Joint Infections (Septic Arthritis) in Dogs

Joint infections develop in the cavities of joints, usually after a wound has occurred in close proximity to the joint itself.

In most cases, canine septic arthritis only affects one joint. Cases of septic arthritis that arise from bacterial spread through the bloodstream may affect multiple joints, and indicate potentially life-threatening sepsis.

In dogs, joint infections are uncommon but serious conditions that can lead to severe complications such as osteoarthritis, bone infections, or sepsis. Dogs showing symptoms of joint infections require prompt veterinary care to reduce the risk of complications and improve outcomes.

Very young, elderly, and immunocompromised dogs are at greater risk of developing joint infections after receiving a wound. Hunting dogs and working dogs are at increased risk of puncture wounds.

Septic arthritis is usually caused by wounds over a joint, such as bite wounds, gunshot wounds, or penetrating injuries by foreign objects. Joint fluid provides ample nutrition to microbes introduced into the joint space, allowing for infection to develop rapidly.

In some cases, septic arthritis results when infection elsewhere in the body spreads through the bloodstream to the joint. Rarely, septic arthritis occurs after an injection into the joint is performed by a veterinarian, which can introduce bacteria from the skin surface into the joint fluid.

Septic arthritis can also result from fungal infection instead of bacterial infection.

Diagnostic tests include:

• Physical examination
• Diagnostic imaging, such as X-rays or ultrasound
• Bloodwork
• Sampling the joint fluid for microscopic evaluation or bacterial or fungal culture
• Biopsy of the affected joint capsule

Treatment focuses on removing the infection from the joint and treating any underlying causes of infection. Many dogs require hospitalization during the treatment period. Treatments include:

• Antibiotic therapy
• Antifungal therapy
• Draining and flushing the affected joint
• Surgical intervention to remove infected tissue
• Anti-inflammatory medications
• Hot and cold packing
• Crate rest

After the infection has resolved, physical therapy and anti-inflammatory medications may be recommended to prevent the joint from developing osteoarthritis.

Treatment often takes up to 4-8 weeks or longer, depending on the severity of infection and the success of treatment. Cases of septic arthritis which are diagnosed quickly typically have a good prognosis, assuming that the causative agent responds to treatment. Cases where treatment is delayed, or the causative bacteria or fungus is resistant to treatment, have a guarded to poor prognosis. In these cases, severe osteoarthritis, bone infections, or sepsis can result.

Septic arthritis can be prevented by minimizing wounds over or near joints, such as by preventing dog fights and reducing exposure to thick brush where thorns or sticks may become embedded in the skin. Providing prompt veterinary attention to dogs showing symptoms of illness can also help catch cases of septic arthritis early, improving prognosis.

Joint infections are uncommon in dogs.

• Antibiotics
• Joint lavage
• Surgical intervention
• Anti-inflammatories
• Supportive care