Hypertension: A High-Yield USMLE Review

Hypertension is chronically elevated arterial blood pressure that acts as a major risk factor for coronary artery disease, heart failure, peripheral arterial disease, and aortic dissection. On the exam it appears both as a silent risk factor driving atherosclerosis and remodeling and as an acute hypertensive emergency with end-organ damage. Recognizing its downstream cardiac consequences and identifying secondary/reversible causes are the key testable themes.

Presentation

• Often asymptomatic and found incidentally on routine measurement
• Severe elevations may present as hypertensive emergency with headache and papilledema (hypertensive encephalopathy) — evidence of end-organ damage
• Headaches and nosebleeds, particularly with upper-extremity hypertension from coarctation of the aorta
• An S4 gallop reflecting atrial contraction into a stiff, hypertrophied ventricle
• A key modifiable risk factor in patients presenting with chest pain/ACS, and a driver of poorly controlled disease that precipitates aortic dissection

Diagnosis

• Blood pressure measurement in both arms — a differential between arms should raise concern for aortic dissection, and arms-greater-than-legs (with radial–femoral delay) suggests coarctation
• Echocardiography — demonstrates left ventricular hypertrophy and preserved EF with elevated filling pressures in hypertensive/HFpEF hearts
• Fundoscopic exam — papilledema indicates hypertensive encephalopathy/emergency with end-organ damage
• Chest X-ray in suspected coarctation — 'figure 3' sign and rib notching from dilated intercostal collaterals in older patients

Management

• Hypertensive emergency (severe BP elevation with end-organ damage such as encephalopathy/papilledema) requires urgent, controlled blood pressure lowering
• Address secondary and reversible causes — e.g., surgical repair of coarctation of the aorta
• Cocaine-associated hypertension: use benzodiazepines to reduce sympathetic tone, plus calcium channel blockers/nitrates for vasospasm, and phentolamine for refractory hypertension
• Long-term risk-factor control and medication adherence to prevent CAD, heart failure remodeling, and aortic dissection

High-yield

• Pressure overload (hypertension, aortic stenosis) → concentric hypertrophy → diastolic dysfunction → eventual systolic dysfunction (Laplace law)
• S4 gallop = stiff ventricle of hypertension/HFpEF; hypertension is a leading cause of HFpEF along with aging, obesity, and diabetes
• BP 210/120 with headache and papilledema = hypertensive emergency (hypertensive encephalopathy)
• Coarctation = secondary hypertension: upper-extremity hypertension, BP arms > legs, radial–femoral delay, systolic murmur in the back, rib notching, 'figure 3' sign
• Poorly controlled hypertension is a classic setup for acute aortic dissection (tearing chest pain to the back, inter-arm BP differential)
• In cocaine-associated hypertension, avoid beta-blockers — unopposed alpha stimulation worsens vasospasm and hypertension

Pitfalls

• Giving a beta-blocker for cocaine-associated hypertension — unopposed alpha-adrenergic stimulation worsens vasospasm and raises blood pressure
• Overlooking an inter-arm blood pressure differential, which can signal aortic dissection rather than simple hypertension
• Forgetting that legs normally have BP ≥ arms — arms-greater-than-legs with radial-femoral delay points to coarctation as a secondary cause
• Attributing severe hypertension with headache to a benign cause and missing papilledema/end-organ damage that defines a hypertensive emergency