumours. Journal of endocrine surgery 2025