14. KERATOMYCOSIS
First described by Leber (Aspergillus species) in 1879
Major cause of blindness in Asia
Incidence low in Britain & North USA
6-53% of all cases of ulcerative keratitis in Asia
Can occur alone or coexist with a bacterial
infection(14.1%)
[Basak et al Indian J Ophthalmol. 2005 Jun;53(2):143]
Earlier phaeoid fungi (Dematiaceous) not considered to
be significant but now are important cause of
keratomycosis .
16. EPIDEMIOLOGY
PREVALENCE
North India
South India
Eastern India
Western India
North India : Aspergillus40% ,Fusarium
16%, Curvularia 8%, 1994- Chander et al.,
Aspergillus 35 %, Fusarium 23%, Acremonium
12%, 1993-Chander et al.
82.3%
46.1%
32.0%
38.9%
South India : 34.4% fungal keratitis,
Fusarium 2007 Bharathi et al, Fusarium
43%, Aspergillus 26%, 30.00% Fungi
keratitis in India isDematitiousof
25% 2003 – Bharathi et al
Total prevalence of fungal
total cases
Total prevalence of fungal keratitis in western 8.00%
countries
IJO Sep 2001
19. ETIOPATHOGENESIS
Over 70 genera can cause mycotic keratitis
Fungi of importance in microbial keratitis
Moniliaceae
-- Aspergillus (90%) Most common cause in World
-- Fusarium(1%)Second most common cause
--Paecilomyces.
--Penicillium.
--Pseudallescheria.
Data in brackets from Dept of ophtahlmology, PGIMER
22. • PATHOGENESIS
-Breach in epithelium
-Compromised cornea
-Immunocompromised
Contact of fungal hyphae with cornea
Filamentous
Yeast
23. FUNGAL ADHERENCE
Filamentous Fibrinogen receptors on mature
conidia of aspergillus and fusarium
Yeast Integrin analogue, Fibronectin
receptor, Adhesive mannoprotn, Aspartyl
proteinase, Factor 6 , Endo. adhesions.
24. PENETRATION
Filamentous fungi: Parallel growth of hyphae to stroma, f/b
release of mycotoxins, proteolytic enzymes, soluble fungal
antigen
Yeast: Proliferate parallel & perpendicular to corneal stroma
f/b release of protease and lipase
25. HOST RESPONSE FILAMENTOUS
inablity of PMN,leucocyte cell for phagocytosis
destruction of corneal stroma
penetrate descement membrane
enterAC
accumulate around lens
seclusion of pupil
fungal glaucoma
26. HOST RESPONSE YEAST
inability of PMN cell to ingest pseudohyphae and hyphae
furstated phagocytosis by PMN
destruction of stroma
melting of cornea
27. CLINICAL FEATURES
•
•
•
•
•
Signs >> symptoms
Manifest within 24 – 48 hours
Patient present within 1st week
EARLY BI-MICROSCOPIC FINDING
Fine or coarse granular infiltrate within the epithelium
and anterior stroma
• Minimal stromal infiltrate
• Epithelial surface is dry rough textured, dirty gray in color
28. CONT………
• Epithelium may be intact or ulcerated.
• Pigmented and delicate ,feathery branching hyphae with
surrounding infiltrate
• Multifocal suppurative microabsscess or satellite lesion
29. CONTD….
• Advanced lesions
o Dense fibrinous material adhering to endothelium and iris
o Total stromal infiltrate and necrosis
32. CLINICAL FEATURE OF CANDIDA INFECTION
• Ulcer is small oval with expanding discrete sharply
demarcated ,dense yellow –white stromal suppuration
• Feathery margins are not seen
33. FUNGAL ENDOPHTHALMITIS
a suppurative inflammation of inner ocular coats
and their adjacent structure
with involvement of anterior chamber and
vitreous fluid,
caused by various fungal agents
35. EPIDEMIOLOGY
The first description of endogenous fungal
endophthalmitis was by Dimmer in 1913
Candida endopthalmitis clinical entity in 1958
In U.S.A. compared to previous decades Endophthalmitis
Increase from last few decades.
Incidence is increasing because of modern medical
practices
USA 30 % candidemia(Last 3 decdes) develop
endopthalmitis, now there is a lower incidence because
of prophylacyic antifungals
CMR, October 2000, p. 662–685
36. PATHOGENESIS ENDOGENOUS
Multifactorial.
It is likely that sustained fungemia with even
saprophytic fungi can lead to endopthalmitis
Gupte et al -contaminant IV fluids,11 / 72 IV fluid samples culture
positive for fungi
At the time of initial infection with some
dimorphic, fungi, such as H. capsulatum & C.
immitis, unrecognized fungemia occurs and often
leads to endophthalmitis.
