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CASE REPORT
Bilateral corneal perforation secondary
to Pseudomonas keratitis in a patient
with multiple injuries
Miriam García-Fernández, PhD1; T. Parra-Rodríguez, MD1; B. Baamonde-Arbaiza, PhD1
ABSTRACT: Microbial keratitis, especially that caused by Pseudomonas aeruginosa, is
associated with intense inflammation and proteolytic activity, which can lead to corneal
perforation. We report a case of bilateral P. aeruginosa keratitis complicated with corneal
perforation in a patient with multiple injuries, managed with tissue adhesive and amniotic
membrane (AM) transplant, followed in a second step by penetrating keratoplasty.
J Emmetropia 2014; 5: 95-97
Microbial keratitis is an unusual yet severe complication
of corneal exposure in the intensive care patient1,2. Keratitis
can lead to corneal ulceration, endophthalmitis, corneal
perforation and loss of vision. Staphylococcus, Streptococcus,
Pseudomonas and the Enterobacteriaceae (Citrobacter,
Enterobacter, Klebsiella, Proteus and Serratia) are the
species most commonly involved in the development of
a nosocomial corneal infection2,3.
Pseudomonas aeruginosa keratitis, triggered by contact
lens wear or corneal trauma, can progress rapidly and
lead to corneal scarring or melting with a profound
impairment of vision. To minimize the damage to corneal
tissue, an appropriate diagnosis and prompt initiation of
appropriate antibacterial therapy are critical4.
The aim of this case report is to describe a case of
bilateral corneal perforation secondary to Pseudomonas
aeruginosa infection in a patient with multiple injuries.
CASE REPORT
A 42-year-old Caucasian male was involved in
a motorcycle accident, suffering multiples injuries
that necessitated intensive care unit (ICU) stay with
Submitted: 11/9/2013
Revised: 02/15/2014
Accepted: 02/27/2014
Department of Ophthalmology, Hospital Universitario Central de
Asturias, Oviedo, Spain.
1
Financial disclosure: The authors have no financial interests
Corresponding Author: Miriam García-Fernández.
Department of Ophthalmology
Hospital Universitario Central de Asturias
C/ Pérez de Ayala, nº 6, 2.º B; 33007 Oviedo (Spain)
Email: [email protected]
© 2014 SECOIR
Sociedad Española de Cirugía Ocular Implanto-Refractiva
prolonged mechanical ventilation. During his stay in
the ICU, routine eye care included ocular lubrication
with artificial tear drops every six hours and ointments
twice a day. On the second day in ICU, he developed
a febrile syndrome with leukocytosis, so empirical
treatment with intravenous cefepime 1 g every 12 hours
was started. The patient went on to develop Pseudomonas
aeruginosa in blood and nasopharyngeal exudates, so
systemic treatment with intravenous colistin 240 mg
every eight hours was initiated. Three days later, ocular
symptoms such as loss of visual acuity and discomfort
began in both eyes. A full ocular examination revealed
bilateral keratoconjunctivitis, so topical antibiotic
treatment was started with ciprofloxacin 0.3% drops
(Oftacilox®, Alcon Cusi S.A., El Masnou, Barcelona),
one drop every eight hours, and fortified antibiotic
amikacin eyedrops, one drop every two hours, and
ceftazidime, one drop every two hours.
After one week of topical antibiotics, patient
discomfort increased, and he described a subjective
loss of visual acuity, decreasing from “count fingers”
to “hand motion”. During the ocular examination,
we could observe the presence of corneal melting
and imminent corneal perforation in both eyes. For
this reason, we decided to use 2-octyl-cyanoacrylate
adhesive and Tachosil (Tachosil®, Nycomed Pharma AS,
Zürich, Switzerland) as tissue adhesive for repair of the
impending corneal perforation followed by amniotic
membrane (AM) transplantation in both eyes. The AM
was sutured with its basement membrane side up to the
edge of the lesion by interrupted 10-0 nylon suturing.
Postoperatively, topical antibiotics were continued.
Total reepithelization was achieved 10 days later.
Two months after surgical repair, severe corneal
scarring could be observed in both eyes with anterior
synechiae but no epithelial defect (Figure 1). Intraocular
ISSN: 2171-4703
95
96
CORNEAL PERFORATION SECONDARY TO PSEUDOMONAS KERATITIS
Figure 1. Biomicroscopic view of right eye two months after surgical repair of impending corneal perforation with cyanoacrylate and
Tachosil as tissue adhesives followed by amniotic membrane (AM)
transplantation.
Figure 2. Biomicroscopic view of left eye two months after penetrating keratoplasty.
pressure was normal. B-Scan Ultrasound revealed
neither retinal detachment nor other alterations.
