SUN-430 - Diagnostic Challenge: Assessment of Adrenal Hypercortisolism in the Setting of ESRD and Blindness

Diagnosis of Hypercortisolism can be challenging, particularly if done on a patient with underlying conditions which can affect the reliability of the results. Screening and confirmatory testing relies on evaluation of normal circadian patterns, overall excess production of cortisol, and appropriate suppression in response to exogenous glucocorticoids, however, requires that the patient does not have any underlying medical conditions which could affect any of the above.

A 64-year-old female with CKD, hypertension, blindness, and type 2 diabetes mellitus on basal insulin was evaluated for a right adrenal adenoma measuring 3.2 x 3.2 x 2.7 cm with 21 Hounsfield units (HU). Initial hormonal workup was negative for pheochromocytoma and hyperaldosteronism. At one-year follow-up, the mass grew to 3.6 x 4.0 x 2.9 cm (19 HU). The patient had progressed to hemodialysis, precluding urinary cortisol testing. AM cortisol post-1 mg dexamethasone suppression test (DST) was elevated, one of two midnight salivary cortisol levels was elevated, ACTH and DHEA-S were low-normal. Surgical resection was recommended due to documented growth, but the patient declined and was lost to follow-up.

One year later, she presented with hypertensive emergency (systolic blood pressure 220s mmHg) and concern for stroke. Despite four antihypertensives (nifedipine, hydralazine, carvedilol, losartan), blood pressure remained uncontrolled and paradoxically worsened with standing. Repeat CT noted no growth of adrenal mass, however no detailed description of the mass was reported. Given refractory hypertension and suspicion for autonomous cortisol secretion, mifepristone 300 mg daily was initiated as a therapeutic trial with close monitoring. Within 24 hours, blood pressure and glucose improved significantly, allowing discontinuation of basal insulin. Outpatient follow-up confirmed sustained improvements with normal potassium levels and stable blood pressure control.

This case highlights the importance of knowing which factors may influence and affect the reliability of results which could ultimately lead to a diagnostic error. Diagnostic interpretation was complicated by ESRD altering cortisol clearance and cortisol binding globulin levels, with variability of test results in relation to the time of hemodialysis. In addition, this patient developed altered circadian rhythms as a result of her total blindness. These physiological disruptions rendered biochemical testing unreliable including DST and midnight salivary cortisol. In our patient, therapeutic trial with mifepristone played both diagnostic and therapeutic roles. Finally, the patient's orthostatic hypertension was particularly noteworthy, a finding that would need to be investigated for its degree of association with hypercortisolism.

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