Pheochromocytoma.

Pheochromocytomas cause the most dramatic life-threatening crises in all of endocrinology. Pheochromocytoma is an explosive clinical syndrome that may be characterized by either severe hypertension associated with cerebral, cardiac, and renal complications or hypotension, or even shock and sudden death. Other emergencies include lactic acidosis, hypoglycemia, hypercalcemic crisis, severe hypokalemic alkalosis, and acute bowel obstruction due to bowel ischemia, necessitating prompt surgical intervention. Better understanding of the mechanisms of catecholamine action and the pathophysiology of pheochromocytoma and the availability of various treatment modalities have made successful management more promising than ever before.