From Hip Effusion to Hemophilia: Unveiling the Cause of Pain in 6-Month-Old Infant. A Case Report.

Introduction: Non-traumatic hip pain in pediatric patients necessitates urgent evaluation due to a wide differential diagnosis, as misdiagnosis can lead to severe complications. This case report details the first known documentation in literature where intra-articular hip bleeding was the initial presentation of hemophilia in an infant, emphasizing the importance of recognizing hematological disorders amid typical orthopedic presentations. Case Report: A 6-month-old male infant with no significant medical history presented with unexplained pain and irritability. Clinical examination demonstrated restricted motion in the right hip, and imaging studies revealed hip effusion. Initial laboratory findings indicated a negative C-reactive protein; however, the activated partial thromboplastin time was prolonged, raising suspicion for a bleeding diathesis. Joint aspiration yielded hemorrhagic fluid, and subsequent tests confirmed a critically low level of coagulation factor VIII, leading to a diagnosis of hemophilia. The patient underwent treatment with factor VIII and was managed with a Pavlik harness, successfully restoring hip stabilization and range of motion. Conclusion: This case highlights the critical need for healthcare providers to consider hemophilia in the differential diagnosis for infants presenting with hip effusion and abnormalities in hemostasis parameters. By documenting a rare case where hemophilia mimicked infection or inflammation, this report aims to improve awareness and diagnostic protocols in pediatric orthopedics. The findings advocate for a cautious approach to invasive procedures in infants when a bleeding disorder has not been ruled out, ultimately enhancing clinical outcomes and advancing our understanding of disease etiology in similar presentations.