Presentations

Abstract

Introduction: Cushing's syndrome (CS) is caused by excess cortisol in the body. While there are many causes of Cushing's syndrome, some of the most common causes include exogenous steroid use and endogenous steroid production such as a pituitary adenoma, an adrenal adenoma, or ectopic ACTH secretion. Various testing modalities can be utilized to determine the etiology of Cushing's syndrome. Commonly used screening diagnostic tests include 24-hour urine cortisol, overnight low dose dexamethasone suppression test, and late-night salivary cortisol. After screening tests, confirmatory tests such as CRH stimulation test and high-dose dexamethasone syndrome can be used to help narrow the etiology. Typical lab assays for cortisol only detect prednisolone, methylprednisolone, or prednisone in terms of exogenous steroids.

Case Information: A synthetic urine glucocorticoid screen was ordered for a 60-year-old female patient presenting with clinical features consistent with Cushing's syndrome. The patient exhibited a constellation of hallmark symptoms, including central obesity with pronounced weight gain, particularly in the face and trunk, which contributed to the development of a characteristic "moon face." She also experienced significant facial redness (plethora), supraclavicular fat pads, and the formation of a dorsocervical fat pad, commonly referred to as a "buffalo hump." These physical changes were accompanied by progressive muscle weakness and proximal myopathy, leading to difficulty in activities such as rising from a seated position. Additionally, the patient complained of easy bruising, skin thinning, and delayed wound healing, particularly on her forearms. Her skin also exhibited purple striae over the abdomen, which is typical in cases of prolonged exposure to high glucocorticoid levels. The patient reported a history of exogenous steroid use, raising suspicion of this as the underlying cause of her Cushingoid appearance. However, despite her pronounced clinical signs, her biochemical workup revealed persistently low levels of urinary free cortisol and adrenocorticotropic hormone (ACTH), leading to a clinical conundrum. To clarify the source of her symptoms, a synthetic urine glucocorticoid screen was ordered to evaluate for the presence of exogenous glucocorticoids that might not be detected by standard assays.

Discussion/Clinical Findings: An elevated triamcinolone acetonide was detected on a synthetic urine glucocorticoid screen, providing a diagnostic explanation for this patient's Cushing's syndrome. The patient explained that she had been rubbing triamcinolone (a topical steroid) on her young daughter who has atopic dermatitis. The patient failed to rinse off her hands after application and instead rubbed the topical steroid into her hands.

Conclusion: A synthetic urine glucocorticoid is a valuable diagnostic test that should be considered in cases of unexplained Cushing's syndrome in the setting of exogenous steroid use with persistently low cortisol and ACTH. Though this laboratory test is a send out test, it can provide significantly helpful information where typical labs do not match clinical presentation.