Necrotizing scleritis is a destructive inflammatory disease of the sclera that may result in disastrous complications such as keratitis, corneal perforation, scleral thinning, perforation, and staphyloma. We report a case of unilateral surgically induced necrotizing scleritis (SINS) following strabismus surgery with cataract surgery presenting with symptoms 5 days after surgery and initially diagnosed as infection. Such early presentation of SINS is rare.
A 63-year-old man presented with complaints of defective vision in both eyes, with the right eye more affected than the left eye. He had no history of systemic disease or any other ocular disease. On examination, he had a best corrected visual acuity of 6/36 in the right eye and 6/18 in the left eye and had 30° of right exotropia. Anterior segment examination showed nuclear sclerosis with posterior subcapsular opacity that was more noticeable on the right side. The rest of the results of anterior segment examination and fundus examination were within normal limits in both eyes. He underwent strabismus surgery (7-mm lateral rectus recession and 4-mm medial rectus resection) and intraocular lens implantation by manual small-incision cataract surgery using a superior scleral tunnel in the right eye.
On the fifth postoperative day, the patient complained of pain, redness, and defective vision in the right eye that became progressively worse over the next 10 days. The patient presented on the 20th postoperative day with best corrected visual acuity of hand motions in the right eye and 6/6 in the left eye. Anterior segment examination of the right eye revealed eyelid edema, congestion, chemosis, and a scleral abscess located above the insertion of the medial rectus muscle with pus pointing and discharging (Figure 1). The cornea was clear, the anterior chamber showed 2+ cells, and the posterior chamber intraocular lens was in situ. Fundus examination showed 360° choroidal detachment with kissing choroidals in the right eye. His random blood sugar level was 105 mg%.
Figure 1. Slit-lamp photograph of the right eye showing scleral abscess with surrounding congestion over the area of the medial rectus muscle.
The patient was treated with intravenous injection of cefotaxime and amikacin and topical gatifloxacin, amikacin, and homatropine after taking a conjunctival swab from the pus pointing area for culture and sensitivity. The culture was positive for Streptococcus pneumoniae, which was resistant to amikacin and sensitive to gatifloxacin and cefazolin. The patient switched to intravenous cefazolin instead of amikacin, but his symptoms worsened and the size of the scleral necrosis enlarged with pus pointing for the next 4 days with retinal and choroidal detachment. A repeat culture on the fourth day did not reveal any organism even though the abscess was enlarging.
The patient was given intravenous dexamethazone 8 mg once daily. Three days after starting steroids, the scleral abscess appeared localized and the patient’s symptoms improved. He switched to oral prednisolone 40 mg/day that was tapered on a weekly basis. Fifteen days after the admission, the scleral abscess was flat with overlying congestion decreased. The sclera showed thinning and disappearance of exudative detachment, but the shallow choroidal detachment persisted. The patient was discharged and returned 15 days later for observation. The scleral abscess was fully healed with thinning of the sclera and uveal show above the insertion of the medial rectus muscle (Figure 2). His choroidal detachment also resolved and his uncorrected visual acuity improved to 6/24.
Figure 2. Slit-lamp photograph of the right eye showing healed abscess with scleral thinning and uveal show over the medial rectus muscle area.
SINS has been reported to occur after all ocular surgeries, especially pterygium and cataract surgery,1–6 but is least commonly reported after strabismus surgery.3,4,7 It is a granulomatous inflammation of the sclera precipitated by surgery that occurs from days to many years after surgery. It is rare in the immediate postoperative period and usually presents later in life, with a mean interval of more than 21 years in a large case series1 and 51 years being the longest reported interval.7
The exact pathogenesis of SINS is not well known but may be the result of hypersensitivity reaction directed against an antigen that is released or altered by tissue injury. That is probably why it is more common after multiple ocular procedures than after a single procedure.3 In one large series, symptoms and signs developed on average 9 months after multiple procedures compared to 9.5 years after a single procedure.3,7 Patients with strabismus surgery alone had a longer latent period (mean = 21.7 years) compared with 5 to 7 months in other patients. Another indication that SINS is an immune-mediated process is that it is highly responsive to systemic corticosteroids and immunosuppressive agents.3,4 A proposed mechanism is that focal ischemia can trigger inflammation, which is why scleral necrosis commonly affects the lateral rectus muscle due to its limited blood supply, although in our patient the involvement was adjacent to the medial rectus muscle.3 Postoperative necrotizing scleritis is known to be associated with autoimmune disease,3,4,7,8 but our patient had no symptoms, signs, or family history of autoimmune diseases and to date has not developed any new systemic symptoms even though a detailed autoimmune screening was not done.
Postoperative infective scleritis was our first clinical diagnosis due to early onset of inflammatory signs and scleral abscess after surgery and because of the isolation of S. pneumoniae from the pus discharging from the abscess. Because the scleral abscess area enlarged immediately, even after treating with sensitive antibiotics, repeat cultures were negative for any organism, and a rapid resolution of inflammation was noted with systemic steroids, we suspected an inflammation as the cause of necrotizing scleritis. It is likely that the initially isolated S. pneumoniae was a contaminant from the ocular surface and therefore the initial antibiotic therapy failed to control what was primarily an inflammatory disease.
Although scleral necrosis after strabismus surgery has been previously reported in 10 adults,1,9,10 our case of primary SINS is unique in that the patient’s symptoms began 5 days after surgery, the scleral abscess appeared early, and early microbiological data suggested infection. There is only one reported case of scleritis occurring as early as 5 days after eye muscle surgery.2 Our case also highlights the fact that a high index of suspicion is necessary for early diagnosis and prompt treatment to prevent vision loss in such cases.
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- Tamhankar MA, Volpe NJ. Atypical necrotizing scleritis after strabismus surgery. J AAPOS. 2008;12:190–192. doi:10.1016/j.jaapos.2007.09.017 [CrossRef]
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- Sridhar MS, Bansal AK, Rao GN. Surgically induced necrotizing scleritis after pterygium excision and conjunctival autograft. Cornea. 2002;21:305–307. doi:10.1097/00003226-200204000-00013 [CrossRef]
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- Karia N, Doran J, Watson SL, Nischal K. Surgically induced necrotizing scleritis in a patient with ankylosing spondylitis. J Cataract Refract Surg. 1999;25:597–600. doi:10.1016/S0886-3350(99)80064-9 [CrossRef]
- Hemady R, Sinze de la Maza M, Raizman MB, Foster CS. Six cases of scleritis associated with systemic infection. Am J Ophthalmol. 1992;114:55–62.
- Kivlin JD, Wilson ME Jr, . Periocular infection after strabismus surgery. J Pediatr Ophthalmol Strabismus. 1995;32:42–49.