Transcript Treatment of Microsporidial Keratitis With Hexamidine

Treatment of Microsporidial
Keratitis with Hexamidine
Alex KH LAU1
Colin SH TAN1
Wee Jin HENG1
1Dept
of Ophthalmology
Tan Tock Seng Hospital, Singapore
The authors have no financial interest in the subject matter of this e-poster.
Introduction
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Figure 1
Microsporidia are tiny, spore-forming,
obligate intracellular eukaryotic protozoa (Figure 1).
 In humans, microsporidia are opportunistic
pathogens that usually cause diseases primarily in
immunocompromised patients with Human
Immunodeficiency Virus (HIV) infection.
 2 clinical entities of ocular microsporidiosis have
been described1:
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Corneal stromal keratitis in immunocompetent patients;
caused by Nosema and Microsporidium and
Superficial punctate keratoconjunctivitis in
immunocompromised individuals; mostly caused by
Encephalitozoon.
Introduction
 Treatment
of ocular microsporidiosis is
difficult and, to date, no definitive treatment
exists.
 Previously described treatment options
include2-9:
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Debridement,
Topical antibiotics (fluoroquinolones,
propamidine isethionate, fumagillin),
Systemic anti-fungals & anti-helminths
(itraconazole, albendazole) and
Topical steroids.
Objectives
 We
present a series of four cases of
microsporidial keratoconjunctivitis in
immunocompetent individuals who were
treated successfully with topical
hexamidine di-isethionate.
Case 1
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48 year old Caucasian male
History of mud entered both eyes during
rugby game in Cambodia.
Visual acuity was 6/12 in the right eye and
intraocular pressure (IOP) was 34mmHg. Slit
lamp examination revealed follicular
conjunctivitis, multifocal subepithelial
infiltrates, 2+ anterior chamber cells, as well
as keratic precipitates on the endothelium
(Figures 2 & 3).
Diagnosis of right microsporidial keratouveitis
was confirmed with modified trichrome stain of
corneal epithelial scrapings.
Patient was HIV negative.
He was treated with hexamidine diisethionate, dexamethasone (preservative
free), moxifloxacin and brimonidine.
Visual acuity recovered slowly to 6/6 over 3
months with minimal subepithelial scarring
(Figure 4).
Figure 2
Figure 3
Figure 4
Case 2
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17 year old Chinese female
Developed redness and pain in the right
eye 2 weeks after contact with mud.
Visual acuity was 6/6 bilaterally. There
were multiple, coarse corneal epithelial &
sub-epithelial infiltrates and follicular
conjunctivitis (Figures 5 & 6).
Diagnosis of microsporidial keratitis was
confirmed with modified trichrome stain.
She was treated with hexamidine diisethionate, levofloxacin and oral
albendazole.
The infection resolved over 3 weeks.
Microsporidia keratitis subsequently
developed in the left eye and was
successfully treated with hexamidine diisethionate.
Figure 5
Figure 6
Case 3
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23 year old Chinese male
Reported redness and pain in the left eye 4
days after contact with mud.
He was treated for viral conjunctivitis with
topical tobramycin and dexamethasone.
Five days later, he developed sub-epithelial
infiltrates which worsened over the following
week (Figures 7 & 8).
A clinical diagnosis of microsporidia keratitis
was made and he was treated with topical
hexamidine and levofloxacin.
Diagnosis was confirmed from corneal
scrapings with modified trichrome stain.
The infection resolved over the next 2
weeks with no corneal scarring (Figure 9).
HIV status was negative.
Figure 7
Figure 8
Figure 9
Case 4
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63 year old Chinese male
Presented with redness, blurring of vision, pain,
photophobia and discharge in the right eye.
VA was 6/7.5 and diffuse subepithelial infiltrates
were seen with few keratic precipitates.
Clinical diagnosis of microsporidial keratitis was
made
He was started on hexamidine di-isethionate and
the keratitis resolved completely after 6 weeks of
treatment.
Discussion
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Our case series reports the successful treatment of ocular microsporidiosis
with hexamidine and its manifestations in healthy, immunocompetent
individuals.
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There are increasing reports describing ocular microsporidiosis in healthy
individuals. This could be explained by the increased awareness of this
rare infection and improvement in the diagnostic techniques10, 11.
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Our first case presented with a moderately severe uveitic response in the
anterior chamber, which has not previously been reported. This could be
due to sterile inflammatory reaction, or may represent a new clinical
manifestation of ocular microsporidiosis.
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Three of the 4 cases in our series developed microsporidial keratitis after
exposure to mud, which is consistent with previous reports of trauma as
one of the predisposing factors for ocular microsporidiosis in healthy
individuals. The others include topical steroid therapy (Case 3) and contact
lens wear.
Conclusion
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Microsporidia are increasingly become
recognised as pathogens in healthy individuals.
 High index of suspicion is required to make the
correct diagnosis, especially in cases presented
with atypical multifocal diffuse epithelial keratitis.
 History of ocular trauma, contact lens wear or
usage of topical steroid therapy are predisposing
factors which should raise the index of suspicion.
 Topical hexamidine di-isethionate is an effective
alternative therapy to microsporidial
keratoconjunctivitis.
References
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