nighthawk

Posted because it's interesting for a few reasons, especially the fact that this apparent adrenal Cushing's (bilateral micronodular hyperplasia) did not present with suppressed ACTH. Those values ranged from 8.9 to 38 pg/mL throughout the day, and yet this was not a mild case biochemically. The investigators--who I should point out are the leading experts on this particular subtype of Cushing's--seemed baffled by the discordant results for locating the source. Furthermore, this novel mutation has a different proposed mechanism of action than previously-identified mutations. Finally, the rather young pediatric patient has been successfully treated with low-dose ketoconazole for five years.

From the abstract (appearing in JCEM Feb 2021): PATIENT We present the case of a 10-year-old child who presented with CS at an early age due to bilateral adrenocortical hyperplasia (BAH). The patient was placed on low-dose ketoconazole (KZL), which controlled hypercortisolemia and CS-related signs. Discontinuation of KZL for even 6 weeks led to recurrent CS. CONCLUSIONS We present a pediatric patient with CS due to BAH and a germline defect in KCNJ5. Molecular investigations of this KCNJ5 variant failed to show a definite cause of her CS. However, this KCNJ5 variant differed in its function from KCNJ5 defects leading to PA. We speculate that GIRK4 (Kir3.4) may play a role in early human adrenocortical development and zonation and participate in the pathogenesis of pediatric BAH. Official: Cushing Syndrome in a Pediatric Patient With a KCNJ5 Variant and Successful Treatment With Low-dose Ketoconazole Pre-print (pdf): https://www.researchgate.net/publication/349635365_Cushing_Syndrome_in_a_Pediatric_Patient_With_a_KCNJ5_Variant_and_Successful_Treatment_With_Low-dose_Ketoconazole

It's because desmopressin stimulates ACTH release in corticotrophs (normal cells) and in corticotrophinomas, i.e., tumor cells in the case of Cushing's disease. This effect has been shown to be higher in CD than in non-CD patients. However, I think the ability of the DDAVP test to discriminate between CD and non-CD is questionable, although I'm not too familiar with that area of the literature. What does your MRI say?

This is a remarkable paper and has big implications for testing and the diagnostic algorithm, especially given who the authors are. The blunt takeaway is do not use salivary cortisol for adrenal Cushing's because it doesn't work. They recommend dex test instead but we know that test has problems too--yes, even in adrenal cases. It's not clear to me if this is generalizable to all mild Cushing's, nor does it appear like cyclical or episodic Cushing's was considered. The other thing is that the technically "better" assay (LCMS) has worse sensitivity than the older, cheaper one (EIA). This is the same thing we saw with the UFC where the older RIAs cross-reacted with cortisol metabolites, so we traded it for the tandem mass spec that produces fewer false positives and more false negatives. I've made all of these points before with my local endo who cited one of the authors of this paper to refute me!

Wow 8.4 on the first try. These are textbook adrenal numbers. I hope your doctors come to their senses.

Hi Amanda, Based on what you posted, this is a slam dunk. If they don't diagnose you quickly you should go elsewhere. The lit recommends removing anything over 4 cm. You actually have convincing biochemical evidence with a rather high UFC and concurrent low ACTH (<10 pg/mL). I'm assuming you're using Quest for the UFC since he said it's not 2x high. Most people don't get to 2x on LC/MS-MS with mild/adrenal Cushing's. Let us know the dex results. The cutoff is 1.8 ug/dL.

Yes, that is common.

This would be a huge loss if the boards close. Surely there's a way to do site backup / archiving. I think the information here is much too valuable to lose forever.