Overview
Clinical Meaning
Pheochromocytomas are catecholamine producing tumors arising from chromaffin cells of the adrenal medulla (90%) or extra adrenal paraganglia (paragangliomas — 10%).
WHNP
WHNP
Pheochromocytomas are catecholamine-producing tumors arising from chromaffin cells of the adrenal medulla (90%) or extra-adrenal paraganglia (paragangliomas — 10%). These tumors synthesize, store, and episodically release catecholamines (norepinephrine, epinephrine, and dopamine) in massive, unregulated quantities. Norepinephrine activates alpha-1 receptors (vasoconstriction → severe hypertension) and beta-1 receptors (tachycardia, increased contractility). Epinephrine activates beta-2 receptors (vasodilation, bronchodilation, hyperglycemia via glycogenolysis) in addition to alpha and beta-1 effects. The episodic nature of catecholamine release causes paroxysmal symptoms: the classic triad of headache, diaphoresis, and palpitations with hypertension. Sustained catecholamine excess causes catecholamine cardiomyopathy (myocardial stunning, takotsubo-like syndrome, dilated cardiomyopathy), malignant hypertension, and metabolic effects (hyperglycemia, weight loss). The '10% rules' (10% bilateral, 10% extra-adrenal, 10% malignant, 10% pediatric) have been revised upward — genetic predisposition is found in 30-40% of cases (SDHx, VHL, RET, NF1 mutations).
Unlock full lesson + practice questions
4 more sections with scenarios, priorities, and review drills.
Final rapid review before practice
Next study step
Finish the lesson first, then choose a focused activity to apply what you just reviewed.
Continue studying
Sign in to save progress on this lesson.
Unlock the interactive lesson quiz with a plan that includes this WHNP pathway. You can still explore topic-filtered questions from the bank hubs below.