Case 1

A 1 year old boy, an only child, presented to an accident and emergency department with a painful, swollen right elbow following minor trauma. Examination and a radiograph showed no evidence of bone injury and he was sent home.

Three days later, he was brought back because of increasing pain and swelling. Joint aspiration yielded haemorrhagic fluid. Osteomyelitis was suspected and he was started empirically on antibiotic treatment. Approximately four weeks later, as the effusion had not resolved, the joint was explored, yielding dark blood, and a biopsy specimen was taken from a localised area of synovitis. Postoperatively the wound bled persistently. A coagulation screen showed normal prothrombin time but prolonged activated partial thromboplastin time (96 s; normal range …