Clinical characteristics and surgery outcomes of unilateral nodular adrenal hyperplasia in primary aldosteronism: study of 145 cases

Abstract

To investigate the clinical characteristics, differential diagnosis, and surgery outcome of unilateral nodular adrenal hyperplasia (UNAH). The clinical data of 145 patients with primary aldosteronism, 67 males and 78 females, aged 37.9 (19-60), including 78 cases of aldosterone-producing adenoma (APA), 14 cases of UNAH, and 55 cases of idiopathic bilateral adrenal hyperplasia (BAH), were collected. Radioimmunoassay was used to examine the blood and urine aldosterone and plasma rennin activity. Automatic biochemical apparatus was used to examine the blood and urine electrolytes, renal functions, and urine microalbumin. Twelve-lead electrocardiography, echocardiography, and plain scanning of enhanced CT scanning of the bilateral adrenals were conducted. Adrenal venous sampling (AVS) was conducted in 62 patients to collect blood samples from vena cava and bilateral suprarenal veins to detect the levels of aldosterone and cortisol. All UNAH patients and 3 BAH patients underwent unilateral adrenalectomy and three APA patients underwent unilateral adrenalectomy or adenoma resection. Then the patients were followed up for 39.2 months. The incidence of UNAH is 9.7% in the primary aldosteronism patients. There were no significant differences in age, gender, duration of hypertension, blood pressure (SBP, DBP), and indexes indicating damages in target organs of hypertension (left ventricular hypertrophy rate, blood creatinine, urine microalbumin, etc) among these three groups. The level of serum potassium of the APA group was significantly lower than that of the BAH group (P < 0.01), and the levels of plasma and urine aldosterone of the APA group were significantly higher than those of the BAH group (P < 0.05 and P < 0.01). The serum potassium of the UNAH group was higher than that of the APA group and lower than that of the BAH group, and the levels of plasma and urine aldosterone of the UNAH group were both higher than those of the APA group and lower than those of the BAH group, however all not significantly (all P > 0.05). The coincidence rate of CT was 50% (7/14) in the UNAH group. The accuracy of AVS for diagnosis of UNAH was 85.7% (12/14). After operation, the serum potassium and plasma aldosterone concentrations returned normal in all the UNAH patients. Blood pressure returned to normal in 50% (7/14) of the UNAH patients, and was improved in the other 50% (7/14) patients. UNAH can be cured by adrenal surgery. The diagnostic values of clinical examination and adrenal CT are limited. AVS is essential in diagnosing UNAH patients.