Serum cortisol is often measured to assess stress axis activity, acute and chronic pain, and psychogenic stress in animals. However, the reliability of this biomarker in dogs remains debated. In this study, researchers investigated whether cortisol levels, measured via Electrochemiluminescence immunoassay (ECLIA), accurately reflect pain severity in dogs with orthopedic conditions such as hip dysplasia, cranial cruciate ligament rupture, and intervertebral disc disease.
The study evaluated thirty dogs, divided into a healthy control group (n = 10) and a pain group (n = 20). Pain group dogs received either NSAID treatment only or a combination of therapy and physiotherapy. Blood samples were collected at the start and after ten days, alongside orthopedic tests including the Ortolani, Barden, drawer sign, and tibia compression tests, with diagnoses confirmed via X-ray.
Although clinical and imaging results confirmed significant pain reduction—especially in the therapy and physiotherapy group—serum cortisol levels did not consistently align with observed improvements. In some cases, cortisol levels increased despite clear clinical recovery, while in others they remained unchanged despite persistent discomfort.
Statistical analysis showed no significant differences between treatment groups, with high variability in results. The findings suggest that while serum cortisol measurement remains a useful tool for certain stress-related assessments, it should not be relied upon as a sole or definitive indicator of pain severity in dogs.
Source: Markovszky, A. K., Weber, C., Biksi, O., Daneş, M., Dumitrescu, E., Muselin, F., Tufarelli, V., Puvača, N., & Cristina, R., Animals, November 1, 2020.