38. PATHOGENESIS ENDOGENOUS
More common in immunocompromised ie pts on
chemo or IV drug abuse
Marked trophism for eye because peculiar blood
supply of the eye.
39. PATHOGENESIS: EXOGENOUS
Occurs in immunocompetent people
Direct introduction of the organisms following
Surgery(Catarct removal with placement of IOL mainly
Candida spp)
Trauma(Mainly Fusarium spp. )
I/O spread from Fungal keratitis
40. EPIDEMIOLOGY
RACE – no racial preponderance
SEX – Male preponderance (3:1)
AGE – Young and middle age.
41. MORBIDITY
Prognosis
depends upon
virulence of organism
extent of involvement
timing
mode of intervention
Prompt
therapy following early diagnosis helps to
reduce visual loss
Visual
outcome of aspergillus endo. is poor d/t
macular involvement.
43. C. ALBICANS
M.C.C of endogenous endopthalmitis
Infection usually starts from Choroid and then spreads to
retina
Non candida albicans fungemia & endopthalmitis is increasing
and is concern because of antimicrobial resistance
45. ASPERGILLUS ENDOPTHALMITIS
A. flavus second MCC
Spreads from lungs to eye
This is f/b A. fumigatus, A. niger, A. terreus, A.
glaucus , & A. nidulans .
46. CRYPTOCOCCAL ENDOPH.
Cryptococci spores survive in pigeons dropping
From lung, fungus – disseminated
haematogenesouly and can affect CNS causing
fungal meningitis & endophthalmitis in eye
Choroids is the probably first site of ocular
infections
48. PRESUMED OCULAR
HISTOPLASMOSIS
Occurs in immunocompetent individuals
Recognized by presence of multiple atrophic chorioretinal
scars w/o vitreous or aqueous humor inflmn.
Affect 2,000 new individuals a year in areas of endemicity and
in some cases may lead to visual loss and blindness
Arises from hematogenous spread
Not detectable in the scars of POH
Strong epidemiological evidence, principally deriving from skin
test surveys, linking the scars to histoplasmosis
49. CLINICAL FEATURES
Symptoms
Visual loss
Pt. may be asymptomatic if the lesion is in the
peripheral retina
Red eye.
Photophobia.
Pain.
Floaters.
Scotoma
50.
Many have a classical appearance with
progressive granulomatous uveitis
diffuse retinitis
deep vitreous abscess.
Time to make diag. from onset of symptoms, 3 d to
4 months.
53. PERIOCULAR INFECTIONS
Agent
Palpebral
Aspergillosis
Blastomycosis
involvement
No of cases in literature
2
12
As a part of generalized or local disease
3
C. albicans
First reported case 1922 case of sporotrichosis
6
Coccidioidomycosis
3
Cryptococcus spp.
Tinea faciale
11
Dermatophyte
Aspergilloma, sporotrichosis Chalazion
5
Paracoccidioidomycosis
7
Rhinosporidiosis
Blastomycosis, Coccidioidomycosis Basal cell carcinoma
5
Sporothrix spp.
54. INFECTIONS OF THE LACRIMAL GLAND
Fungi found to account for only 5% of infections .
14% of cases of congenital dacryocystitis
Principally Aspergillus spp. and C. albicans implicated
Epiphora is only clinical finding
Lid edema, conjunctival injection, and swelling in the
medial canthus; pressure over the area usually results in
a purulent discharge through the lower punctum
Thomas, CMR, Oct 2003,
55. FUNGAL INFECTIONS OF ORBIT
Proximity of sinuses to orbit, susceptible host & pathogen
Zygomycosis
Rhinoorbitocerebral : one-third to one-half of all cases,
Incidence increasing
Major risk factor : uncontrolled diabetes mellitus(70% DKA)
Other predisposing factors
Chronic alcoholism
Renal transplantation
Hematological malignancies
Steroid therapy
Breach of skin
Starts with symptoms consistent with sinusitis Bloody nasal
discharge Diplopia and loss of vision
Chakrabarti et al., 2006
56. INFECTIONS OF ORBIT
Invasive aspergillosis
Increased frequency infection :widespread prophylaxis with
fluconazole
[VanBurikJH et al. The effect of prophylactic fluconazole on the clinical Spectrum of fungal diseases
in bone marrow transplant recipients with special attention to hepatic
candidiasis.Medicine(Baltimore) 1998;77:246−54.]
Exact prevalence of invasive aspergillosis in India is not known
[Chakrabarti et al , Japanese Journal of Medical Microbiology vol 49, 165-72, 2008]
57. INVASIVE ASPERGILLOSIS
Other fungi mimicking aspergillosis
Bipolaris spp.
