Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which hormone levels are typically altered in Conn's syndrome?

1. Elevated renin

2. Decreased cortisol

3. Increased aldosterone

4. Decreased epinephrine

The correct answer is: Increased aldosterone

In Conn's syndrome, also known as primary hyperaldosteronism, the key hormonal alteration involves increased levels of aldosterone. This condition is primarily characterized by the excessive production of aldosterone from the adrenal glands, often due to an adenoma (a benign tumor) or hyperplasia of the adrenal cortex. The elevated aldosterone levels lead to sodium retention, potassium excretion, and an increase in blood pressure as a result of sodium and water retention. The scenario is characterized by a feedback mechanism where elevated aldosterone causes suppression of renin due to increased blood volume and pressure; therefore, renin levels would typically be low rather than elevated. The production of cortisol, another hormone from the adrenal cortex, remains intact, so cortisol levels are generally normal, and noradrenergic activity, as reflected in epinephrine, is not the primary concern in Conn's syndrome. Understanding these hormonal dynamics is essential in diagnosing and managing conditions like Conn's syndrome, emphasizing the significance of recognizing high aldosterone as the hallmark of this syndrome.