Question

A 41 year old female presents with menstrual irregularities for the past several months. She also complains of increased hair growth on her face, and notes that at a recent health screening fair, she was told that she had "pre-diabetes." Her only medication is paroxetine. On physical examination, the patient's blood pressure is 160/94, and numerous purple striae are noted on the patient's abdomen. There is increased subcutaneous fat deposition in the skin of the cheeks and in the posterior cervical region. A 24-hour urine collection for cortisol is markedly elevated. Following the administration of high-dose dexamethasone, the patient's cortisol level decreases by 90%. Which of the following is the most likely cause of these findings in this patient?

A. McCune-Albright syndrome
B. Pituitary adenoma
C. Adrenal adenoma or carcinoma
D. Ectopic production of ACTH by a lung tumor
E. Surreptitious use of exogenous glucocorticoids

Answer 1

The findings suggest that the patient has Cushing's syndrome, most likely caused by a pituitary adenoma option (b), due to the significant decrease in cortisol levels following high-dose dexamethasone, indicating a pituitary source of ACTH overproduction.

Step-by-step explanation:

The most likely causes of the findings presented by the 41-year-old female patient include menstrual irregularities, increased hair growth on her face (hirsutism), pre-diabetes, high blood pressure, and purple striae on the abdomen.

Increased subcutaneous fat deposition in the face (moon face) and posterior cervical region (buffalo hump), and a marked decrease in cortisol levels after high-dose dexamethasone administration, is a condition known as Cushing's syndrome.

This condition is often associated with a pituitary adenoma that overproduces ACTH. The diagnosis is supported by the significant decrease in cortisol levels after dexamethasone administration, which suggests an endogenous source of cortisol excess that is responsive to negative feedback, characteristic of a pituitary source as opposed to an adrenal tumor, ectopic ACTH production, or exogenous glucocorticoid use.