NECROTISING FASCIITIS. C. Eze 1 , J. Wiese 1 ; 1 Tulane University, New Orleans, LA (Tracking ID #77055) LEARNING OBJECTIVES: 1. Recognize the signs of deep fascial infections. 2. Use the physical examination to prompt timely surgical intervention for necrotizing fasciitis. CASE INFORMATION: A 21 year-old Hispanic-speaking man presented with four days of left leg pain, swelling and fever after a spider bite. He had a temperature of 103 F, a heart rate of 128, and a blood pressure of 128/70. His left lateral leg was warm, edematous and tender. There was a 1 cm ulcer without drainage or necrosis. The pulses, sensation and range of motion of were normal. A plain film of his leg showed no soft tissue air or bone involvement. His WBC count was 22,000; the remaining laboratory values were normal. Blood cultures were obtained and he was empirically started on gatifloxacin due to a penicillin allergy. After 48 hours, he showed no improvement. Bullae and ecchymosis were noted on the second day; he lost sensation of the overlying skin on the third day. His antibiotic coverage was broadened to include coverage for MRSA. An MRI revealed fluid collections between the muscle and fascia consistent with necrotizing fascitis. An emergent fasciotomy and posterior compartment release were peformed. Wound cultures grew group A Strep. and Strep. milleri. IMPLICATIONS/DISCUSSION: The timely diagnosis of necrotizing fasciitis is important to preventing tissue damage, systemic toxicity, limb loss or death. Cellulitis not responsive to antibiotics, or the appearance of ecchymosis, bullae or anesthesia should prompt consideration of this diagnosis. The physical examination reflects the deep fascial structured damaged by the advancing infection. Ecchymosis, bullae and anesthesia reflect the damaged vessels, skin planes and nerves. While MRI is useful, establishing a timely pre-test probability prompting surgical exploration is the gold standard for making the definitive diagnosis. The closed space of deep fascial infections renders them immune from systemic antibiotics; treatment requires immediate surgical release. Antibiotics only buy time for surgical intervention.