Open Journal of Ophthalmology, 2013, 3, 73-75
http://dx.doi.org/10.4236/ojoph.2013.33018 Published Online August 2013 (http://www.scirp.org/journal/ojoph) 73
Necrotizing Scleritis Associated with 5-Fluorouracil and
Sub-Tenon’s Block in Patient with Previous
Trabeculectomy: A Case Report
Tuan A. Tran1*, Jeremy O’Connor2, Xavier Fagan3, Tu Tran2, Dan Nguyen2
1Department of Politecnico Ophthalmology, Sydney Eye Hospital , Sydney, Austra lia; 2Department of Glaucoma, Victorian Eye and
Ear Hospital, Melbourne, Australia; 3Department of Medical Ophthalmology, Victorian Eye and Ear Hospital, Melbourne, Australia.
Received April 24th, 2013; revised May 30th, 2013; accepted June 17th, 2013
Copyright © 2013 Tuan A. Tran et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Necrotizing scleritis is the most severe form of scleritis with a significant threat to vision and globe integrity. It can be
infectious, surgically induced necrotizing scleritis (SINS) or systemic autoimmune associated. We report a case of ne-
crotizing scleritis associated with 5-fluorouracil (5-FU) at the site of sub tenon’s block in a patient with previous trabe-
culectomy. To our knowledge, this is the first reported case of necro tizing scleritis associated with 5-FU. This may im-
plicate alternative approaches to local anaesthetic techniques when using adjunctive 5-FU.
Keywords: Necrotizing Scleritis; 5-Fluorouracil; Sub-Tenon’s Block; Glaucoma
1. Case Report
A 74-year-old man with a 43-year history of primary
open angle glaucoma (POAG) had recent bilateral
trabeculectomies with Mitomycin C (MMC) (0.2 mg/ml
for 3 minutes). Regular reviews demonstrated well func-
tioning blebs and each trabeculectomy was followed up
with three sub-conjunctival 5-FU injections. Medical
history included non-insulin dependent diabetes.
He subsequently developed a right eye cataract and
underwent routine phacoemulsification and intraocular
lens insertion with a temporal clear corn eal wound. Peri-
operative sub-conjunctival 5-FU (5 mg/0.1ml) was in-
jected in the superior fornix above the bleb to minimise
bleb fibrosis. The operation was performed with a sub-
Tenon’s block through an inferonasal conjunctival inci-
sion with 4 ml of lignocaine 2%.
On day one post-operative review, visual acuity with
pinhole (VA-PH) was 6/12 (20/40), intraocular pressure
(IOP) was 12 mmHg and examination was otherwise
unremarkable. He was started on two hourly topical
Prednisolone Acetate 1% and Phenylephrine Hydroch-
loride 0.12% (Prednefrin Forte 1%, Allergan Aust. Pty
Ltd) and four times daily chloramphenicol 0.5%.
On week one post-operative review, significant pain
was noted. Examination revealed VA-PH reduced to 6/18
(20/60), IOP was 14 mmHg. At the site of sub-Tenon’s
block, there was a localised lesion of episcleritis with a
focal area of avascular sclera. No further 5-FU was given
and he was commenced on oral Ibuprofen 400 mg three
times a day.
The following week, VA-PH was 6/12 (20/40), IOP
remained at 14 mmHg and the non-healing conjunctival
defect persisted. There was significant pain preventing
the patient from sleep, which instigated surg ical debride-
ment under peribulbar block. Swabs were taken for
microscopy and culture whilst debrided conjunctival and
Tenon’s tissue were sent for histopathology. Due to a
possible infective cause the conjunctival defect was not
closed.
One week post-debridement, pain persisted accompa-
nied with a reduction in VA to 6/36 (20/120) whilst IOP
was 10 mmHg. The area of avascular sclera increased in
size, measuring 5.2 mm × 4.0 mm Figure 1. C ultures
showed no growths while histology demonstrated non-
specific inflammation and no fungal elements.
