Selective venous sampling for ACTH in Cushing's syndrome: differentiation between Cushing disease and the ectopic ACTH syndrome.
We performed selective venous catheterization and sampling for ACTH in six patients with ACTH-secreting pituitary adenomas (Cushing's disease) and four patients with occult ectopic ACTH-secreting neoplasms. In five patients with Cushing's disease in whom the inferior petrosal sinus could be catheterized, ACTH levels were unequivocally higher than simultaneous peripheral values: The ratio was greater than 2.0, with a range of 2.2 to 16.7. In contrast, the inferior petrosal sinus-to-peripheral ACTH ratio in three patients with ectopic ACTH secretion was less than 1.5. In the fourth patient, an arteriovenous gradient of 6.8 was shown 2 years before a bronchial carcinoid tumor was clinically apparent. Central-to-peripheral ACTH ratios at the level of the jugular bulb and jugular vein were not diagnostic. We conclude that selective venous ACTH sampling from the inferior petrosal sinus is a reliable and useful aid in the differential diagnosis of Cushing's syndrome when standard clinical and biochemical studies are inconclusive.
D000182:ACTH Syndrome, Ectopic / Q000175:diagnosis*; D000236:Adenoma / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000097:blood* / Q000378:metabolism; D000328:Adult; D000368:Aged; D001984:Bronchial Neoplasms / Q000378:metabolism; D002276:Carcinoid Tumor / Q000378:metabolism; D002404:Catheterization; D003392:Cranial Sinuses; D003480:Cushing Syndrome / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009384:Paraneoplastic Endocrine Syndromes / Q000175:diagnosis*; D010911:Pituitary Neoplasms / Q000378:metabolism
D000324:Adrenocorticotropic Hormone