SUN-377 Adrenal Incidentaloma Evaluation in Critical Illness: A Diagnostic Dilemma

Abstract

Background: Adrenal incidentalomas (AIs) are a “disease of modern technology” with a prevalence of ~5%, expected to increase as imaging modalities become more sensitive and widely available. While the majority of AIs are benign, ~15% are malignant or associated with hormone over secretion, thus all AIs require prompt investigation. The recommended diagnostic testing for AIs is validated in healthy outpatient subjects, with no established algorithm for the inpatient/critical illness setting. Clinical Case: A 66 year-old male with hypertension and type 2 DM, recent myocardial infarction, presented in cardiogenic shock. His course was complicated by an episode of cardiac arrest with successful resuscitation. Due to inotrope and intra-aortic balloon pump dependency, he was urgently evaluated for left ventricular assist device (LVAD). A non-contrast abdominal CT obtained during pre-LVAD workup, showed a 2.4 x 1.9 cm right adrenal nodule of indeterminate density. The review of systems was positive for erectile dysfunction, and negative for easy bruising, facial plethora, fractures, proximal muscle weakness or weight changes. Physical examination revealed absence of Cushingoid features. Laboratory testing showed an abnormal overnight 1mg dexamethasone suppression test (DST) (12.1 mcg/dL , n: < 1.8 mcg/dL), elevated ACTH (75pg/mL, n: 7-69pg/mL), elevated AM serum cortisol (40.7 mcg/dL, n: 5-23 mcg/dL), elevated PM serum cortisol (21.7 mcg/dL, n: 3-15 mcg/dL). He had normal 24-hour urinary free cortisol, serum DHEAS, plasma renin activity and aldosterone concentration. Repeat adrenal CT scan showed a 1.6 x 1.9 cm R adrenal nodule, non-contrast density 33 HU, venous phase 99 HU and delayed phase 55 HU (washout 45%) concerning for pheochromocytoma. However, plasma and urine metanephrines and catecholamines were normal. The absence of Cushingoid features and evidence of ACTH dependent hypercortisolism with normal diurnal variation (despite an abnormal DST) ruled out Cushing’s syndrome, and the patient successfully underwent LVAD surgery. A literature review revealed only 2 AI cases evaluated during critical illness. While both cases had an abnormal DST without normal diurnal variation, only one case had similar ACTH dependent hypercortisolemia. Conclusion: This case illustrates the dilemma surrounding the evaluation of AIs in the setting of critical illness, the lack of inpatient/critical illness specific guidelines and the importance of clinical assessment. Furthermore, it suggests a possible diagnostic approach that can be considered in similar clinical situations.