A 62-year-old woman has a 3-day history of fever and left knee pain and swelling. She has a 30-year history of rheumatoid arthritis treated with methotrexate and nonsteroidal anti-inflammatory drugs. On examination, temp 37.8C, BP 140/78 mmHg, and HR 86/min. The left knee is swollen, red, warm, and tender to palpation with limited range of motion because of pain. Synovial fluid analysis shows leukocytes count is 75,000/uL with 69% neutrophils. Gram stain is positive for gram positive cocci clusters Which would be the most appropriate initial antibiotic therapy pending culture results
سؤال مجاني 3 من 10 اليوم · اشترك وكمّل بدون حد
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الإجابة والشرح
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الإجابة: D. Vancomycin
Septic arthritis with gram-positive cocci in clusters = Staphylococcus aureus. Before sensitivities are known, empiric therapy must cover MRSA, so IV vancomycin is the choice (the lecture's empiric septic arthritis regimen is vancomycin-based). Nafcillin and cefazolin cover only MSSA, and ceftriaxone does not cover MRSA.
ليش كل خيار صح أو غلط
-
A
ليش غلط
Cefazolin is a first-generation cephalosporin for Strep and MSSA; the cephalosporin listed for MRSA is the 5th-generation ceftaroline. With gram-positive clusters, MRSA must be covered until culture returns.
✓ Antibiotics 🍓.pdf · p. 1 -
B
ليش غلط
Ceftriaxone covers the gonococcus but not MRSA: ceftaroline is the first cephalosporin with MRSA activity ("ceftriaxone + MRSA coverage"). Gram-positive clusters need MRSA cover.
✓ Antibiotic-1 (3).pdf · p. 15 -
C
ليش غلط
Nafcillin is an anti-staph penicillin, the drug of choice for methicillin-sensitive Staph (MSSA). It does not cover MRSA, which must be covered empirically.
✓ Antibiotic-1 (3).pdf · p. 12 -
D
ليش صح
The lecture's empiric regimen for septic arthritis is IV vancomycin plus ceftriaxone, aimed at Staph. aureus and gonococcus. Gram-positive cocci in clusters point to Staph. aureus, so vancomycin is the drug to start.
✓ Antibiotic-1 (3).pdf · p. 36
- المصدر
- Antibiotic-1 (3).pdf · p. 36
Antibiotic-1 (3).pdf · p. 20 - المحاضرة
- Antimicrobials · Infectious Diseases · Module B
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