Overview
Clinical Meaning
At the NP level, Cushing syndrome evaluation requires sophisticated application of the diagnostic algorithm and nuanced management decisions.
WHNP
WHNP
At the NP level, Cushing syndrome evaluation requires sophisticated application of the diagnostic algorithm and nuanced management decisions. The 1 mg overnight dexamethasone suppression test (DST) has ~95% sensitivity but only ~80% specificity -- false positives occur with depression, alcoholism, obesity, OCP use (estrogen increases cortisol-binding globulin, elevating total cortisol), and CYP3A4 inducers (phenytoin, carbamazepine accelerate dexamethasone metabolism, causing inadequate suppression). The 48-hour low-dose DST (2 mg/day × 2 days) improves specificity. Late-night salivary cortisol measures FREE cortisol and is not affected by CBG levels. The inferior petrosal sinus sampling (IPSS) with CRH stimulation is the gold standard to distinguish pituitary from ectopic ACTH: a central-to-peripheral ACTH ratio ≥2 (baseline) or ≥3 (post-CRH) confirms pituitary source.
Unlock full lesson + practice questions
4 more sections with scenarios, priorities, and review drills.
Final rapid review before practice
Next study step
Finish the lesson first, then choose a focused activity to apply what you just reviewed.
Continue studying
Sign in to save progress on this lesson.
Unlock the interactive lesson quiz with a plan that includes this WHNP pathway. You can still explore topic-filtered questions from the bank hubs below.