Importance of Clinical-Epidemiological History for Proper Identification and Therapeutic Management in a Case of Septic Arthritis

Septic arthritis (SA) is an infectious condition most often caused by Gram-positive bacteria, although other agents may also be involved. The most common mechanism of infection is hematogenous spread; however, direct inoculation through trauma or animal bites and infection by contiguity are also possible. Diagnosis involves clinical, laboratory and radiological criteria, and a well-directed clinical history is essential. Pasteurella multocida, a Gram-negative coccobacillus found in the airways of domestic animals, has the potential to cause infections ranging from skin and soft tissue disease to severe systemic infections. Proper collection of epidemiological data is crucial for clinical reasoning and therapeutic decision-making. ERP, 76 years old, with a history of cardiomyopathy, presented with a small, lacerated wound of shallow depth on the second right finger. Two days after trauma, he developed worsening pain involving the entire hand, wrist and right forearm; on day 3, he deteriorated clinically, and although afebrile, sought medical care. There were no systemic changes, but labs showed leukocytosis 19,000/mm³, ESR 41 mm, CRP 232 mg/L. A diagnosis of septic arthritis was made, and surgical exploration was performed the same day, revealing a purulent collection extending to the flexor retinaculum. Material was collected for culture and empirical antibiotic therapy was started. At 48 hours after surgery, Pasteurella multocida was identified and the infection control team promptly recommended switching to amoxicillin-clavulanate. After hospital discharge and outpatient follow-up, the patient completed 14 days of antibiotic therapy with clinical and laboratory improvement. During clinical investigation, it was identified that the patient had direct contact with rescued dogs and, after the trauma, handled water containers for the animals without PPE, which may have favored inoculation. This case reinforces the importance of epidemiological history in the assessment of suspected SA, particularly when uncommon agents are involved. Pasteurella multocida is traditionally associated with soft tissue infections but can also cause joint infections. Early surgical intervention and targeted antibiotic therapy were essential for infectious control. This report contributes to increased awareness of less frequent pathogens and underscores the role of broad, incisive clinical assessment in managing osteoarticular infections.