EN12 - Hypothalamic-pituitary-adrenal Axis Recovery Following Intermediate-acting Glucocorticoids Therapy in Dogs

Abstract: Background:In dogs, duration of hypothalamic-pituitary-adrenal axis(HPA-axis)suppression after intermediate-acting systemic glucocorticoids(IAGC)therapy is reported to vary from a few days up to 7 weeks after GC discontinuation. However, this data derives mainly from experimental studies on healthy dogs and not from animals with spontaneous disease.




Hypothesis and Objective:to determine the timeline for recovery of the HPA axis in a group of chronically-ill dogs treated with IAGC.




Animals:Seventeen client-owned dogs that received IAGC for at least one week.




Methods:Single-center prospective observational study. ACTH stimulation test, endogenous ACTH (eACTH), serum biochemistry and urinalysis were performed at T0(2-6 days after IAGC discontinuation)and then every two weeks until the documentation of HPA-axis recovery (post-ACTH cortisol >6 μg/dl).




Results: Median time of the HPA axis recovery was 3 days (2-133 days). 11/17 dogs (65%) showed recovery of the HPA-axis at T0, 3/17 (17%) after 15-17 days and one dog (6%) at 31, 64, 133 days, respectively. Cumulative dose, maximum dose, median daily dose, duration of treatment with IACG and body weight were not correlated with the timing of HPA-axis recovery. ALT, GGT, ALP and eACTH were significantly correlated with the post-ACTH cortisol(rs=-0.45,P = 0.0059; rs=-0.33,P = 0.047; r=-0.30,P = 0.045, rs=0.44,P = 0.008, respectively). Timing of HPA-axis recovery in dogs underwent alternate-day tapering process was not different compared to dogs who did not (3.5 vs 3 days, P = 0.98).




Conclusion and clinical importance:The majority of dogs showed recovery of the HPA-axis within 4 days after IAGC discontinuation. However, 12% of dogs required more than 8 weeks.