Examkin

Question

Difficulty: MediumEndocrinology and Metabolism

A 4242-year-old man presents to the clinic for follow-up of hypertension. His blood pressure remains poorly controlled at 165/100165/100 mmHg despite adherence to maximum doses of amlodipine, lisinopril, and chlorthalidone. Laboratory results reveal a serum potassium level of 3.13.1 mEq/L. The physician suspects secondary hypertension due to primary hyperaldosteronism.

Arrange the following diagnostic steps in the correct sequential order to evaluate and localize this patient's suspected condition.

  1. 1Measure plasma aldosterone concentration and plasma renin activity (PAC/PRA ratio)
  2. 2Perform an intravenous saline suppression test or oral salt loading
  3. 3Obtain a high-resolution computed tomography (CT) scan of the adrenal glands
  4. 4Perform bilateral adrenal venous sampling (AVS)

Answer

The correct sequence for the evaluation of primary hyperaldosteronism is: 1) Biochemical screening with a PAC/PRA ratio, 2) Confirmatory testing with salt loading, 3) Anatomical localization with an adrenal CT scan, and 4) Functional lateralization with adrenal venous sampling.
The correct evaluation of primary hyperaldosteronism follows a strict stepwise protocol to avoid unnecessary invasive procedures or surgeries. First, patients with risk factors (e.g., resistant hypertension, hypokalemia) undergo screening with a PAC/PRA ratio. If positive, the autonomous nature of aldosterone secretion must be confirmed, typically with a saline suppression test. Once the biochemical diagnosis is secure, anatomical imaging with an adrenal CT scan is performed. Finally, because non-functioning adrenal incidentalomas are common, particularly in older adults, adrenal venous sampling is required to functionally confirm which adrenal gland is hypersecreting aldosterone before pursuing surgical resection.

Step-by-Step Solution

1
Biochemical Screening
Measurement of plasma aldosterone concentration and plasma renin activity (PAC/PRA ratio).
To identify patients with possible primary hyperaldosteronism among those with resistant hypertension or hypokalemia.
2
Biochemical Confirmation
Intravenous saline suppression test or oral salt loading.
To definitively diagnose primary hyperaldosteronism by demonstrating that aldosterone production is autonomous and fails to suppress with sodium loading.
3
Anatomical Localization
High-resolution computed tomography (CT) of the adrenal glands.
To rule out large adrenocortical carcinomas and guide the radiologist prior to adrenal venous sampling.
4
Functional Lateralization
Bilateral adrenal venous sampling (AVS).
To distinguish between a unilateral aldosterone-producing adenoma (cured by surgery) and bilateral adrenal hyperplasia (treated medically), as CT imaging can be misleading due to non-functioning adrenal incidentalomas.

Key Concept

The diagnostic algorithm for primary hyperaldosteronism (Conn syndrome) strictly proceeds from biochemical screening to biochemical confirmation, followed by anatomical localization, and finally functional lateralization.
Estimated Time:1m 30s
Rate this question

Topics

Endocrinology and Metabolism

More questions from this topic