Pheochromocytoma
Formal Definition
A catecholamine-secreting neuroendocrine tumor arising from the chromaffin cells of the adrenal medulla (extra-adrenal paragangliomas arise from sympathetic ganglia and are functionally similar); classically presents with the triad of episodic headache, sweating, and tachycardia/palpitations, alongside paroxysmal hypertension; diagnosis requires biochemical confirmation (elevated plasma free metanephrines or 24-h urinary fractionated metanephrines) followed by imaging (CT/MRI abdomen), and definitive treatment is surgical resection after alpha-blockade with phenoxybenzamine or doxazosin.
How It's Used on the Ward
"Pheo" — the rare adrenaline-producing tumor of the adrenal gland (about 0.1-0.6% of hypertensives); the classic teaching triad is headache + sweating + palpitations with episodic hypertension; think of it in patients with paroxysmal symptoms triaged to the ED multiple times before the diagnosis is finally made.
Example
""34-year-old woman with 4 ED visits in 6 months for hypertensive episodes (BP 220/118), headaches, diaphoresis, palpitations — each time discharged as "panic attack" or "anxiety." Plasma free metanephrines: 1,840 pg/mL (normal <205). CT abdomen: 4cm right adrenal mass with Hounsfield units 35, heterogeneous enhancement. Diagnosis: pheochromocytoma. Started phenoxybenzamine 10mg BID, titrated up over 2 weeks to BP normalization. Surgical date set after sufficient alpha-blockade.""
Clinical Context
"Rule of 10s": 10% bilateral, 10% extra-adrenal (paraganglioma), 10% malignant, 10% familial, 10% in children, 10% recur after surgery (less accurate now — up to 30% are familial, fewer malignant). Genetics: RET (MEN2A/2B), VHL, SDHB/SDHD (paraganglioma syndromes), NF1. Diagnostic testing: plasma free metanephrines (most sensitive single test), 24h urinary fractionated metanephrines and catecholamines. Imaging: CT/MRI abdomen to localize; MIBG or PET/CT for metastatic workup. Pre-op management: alpha-blockade FIRST (phenoxybenzamine non-selective or doxazosin selective, titrated over 7-14 days), then beta-blockade ONLY after adequate alpha-blockade (beta-blockade alone causes hypertensive crisis from unopposed alpha stimulation). Surgical removal (laparoscopic adrenalectomy if feasible). Rule out MEN2: check calcitonin/PTH/RET, plasma metanephrines, ionized calcium before surgery if suspicious.