He was admitted for further investigations and treat-
ment. Vasculitic, autoimmune, treponemal/syphilis and
TB tests were negative. A second debridement was per-
formed. Repeat conjunctival, episcleral and scleral bio-
psies demonstrated unremarkable cultures and histology
*Corresponding a uthor.

Necrotizing Scleritis Associated with 5-Fluorouracil and Sub-Tenon’s Block in Patient with Previous
Trabeculectomy: A Case Report
74
Figure 1. Necrotizing scleritis at site of sub-tenon’s block
three weeks post cataract and one week after initial de-
bridement (note lack of sloughing at base). Area measuring
5.2 mm × 4.0 mm.
once again.
He was commenced on intensive topical Prednefrin
Forte, high dose oral Prednisolone (75 mg daily) and
intravenous Ceftriaxone (1 g daily). Given the results of
all these investigations; the provisional diagnosis was
necrotizing scleritis secondary to 5-FU in the setting of
sub-Tenon’s block.
Despite intensive treatment for one week, there was
progression of thinning and avascular scleral area (6 mm
× 4.0 mm) Figure 2. In view of worsening diabetic
control, oral steroids were promptly weaned. The scleritis
only showed resolution once a contralateral conjunctival
graft was successfully implanted 6 weeks post-cataract
surgery to close the persistent epithelial defect Figure 3.
2. Discussion
Necrotizing scleritis is characterized by severe pain with
areas of capillary closure producing a porcelain white
sclera or a violaceous discolouration due to thinning and
underlyi ng uveal expos ure .
The main causes are infectious, systemic autoimmune
associated and Surgically Induced Necrotizing Scleritis
(SINS). SINS typically involves the site of surgery, has
an association with underlying systemic autoimmune
diseases and time of onset is nine months on average [1].
This case is unlikely due to any of these causes due to
negative cultures, serology (including autoantibodies),
rapid onset of scleritis and distant location of phaco emul-
sification wounds relative to the area of scleritis.
Systemic autoimmune diseases have high association
with necrotizing scleritis, particularly Rheumatoid Arth-
ritis and other ANCA associated vasculitides [1]. It has
been reported that necrotizing scleritis is the type most
associated with systemic disease (80%) [2], while 92%
have evidence of systemic disease upon of presentation
of scleritis [3].
Figure 2. Despite one week of high-dose oral prednisolone
there was continuing progression with further thinning and
increase in size to 6 mm × 4.0 mm.
Figure 3. Resolution by conjunctival graft performed 6
weeks after sub-tenon’s block and adjace nt 5-fluor our acil.
Antimetabolites, predominantly MMC, have been at-
tributed to post-operative necrotizing scleritis, however
none to our knowledge have been reported with 5-FU.
5-FU is a pyrimidine analogue with several cytotoxic
effects useful in promoting apoptosis of Tenon’s capsule
fibroblasts therefore preventing excessive scarring in
primary filtration surgery [4].
Although exact mechanisms of the inciting injury are
unclear, we hypothesize the process of the necrotizing
scleritis may be due to tracking of 5-FU inferiorly after
injection and pooling in the area of conjunctival/Tenon
defect. Non-healing conjunctival epithelium is said to be
a risk factor of necrotizing scleritis [5]. In our case, the
overlying tissue from the sub-Tenon’s block never healed.
We believe this is unlikely due to the lignocaine and is
more likely due to the inhibition of healing from adjacent
5-FU. Furthermore, th e lack of overlyin g conjun ctiva and
Tenon’s prolonged and exacerbated the scleritis through
attenuation of scleral healing.
To our knowledge, this is the fir st reported case of ne-
crotizing scleritis within the immediate post-operative
phase relating to 5-FU and sub-Tenon’s blocks. This may

Necrotizing Scleritis Associated with 5-Fluorouracil and Sub-Tenon’s Block in Patient with Previous
Trabeculectomy: A Case Report
75
implicate alternative approaches to local anaesthetic in
patients with concurrent 5-FU in patients with previous
trabeculectomy.
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