Diagnosis of naturally occurring canine hypercortisolism: survey of Australian veterinarians

Naturally occurring hypercortisolism in dogs is commonly investigated in primary care practice. However, there is a poor understanding of the preference and interpretation of diagnostic tests by Australian veterinarians. This study aimed to investigate the diagnostic processes used by Australian primary care veterinarians via an anonymous online survey consisting of multiple-choice and short-answer questions. The survey was completed by 399 respondents. When hypercortisolism was suspected, 392 performed adrenal function testing, while seven used treatment trials. With consistent clinical signs but no clinicopathological abnormalities, 354 performed screening tests, and 312 in dogs with consistent clinicopathological abnormalities but no clinical signs. For veterinarians who performed function testing, 296 used the same screening tests regardless of the magnitude of pre-test suspicion; 266 used either an adrenocorticotropic hormone (ACTH) stimulation test or low-dose dexamethasone suppression test (LDDST) alone. Even in the absence of financial constraints, 158 of 399 respondents almost never attempted differentiation between ACTH-dependent and ACTH-independent disease. For those attempting differentiation, 178 used abdominal ultrasound and 102 used LDDST. Approximately half of all respondents indicated that specialist referral was not offered to any of the preceding 10 cases suspected of hypercortisolism. Hypercortisolism is frequently diagnosed in dogs without consistent clinical signs or without performing routine clinical pathology tests, raising concerns for overdiagnosis. A large proportion of respondents rarely attempted to differentiate between causes of hypercortisolism, possibly affecting long-term management and prognosis. Referral to a specialist is rare, suggesting the condition is predominantly managed in primary care practice.