Diagnosing Secondary Hypertension

Secondary hypertension arises from underlying medical conditions, such as renal or endocrine disorders, rather than primary causes. Clinical indicators include onset before age 40, resistant hypertension requiring multiple agents, or sudden worsening of blood pressure. Primary aldosteronism represents the most common endocrine cause, often presenting insidiously without classic symptoms. Diagnostic approaches prioritize the aldosterone-renin ratio, ideally performed before initiating antihypertensive therapy to avoid interference with the renin-angiotensin-aldosterone system. While renal vascular disease and obstructive sleep apnea also contribute to secondary hypertension, screening for rarer conditions like pheochromocytoma should remain symptom-driven to minimize false positives. Clinical evaluation requires a thorough cardiovascular examination, including assessment for radio-femoral delay and signs of target organ damage, alongside a detailed medication history to exclude drug-induced causes.