Ultrasonographic Changes of Adrenal Glands Size under Trilostane Therapy, Their Correlation with Clinical Signs and Endocrine Tests and Possibility of Introducing Ultrasound as Additional Monitoring Modality of Cushing’s Syndrome

Abstract

A prospective study of 15 dogs with diagnosed Cushing's syndrome was made to find a correlation between adrenal size enlargement, clinical signs and results of an ACTH stimulation test. To our knowledge, no study was made trying to correlate changes in adrenal size, response to therapy and ACTH stimulation test results. Ultrasonographic evaluation and an endocrine test (ACTH stimulation test/"pre pill") were performed in each dog two weeks after initiating the therapy, two to four weeks after changing the dosage of trilostane and ideally 10 weeks after establishing the right dosage of trilostane (two owners showed up later on date due pandemic of COVID-19). The results indicate that there is correlation between adrenal size enlargement and response to trilostane therapy. In this study, all dogs that had increase in adrenal gland size of more than 7% showed as well clinical improvement of HAC (hyperadrenocorticism) signs under trilostane therapy. Further, possible multicentric, studies should be performed to verify assumed correlation between adrenal size enlargement and positive response to trilostane therapy.