Diagnosis and Management of Chronic Nonbacterial Osteomyelitis in a Dog.

This case presents the first documented successful medical management of chronic nonbacterial osteomyelitis (CNO) in a small dog-a condition rarely described in veterinary medicine. A 4-year-old castrated male Pomeranian dog weighing 4.6 kg was presented with a 3-week history of right hindlimb lameness. Radiographic examination revealed osteolytic lesions, periosteal reactions, and decreased muscle mass in the affected limb. Microbial and blood culture tests showed negative results, whereas cytological and histopathological analyses of the right distal femur confirmed neutrophilic inflammation and osteomyelitis, leading to a diagnosis of CNO. Clinical and radiographic improvements were observed following administration of bisphosphonates, disease-modifying anti-rheumatic drugs, and glucocorticoids. This case underscores the possibility of non-infectious osteomyelitis in dogs and suggests that adapting human treatment strategies may be beneficial. Further research is needed to clarify the diagnostic criteria and pathophysiology of CNO in veterinary medicine.