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ACTH level: This test helps distinguish an adrenal source (ACTH independent) from an ACTH dependent cause. A very low ACTH level suggests the problem is coming from the adrenal glands, and not the pituitary gland.
High dose Dexamethasone suppression test: This test helps to distinguish patients with excess production of ACTH due to pituitary adenomas from those with ectopic ACTH-producing tumors. Patients are given 2 mg dexamethasone by mouth every 6 hours for 2 days. A 24-hour urine collection for cortisol is performed on the second day of the test. Cortisol suppression suggests a pituitary tumor. A similar test is performed using a single dose of 8 mg at midnight, and a fasting blood draw for cortisol the next morning.
Petrosal sinus sampling: This test may be required to separate pituitary from ectopic causes of ACTH-dependent Cushing's syndrome in patients with a normal pituitary gland on brain MRI scan. Catheters are placed through a vein in the upper thigh/groin region and are threaded through the blood vessels to the petrosal sinuses, which surround the pituitary gland. ACTH levels higher in the petrosal sinuses than in a forearm vein indicate the presence of a pituitary adenoma (Cushing's disease); similar levels suggest ectopic ACTH syndrome.
Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. As a Stanford Health Care patient, you may have access to the latest, advanced clinical trials.
Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future.