N10 - Causal Agents and Imaging in 85 Dogs Diagnosed with Discospondylitis (2018-2022)

Background: Discospondylitis is a well-known cause of spinal pain and, sometimes, neurologic deficits, but the infectious causes can be difficult to identify.

Objectives: To describe clinical features, imaging characteristics, infectious agents, and outcomes in dogs diagnosed with discospondylitis.

Animals: Eighty-five client-owned dogs with an imaging diagnosis of discospondylitis.

Methods: Prospective case series systemically evaluated by serology and culture for etiology. Cases were classified as definitive (infectious etiology confirmed) or presumptive (imaging consistent with discospondylitis, no agent identified). Signalment, imaging findings, etiologic agents, and outcomes were recorded.

Results: A definitive diagnosis was made in 45 of 85 dogs. Labradors (n=14) and German shepherds (n=15) were the most commonly affected breeds. Of 70 blood cultures, 28 were positive (40%), while 12 of 76 urine cultures were positive (16%). Ten dogs were confirmed to have Brucella canis, ten had Aspergillus, and the remaining had various bacterial infections. Forty-eight (56%) of dogs had multifocal lesions, with the L7/S1 disc space being the most affected site (46%). Subluxation was present in 9.4% of dogs. Fifty-six percent of dogs were treated with antibiotics for over 3 months. Eight of ten dogs diagnosed with fungal disease were still alive at follow-up (0 to 15 months). Five of seven dogs that underwent stabilization surgery had favorable outcomes.

Conclusions: Systemic investigation of causative agents of discospondylitis detected a definitive diagnosis in over 50% of the cases and suggested a high prevalence of Brucella canis and fungal infections. Fungal discospondylitis can be managed satisfactorily with antifungal medications in certain cases.