Preseptal and orbital cellulitis — formative SAQs

SAQ 1 (10 marks)

A 5-year-old child presents to the emergency department with a two-day history of right eyelid swelling and erythema following a viral upper-respiratory infection. On examination the child is febrile to 38.8 degrees Celsius and irritable. The right eye is proptotic, with marked chemosis, limited eye movement in all directions of gaze, and pain on attempted movement. Visual acuity is reduced compared with the left eye, and there is a relative afferent pupillary defect on the right. ^[1]

Question: Outline the diagnosis, the immediate investigations and the stepwise management of this child, including the medical-versus-surgical decision. (10 marks) ^[1]

Model answer

Diagnosis and recognition (2 marks). The diagnosis is orbital (postseptal) cellulitis. The proptosis, chemosis, ophthalmoplegia, pain on eye movement, reduced visual acuity and relative afferent pupillary defect, in a febrile unwell child, are the classic orbital signs indicating that infection has crossed the septum and involved the orbital contents. The likely source is ethmoid sinusitis spreading through the thin lamina papyracea. This is a sight- and life-threatening emergency requiring immediate admission and senior review. ^[1]

Immediate investigations (2 marks). Take blood cultures and inflammatory markers before antibiotics. Obtain urgent contrast-enhanced computed tomography of the orbits and paranasal sinuses to define the sinus source and to look for a subperiosteal or orbital abscess or intracranial extension. Do not delay intravenous antibiotics while waiting for imaging. Assess and document visual acuity, colour vision and the pupillary reaction at presentation and serially thereafter, because deterioration is the trigger for urgent surgical decompression. ^{[6] [1]}

Immediate management and intravenous antibiotics (2 marks). Admit, establish intravenous access, and start broad-spectrum intravenous antibiotics immediately after blood cultures. Give ceftriaxone 50 mg per kilogram (maximum 2 g) once daily intravenously plus flucloxacillin 25 to 50 mg per kilogram (maximum 2 g) every six hours intravenously, covering the Staphylococcus aureus and streptococci that dominate paediatric orbital disease. Add metronidazole 7.5 mg per kilogram (maximum 400 mg) every eight hours if anaerobic or dental concern is present, and vancomycin or clindamycin if MRSA is suspected. Refer urgently to ophthalmology and ear-nose-and-throat surgery. ^{[8] [11]}

The medical-versus-surgical decision (2 marks). The contrast CT, together with the visual compromise (reduced acuity and a relative afferent pupillary defect), mandates urgent surgical drainage if an abscess is demonstrated. The age-based criteria allow a trial of intravenous antibiotics only for a medial subperiosteal abscess in a child under nine years with normal vision; this child has visual compromise, which is an absolute indication for surgery regardless of age or abscess site. Any deterioration in vision pending surgery is the trigger for immediate surgical decompression, because optic nerve ischaemia becomes irreversible within hours. ^{[7] [8]}

Disposition and safety-netting (2 marks). Admit to a monitored bed under combined paediatric, ophthalmology and ENT care. Continue intravenous antibiotics, monitor vision and orbital signs serially, and drain the abscess urgently. Transition to oral antibiotics on clinical improvement to complete a total course guided by severity and culture results. At discharge, arrange ophthalmology follow-up, address any underlying sinus disease, and give a clear safety-net for spreading redness, fever, pain on eye movement or visual change. The prognosis is good with prompt recognition and treatment, but delayed surgery risks permanent visual loss. ^{[1] [11]}