Unmasking Hemophilia B After Hip Aspiration: A Case Report

A 7-year-old boy presented with excruciating hip pain for 1 day, unable to bear weight. Magnetic resonance imaging (MRI) revealed small hip joint effusion and synovitis, which was treated by urgent operative aspiration to rule out infection. Subsequently, the postoperative site bled continuously, despite compression. The hip wound and blood cultures showed no growth. He was examined by a hematologist and had normal coagulopathy lab results. He was discharged and went home 4 days after aspiration and was scheduled for outpatient hematology work-up. He was readmitted 11 days after aspiration with continued pain and MRI was repeated, showing large hip hemarthrosis. Lab results at that time showed a prolonged partial thromboplastin time of 43.9 seconds. The patient was given fresh frozen plasma. The hip effusion was stable on ultrasound. He was found to have low factor IX <17% consistent with hemophilia B and was given recombinant factor IX (Benefix) of 2,000 units. The following day, his pain was markedly improved and he was discharged. At the 4-month follow-up, the patient was fully ambulatory.

This is a case of unexpected bleeding after hip aspiration which led to the life-changing diagnosis of Hemophilia B in a pediatric patient. Orthopedists should be wary of bleeding dyscrasias and involve consultants as needed.