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Zorluk: Çok zorDiagnostic Workup and Test Sequencing

A 4545-year-old man is evaluated for resistant hypertension. His blood pressure is 168/98168/98 mmHg despite adherence to maximum tolerated doses of amlodipine, lisinopril, and hydrochlorothiazide. Laboratory studies reveal a serum potassium level of 2.92.9 mEq/L. The patient is transitioned to doxazosin and verapamil to stabilize his blood pressure without interfering with hormonal testing. Four weeks later, his plasma aldosterone-to-renin ratio is 4545 ng/dL per ng/(mL ⋅\cdot h) (normal <20< 20). An intravenous saline infusion suppression test demonstrates a post-infusion plasma aldosterone concentration of 1414 ng/dL (normal <5< 5 ng/dL), confirming primary aldosteronism. A dedicated adrenal-protocol computed tomography (CT) scan reveals a 1.51.5-cm hypodense nodule in the left adrenal gland and a normal-appearing right adrenal gland. The patient is otherwise healthy and expresses a strong preference for definitive surgical management if feasible. Which of the following is the most appropriate next step in the diagnostic workup?

  1. A
    Left laparoscopic adrenalectomy
  2. B
    Magnetic resonance imaging of the abdomen
  3. C
    Initiation of spironolactone therapy
  4. Adrenal venous samplingCevap
  5. E
    Repeat plasma aldosterone-to-renin ratio

Cevap

Adrenal venous sampling
The correct answer is adrenal venous sampling (AVS). The diagnostic sequencing for primary aldosteronism involves three distinct phases: screening, biochemical confirmation, and subtype classification (localization). This patient has already undergone appropriate screening (elevated aldosterone-to-renin ratio) and confirmation (failure to suppress aldosterone with intravenous saline). The next step for patients who desire and are candidates for surgical cure is localization. While the adrenal CT shows a unilateral nodule, CT imaging is notoriously inaccurate for determining the functional source of aldosterone excess in patients over age 3535. Because non-functioning adrenal incidentalomas become increasingly common with age, a unilateral nodule seen on imaging might be non-functioning, while the actual aldosterone excess stems from radiographically occult bilateral micronodular hyperplasia. Therefore, guidelines mandate AVS to definitively lateralize aldosterone production in all patients >35> 35 years old before unilateral adrenalectomy is performed. Patients <35< 35 years old with spontaneous hypokalemia, marked aldosterone excess, and a unilateral cortical adenoma on CT may bypass AVS and proceed directly to surgery.

Adım Adım Çözüm

1
Identify the patient's confirmed diagnosis.
The patient has biochemically confirmed primary aldosteronism (positive screening ratio, positive saline suppression test).
Establishing the definitive biochemical diagnosis is the first step before pursuing localization studies.
2
Evaluate the initial localization imaging.
Adrenal CT shows a unilateral 1.5-cm left adrenal nodule. The patient desires surgical management.
CT imaging helps identify large masses (e.g., adrenocortical carcinoma) and outlines venous anatomy, but is often functionally misleading.
3
Determine the indication for functional lateralization testing based on patient age and imaging.
Because the patient is older than 35, the structural finding on CT must be functionally confirmed using adrenal venous sampling.
Non-functioning adrenal incidentalomas are highly common in older adults. Adrenal venous sampling differentiates a functional unilateral adenoma from bilateral hyperplasia with an incidental non-functioning nodule.

Anahtar Kavram

In patients older than 3535 years with confirmed primary aldosteronism who are candidates for surgery, adrenal venous sampling (AVS) is required to functionally lateralize aldosterone production, even if a unilateral nodule is present on CT imaging.
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Diagnostic Workup and Test Sequencing

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