USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

What is the primary diagnosis when a patient presents with hypertension and hypokalemia, along with decreased renin and increased aldosterone?

1. Aldosterone production tumor

2. Bilateral adrenal hyperplasia

3. CAH

4. Adrenal tumor

The correct answer is: Bilateral adrenal hyperplasia

The scenario presented involves a patient with hypertension, hypokalemia, decreased renin, and increased aldosterone levels. This clinical picture is indicative of primary hyperaldosteronism, commonly known as Conn's syndrome. When examining the components of the patient's condition, the key elements are the elevated levels of aldosterone and the decreased levels of renin. In primary hyperaldosteronism, either due to an adrenal adenoma or idiopathic bilateral adrenal hyperplasia, the excessive production of aldosterone occurs independently of the renin-angiotensin system, leading to suppression of renin secretion. In this case, since the condition mentioned corresponds specifically to bilateral adrenal hyperplasia, which results in overproduction of aldosterone from both adrenal glands, it explains the combination of hypertension and hypokalemia due to excessive sodium retention and potassium excretion. This form of hyperaldosteronism is more common than unilateral adrenal adenoma and fits the clinical picture well. While an aldosterone-producing tumor could also cause similar symptoms, the hallmark of bilateral adrenal hyperplasia differentiates it as the primary diagnosis here. In conditions such as congenital adrenal hyperplasia (CAH), there are usually other hormonal abnormalities and a different clinical presentation. Thus, in this