An Unusual Case Study of Idiopathic Bilateral Deep Vein Thrombosis and Osteonecrosis of the Left Distal Tibia in an 11-year-old Girl.

Introduction: Deep vein thrombosis (DVTs) in children is rare, normally linked to pathologies such as major traumatic injury, thrombophilia, and malignancy. Osteonecrosis is still poorly understood. There is growing support to include hypercoagulable states as a predisposing factor, however, no definitive correlation has been found. At present, there are no conclusive literature on the links between osteonecrosis and DVT. Case Presentation: This report describes an unusual and rare case of osteonecrosis and idiopathic DVT in an 11-year-old girl who initially presented with a sprained left ankle. On follow-up, pain was persistent and subsequent radiological investigations revealed extensive DVT, and magnetic resonance imaging scan revealed osteonecrosis of the distal left tibia. Initial blood tests were normal, however with follow-up with hematology, a diagnosis of antithrombin deficiency was made, with the treatment of lifelong anticoagulation. Our patient had continued orthopedic input for clinical and radiographic surveillance to monitor leg length discrepancy. Conclusion: This case highlights the need to engage in close follow-up and the cautionary care required when young children present with non-resolving severe pain, to consider osteonecrosis and DVT. Our case also highlights the need for further research into the relationship between minor injuries and DVTs and osteonecrosis in children, and the potential synergistic relationship between DVTs and osteonecrosis.