Necrotizing scleritis following pterygium excision

Use of Autologous Fascia Lata in Management of Necrotizing Scleritis following Bare Sclera Pterygium Excision

Hatem Kobtan MD FRCS (Ed) (Glasg) Dina koptan MSC Cairo University

The Authors have no financial disclosure

Ocular History and Examination •

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55 year old male presented with scleral thinning (OS) one week following uneventful primary pterygium excision using bare sclera technique. Penetrating keratoplasty + ECCE & PCIOL implantaton 1 month earlier. The sclera bed is markedly thinned, avascular with blue coloration of the underlying uvea. Necrotizing scleritis

Kobtan

ASCRS 2010

Investigations •

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A swab with culture and senstivity was taken to exclude microbial infections and a systemic work up to detect underlying connective tissue disorder : CBC, ESR, urea and electrolytes, liver function test. CH50 (total haemolytic complement). C reactive protein (CRP). Rheumatoid factor. Antinuclear antibody (ANA). Anti-double stranded DNA. Chest radiography. The results of the above tests came out as negative Necrotizing scleritis

Kobtan

ASCRS 2010

Intra operative • Autologous fascia lata was considered as an option to cover the area of scleral melt. • The sutured fascia was covered with a rotational conjunctival flap.

Intra-operative appearance of the harvested fascia lata

Necrotizing scleritis

Kobtan

ASCRS 2010

Immediate post operative

Necrotizing scleritis

Kobtan

ASCRS 2010

One week post operative • One week later the fascia started to retract near the limbus revealing the underlying progression of scleral melt (yellow arrow). • Systemic steroids 80 mg/day and Azathioprine 150 mg/day were therefore added for next 9 month.

Necrotizing scleritis

Kobtan

ASCRS 2010

36 Week post operative •The fascia lata has been incorporated into underlying scleral bed with adequate vascularization of the overlying conjunctiva. •No recurrence of the necrotizing scleritis was observed for 9 month postoperative. •The response to immune suppression supports a primary autoimmune etiology.

Necrotizing scleritis

Kobtan

ASCRS 2010

Etiology of SINS • Surgically induced necrotizing scleritis (SINS) has been reported to occur after cataract extraction, trabeculectomy, squint surgery and surgery for retinal detachment. •

Scleral melting and necrosis is also a well reported complication following pterygium surgery with the use of adjunctive irradiation or treatment with MMC.

 Systemic immunosuppressives have been found to be successful in the treatment of SINS.  Vasculitis with fibrinoid necrosis and neutrophil invasion of the vessel wall was present in the scleral and the conjunctival specimens of our patient. Necrotizing scleritis

Kobtan

ASCRS 2010

Immunopathology of SINS • Autoimmunity This derives from the fact that associated clinical or serological markers for connective tissue disorders are present in 62% of cases.

• Hypersenstivity Immune complexes have been found in & around episcleral vessel walls.

Necrotizing scleritis

Kobtan

ASCRS 2010

• The term "bare sclera" is used to describe the surgical denudement of episcleral tissue and vessels which occurs when pterygium tissue is aggressively removed, leaving a bare and avascular scleral bed. • Excessive cautery promotes this avascular state causing localized ischaemia at the surgical site resulting from disruption of episcleral vasculature. • Bare sclera technique is certainly not very efficacious and may not be quite as safe as we had previously thought.

References • Zainah Alsagoff, Donald T H Tan, S-P Chee. Necrotising scleritis after bare sclera excision of pterygium. Br J Ophthalmol 2000;84:1050-1052 • M R Vagefi, D A Hollander, G D Seitzman and T P Margolis. Bilateral surgically induced necrotising scleritis with secondary superinfection. Br J Ophthalmol 2005;89:124-125

• Young AL, Wong SM, Leung AT, Leung GY, Cheng LL, Lam DS, Successful treatment of surgically induced necrotizing scleritis with tacrolimus.Clin Experiment Ophthalmol. 2005 Feb;33(1):98-9.