Soft Tissue & Bone Infections

Case 2:

Mr. Solo, a 33 year old man, is admitted to your team with left lower extremity pain and erythema. He states that he thinks his symptoms started when he was “accidentally” scratched by an Ewok about 3 days prior to admission (but he also states he may have been bitten by a spider). He is afebrile but tachycardic to 102, and on exam, the erythematous region he had previously looks bigger than it did a few hours ago. His only new complaint is that he thinks his sensation has decreased in that area. You currently have him on cefazolin IV. In addition to ordering a CT with contrast of the left leg, what is your next step?

a.       Discontinue cefazolin and start vancomycin to cover MRSA.

b.       Discontinue cefazolin and start pip-tazo.

c.       Discontinue cefazolin and start vancomycin and pip-tazo.

d.      Discontinue cefazolin and start vancomycin, pip-tazo, and clindamycin.

Explanation:

Loss of sensation, in addition to systemic signs of toxicity (fevers, chills, altered mental status, hypotension), could be hints of an underlying necrotizing process, not just “pain out of proportion to exam,” woody induration and crepitus. It’s important to always keep necrotizing fasciitis in mind so that it can be managed appropriately!

In terms of empiric antibiotic therapy, we need to cover all potential causes of necrotizing fasciitis, including MRSA, gram-positive and gram-negative organisms, and anaerobes—vancomycin, pip-tazo and clindamycin is the best answer choice (D). Remember that clindamycin is NOT for anaerobic coverage, but to inhibit toxin formation by group A streptococci (Strep pyogenes) and Clostridium species.

As a side note, clindamycin is typically only continued until the patient is clinically and hemodynamically stable for 48-72 hours (that is, not in septic shock); we’ll discuss other duration recommendations in the module.