Septic Arthritis in Dogs and Cats

Infectious arthritis is most frequently associated with bacterial agents such as staphylococci, streptococci, and coliforms. Causes include hematogenous spread or penetrating trauma, including surgery. Other agents producing a septic arthritis include rickettsia (Rocky Mountain spotted fever Rocky Mountain Spotted Fever in Dogs Spotted fevers are diseases caused by a set of related bacteria in the Rickettsia genus, of which Rocky Mountain spotted fever is the most severe. After transmission of the pathogen through... read more , ehrlichiosis) and spirochetes (borreliosis Lyme Borreliosis in Animals Lyme borreliosis is a vector-borne zoonotic disease transmitted by ticks infected with spirochetal bacteria belonging to the genus Borrelia. Affected dogs typically present with intermittent... read more ).

Clinical signs of septic arthritis include lameness, swelling, pain of affected joint(s), and systemic signs of fever, malaise, anorexia, and stiffness. Radiography may reveal joint effusion in early cases and degenerative joint disease in chronic conditions. Arthrocentesis reveals increased levels of WBCs, especially neutrophils. The synovial fluid may be grossly purulent. Bacterial culture and antimicrobial sensitivity testing may confirm the diagnosis. Serologic testing is used for nonbacterial agents. Treatment is with appropriate IV and oral antibiotics, joint lavage, and surgical debridement in severe cases.