Sir,

Posterior scleritis is a common cause of diagnostic confusion because of its variable clinical signs and symptoms.1 We discuss a case of posterior scleritis that presented with classical signs and symptoms of orbital cellulitis. To our knowledge this clinical picture has not been previously reported.

Case report

A 63-year-old lady presented with a 7-day history of a painful, red left eye and periorbital oedema. There was no history of trauma, precipitating lid lesions or sinusitis. On examination her visual acuity was 6/9 OD, 6/12 OS. She had periorbital oedema and conjunctival injection with chemosis (Figure 1). Left eye movements were restricted horizontally and on downgaze. There was no proptosis. Intraocular pressures and fundal examination were normal, and she was apyrexial. A clinical diagnosis of orbital cellulitis was made and sinusitis was excluded by the otolaryngologist. The patient was admitted and started on intravenous antibiotics.

Figure 1
figure 1

Left eye showing upper lid erythema, oedema, and conjunctival injection with chemosis.

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The following day the chemosis had worsened and the anterior chamber was shallow. Intraocular pressure was 25 mmHg OS and fundal examination showed 360° choroidal effusions. Ultrasound scan showed a choroidal ring detachment and scleral thickening posteriorly (Figure 2). The diagnosis was revised to one of posterior scleritis and the patient was started on oral anti-inflammatories, topical steroids, and mydriatics. Within 24 h the lid oedema and conjunctival chemosis resolved. Systemic investigations showed no abnormality.

Figure 2
figure 2

Ultrasound scan showing posterior scleral thickening and an anterior choroidal detachment.

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Comment

Orbital cellulitis and posterior scleritis are both potentially life-threatening conditions that require urgent management. The patient described appeared clinically to have orbital cellulitis but was apyrexial with no obvious infective source. This illustrates that caution should be exercised when making a diagnosis of orbital infection in the absence of any obvious cause for or indicators of infection.

Posterior scleritis often presents a diagnostic challenge as it can frequently mimic other pathologies1, 2, 3, 4, 5 and is almost certainly an underdiagnosed condition. It is commonly misdiagnosed because the presenting signs and symptoms are determined by the location and severity of the inflammation and its relationship to surrounding structures.5 The inflammation appears to have spread anteriorly, involving the upper lid structures causing lid swelling and simulating cellulitis.