What's the diagnosis? By Dr. Michael Tom
Wed, 05/29/2019 - 10:23am
A 53 yo male with a history of IV drug use presents with an abscess to his lower extremity. He states he was injecting into the affected area 2-3 days prior to onset of symptoms. He is well appearing but complains of severe pain and subjective fevers. There is an exquisitely tender, fluctuant area on his anterior leg. X-ray is shown. What's the diagnosis? Scroll down for answer.
Answer: Necrotizing soft tissue infection
- High risk groups: IVDU, diapetics, those with contaminated traumatic wounds, other immunocompromised
- Typically polymicrobial (Type 1) vs monomicrobial (Type 2, Group A strep)
- Exam findings similar to those of cellulitis with possibly crepitus, bullae, and pain out of proportion to physical appearance
- Characterized by rapid progression, systemic toxicity, high mortality
- Diagnosis may be made on plain x-ray but CT is more reliable; gas in tissues on imaging is specific but not sensitive for this disease process
- Treatment involves emergent surgical consultation for debridement as well as broad spectrum antibiotics (vancomycin with piperacillin/tazobactam or cefepime, PLUS clindamycin for inhibition of toxin production in Group A strep or Clostridial infections)
- Immunocompromised contacts of patients diagnosed with necrotizing Group A strep infection should receive prophylaxis
- See also EMDaily NSTI's
Kelly EW, Magilner D. Soft Tissue Infections. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e New York, NY: McGraw-Hill; 2016.