Alternaria spp.
Curvularia spp.
C. immitis
B. dermatitidis
Histoplasma spp.
Penicillium spp.
C/F
orbital inflammation & a red proptotic eye with or without
associated pain
ophthalmoplegia may develop
Embolization of vessels of the optic nerve, or direct
involvement of the nerve may occur
58. FUNGAL CONJUNCTIVITIS
Can occur indepently or with keratomycosis
Clinically rare entity
Fungi may be present without causing inflammation in~
25% pts
Topical application tetracycline X 4 wks increased
prevalence 28.7%
[Nema, H.V., O.P. Ahuja, A. Bal and L.N. Mohapatra, Effects of topical corticosteroids
and antibiotics on mycotic flora of conjunctiva. Am. J. Ophthal., 1968. 65: p. 747–750].
Topical applications of corticosteroids X 3 wks increase
prevalence of fungi 18.8-67%
[Mitsui, Y. and J. Hanabusa, Corneal infections after cortisone therapy.
Br. J.Ophthal., 1955. 39: p. 244–250.]
C. albicans follows steroid LA Pseudomembrane
Other organisms Aspergillus, Blastomycosis, Sporothrix,
Coccidiodomycosis
59. EXPERIMENTAL MODELS FK
Albino, wild rabbit , Dutch belted rabbit
Previously immunocompromised
Fractionated cobalt whole-body radiation
administration of antilymphocyte serum
corticosteroids locally or systemically
alloxan-induced diabetes
Intra lamellar injection or Superficial inoculation of
spore suspension
60. CONTD..
IL inoculation :
C. albicans, C. krusei, C. tropicalis, C. pseudotropicalis,
Aspergillus spp., Cephalosporium spp., F. solani, Lasiodiplodia sp.
Superficial inoculation:
C. albicans, C. tropicalis, C. pseudotropicalis, Aspergillus spp.,
Allescheria boydii, Cephalosporium spp., Geotrichum sp.
Antibacterial prophylaxis & use of characterized strain
ensures reproducibilty.
IO penetration of ketokonazole in rabbit has been tried
as a therapeutic modaliities
61. OTHERS
Mice
BALB/c mice
ip cyclophosphamide 180 mg/kg 1,3, & 5d
Scarified corneas /keratoplasty rat cornea in b/w space
topically inoculated
Easy handling
Rat
Wistar rats or Lewis rats
Suitable size & immune response
Size of eyes better surgical manipulation
Pigs
Large size, ease of fitting contact lens
Owl monkeys
Not better than Rabbit keratomycosis model
62. ENDOPHTHALMITIS MODELS
Rabbits
Both immunocompetent and immunocompromised rabbits are used
Used mainly for endogenous endophthalmitis
0.5 ml of 2 X 107 org/ ml into auricular vein
intravitreal inoculation of 1,000 CFU of susceptible C. albicans
Junko et al Jpn. J. infect. Dis., 60, 33-39, 2007
Mice
Fusarium solani in immunocompetent mice
Inocula of 5 x 10(6) conidia
injected into the lateral tail vein
Mayayo et al Med Mycol. 1998 Oct;36(5):249-53
65. LABORATORY DIAGNOSIS
Sample collection and transport
Biopsy
Corneal scraping, corneal button
AC tap
Vitreous tap
Fluids
Lens
Swabs not encouraged
Sterile leak proof container ASAP
Delay 4°C with exception of blood and vitreous (30-37°C ) &
swab (15%)
66. SAMPLES
Detailed examination of affected eye using slit lamp
Tissues diagnostic material harvested by
experienced ophthalmologist after LA or SA
Biopsy
Scraping :15 Bard – parker surgical blade from the base &
margin(thoroughly) of ulcer aseptically or Kimura’s platinum
spatula
Impression smear(Jain et al 2006 – PGIMER, Chandigarh –
equally sensitive and specific as Scrappings)
Vitreous tap 300 microL using 23 G needle
Aqeous tap 200 microL using 23 G needle
67. CONVENTIONAL TECHNIQUES
Direct microscopy
Rapid and cost effective
10% KOH preparation
Gram & Geimsa stain
Calcoflour Stain – Easy and fast
H&E, GMS, PAS, cytologic preparation
Culture
SDA, Blood agar,
CHROM agar
Susceptibility testing
According to CLSI guidelines
68. CONVENTIONAL
Nonspecific fluorescent stain – {calcoflour
white, blankophor, uvitex 2B} –
used in tissue sections and
cytopathologic preparation of rapid diagnosis of mycotic infections.
