Review Question - QID 100417

This patient’s presentation is consistent with a pheochromocytoma producing excessive levels of catecholamines (epinephrine and norepinephrine). Common symptoms of pheochromocytoma include: episodic hypertension, palpitations, tachycardia, diaphoresis, tremors, anxiety, and headache.

Increased plasma free metanephrines (breakdown product of catecholamines) is the gold standard test for screening and diagnosis of pheochromocytoma. Repetitive paroxysmal episodes consisting of the symptoms described above are classic for a catecholamine-secreting tumor. Pheochromocytomas most often are the result of a benign unilateral adenoma arising in the adrenal medulla.

Hart discusses the diagnosis and management of pheochromocytoma, concluding that it is an uncommon but possibly deadly cause of hypertension that can be remedied through surgical excision. The location of the lesion and intermittent nature of catecholamine release from the pheochromocytoma can make the diagnosis challenging. Optimal management includes pre-operative treatment with alpha-adrenergic blocking agents.

Pacak et al. review the disease associations of pheochromocytoma. They conclude that pheochromocytoma/paraganglioma is a rare catecholamine-secreting tumor that is invariably fatal without prompt recognition and proper treatment. Patients with MEN2 who suffer from this condition have more paroxysmal attacks and more frequently have hypertension and other cardiovascular problems in comparison to patients with VHL who have this condition.

Illustration A depicts a CT scan of a pheochromocytoma in the left adrenal medulla.

Incorrect Answers:
Answer 1: VMA levels would be expected to increase in the setting of catecholamine excess, as VMA is a degradation product of both norepinephrine and epinephrine.
Answer 3: Hyperhidrosis (excessive sweating), not anhidrosis, is a common manifestation of pheochromocytoma.
Answer 4: Increased levels of catecholamines inhibit peristalsis, leading to ileus and decreased intestinal motility, not diarrhea.
Answer 5: Hyperglycemia is more common in pheochromocytoma due to increased glycogenolysis and gluconeogenesis.