Pheochromocytoma

Epidemiology

Classic Triad: Episodic Palpitations, Headache, and Diaphoresis (sweating). This triad combined with hypertension is highly suggestive.
Hypertension: Can be sustained or paroxysmal (episodic) and is the clinical hallmark. May present as a hypertensive crisis.
Other Symptoms (the "5 Ps"): In addition to the triad, patients may experience high Pressure (HTN) and Pallor. Anxiety, a sense of impending doom, tremor, and weight loss are also common.

Condition	Key Differentiating Features	Confirmatory Test
Anxiety/Panic	Psychological triggers; lacks severe paroxysmal HTN; may respond to psychiatric meds.	Normal metanephrines.
Hyperthyroidism	Persistent symptoms (not spells); goiter, proptosis; fine tremor.	Low TSH, High T4/T3.
Carcinoid Syndrome	Classic triad: Flushing, Diarrhea, Wheezing; right-sided heart valve disease.	High urinary 5-HIAA.
Illicit Drug Use	History of use; positive urine toxicology screen.	Positive tox screen; metanephrines normalize with abstinence.
Clonidine Withdrawal	History of abrupt clonidine cessation; symptoms resolve with clonidine re-administration.	Clonidine suppression test.
Essential HTN	Often asymptomatic; lacks paroxysmal spells; responds to standard antihypertensives.	Normal metanephrines.

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