Management of Suspected Septic Arthritis or Soft Tissue Infection

Clinical Assessment

The combination of joint pain, swelling, warmth, and elevated white blood cell count is highly suggestive of a bacterial infection of the joint or surrounding soft tissue, according to the Infectious Diseases Society of America 2, 1
An elevated absolute neutrophil count warrants careful assessment for bacterial infection, even in the absence of fever, as recommended by the American College of Physicians 1
Leukocytosis has a likelihood ratio of 3.7 for bacterial infection, as reported by the Infectious Diseases Society of America 3, 4
Even a mildly elevated white blood cell count with elevated neutrophils significantly increases the probability of an underlying bacterial infection, according to the American College of Physicians 1

Obtain joint fluid aspiration for Gram stain and culture, as recommended by the Infectious Diseases Society of America 2
Obtain joint fluid aspiration for crystal analysis to rule out gout/pseudogout, according to the American College of Rheumatology 1

Start empiric antibiotics immediately after obtaining cultures, as recommended by the Infectious Diseases Society of America 2, 5
For non-critically ill patients with suspected septic arthritis or soft tissue infection, use cefazolin for clean wounds, according to the Infectious Diseases Society of America 5
For patients with signs of systemic illness, broader spectrum coverage may be needed, as recommended by the Infectious Diseases Society of America 2
Consider adding anti-MRSA coverage if risk factors are present, according to the Infectious Diseases Society of America 5

Surgical drainage or debridement is often necessary for abscesses or purulent collections, as recommended by the Infectious Diseases Society of America 2, 5

Monitor clinical response including resolution of pain, swelling, and warmth, and normalization of white blood cell count, as recommended by the American College of Physicians 1
Overlooking the significance of elevated white blood cell count and neutrophilia, even in the absence of fever, can lead to delayed diagnosis, according to the American College of Physicians and the Infectious Diseases Society of America 1, 3