Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2005) 10 P57

SFE2005 Poster Presentations Pituitary (11 abstracts)

The low dose dexamethasone suppression test with CRH is not reliable following pituitary surgery

A Abdulali , A Banerjee , N Martin , W Dhillo , JF Todd , N Mendoza & K Meeran

Hammersmith Hospital Trusts, London, United Kingdom.

The definition of early cure post transphenoidal surgery (TSS) for Cushing’s disease continues to be debated. The low dose dexamethasone suppression test with corticotrophin releasing hormone (LDDST-CRH) is a test for diagnosis of Cushing’s; however it has not been validated in early post TSS to determine remission. The aim of this study was to determine whether the combined LDDST-CRH test could be used in post TSS patients.

The combined LDDST-CRH test was adapted to be used as a standard on all cases of TSS 48 hours post operatively. The patients were put on dexamethasone 0.5 mg 6 hourly starting 48 h postoperatively. A cortisol >50 nM is taken as “failure” of LDDST while a cortisol of >38 nM is taken as failure of CRH testing.

Histological proven cases included 4 Cushing’s (mean age 35 years with 100% females) and 16 non-Cushing’s (mean age 48 years, with 53% females); 7 acromegalics, 8 non-functioning macroadenoma (NFA) and 1 Rathe Cleft Cyst.

Two from four Cushing’s patients passed the combined LDDST-CRH and are currently in remission. The other two failed on both parts of LDDST-CRH, one has been treated with radiotherapy and the other is under review.

Of the seven acromegalics, 6/7 passed the LDDST and 2/7 of the acromegalics failed CRH testing. Of the NFAs 3/8 passed the LDDST and 3/7 who had the CRH testing went on to fail this. The one case of Rathe Cleft Cyst passed the LDDST and failed the CRH testing.

In summary LDDST-CRH testing post TSS in Cushing’s patients was consistent however the test gave 7 false positives in the non-Cushing’s patients who were histological proven not to have Cushing’s disease.

LDDST-CRH testing should not be performed immediately postoperatively in any patients. The addition of CRH causes almost all patients to develop a false positive result postoperatively.

Volume 10

196th Meeting of the Society for Endocrinology and Society for Endocrinology joint Endocrinology and Diabetes Day

Society for Endocrinology 

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