Light-intensity Activity-related Nausea: An Unusual Presentation of Pheochromocytoma.

Pheochromocytomas are rare neuroendocrine tumors arising from chromaffin cells of the adrenal gland. Because of their highly variable clinical spectrum, these tumors often go undiagnosed and result in life-threatening complications. The typical presentations include episodic headache, palpitations and sweating accompanied with sustained or paroxysmal hypertension. However, less than half of pheochromocytoma patients have these classic symptoms. Many patients present with atypical symptoms, which could be overlooked. Our case represents an unusual presentation of pheochromocytoma, which is not well recognized as a possible manifestation. A 60-year-old woman presented with light-intensity-related nausea, which progressed to severe vomiting with hypovolemic shock. An unexpected adrenal mass was found during sonographic evaluation of the volume status. Pheochromocytoma was confirmed by 24-hour urine fractionated metanephrines and a computed tomography (CT) scan. In pheochromocytomas, the elevation of circulating catecholamines activates alpha-adrenergic receptors in the area postrema, which then initiates the emetic cascade. Light-intensity activity-related nausea and vomiting, especially when present with other symptoms of catecholamine excess, could be considered as a clinical presentation of pheochromocytomas.