Introduction

• Septic arthritis or infectious arthritis is where infectious microorganisms are found within one or more synovial joints.
• Cause: most commonly cause by hematogenous spread of pathogenic microorganisms from primary foci of infection such as abscesses, dental disease, traumatic skin wounds (bites), contaminated surgery, upper respiratory tract infection (URTD). Septic arthritis can be an extension of primary osteomyelitis such as pododermatitis on plantar/palmar surfaces of the feet.
• Signs: lameness associated with soft tissue swelling, pain over joints and heat.
• Diagnosis: radiography, synovial fluid analysis.
• Treatment: address underlying causes, systemic antibiotics to achieve control, surgical debridement of the synovium (open arthrotomy).
• Prognosis: good if diagnosed immediately; guarded to poor if advanced disease or multiple joints involved.

Pathogenesis

Etiology

• Pyogenic bacteria such as Pasteurella Pasteurella multocida, Staphylococci Staphylococcus spp and anaerobic bacteria.

Predisposing factors

General

• Immunosuppression.
• Chronic bacterial infection resulting in ascending spread to the joint or hematogenous spread.
• Penetrating injury into the joint.

Pathophysiology

• Ascending spread of pathogen (bacterial, spirochetal, mycoplasmal, rickettsial, viral, fungal or protozoan) from infection.
• Hematogenous spread of pathogen or direct entry of bacteria into the joint due to injury.
• Disruption of joint homeostasis; abnormal membrane and cartilage functions, nutrition and joint biomechanics.

Diagnosis

Treatment

Outcomes