Imaging studies in a case of infectious scleritis after pterygium excision.

A 44-year-old woman presented with a painful red eye for 2 weeks. Ultrasound biomicroscopy and optical coherence tomography were instrumental in the diagnosis and management of this case of infectious scleritis associated with previous pterygium excision complicated by choroidal and retinal detachments.

INTRODUCTION

Infectious scleritis associated with ocular surgery is a rare entity, which often results in potentially destructive complications with loss of vision or the globe.1–9 Herein, we describe the use of immersion ultrasound biomicroscopy (UBM) and spectral-domain optical coherence tomography (OCT) studies of postoperative necrotizing scleritis complicated by choroidal and retinal detachments.

CASE REPORT

A 44-year-old Hispanic female, previously healthy, was referred for autoimmune scleritis of the right eye, refractory to two-week course of oral prednisone, indomethacin, hydrocodone/acetaminophen, as well as, prednisolone acetate 1% and homatropine 5% eye drops. Initial visual acuity was 20/200, right eye, and 20/40, left eye; intraocular pressure was normal in both eyes. Slitlamp biomicroscopy revealed mild discharge, engorged episcleral and scleral vessels, and a nummular plaque of avascular sclera with necrosis and adjacent corneal infiltration in the nasal quadrant [Figure 1]. The anterior chamber was shallow, with 1+ cells and 1 clock hour of posterior synechiae. The anterior vitreous and funduscopic examination was normal. The left eye was remarkable only for trace anterior stromal scar in the nasal region of the cornea adjacent to a conjunctival scar. Further query revealed a history of pterygium excision 15 years prior to presentation in Mexico.

Figure 1

External photography showing conjunctival chemosis, engorged episcleral and scleral vessels, nummular scleral area of avascularity and necrosis, and small perilimbal corneal infiltration adjacent to scleral lesion

The patient was instructed to begin empiric topical antibiotics (fortified vancomycin 50 mg/ml, fortified tobramycin 14 mg/ml, and moxifloxacin 0.05% Q1H) with the diagnosis of necrotizing sclerokeratitis associated with pterygium excision in the right eye. The culture was positive for Pseudomonas aeruginosa. On day 3 after presentation, fundus examination was suggestive of double retinal and choroidal detachment.

Immersion UBM with a 35-MHz probe of the right eye showed a shallow anterior chamber with anterior rotation of the ciliary body and elimination of the ciliary sulcus in all quadrants. There was 360° annular choroidal thickening that was lacey in appearance without any loculated serous fluid [Figures 2a and b]. Contact B-scan ultrasonography with a 10-MHz probe showed a relatively clear vitreous cavity with an elevated peripheral choroidal detachment, nasally and inferiorly [Figures 2c and d]. There was a mobile serous retinal detachment in the peripapillary region, with macular involvement. No definite echographic T-sign was present; and retinal tear or mass was also not observed. Spectral-domain OCT confirmed detachment of the macula [Figure 2e]. Small vitreous opacities and multiple precipitates in the subretinal space were also evident.

Figure 2

Advanced imaging studies of complications of infectious scleritis, (a) 35-MHz immersion ultrasound biomicroscopy demonstrating shallow anterior chamber, thickened and anteriorly rotated ciliary body (arrow), and elimination of the ciliary sulcus, (b) Thickened episcleral, scleral, and choroidal tissues are evident in the magnified view, (c) 10 MHz B-scan utrasonography showing double retinal and choroidal detachment, longitudinal-12 (L-12) view and (d) longitudinal-macular (L-mac) view. Spectral domain optical coherence tomography showing vitreous clumps (dotted arrows and circles), subretinal fluid, and subretinal precipitates (solid arrow)

The patient's clinical condition stabilized with diminution of pain and scleral necrosis. Repeat B-scan 2 weeks after initial presentation showed complete resolution of the peripheral choroidal detachment with persistent serous macula-off retinal detachment. At week 3, the nummular necrosis ceased with new vascular growth and re-epithelialization [Figure 3a]; and visual acuity improved to 20/60 with resolution of subretinal fluid on OCT [Figure 3b].

Figure 3

Resolution of infectious scleritis lesion after a 3-week course of fortified tobramycin and fortified vancomycin, and moxifloxacin 0.05%, (a) External photograph, (b) Optical coherence tomography image showing resolution of serous retinal detachment

DISCUSSION

Etiologies of scleral inflammation include immune-mediated, infectious, tumors, lymphoma, and drug-induced. Regarded as a rare complication following pterygium excision, infectious scleritis may occur within days to as late as two to four decades postoperatively.1–3 Adjunctive therapies, e.g. β-irradiation, mitomycin C, or excessive cauterization, have been implicated in the pathogenesis of infectious scleritis after pterygium excision. Early diagnosis is essential and delayed management leads to prolonged hospitalization, repeat debridement, poor visual outcome, and loss of globe.2–9 The clinical course of this patient with delayed diagnosis and initial treatment with oral prednisone was complicated by choroidal and retinal detachment. Early surgical intervention has been advocated to decrease bacterial load and improve antibiotic penetration.236 Our own series10 also suggests that early debridement is associated with improved visual prognosis and globe preservation. This is especially important as infectious and necrotizing scleritis is much more likely to be vision threatening compared to other causes of scleritis.

The present case highlights the utility of UBM and OCT for the evaluation and management of infectious scleritis. Along with the clinical history of pterygium excision, these imaging modalities eliminated other causes of scleral inflammation and retinal detachment and aided in evaluating disease progression and managing the clinical course. To the best of our knowledge, this is the first report of ultrasonographic findings of anteriorly rotated ciliary body and double choroidal and retinal detachment, as well as OCT findings of cells in the vitreous cavity and possible lipofuscin-laden macrophages in the subretinal space, in this disease entity. Both UBM and OCT are effective imaging modalities that may be used as adjuncts to the diagnosis and management of complex cases of infectious scleritis.