Pyrexia in juvenile dogs: a retrospective analysis of diagnosis and clinical features of 115 Australian cases

Pyrexia is a non-specific clinical sign associated with many diseases in dogs. This case series examines the final diagnoses, breed distribution and outcomes in dogs aged 18 months or under with pyrexia >24 h duration. Medical record databases of 11 Australian emergency and referral hospitals between 1st January 2020 and 31st January 2025 were searched to identify dogs up to 18 months old presenting with pyrexia. Cases were included if the duration of pyrexia was >24 h and the medical records were complete. Information extracted from the medical record included signalment, history (including previous treatment), duration of clinical signs, results of diagnostic tests and final diagnosis. There were 115 cases identified. Of these, 68/115 had a non-infectious inflammatory cause, and 45/115 had an infectious or antibiotic-responsive cause. The most common diagnoses were steroid-responsive meningitis arteritis (35/115), hypertrophic osteodystrophy (9/115), aspiration pneumonia (8/115) and immune-mediated polyarthritis (4/115). The most common breeds were crossbreed (16/115), Kelpie (14/115), German Shepherd (14/115), Border Collie (12/115), Golden Retriever (8/115) and Corgi (7/115). Overall, 99/115 dogs recovered, 9/115 were euthanased, 5/115 were lost to follow up and 2/115 died. This population of dogs with pyrexia had a heterogenous distribution of diagnoses, reinforcing the need for diagnostic investigations in pyrexic young dogs prior to treatment. This is the largest study of pyrexia in juvenile dogs in Australia, and infection was more common than in international studies. These data are useful for a broad range of veterinarians in clinical practice to inform their diagnostic testing and treatment choices.