What should be done for a 35-year-old patient with newly controlled Hypertension (HTN) on lisinopril (Angiotensin-Converting Enzyme Inhibitor) who presents with palpitations and diaphoresis?

Urgent Evaluation for Secondary Hypertension (Pheochromocytoma)

This 35-year-old patient with newly diagnosed hypertension presenting with episodic palpitations and diaphoresis requires immediate screening for pheochromocytoma, as this triad of symptoms in a young hypertensive patient is highly suggestive of a catecholamine-secreting tumor. 1, 2

Immediate Diagnostic Workup

Screen for Pheochromocytoma

• Obtain 24-hour urine collection for metanephrines and vanillylmandelic acid (VMA) or plasma free metanephrines immediately 2, 3
• The combination of hypertension, palpitations, and diaphoresis represents the classic triad of pheochromocytoma, which can present with paroxysmal symptoms even when blood pressure appears controlled between episodes 2, 4
• Young age (35 years) makes secondary hypertension more likely than essential hypertension 1

Additional Critical Testing

• 12-lead ECG to evaluate for arrhythmias as palpitations may indicate atrial fibrillation or other arrhythmias common in hypertensive patients 1, 5
• Serum electrolytes (potassium, magnesium, calcium), renal function, and glucose to identify metabolic causes 1, 6
• Thyroid function tests to exclude hyperthyroidism as a cause of palpitations and diaphoresis 5

Clinical Context and Risk Assessment

Why Pheochromocytoma Must Be Ruled Out

• Pheochromocytoma can cause catastrophic complications including hemorrhagic stroke, even in young patients 3
• The tumor occurs in less than 1% of hypertensive patients but is life-threatening if missed 4
• Paroxysmal symptoms (episodic rather than continuous) are characteristic of catecholamine-secreting tumors 2, 4
• If pheochromocytoma is present, continuing ACE inhibitor monotherapy without alpha-blockade first is dangerous 6, 2

Alternative Diagnoses to Consider

• Paroxysmal hypertension syndromes including panic attacks, pseudopheochromocytoma, or baroreflex failure present similarly but require different management 4
• Cardiac arrhythmias (atrial fibrillation, supraventricular tachycardia) are common in hypertensive patients and cause palpitations 1
• Hyperthyroidism can mimic these symptoms 5

Management Pending Workup

Blood Pressure Control

• Continue lisinopril but do NOT add beta-blockers until pheochromocytoma is excluded 6, 2
• Beta-blockade without prior alpha-blockade in pheochromocytoma can precipitate hypertensive crisis 2
• If blood pressure remains uncontrolled, add a calcium channel blocker (amlodipine 5-10 mg daily) or thiazide-like diuretic (chlorthalidone 12.5-25 mg daily) as these are safe in pheochromocytoma 1

Monitoring and Follow-up

• If pheochromocytoma screening is positive: immediate referral to endocrinology and initiation of alpha-blockade (phenoxybenzamine or doxazosin) before any surgical intervention 2, 3
• If screening is negative: consider 24-48 hour Holter monitoring to capture arrhythmias during symptomatic episodes 5
• Assess for other secondary causes including renal artery stenosis, primary aldosteronism, or obstructive sleep apnea 1

Critical Pitfalls to Avoid

• Never start beta-blockers in a patient with suspected pheochromocytoma before alpha-blockade as this can cause unopposed alpha-adrenergic stimulation and severe hypertensive crisis 2
• Do not dismiss paroxysmal symptoms as anxiety without excluding organic causes, particularly in young-onset hypertension 3, 4
• Avoid attributing symptoms to ACE inhibitor side effects (which typically cause cough, not palpitations and diaphoresis) 6
• Do not delay imaging (abdominal CT or MRI) if biochemical testing suggests pheochromocytoma 2, 3

If Pheochromocytoma is Confirmed

• Initiate alpha-adrenergic blockade first (doxazosin starting at 1 mg daily, titrating to effect) for at least 7-14 days 2, 3
• Add beta-blocker only after adequate alpha-blockade is established 2
• Ensure adequate hydration and salt intake to expand intravascular volume 2
• Refer for surgical resection after medical optimization 3
• Consider genetic testing for hereditary paraganglioma syndromes (SDHB, SDHD mutations) especially given young age 3