A 33-year-old woman presents with hypertension (BP 158/96), tachycardia (HR 102), and progressive central obesity with proximal muscle weakness. Laboratory studies show elevated 24-hour urinary free cortisol at 285 mcg/day (normal <50) and ACTH 68 pg/mL, consistent with ACTH-dependent Cushing syndrome. Pituitary MRI shows no discrete adenoma. She denies recent weight loss or cough. Which test best distinguishes pituitary from ectopic ACTH secretion?
- A)Water deprivation testing
- B)Inferior petrosal sinus samplingGABARITO
- C)Urine metanephrine measurement
- D)Cosyntropin stimulation testing
- E)Serum calcitonin measurement
Explicação
Inferior petrosal sinus sampling compares central and peripheral ACTH levels and is the best test when ACTH dependent Cushing syndrome is confirmed but pituitary imaging is nondiagnostic. A central to peripheral ACTH gradient supports a pituitary source. This ... Ver explicação completa e trilha adaptativa →