Correlação entre a resposta ao teste de supressão com baixa dose de dexametasona com a dose final de trilostano em cães com hipercortisolismo pituitário-dependente

Abstract

Hyperadrenocorticism is an endocrinopathy frequently diagnosed in dogs, with pituitary- dependent hyperadrenocorticism (PDH) being its most common form. The low-dose dexamethasone suppression test (LDDST) is widely used for the diagnosis of the disease and may provide information about the response of the hypothalamic–pituitary–adrenal axis. The aim of this study was to evaluate the possible association between cortisol values obtained during the LDDST and the final trilostane dose used in the treatment of dogs with PDH. A retrospective study was conducted through the analysis of medical records of dogs examined at a veterinary hospital, diagnosed with PDH using the LDDST and treated with trilostane. Basal cortisol values, as well as cortisol concentrations four and eight hours after the administration of low dose dexamethasone (4 h and 8 h post-dexamethasone, respectively), were collected, along with the final trilostane dose used for disease control. Demographic characteristics of the animals included in the study were also analyzed. A moderate positive correlation was observed between cortisol values measured at the fourth hour of the LDDST and the final trilostane dose, indicating that higher 4 h post-dexamethasone cortisol concentrations were associated with higher trilostane doses required to control the disease. In conclusion, cortisol measured at the fourth hour of the LDDST may represent an additional useful parameter for understanding the therapeutic response and for establishing a more individualized trilostane dosing regimen in dogs with PDH.