Snapshot A 29-year-old man presents to the emergency department 1 day after being in a fist fight at a bar. He punched his opponent in the mouth after having an argument, which resulted in a laceration of his dorsal hand. When he went home, he attempted to wash the laceration with soap and water and applied antibiotic cream. One day later, he developed swelling of the hand and pus was draining. Physical examination is notable for marked swelling in the ulnar aspect of the hand and severe tenderness over the fourth metacarpal joint, and pus is noted to be draining from the joint. Sensory examination is normal, and strength examination is limited by pain. In the emergency department, he obtained a radiograph of the hand, which did not demonstrate any acute fractures or foreign bodies. He immediately received a tetanus booster, and orthopedics was consulted for possible irrigation and drainage of the joint. Given the clinical extent of the infection, he is started on intravenous ampicillin-sulbactam. Introduction Definition login to view 2 more bullets Microbiology login to view 9 more bullets Epidemiology incidence login to view 3 more bullets ETIOLOGY Pathogenesis login to view 6 more bullets Presentation Symptoms/physical exam login to view 14 more bullets Imaging Radiography of the involved body part (e.g., hand) login to view 2 more bullets Studies Wound and blood cultures (aerobic and anaerobic) login to view 2 more bullets Treatment Conservative login to view 3 more bullets Medical login to view 35 more bullets Operative login to view 13 more bullets Complications Septic arthritis Osteomyelitis Deep soft tissue infection Prognosis Excellent in patients who promptly seek medical attention