A 4-year-old boy presents to the emergency department with acute-onset limping and an inability to bear weight on his right lower extremity. His parents report that he developed a high fever earlier today. He was previously healthy and has no recent history of trauma. Temperature is 39.1°C (102.4°F), blood pressure is 100/65 mm Hg, and pulse is 125/min. On examination, the patient is distressed. The right hip is held in a position of flexion, abduction, and external rotation. Passive range of motion of the right hip elicits severe pain. There is no overlying erythema or swelling. Arrange the following steps in the most appropriate chronological order for the evaluation and management of this patient's condition.
- 1Order plain radiographs of the right pelvis and femur, along with serum inflammatory markers (ESR, CRP, and WBC count).
- 2Obtain a bedside ultrasound of the affected joint to detect the presence of a fluid collection.
- 3Perform image-guided aspiration of the synovial fluid for cell count, Gram stain, and culture.
- 4Administer broad-spectrum intravenous antimicrobial therapy.
Cevap
The correct sequence is: Plain radiographs and inflammatory markers, followed by ultrasound of the hip, then diagnostic joint aspiration, and finally administration of intravenous antibiotics.
In a child presenting with an acute limp, fever, and refusal to bear weight, the initial step is to obtain plain radiographs to rule out trauma or bony lesions, and measure serum inflammatory markers (WBC, ESR, CRP) to assess the risk of septic arthritis using the Kocher criteria. If the initial evaluation shows elevated inflammatory markers, an ultrasound of the hip is indicated to identify the presence of a joint effusion. Once a joint effusion is confirmed, diagnostic arthrocentesis must be performed to obtain synovial fluid for cell count, Gram stain, and culture. Finally, empiric intravenous antibiotics should be administered immediately after the joint aspiration is completed, as giving antibiotics prior to aspiration can sterilize the culture.
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Anahtar Kavram
The sequential evaluation of suspected pediatric septic arthritis involves initial radiographs and lab markers (Kocher criteria), followed by ultrasound for effusion, diagnostic arthrocentesis, and finally empiric antibiotics.