Utility of a corticotropin‐releasing hormone test to differentiate pituitary‐dependent hyperadrenocorticism from cortisol‐producing adrenal tumors in dogs

• Published in: Journal of Veterinary Internal Medicine Vol. 36; no. 1; pp. 29 - 38
• Main Authors: Tanaka, Sachiyo, Suzuki, Shuji, Sato, Asaka, Teshima, Takahiro, Mori, Akihiro, Sako, Toshinori, Tanaka, Aki, Hara, Yasushi
• Format: Journal Article
• Language: English
• Published: Hoboken, USA Wiley 01.01.2022; John Wiley & Sons, Inc
• Subjects: Abdomen; ACTH; Adrenal Gland Neoplasms; Adrenal Gland Neoplasms - diagnosis; Adrenal Gland Neoplasms - veterinary; Adrenal glands; Adrenocortical Hyperfunction; Adrenocortical Hyperfunction - diagnosis; Adrenocortical Hyperfunction - veterinary; Animals; Beagle; canine; corticotropin; Corticotropin-Releasing Hormone; cortisol; Cushing syndrome; diagnosis; Dog Diseases; Dog Diseases - diagnosis; Dogs; Drug dosages; Hormones; Hydrocortisone; hyperadrenocorticism; Laboratory animals; Life sciences; Pituitary gland; Prospective Studies; SF600-1100; SMALL ANIMAL; Teaching hospitals; Tumors; Ultrasonic imaging; ultrasonography; Veterinary medicine; Japan; ACTH; cortisol; diagnosis; canine; Cushing syndrome
• ISSN: 0891-6640; 1939-1676; 1939-1676
• DOI: 10.1111/jvim.16336

Background Hyperadrenocorticism (HAC) is a common endocrine disorder in dogs; however, there are no reports on the use of the corticotropin‐releasing hormone test (CRHT) to differentiate between pituitary‐dependent hyperadrenocorticism (PDH) and cortisol‐producing adrenal tumors (CPATs), both causative of HAC. Objectives To evaluate the usefulness of CRHT as a tool to differentiate between PDH and CPAT in dogs and to determine the reference intervals for CRHT in healthy, PDH, and CPAT dogs. Animals Dogs diagnosed with PDH (n = 21), CPAT (n = 6), and healthy beagle dogs (n = 33). Methods This prospective study included dogs with a definitive diagnosis of PDH and CPAT and healthy beagle dogs, in which CRHT was performed, were prospectively evaluated. We investigated the correlations of CRHT (endogenous adrenocorticotropic hormone [ACTH] concentration, endogenous ACTH concentration [EAC], and poststimulation ACTH concentration [PAC]) with pituitary‐to‐brain ratio (PBR) (in PDH) and with indices of adrenal ultrasonography (smaller and larger adrenal gland dorsoventral thickness in PDH and CPAT). Results For EAC, the area under the curve (AUC) was 0.95, with a cutoff value of 26.3 pg/mL (sensitivity: 90.62%, specificity: 87.50%). The AUC for PAC was 0.96 with a cutoff value of 54.5 pg/mL (sensitivity: 100.00%, specificity: 66.67%). The 95% reference interval for CRHT in healthy (control) dogs ranged 5.00 to 79.8 pg/mL (1.10‐17.57 pmol/L) for EAC, and 1.92 to 153.42 pg/mL (0.42‐33.78 pmol/L) for PAC. There was no significant correlation between PBR and CRHT, nor adrenal size and CRHT. Conclusions and Clinical Importance CRHT appears to be a rapid and reliable test for differentiating PDH from CPAT in dogs.