Felis ISSN 2398-2950

High-dose dexamethasone suppression test

Synonym(s): HDDST

Contributor(s): David Bruyette, Carmel Mooney, Yvonne McGrotty

Overview

  • A high dose of dexamethasone inhibits pituitary ACTH secretion through negative feedback and hence this decreases plasma [cortisol] Endocrinology: hypopituitary adrenal axis - diagram .

Sampling

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Tests

Availability

  • [Cortisol] available at many commercial laboratories.

Validity

Sensitivity

  • Good for identifying pituitary tumors.

Specificity

  • Some pituitary tumors (macroadenomas?) respond like adrenal tumors.

Technique (intrinsic) limitations

  • [Plasma cortisol] does not suppress in approximately 50% of PDH cases probably because ACTH is released from the pars intermedia rather than the pars distalis and the pars intermedia is less sensitive to the negative feedback of high [plasma cortisol].
  • Does not differentiate adrenocortical adenomas from adrenocortical carcinomas.

Technician (extrinsic) limitations

  • Must be able to give intravenous injection of dexamethasone and collect subsequent blood samples without stressing animal.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Boland L A & Barrs V R (2017) Peculiarities of feline hyperadrenocorticism - Update on diagnosis and treatment. J Feline Med Surg 19, 933-947 PubMed.


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