Hip pain - an uncommon cause of extensive deep vein thrombosis (DVT) in the paediatric age group: a case report.

Deep vein thrombosis (DVT) in the pediatric population remains an infrequent yet clinically significant entity, with an estimated incidence of 0.07-0.14 per 10,000 children. We describe a unique case involving a previously healthy 16-year-old female who presented with progressively worsening left hip pain radiating to the knee, inability to weight bear, and associated limb heaviness with a purple discoloration on standing. Clinical evaluation revealed unilateral leg swelling, increased girth, and pain on passive joint movement, while initial radiographs were unremarkable; however, a markedly elevated D-dimer level prompted further investigation with Doppler ultrasound, which confirmed an extensive iliofemoral DVT. Owing to the lack of pediatric-specific guidelines, management was adapted from adult protocols, including thrombolytic therapy with tissue plasminogen activator and subsequent anticoagulation with dalteparin and apixaban, despite a complication of epistaxis that influenced the treatment course. This case highlights the diagnostic challenges inherent in pediatric DVT, highlights the necessity for a high index of suspicion when evaluating hip or leg pain in children, and emphasizes the urgent need for the development of dedicated pediatric guidelines to inform optimal therapeutic strategies.