Case presentation A 10-year-old boy has been brought to the emergency department by his father. The youngster was playing in a playground when he developed a swollen and painful right knee. The boy describes recurrent episodes of pain and swelling in his knees and shoulders over the last year or so. He cannot remember any history of trauma. However, he has a history of multiple blood transfusions, but he is unsure of the reason for these.

Examination The boy has painful, tensely swollen, warm, and diffusely tender knee and shoulder joints. He also has multiple bruises on his legs and arms. What is the most probable diagnosis for this boy? ##Disclaimer## The content provided on Docplexus is intended for educational purposes only. While we strive to ensure its accuracy, we make no warranties, explicit or implied, about the suitability, reliability, or adequacy of the information,…