A 52 you male PMH of uncontrolled DM presents with four days of left arm pain.  Exam significant for foul odor, tissue necrosis, crepitus over clavicle and shoulder, decreased ROM.  An x-ray is shown.  What's the diagnosis?  Scroll down for answer.

A CT was obtained as well

Answer:  Necrotizing fasciitis, extensive subcutaneous air within tissue

• Risk factors:  DM, ETOH abuse, peripheral vascular disese, immunodeficiency, IV drug abuse, penetrating trauma
• Up to 75% of infections are polymicrobial (aerobic and anaerobic bacteria)
• Infection can spread rapidly, usually presents over hours
• Exam: erythema, edema, severe pain out of proportion to external findings, fever, less commonly crepitus and skin bullae / necrosis
• Treatment involves prompt surgical debridement, antibiotics alone are ineffective.
• ED management: stat surgical consult, IV fluid resuscitation, broad spectrum IV antibiotics to cover gram positive, gram negative and anaerobic bacteria - for example piperacillin-tazobactam plus vancomycin plus clindamycin for it's antitoxin effects

Reference

Kelly, E., & Magilner, D. (2016). Soft Tissue Infections. In Tintinalli's emergency medicine: A comprehensive study guide. New York, NY: Mc Graw-Hill Education.