Chander et al. Sensitivity of Calcofluor white – 95.2% compared to
71.4 % for KOH and culture.
fluorescent microscope
wavelength of 365 nm.
Acridine orange staining – useful in early diagnosis of
keratomycosis
PAS (Periodic acid schiff) stain can also use.
69. CULTURE
Corneal scraping inoculated on agar plate as a ‘C’ or ‘S’
shaped streak incubated at 25 & 37°C X 4wks
Fungal growth in the form of the streak ensure that the
growth is from the inoculum / specimen rather than a
laboratory contaminant.
Two sets of SDA with antibiotic, inoculated and incubated
at 250 C & 370C separately x 4 wks.
Keeping a possibility of dimorphic fungi
70. CULTURE
Vitreous fluid inoculated on routine fungal culture
media .
Vitreous sample should be concentrate either by
centrifugation
Millipore filtration
71. CULTURE
All the culture checked
everyday during first week and
twice a week during next 3 week weeks.
Positive culture are more convincing
when growth is obtained on more than one occasion.
73. MOLECULAR TECHNIQUES
PCR based detection methods
PCR
Rapid molecular identification of fungal pathogens in corneal samples from suspected
keratomycosis cases. J Med Microbiol. 2006 Nov;55(Pt 11):1505-9.
PCR - SSCP
Sensitive and rapid polymerase chain reaction based diagnosis of mycotic keratitis
through single stranded conformation polymorphism. Am J Ophthalmol. 2005
Nov;140(5):851-857.
Nested PCR
Comparative study of Gram stain, potassium hydroxide smear, culture and nested PCR in the
diagnosis of fungal keratitis. Ophthalmic Res. 2010;44(4):251-6.
74. MOLECULAR TECHNIQUES
PCR-RFLP
Diagnosis of Aspergillus fumigatus endophthalmitis from formalin fixed paraffinembedded tissue by polymerase chain reaction-based restriction fragment
length polymorphism Indian J Ophthalmol. 2008 Jan-Feb;56(1):65-6.
Real time quantitative PCR
Detection and quantification of pathogenic bacteria and fungi using
real-time polymerase chain reaction by cycling probe in patients with
corneal ulcer. Arch Ophthalmol. 2010 May;128(5):535-40.
75. PRINCIPLES OF TREATMENT
As with any other fungal infection , look & treat for
any predisposing illness
Confirm lab diagnosis
Look for and treat any superadded infection
Remember
Poor penetration of antifungal drugs
Corticosteroids are contraindicated
Use both surgical and medical approach whenever needed
Close follow up is required
76. FUNGAL KERATITIS
Superficial (early keratitis):
Topical natamycin (5%) (hyphae)
Topical 0.15% amphotericin B or topical fluconazole (yeasts)
Debridment of the epithelium
Deeper and larger lesions:
Subconjunctival or intravenous miconazole
Ketoconazole, itraconazole, fluconazole or voriconazole (p.o.)
Intracameral amphotericin B
Surgical treatment:
Cyanoacrylate tissue adhesive
Amniotic membrane transplantation
Penetrating keratoplasty
78. EXOGENOUS ENDOPHTHALMITIS
Intraocular (intracameral ± intravitreal) amphotericin B
Intravitreal voriconazole or miconazole
Subconjunctival antifungal agents: when associated with
keratitis
Systemic antifungal agents:
fluconazole, ketoconazole, voriconazole, itraconazole, m
iconazole, and amphotericin B: important in
immunocompromised patients
Pars plana vitrectomy
79. MUCORMYCOSIS
Radical surgery+ antifungal therapy + correcting
underlying conditions
Amphotericin B Ist DOC(Amphotericin B given IV at
a daily dose of 1.0-1.5 mg/kg infused during 2-4 hr
for a total of 1-4 g)
Lipid formulations of amphotericin B alternative
Ferri: Practical Guide to the Care of the Medical Patient, 8th ed
80. INVASIVE ASPERGILLOSIS
Voriconazole 6 mg/kg IV q12h for 2 doses, then
4 mg/kg q12h PO Rx for adults is 200 mg bid or
4 mg/kg bid.
Caspofungin in pts who fail to respond to or are
unable to tolerate other antifungal drugs. The
recommended dosage is 70 mg on the first day and
50 mg qd thereafter given as a single dose IV over
1 hr.
Ferri: Practical Guide to the Care of the Medical Patient, 8th ed
81. Even though we cannot live forever, let our eyes live and give
sight for the needy! I have pledged my eyes, you can do that too..
Hinweis der Redaktion
Pt of mucorycosis, CT left Mucormycosis of LE, Rt invasive aspergillus eroding Lamina papyracea, Autopsy sphenoid pus which showed