SAT-220 A Misdiagnosis Causing a Feared Complication

Abstract

Adrenal incidentalomas are being increasingly found with the widespread use of thoracic and abdominal imaging. Clinicians must determine the nature of the mass to decide what treatment, if any, is needed. All patients should undergo biochemical testing to rule out hypercortisolism, pheochromocytoma and if hypertension is present, primary hyperaldosteronism. These patients should ideally be evaluated by endocrinologists as misdiagnosis can lead to complications. A 60-year-old African American female with a history of hypertension and type 2 diabetes, was admitted to the internal medicine ward with intractable vomiting, abdominal pain and hypotension. Two weeks prior to admission, she had undergone a left sided adrenalectomy for a diagnosis of primary hyperaldosteronism. An adrenal adenoma was incidentally found 1 year before surgery during abdominal imaging done for diverticulitis. She was immediately referred to a surgeon for further work up and evaluation. The work up done for the adrenal incidentaloma included renin, aldosterone and plasma fractionated metanephrines. Plasma renin was low (0.2 ng/mL/hr, n: 0.5-4.0 ng/mL/hr), and Aldosterone was normal (8.1 ng/dL, n<16 ng/dL) and the Aldosterone/ Renin ratio was elevated. No confirmatory test was done and no evaluation for hypercortisolism was done either. Plasma fractionated metanephrines were normal. During current hospitalization, an AM cortisol was 1.5 mcg/dL (n: 6-28 mcg/dL). An ACTH stimulation test was done which showed an inadequate response. She was subsequently started on stress dose steroids with rapid improvement in her symptoms. She was discharged with hydrocortisone and has been followed in our endocrinology clinic. She has yet to fully recover HPA axis but is currently on low dose Hydrocortisone and doing well. This patient was misdiagnosed with primary hyperaldosterenism when she most likely had subclinical hypercortisolism. Patients with primary hyperaldosteronism typically have plasma aldosterone > 15 ng/dL and low levels of plasma renin, with a ratio of plasma aldosterone to plasma renin activity > 20. Low levels of both plasma renin activity and aldosterone suggest nonaldosterone mineralocorticoid excess. Cushing syndrome can cause similar findings. Confirmatory tests should be done, and most patients require bilateral catheterization of the adrenal veins to measure cortisol and aldosterone levels to confirm whether the aldosterone excess is unilateral or bilateral. A 1 mg overnight dexamethasone suppression test is recommended for all adrenal incidentaloma patients to exclude asymptomatic hypercortisolism.