Evaluation of baseline cortisol, endogenous ACTH, and cortisol/ACTH ratio to monitor trilostane treatment in dogs with pituitary-dependent hypercortisolism.

Abstract

BACKGROUND:

The effectiveness of trilostane treatment is currently monitored by regular ACTH stimulation tests, which are time-consuming and expensive. Therefore, a monitoring system without a stimulation protocol and with less client expense would be preferable.

HYPOTHESIS/OBJECTIVES:

The aim of our study was to evaluate if baseline cortisol, endogenous ACTH (ACTH) concentration or the baseline cortisol to ACTH ratio (cortisol/ACTH ratio) could replace the ACTH stimulation test.

ANIMALS:

Forty trilostane-treated dogs with pituitary-dependent hypercortisolism (PDH) were included in this prospective study.

METHODS:

A total of 148 ACTH stimulation tests and 77 ACTH concentrations and cortisol/ACTH ratios were analyzed. Control of cortisol release was classified according to cortisol concentration after ACTH administration as excessive (<1.5 μg/dL; group 1), adequate (1.5-5.4 μg/dL; group 2), or inadequate (>5.4 μg/dL; group 3).

RESULTS:

Baseline cortisol concentrations had considerable overlap between excessively, adequately, and inadequately controlled dogs. Only baseline cortisol >4.4 μg/dL (in 12% of tests) was a reliable diagnosis of inadequate control. Endogenous ACTH concentrations did not differ between groups. The overlap of the cortisol/ACTH ratio between groups was large. Correct classification was only possible if the cortisol/ACTH ratio was >15, which occurred in 4% of tests.

CONCLUSIONS AND CLINICAL IMPORTANCE:

To monitor trilostane treatment the ACTH stimulation test cannot be replaced by baseline cortisol, ACTH concentration, or the cortisol/ACTH ratio.

• Authors: W A Burkhardt, F S Boretti, C E Reusch, N S Sieber-Ruckstuhl
• Journal: Journal of veterinary internal medicine (J Vet Intern Med) 2013 Jul-Aug Vol. 27 Issue 4 Pg. 919-23 ISSN: 1939-1676 [Electronic] United States
• PMID: 23701195 (Publication Type: Evaluation Study, Journal Article)
• Copyright: Copyright © 2013 by the American College of Veterinary Internal Medicine.

Chemical References

• Enzyme Inhibitors
• Dihydrotestosterone
• Adrenocorticotropic Hormone
• trilostane
• Hydrocortisone

Topics

• Adrenocorticotropic Hormone (blood)
• Animals
• Cushing Syndrome (drug therapy)
• Dihydrotestosterone (analogs & derivatives, therapeutic use)
• Dog Diseases (blood, drug therapy)
• Dogs
• Enzyme Inhibitors (therapeutic use)
• Female
• Hydrocortisone (blood)
• Male
• Reference Values