PNA Medical Corner: Testing for Cushing’s
This month the PNA Medical Corner showcases an article co-written by four members of the PNA, Drs. Quinones-Hinojosa, Gallia, Wand and Salvatori, all of Johns Hopkins in Baltimore. The study looks at methods to diagnose Cushing’s Disease, and is entitled Venous Sampling for Cushing Disease: Comparison of Internal Jugular Vein and Inferior Petrosal Sinus Sampling. The authors conclude that IJVS should not be routinely used to determine if the pituitary is to blame for high ACTH levels. It was published online in the journal Endocrine Practice on May 23, 2016.
Drs. Alberto Quinones-Hinojosa, Gary Gallia, Gary Wand and Roberto Salvatori
Here is the abstract:
Endocr Pract. 2016 May 23. [Epub ahead of print]
VENOUS SAMPLING FOR CUSHING DISEASE: COMPARISON OF INTERNAL JUGULAR VEIN AND INFERIOR PETROSAL SINUS SAMPLING.
Radvany MG1, Quinones-Hinojosa A2,3, Gallia GL2,3, Wand GS4,3, Salvatori R4,3.
• 1From: 1 WellSpan Radiology and Neurosciences York, PA 17402.
• 22 Department of Neurosurgery and.
• 32,3 Pituitary Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
• 43 Department of Medicine, Division of Endocrinology, and.
Because MRI fails to detect many ACTH-secreting pituitary adenomas, inferior petrosal sinus sampling (IPSS) is considered the gold standard to differentiate Cushing Disease (CD) from ectopic ACTH secretion syndrome (EAS). Some authors have suggested internal jugular vein sampling (IJVS) as an alternative to IPSS.
We simultaneously compared IJVS to IPSS in 30 consecutive patients referred for ACTH-dependent Cushing syndrome and equivocal MRI exams. Five sites were simultaneously sampled in each patient (right and left IPS, right and left IJV, and femoral vein) before and after the administration of corticotrophin releasing hormone or desmopressin. The test was considered consistent with CD when the IPS:peripheral ratio was >2 at baseline or >3 after stimulus, and the IJV:peripheral ratio was >1.7 at baseline or >2 after stimulus.
In 27/30 patients, IPSS results were consistent with a central source of ACTH. Two of the other 3 patients had EAS (one lung carcinoid and one occult), and one had pathology-proven CD. The sensitivity of IPSS was 96.4%. Only 64.2 % of these patients had results meeting criteria for a central source of ACTH by IJVS criteria. Twenty patients with centralizing IPPS have undergone pituitary surgery. Of these, in 16 the central origin of excessive ACTH was confirmed with certainty. Among these 16 patients IPSS' sensitivity was 93.8%, while 5 had false negative IJVS (68.7% sensitivity).
These results do not support the routine use of IJVS in establishing if the pituitary is the source of excessive ACTH.