Amniotic membrane transplantation in surgically induced necrotizing scleritis with peripheral ulcerative keratitis.

A case of surgically induced necrotizing scleritis (SINS) after manual small incision cataract surgery that was associated with peripheral ulcerative keratitis (PUK) at a different site. Neither pathology responded to systemic steroids and progressed to become sight threatening, which is unusual. Progression of SINS was aggressive enough to cause a limbal wound gape, similarly PUK extended up to Descemet's membrane and emergency amniotic membrane transplantation (AMT) was required to save the globe. AMT may regress the scleral and corneal melting successfully. It is not common to observe SINS with PUK at a different site that is unresponsive to systemic steroids. AMT, though palliative treatment, was effective at treating this condition successfully.

INTRODUCTION

Surgically induced necrotizing scleritis (SINS) is a rare but serious complication of ocular surgery. It has been observed with most types of ocular surgeries.1–5 It typically occurs postoperatively as intense scleral necrosis adjacent to the site of previous scleral or limbal incision.16 It may or may not be associated with serious ocular complications such as peripheral ulcerative keratitis (PUK), which is always present adjacent to the SINS site.7 This may progress to perforation with poor visual prognosis. Therefore early diagnosis and prompt management in the form of immunosuppressant and/or surgical treatment in the form of amniotic membrane transplantation (AMT) is required for successful management.89

SINS was first recognized in 1976 by Arensten et al., who described four patients who developed marginal corneal ulceration after cataract surgery.10 Lyne and Lloyd-Jones11 in 1979 described a series of patients without a history of scleritis who developed scleral inflammation around a surgical wound.

In this case report, we present an interesting case of postcataract surgery SINS at the superior limbus with exacerbation of PUK at a nasal site during the course of SINS. SINS and PUK were unresponsive to medical therapy and continued to progress. We document management of these pathologies with globe saving AMT.

CASE REPORT

A 65-year-old male presented with complaints of gradual diminished vision that was greater in right eye. He gave history of blurring of vision with watery discharge bilaterally and was diagnosed with PUK and treated successfully 2 years prior to presentation. On examination his visual acuity was counting finger at 2 feet in right eye and 20/100 in the left eye. Intraocular pressure in both eyes was 16 mmHg with applanation tonometry. Slit-lamp examination showed both eyes with peripheral degeneration at the nasal limbus without thinning of cornea, with nuclear sclerosis grade III with posterior subcapsular opacity in the right eye and nuclear sclerosis grade II in left eye. Fundus examination was normal. The patient underwent uneventful manual small incision cataract surgery in the right eye. He was discharged with instruction to instill topical prednisolone acetate six times a day, moxifloxacin four times a day and cyclopentolate at night. At the 5 days postoperatively, the patient presented with scleral melting and thinning of the superior sclera from 11 o’ clock to 1 o’ clock at the incision site. The patient was diagnosed with SINS and systemic immunosuppression in the form of a pulse of methylprednisolone 500 mg followed by prednisolone 20 mg was started along with topical steroid drops. Ageneral physical examination was performed that was negative for systemic vasculitis or arthritis. A chest X-ray and blood tests including a full blood count, erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor, antinuclear antibody, and anti-neutrophil cytoplasmic antibody tests were performed. These tests were normal. Urinanalysis was normal.

SINS did not respond to steroid therapy and progressed further to create wound gap and a shallow anterior chamber. Simultaneously, the nasal corneal periphery showed PUK in the form of crescent shaped superficial corneal thinning at the previous site of corneal degeneration [Figure 1]. To prevent globe perforation, a multilayered AMT with conjunctival resection was performed at the site of scleral necrosis. PUK was superficial, hence no active surgical treatment was performed. Systemic steroids were continued along with topical steroid drops. Three days after AMT, scleral necrosis began to resolve with a well formed anterior chamber however, PUK increase in depth up to Descemet's membrane [Figure 2]. Again, to prevent perforation, a multilayered AMT was performed with conjunctival resection. Systemic steroids were reduced to 10 mg maintenance dose within a week. Topical prednisolone was continued. Steroids were tapered down and stopped within a month. Scleral as well as corneal melting improved after AMT. Complete healing took place within 15 days of AMT [Figure 3. There was no recurrence of SINS and PUK after 6 months follow-up.

Figure 1

SINS on 5th day of surgery with thin PUK

Figure 2

After AMT at SINS site, SINS healing and PUK progressing

Figure 3

Complete healing after AMT for SINS and PUK

DISCUSSION

Surgically induced necrotizing scleritis has been reported to occur after cataract extraction, trabeculectomy, squint surgery, pterygium surgery, and surgery for retinal detachment.1–5 In SINS there is a variable latent period between surgery and presentation, which may vary from 1 day to 51 years.7 The area of scleral melt tends to develop adjacent to the surgical wound16 and may extend to involve the cornea and whole anterior segment. These cases may or may not be associated with inflammation and PUK adjacent to SINS.7

Causative factors such as local ischemia due to disruption of episcleral vasculature during ocular surgery and excessive use of cautery have been implicated in the pathogenesis of SINS. However, the rapid response to immunosuppressive agents also supports the view of an immunologic reaction involved in the pathogenesis.812 The pathogenesis of PUK and SINS has not been fully elucidated, but both T cell and antibody mediated pathways have been implicated in the disease process.1314 This pathogenesis explains the simultaneous presence of SINS and PUK.

Medical management of SINS and PUK has included immunosuppression with oral steroids, methylprednisolone + cyclophosphamide and more recently tacrolimus8 in a patient who was unresponsive to cyclophosphamide and azathioprine. Surgical intervention in the form of tectonic scleral or corneal tissue patch grafts and amniotic membrane grafts8 has been reported.

Our patient presented with SINS following manual small incision cataract surgery on the 5th postoperative day. There was no history of over-cauterization. The inflammation in the form of scleral necrosis was noted adjacent to the limbal incision from 11 o’ clock to 1 o’ clock. Additionally PUK was noted at the nasal limbus at the 3 o’ clock position which corresponded to the site of preoperative peripheral corneal degeneration (perhaps a healed PUK). No side port incision was performed at the 3 o’ clock position, hence it was not surgically induced but reactivation of PUK due to SINS. This can be explained on the basis of a common pathogenesis for both diseases.1314 The patient had no serological evidence for connective tissue disease. Therefore the patient was diagnosed with SINS and reactivation of PUK on the basis of ocular surgery, absence of clinical or serological signs of systemic auto-immune disease and development of necrotizing scleritis close to the previous surgical injury.9

SINS and PUK did not respond to local and systemic steroid therapy, which was very unusual. AMT was performed to reduce inflammation and to prevent globe perforation keeping in mind that the surgical treatment, although palliative and temporary, is an important adjuvant for treating these cases.9 The resection of the conjunctiva adjacent to the necrotic area has been described as an efficient technique for diminishing the concentration of proteases, as well as for the temporary interruption of the local inflammatory process, reducing the input of pro-inflammatory cytokines.4 In a severe case, the amniotic membrane helps in controlling the inflammation in the area of the implant. The patient responded well to AMT and both scleral as well as the corneal melt completely healed within 15 days. No further immunosupressants were required. Though SINS is a rare postoperative complication, it can occur in association with PUK which required prompt diagnosis and early treatment to achieve good prognosis.

CONCLUSION

SINS is a serious entity which can reactivate PUK and requires prompt and aggressive therapy to prevent the potentially devastating ocular sequalae. Conjunctival resection and amniotic membrane grafting may be essential to prevent complications such as globe perforation by interrupting the local immunologic events in severe cases.