Category: Adrenal Disorders

Monitor: 15

15 - A CASE OF UNEXPLAINED ACTH-DEPENDENT CUSHING'S DISEASE

Saturday, Apr 27
10:30 AM – 11:00 AM

Objective : In critically ill patients, over activation of hypothalamic pituitary axis can cause hypercortisolism with otherwise unexplained Cushing’s disease. We present a case of ACTH dependent Cushing’s disease with possible stress induced hypercortisolism


Methods : N/A


Results : A 62 year old male was transferred from an outside hospital after a prolonged course for necrotic colonic abscess requiring colon resection. Post-operative course was complicated by acute respiratory failure leading to intubation. He was found to have an incidental 2.5cmx4cm left adrenal adenoma. Clinically, patient had central obesity, moon facies, DM type II diagnosed a year ago. Lab work revealed elevated AM cortisol 59mcg/dL, midnight cortisol 57mcg/dL, 24 hour urinary cortisol 621mcg/24 hrs, elevated ACTH 501pg/mL and no suppression on low and high dose Dexamethasone stress test (DST). Aldosterone renin ratio, urine and plasma metanephrines were normal. MRI pituitary showed a 6 mm pituitary microadenoma. Ketoconazole was started to lower the cortisol levels with inadequate response. Repeat imaging showed bilateral adrenal hyperplasia. Highest cortisol level was noted to be 106.9mcg/dL. Metyrapone was arranged and started at 250mg Q6H and increased to 2.5gm/day. Ketoconazole was discontinued due to thrombocytopenia. Ectopic source of ACTH production could not be located on a PET CT or Octreoscan imaging. An improvement in his mental status and blood glucose was noted with lowered cortisol levels with Metyrapone. Lowest cortisol level noted was 46.6mcg/dL. At this point, an IPSS was done to differentiate between pituitary and ectopic origin of ACTH but the results were not interpretable due to a sample collection error. No further evaluation was pursued as the patient decided hospice


Discussion :

Majority of patients with ACTH dependent Cushing’s syndrome have a pituitary corticotroph adenoma rather than ectopic ACTH secretion while ectopic CRH secretion is rare. ACTH secretion by pituitary adenomas is only relatively resistant to negative feedback regulation by glucocorticoids hence results in normal or mildly elevated ACTH. In contrast, most nonpituitary tumors with ectopic ACTH are completely resistant to feedback inhibition, causing significantly elevated ACTH levels. Elevated ACTH levels reflect tumoral secretion that causes bilateral adrenocortical hyperplasia and hyperfunction. In our patient, elevated cortisol and ACTH levels were likely due to an ectopic source, as ACTH levels were not suppressed by high dose DST. Patient’s recent surgery could also have contributed to stress induced hypercortisolism. Advance imaging was unable to locate the ectopic source.Thus, he underwent IPSS


Conclusion : N/A

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Fatima M. Kazi

Internal Medicine Resident
Advocate Christ Medical Center
Oak Lawn, Illinois

I am currently a PGY-2 Internal Medicine resident. I am deeply interested in pursuing a career in Endocrinology.

Shahnaz Siddiqui

Internal Medicine Resident
Advocate Christ Medical Center

PGY-1 Internal Medicine Resident

Vallari Kothari

Endocrinology Fellow
University of Illinois at Chicago, Illinois

Endocrinology Fellow
Division of Endocrinology, Diabetes and Metabolism
University of Illinois at Chicago

Joseph Zapater

Endocrinology Fellow
University of Illinois at Chicago

Endocrinology Fellow
Division of Endocrinology, Diabetes and Metabolism
University of Illinois at Chicago

Tahira Yasmeen

Section Chief of Endocrinology Site Director for UIC Endocrinology Fellowship Chair, Glycemic Control Committee, ACMC Associate Professor of Clinical Medicine, UIC
UIC/Advocate
oak lawn, Illinois

Section Chief of Endocrinology
Site Director for UIC Endocrinology Fellowship
Chair, Glycemic Control Committee, ACMC
Associate Professor of Clinical Medicine, UIC

Fatima M. Kazi

Internal Medicine Resident
Advocate Christ Medical Center
Oak Lawn, Illinois

I am currently a PGY-2 Internal Medicine resident. I am deeply interested in pursuing a career in Endocrinology.