Paradoxical Cerebral Fat Embolism in an Adolescent PLHA: A Convergence of Trauma, ART Induced Hypercoagulability, and Septal Heart Defect

Fat embolism syndrome (FES) is a life-threatening complication following long bone fractures, primarily affecting the pulmonary circulation. However, cerebral fat embolism (CFE) is a rare yet severe variant that can occur when fat emboli bypass the lungs through a right-to-left cardiac shunt, such as an atrial septal defect (ASD). In individuals with HIV on antiretroviral therapy (ART), persistent endothelial dysfunction and ART-induced hypercoagulability predispose them to an exaggerated thrombo-inflammatory state, amplifying the risk of paradoxical embolism. We describe a 14-year-old male with perinatally acquired HIV on ART who presented after a high-impact road traffic accident. The patient sustained comminuted fractures of the right femoral shaft, tibia, and femoral condyle. Initially neurologically intact (Glasgow Coma Scale [GCS] 15), he experienced rapid neurological deterioration (GCS dropped to 8), alongside respiratory distress and acute respiratory distress syndrome (ARDS)-like symptoms. Urgent evaluation with a 2D echocardiogram revealed an ASD with a right-to-left shunt, strongly supporting the diagnosis of paradoxical cerebral fat embolism. This case illustrates how trauma, combined with HIV-related endothelial dysfunction, ARTinduced hypercoagulability, and a congenital cardiac anomaly, can converge to precipitate severe neurological decline through paradoxical embolism.