Correct Answer
Your Answer: Primary hyperaldosteronism
Only 5-10% of patients with hypertension have a secondary cause, but it is important to identify these patients for curative management. Secondary causes of hypertension mostly result from hormonal or renovascular abnormalities, or both.
Primary hyperaldosteronism is a common cause of secondary hypertension, with a prevalence of 5-20% among resistant hypertensive patients - in other words, those who do not reach their BP goal on full doses of an appropriate three-drug regimen including a diuretic.
Primary hyperaldosteronism results from an autonomous excess production of aldosterone by the adrenal gland due to a tumor or adrenal hyperplasia. It causes an increase in intravascular volume and chronic suppression of renin activity.
Hypokalemia is a prominent feature in many patients with this condition, particularly if they have received diuretic therapy.
References:
Calhoun DA, Zaman MA, Nishizaka MK. Resistant hypertension. Curr Hypertens Rep 2002;4:221–8.
Oparil S, Zaman MA, Calhoun DA. Pathogenesis of hypertension. Ann Intern Med (in press).
Stowasser M. Primary aldosteronism: Rare bird or common cause of secondary hypertension. Curr Hypertens Rep 2001;3:230–9.