#46 - Periorbital and Orbital Cellulitis

It's just a swollen eye… right? 👀 But when does a simple eyelid infection become a sight-threatening emergency? In this episode, we take a first principles approach to Periorbital and Orbital Cellulitis, breaking down the anatomy, pathophysiology, and clinical reasoning behind these two commonly confused conditions. We discuss why the orbital septum matters, how a seemingly innocent sinus infection can spread into the orbit, and the key red flags that help you distinguish periorbital from orbital cellulitis. From proptosis and painful eye movements to RAPDs, imaging, and antibiotic management, we work through how you would approach a patient presenting with a swollen, red eye in the ED. Whether you're on your paediatric or ophthalmology placement, preparing for OSCEs, or just trying to remember what lies behind the orbital septum, this episode will help you recognise when an eye infection is more than meets the eye. === Other links === Check out our 1PM Notion website for medical study notes, free Anki flashcards, and podcast episodes! 1PM Website: https://1pm.notion.site/4510c91c17314baf8f6b8e30b59159bb?v=e9a7d53846c842ba9b0b79836ef6020a Instagram: https://www.instagram.com/firstprinciplesofmedicine Recorded 19 August 2026. Hosts: Truman Lo, Titus Leong, Sithum Fernando, Eric Ny. Produced by Truman Lo.