LEARNING POINTS: Simultaneous autonomous overproduction of
cortisol and
aldosterone is increasingly recognised although still apparently uncommon.Because
cortisol levels are used during AVS to correct for differences in dilution of adrenal with non-adrenal venous blood when assessing for lateralisation, unilateral
cortisol overproduction with contralateral suppression could confound the interpretation of AVS resultsMeasuring plasma
metanephrine during AVS to calculate lateralisation ratios may circumvent this problem.