Secondary hypertension can be caused by which condition?

• A. Kidney disease
• B. Obesity
• C. Primary hyperthyroidism
• D. Salt sensitivity

Answer: (A)

Secondary hypertension is high blood pressure that has an identifiable underlying cause. Kidney disease fits this pattern because the kidneys regulate blood pressure through fluid balance and the renin–angiotensin–aldosterone system. When kidney function is impaired or renal perfusion drops, renin release increases, angiotensin II causes vasoconstriction, and aldosterone promotes sodium and water retention. The result is higher blood pressure that stems from a specific pathological process in the kidneys.

Obesity raises blood pressure and is a major risk factor for developing essential (primary) hypertension, but it’s not a discrete underlying disease that directly drives a secondary form of hypertension. Salt sensitivity describes how blood pressure responds to salt intake and is also more about a pattern seen in primary hypertension rather than a separate disease causing hypertension. Primary hyperthyroidism can influence BP, but it’s not one of the classic, identifiable secondary causes doctors rely on when defining secondary hypertension.