Bilateral aldosterone-producing adenomas: differentiation from bilateral adrenal hyperplasia.
BACKGROUND
Primary aldosteronism (PA) is a common curable disease of secondary hypertension. Most such patients have either idiopathic bilateral adrenal hyperplasia (BAH) or unilateral aldosterone-producing adenoma (APA). Bilateral APAs are reportedly extremely rare.


OBJECTIVE
To compare the distinctive characteristics, clinical course, and outcomes of bilateral APA vs. BAH.


METHODS
Retrospective record review.


METHODS
From July 1994 to Jan 2007, 190 patients diagnosed with PA underwent surgical intervention at our hospital. Bilateral APA was diagnosed in 7/164 patients with histologically-proven APA. Twenty-one patients diagnosed as BAH, and 21 randomly selected of unilateral APA patients, matched by age and sex served as controls.


RESULTS
Patients with bilateral APA had similar blood pressure, arterial blood gas analysis, spot urinary potassium to creatinine ratio and clinical symptoms to those with BAH, but lower serum potassium levels (p = 0.027), lower plasma renin activity (p = 0.037), and higher plasma aldosterone concentrations (p = 0.029). Aldosterone-renin ratio (ARR) after administration of 50 mg captopril was higher in bilateral APA than in BAH patients (p = 0.023), but not different between unilateral APA and BAH (p = 0.218). A cut-off of ARR >100 ng/dl per ng/ml/h and plasma aldosterone >20 ng/dl after captopril significantly differentiated bilateral APA from BAH. Bilateral subtotal adrenalectomy normalized blood pressure and biochemistry in all patients with bilateral APA.


CONCLUSIONS
Bilateral APA, presenting simultaneously or sequentially, may not be a rare disease, accounting for 4.3% of APA in this sample. The clinical presentations of bilateral functional adenoma are not different from BAH, but patients with low serum potassium and ARR >100 after captopril should be carefully evaluated for bilateral adenoma.
Wu
V C
VC
Clinical Research Building, Department of Internal Medicine, National Taiwan University Hospital, No. 7 Chung-Shan South Road, Taipei 100, Taiwan.
Chueh
S C
SC
Chang
H W
HW
Lin
W C
WC
Liu
K L
KL
Li
H Y
HY
Lin
Y H
YH
Wu
K D
KD
Hsieh
B S
BS
D000236:Adenoma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D000306:Adrenal Cortex Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D000311:Adrenal Glands / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000096:biosynthesis*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000378:metabolism / Q000473:pathology; D006965:Hyperplasia / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies
D000450:Aldosterone