A 31-year-old woman comes to the office due to a 6.8-kg (15-lb) weight gain over the last few months. She has been unable to lose weight despite rigorous dieting and regular exercise. The patient also has experienced weakness and cannot lift weights that she was able to lift before the onset of her symptoms. Her menstrual periods have been irregular for the last few months, and she has had increasing anxiety and insomnia for which she has started seeing a clinical psychologist. Medical history is unremarkable. She drinks wine only on rare occasions and quit smoking 7 years ago after a 5-pack-year history. On examination, blood pressure is 160/100 mm Hg and pulse is 88/min and regular. Neurologic examination shows proximal muscle weakness. Dark terminal hair is present on the lower abdomen. Fasting laboratory results are as follows: Which of the following is the most appropriate next step in evaluating this patient's condition?

Question

A 31-year-old woman comes to the office due to a 6.8-kg (15-lb) weight gain over the last few months.  She has been unable to lose weight despite rigorous dieting and regular exercise.  The patient also has experienced weakness and cannot lift weights that she was able to lift before the onset of her symptoms.  Her menstrual periods have been irregular for the last few months, and she has had increasing anxiety and insomnia for which she has started seeing a clinical psychologist.  Medical history is unremarkable.  She drinks wine only on rare occasions and quit smoking 7 years ago after a 5-pack-year history.  On examination, blood pressure is 160/100 mm Hg and pulse is 88/min and regular.  Neurologic examination shows proximal muscle weakness.  Dark terminal hair is present on the lower abdomen.  Fasting laboratory results are as follows:  Which of the following is the most appropriate next step in evaluating this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d0bb_8614_bc81_6b5cbfb2538d_MD0003_00 This patient has weight gain, psychiatric symptoms, hirsutism, hypertension, and hyperglycemia. This constellation of findings is consistent with hypercortisolism (Cushing syndrome). This condition is most commonly due to exogenous administration of glucocorticoids, but can also be due to an ACTH-producing pituitary tumor (Cushing disease), ectopic ACTH production (eg, small cell lung cancer), or primary adrenal disease. The initial step in the evaluation is to confirm hypercortisolism with a late-night salivary cortisol assay, 24-hour urine free cortisol measurement, and/or overnight low-dose dexamethasone suppression test. Two of these first-line tests should be abnormal to establish the diagnosis. If hypercortisolism is confirmed, ACTH levels are measured to differentiate ACTH-dependent (ie, Cushing disease, ectopic ACTH) from ACTH-independent (eg, adrenal adenoma) causes (Choice C). (Choice A) Early-morning cortisol levels will be low or low-normal in patients with primary adrenal insufficiency. However, there is considerable overlap in cortisol levels in normal subjects and those with Cushing syndrome, and this test has low utility in the evaluation of hypercortisolism. (Choice D) The ratio of plasma aldosterone to plasma renin activity is useful to evaluate primary hyperaldosteronism, which typically presents with hypertension and hypokalemia. This patient's hyperglycemia and psychiatric and menstrual symptoms are more consistent with hypercortisolism. (Choice E) Hyperandrogenism can be seen in Cushing syndrome due to ACTH-induced adrenal androgen production or co-secretion of cortisol and testosterone by an adrenal tumor. Testosterone levels may be useful in evaluating hirsutism, but would not explain this patient's constellation of findings consistent with Cushing syndrome. Educational objective: The initial step in the evaluation of Cushing syndrome is to confirm hypercortisolism with a late-night salivary cortisol assay, 24-hour urine free cortisol measurement, and/or overnight low-dose dexamethasone test. If hypercortisolism is confirmed, ACTH levels are measured to differentiate ACTH-dependent from ACTH-independent causes. References: The diagnosis of Cushing syndrome: an Endocrine Society Practice Guideline. (http://www.ncbi.nlm.nih.gov/pubmed/18334580)

A 31-Year-Old Woman Comes to the Office Due to a 6.8-Kg