Bilateral medial medullary and spinal cord infarctions presenting as locked-in syndrome in an adolescent with primary antiphospholipid syndrome

Bilateral medial medullary infarction (BMMI) is a rare stroke subtype in the paediatric population characterised by quadriplegia, cranial nerve dysfunction and respiratory failure. MRI typically reveals a 'heart-shaped' sign in the medial medulla on diffusion-weighted imaging (DWI). Paediatric stroke aetiologies, including vasculopathy, thrombophilia and cardioembolic disease, differ from those in adults. Antiphospholipid syndrome (APS) is a rare but important cause of paediatric stroke.We report an adolescent male presenting with acute quadriplegia, bulbar dysfunction and respiratory failure with intact cognition, consistent with locked-in syndrome. MRI confirmed BMMI with concurrent spinal cord infarction, and APS was diagnosed based on persistently elevated anticardiolipin antibodies. Anticoagulation therapy and rehabilitation were initiated. However, minimal neurological improvement was observed at 1-year follow-up. This case highlights the rarity of BMMI in children and underscores the importance of early diagnosis and management as well as the recognition of uncommon causes such as APS.