Critical Care Medicine-Infections and Immunologic Disease>>>>>Soft-Tissue, Bone, Joint Infections
Question 2#

A 20-year-old female college student presents with fever and a painful left knee for the last 3 days. She denies any recent trauma and was treated last week for a urinary tract infection. Her vital signs are T 38.8°C, HR 112 beats/min, RR 24 breaths/min, BP 78/42 mm Hg, and O2 saturation 98% on RA. Physical examination reveals a swollen and erythematous knee with decreased range of motion. Joint aspiration demonstrates white blood cell (WBC) 20,000, with 80% neutrophils and calcium pyrophosphate crystals, and no organism are seen on gram stain. In addition to fluid administration, which of the following interventions is most appropriate?

A. No further treatment warranted
B. Administer vancomycin and ceftriaxone
C. Administer intra-articular glucocorticoids
D. Administer indomethacin

Correct Answer is B

Comment:

Correct Answer: B

In patients who present with an acutely painful and swollen joint, prompt identification and treatment of septic arthritis can substantially reduce morbidity and mortality. An associated skin, urinary tract, or respiratory infection should provide insight to the likely pathogen. Definitive diagnosis is established by identification of bacteria in the synovial fluid. Gram stain is positive in many cases, but the absence of bacteria on initial gram stain should be considered conclusive evidence of the absence of infection. Empiric IV antibiotic therapy should be administered while awaiting culture results. Antibiotic therapy should cover (1) methicillin-resistant Staphylococcus aureus (which can be treated with vancomycin) and (2) gram-negative organisms such as Klebsiella pneumoniae and Neisseria gonorrhoeae (which are typically treated with ceftriaxone or thirdgeneration cephalosporin). In addition to antibiotic therapy, patients with septic arthritis should have orthopedic evaluation for irrigation and debridement. Septic arthritis can cause the release of calcium pyrophosphate crystals from cartilage, so the finding of such crystals does not rule out infection. Intra-articular steroids or indomethacin would relieve acute joint inflammation but would not treat the underlying infection nor be immediately appropriate treatment.

References:

  1. Sharff KA, Richards EP, Townes JM. Clinical management of septic arthritis. Curr Rheumatol Rep. 2013;15:332.
  2.  Carpenter CR, Schuur JD, Everett WW, Pines JM. Evidence-based diagnostics: adult septic arthritis. Acad Emerg Med. 2011;18:781-796.
  3. Margaretten ME, Kohlwes J, Moore D, Bent S. Does this adult patient have septic arthritis? JAMA. 2007;297:1478-1488.