Answer :
Final answer:
The next best step is to refer the child to a pediatric orthopedic specialist or pediatric rheumatologist and consider getting a hip ultrasound, starting NSAIDs for pain relief, and additional laboratory tests like CRP.
Explanation:
The clinical presentation of a 5-year-old male with a history of a cold, now presenting with a limp and effusion in the hip, normal X-rays, an elevated ESR, a slightly increased temperature, and normal WBC count suggests a possible transient synovitis or early septic arthritis.
The next best step in management should be prompt referral to a pediatric orthopedic specialist or a pediatric rheumatologist for further evaluation. In the meantime, obtaining a hip ultrasound to assess for effusion, starting nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief, and considering further laboratory tests such as a C-reactive protein (CRP) might be advised.
Given that X-rays are normal, this step is unlikely to reveal osseous abnormalities but can exclude other conditions such as fractures. A normal WBC count does not rule out infection, and hip effusions in children can be due to various causes, including infectious, inflammatory, and traumatic.