Primary aldosteronism: diagnosis and noninvasive lateralization procedures

Area of Science:

• Endocrinology
• Nephrology
• Surgical Pathology

Background:

• Primary aldosteronism is a common cause of secondary hypertension.
• Accurate subtyping of primary aldosteronism is crucial for guiding treatment decisions.
• Distinguishing aldosterone-producing adenoma (APA) from idiopathic adrenal hyperplasia (IAH) presents diagnostic challenges.

Purpose of the Study:

• To evaluate the diagnostic utility of clinical, laboratory, and imaging data in differentiating APA from IAH.
• To compare the accuracy of computed tomography (CT) and adrenal scintiscanning in classifying adrenal pathology.

Main Methods:

• Analysis of clinical and laboratory data, including supine and upright plasma aldosterone and plasma renin activity.
• Review of imaging results from computed tomography (CT) and adrenal scintiscan in 72 patients with primary aldosteronism.
• Correlation of diagnostic findings with histopathological classification post-adrenalectomy.

Main Results:

• Routine clinical and laboratory data showed limited value in differentiating APA (n=59) from IAH (n=13).
• Computed tomography correctly classified adrenal lesions in 80% of patients, superior to adrenal scintiscan (69%).
• Adrenal scintiscan exhibited a high rate of incorrect results, and small adenomas (<1 cm) and hyperplasia can be missed by CT.

Conclusions:

• Clinical and biochemical markers are insufficient for definitive differentiation between APA and IAH.
• Computed tomography is a more reliable imaging modality than adrenal scintiscan for classifying adrenal pathology in primary aldosteronism.
• Limitations in imaging detection necessitate careful interpretation, especially for small adenomas and adrenal hyperplasia.