Six months after surgery, once ocular and systemic
stability was achieved, the patient underwent
penetrating keratoplasty, with removal of anterior
synechiae from the left eye. Postoperative treatment
consisted of slow tapering of the systemic high-dose
corticosteroid therapy (prednisone 60 mg) and topical
treatment with tobramycin and dexamethasone
ophthalmic drops (Tobradex®, Alcon Cusi S.A.,
El Masnou, Barcelona) and ciprofloxacin 0.3%
(Oftacilox®) four times a day, and atropine twice a day
during the first week, which was tapered slowly over
the following two months.
Postoperative progress was good and the patient’s
visual acuity improved to 0.8 (in decimal notation)
two months after surgery (Figure 2). Six months
later, penetrating keratoplasty in right eye was also
performed, with excellent functional and anatomical
outcomes.
The severity of bacterial keratitis is dependent on
the host response and the integrity of the underlying
cornea. The virulence of the bacteria is crucial.
P. aeruginosa, Staphylococcus aureus, and Streptococcus
pneumonia all have the ability to adhere to the edge or
base of an epithelial defect. This has been attributed to the
presence of appendages called fibrillae (Gram-positive)
or fimbriae (Gram-negative) that allow for interaction
between specific receptors on the corneal epithelium
and the surface of these appendages. Moreover,
Pseudomonas and Serratia have proteoglycanase activity,
which can liquefy the corneal stroma and contribute to
the virulence of these microorganisms3.
Therefore, microbial keratitis caused by P. aeruginosa
is associated with intense inflammation and excessive
proteolytic activity. If proper management is not
initiated, the cornea tends to become perforated, resulting
in severe ocular consequences, such as development of
cataract, glaucoma and even endophthalmitis. Corneal
perforation is caused by stromal necrosis and may occur
DISCUSSION
JOURNAL OF EMMETROPIA - VOL 5, APRIL-JUNE
CORNEAL PERFORATION SECONDARY TO PSEUDOMONAS KERATITIS
earlier in fulminating infection or later, if treatment is
unsuccessful5.
The aims of treatment are to prevent the
infection spreading, eliminate the pathogen, control
inflammation, promote wound healing, and prevent
perforation. If a patient develops a perforation, the size
must be taken into consideration. If the perforation is
less than 1-2 mm in diameter, a cyanocrylate adhesive
with or without a patch graft should be attempted6. If
this fails or in the case of larger perforations, therapeutic
penetrating keratoplasty will be needed after intensive
topical, and sometimes systemic antibiotic therapy, for
days in order to eradicate bacteria from the cornea as
best as possible5.
On the other hand, preserved human AM, which
has been reported to have anti-inflammatory, antiproteolitic and antimicrobial activities, has been used
to promote wound healing and to prevent perforation
in infectious keratitis, including P. aeruginosa keratitis,
with good results, as occurred in our case5,7,8.
The antibacterial properties of human AM have been
previously described9. Possible explanations include
intimate adherence of the AM to the wound surface,
or the presence of antimicrobial peptides (defensins)10.
Moreover, AM can act as a drug reservoir system
as it does not interfere with the ocular penetration of
topical antibiotics in corneas with epithelial defects5,8.
Moreover, AM can also protect the ocular
surface from being exposed to unwanted proteolytic
damage caused by proteases released by bacteria and
inflammatory cells. Moreover, it has been reported
that AM contains various protease inhibitors which
suppress the matrix-degrading activity of collagenase,
plasmin and trypsin11. Although AM did not directly
inhibit pseudomonal proteases, it may work indirectly
by inhibiting host proteases which are activated by
microbial proteases.
The possibility of treatment of P. aeruginosa keratitis
with combined corneal cross-linking and human
amniotic membrane transplantation has even been
described12.
Recently, a place for immune intervention in
P. aeruginosa keratitis has been proposed. Some studies
have been published that may identify potential targets
for immune intervention that could regulate the
severity of the host response, and subsequently, its effect
on blindness and visual impairment. For example, it
has been shown that patients infected with P. aeruginosa
expressing exotoxin exoS had a better outcome in terms
of visual acuity following treatment compared with P.
aeruginosa expressing exoU, possibly because it causes
less severe disease13.
97
However, and as has been shown in our case report,
the last step for recovery of visual acuity depends in
most cases on achieving acceptable anatomical and
functional outcomes with penetrating keratoplasty.
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JOURNAL OF EMMETROPIA - VOL 5, APRIL-JUNE
First author:
Miriam García-Fernández, PhD
Department of Ophthalmology. Hospital
Universitario Central de Asturias
Oviedo, Spain