A 12-year-old boy is brought to the clinic by his parents due to a 3-month history of episodic headaches, rapid heartbeat, and profuse sweating. The mother describes these episodes as “spells” that occur unexpectedly, lasting up to an hour, and leaving him exhausted. He has lost 4 kg (8.8 lbs) over this period despite a normal appetite. He has no significant past medical history, takes no medications, and has no known allergies. Family history is notable for a paternal uncle who had surgery for a “neck tumor” in his twenties. He appears anxious and pale. He is afebrile. His blood pressure is 155/100 mmHg with a heart rate of 115 bpm.