Cellulitis, abscess and necrotising soft-tissue infection: Case

This toddler presents with eyelid swelling, erythema, and fever complicated by proptosis and painful eye movement, which together shift the working diagnosis from simple periorbital cellulitis to orbital cellulitis. The preceding upper respiratory symptoms point to ethmoid sinusitis as the source, because the thin lamina papyracea allows infection to spread from the ethmoid sinus into the orbit. This is the critical distinction that determines imaging, admission, and the threshold for surgery. ^[1]

Clinical findings

The key findings are the proptosis and the reluctance to move the eye, which signal extension of infection posterior to the orbital septum. The candidate should distinguish periorbital cellulitis, which involves the eyelid and superficial tissues anterior to the septum and in which the child is well with no proptosis or visual change, from orbital cellulitis, which lies posterior to the septum and threatens vision and intracranial spread. The presence of proptosis, painful eye movement, and systemic fever in this child makes orbital cellulitis the working diagnosis. ^[1]

The examination should assess visual acuity, eye movements, pupillary responses, and the degree of proptosis, and should look for signs of intracranial spread such as meningism or a reduced conscious level. The differential includes periorbital cellulitis, orbital cellulitis with or without a subperiosteal or orbital abscess, dacryocystitis, and allergic eyelid swelling, but the proptosis and painful eye movement make a preseptal cause unlikely. ^[1]