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Anterior Segment > Infectious Corneal Disorders > Flashcards

Infectious Corneal Disorders Flashcards

1
Q

what G+ bacteria are implicated in infectious keratitis

A

staph aureus & strep pyogenes

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2
Q

what G- bacteria are implicated in infectious keratitis

A

pseudomonas aeruginosa & neiserria gonorrhea

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3
Q

what does staph require to cause an infectious keratitis

A

significant corneal epithelium compromise

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4
Q

how does neiserria gonorrhea cause an infectious keratitis

A

it can penetrate intact corneal epithelium

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5
Q

what viruses are implicated in infectious keratitis

A

herpes simplex & herpes zoster

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6
Q

what fungi are implicated in infectious keratitis

A

aspergillus, fusarium & candida

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7
Q

what parasites are implicated in infectious keratitis

A

acanthamoeba

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8
Q

when pain = presentation of infectious keratitis, what organism causes the infection

A

bacterial & viral

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9
Q

when pain < presentation of infectious keratitis, what organism causes the infection

A

fungal

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10
Q

when pain&raquo_space; initial presentation of infectious keratitis, what organism causes the infection

A

acanthamoeba

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11
Q

what are the common signs of infectious keratitis

A
  • conjunctival hyperemia
  • anterior chamber inflammation
  • large epithelial ulceration overlying corneal infiltrate
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12
Q

what is the major risk factor for infectious keratitis & why

A

CL wear

  • corneal epithelial hypoxia
  • bacterial adherence to lens surface
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13
Q

what are other risk factors for developing an infectious keratitis

A
  • trauma
  • ocular surface diseases
  • immunosuppression (HIV/AIDS, diabetes)
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14
Q

corneal infiltrates are

A

leukocyte infiltration into corneal stroma

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15
Q

is a hypersensitivity reaction to an antigen an infectious or non-infectious corneal infiltrate

A

non-infectious

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16
Q

when the immune system is directly battling an infectious organism, is that a infectious or non-infectious corneal infiltrate

A

infectious

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17
Q

corneal infiltrates: infectious or non-infectious

  • larger & solitary
A

infectious

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18
Q

corneal infiltrates: infectious vs. non-infectious

  • peripheral/scattered
A

non-infectious

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19
Q

corneal infiltrates: infectious vs. non-infectious

  • overlying epithelial defect stains well w/ NaFl
A

infectious

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20
Q

corneal infiltrates: infectious vs. non-infectious

  • anterior chamber inflammation
A

infectious

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21
Q

corneal infiltrates: infectious vs. non-infectious

  • commonly unilateral
A

infectious

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22
Q

corneal infiltrates: infectious vs. non-infectious

  • milder level of discomfort
A

non-infectious

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23
Q

corneal infiltrates: infectious vs. non-infectious

  • injected “angry” eye
A

infectious

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24
Q

when should a corneal culture be performed

A
  • when ulcer does not respond to aggressive therapy
  • a large, central ulcer is present
  • case history & clinical presentation point away from the common organisms
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25
Q

blood agar is a routinely used media for what

A

most bacteria & fungi

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26
Q

chocolate agar is a routinely used media for what

A

N. gonorrhea

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27
Q

sabouraud is a routinely used media for what

A

fungi

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28
Q

MacConkey agar is a routinely used media for what

A

G- bacteria

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29
Q

MacConkey agar is optimal for what organism

A

pseudomonas

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30
Q

clinical findings:

  • circumlimbal injection
  • stromal edema
  • folds in Descemet’s membrane
  • anterior chamber reaction: WBCs
  • conjunctival & eyelid chemosis
A

bacterial keratitis

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31
Q

what are the late complications in bacterial keratitis

A

scarring & perforation

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32
Q

what type of topical antibiotic is used to treat bacterial keratitis

A

broad spectrum (G+ & G-)

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33
Q

why is a topical cycloplegic used to manage bacterial keratitis & which cycloplegic drops are used, how frequently & which one is more preferable

A
  • cyclopentolate 1%
  • homatropine 5% → preferable bc it lasts longer
  • BID-TID
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34
Q

in bacterial keratitis, when can steroids be used as treatment

A

when the epithelial defect is healed

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35
Q

how often should you see a patient with bacterial keratitis

A

daily until significant improvement

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36
Q

what is a small, non-central ulcer & infiltrate < 1.5mm

A

microbial keratitis

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37
Q

how do you treat a microbial keratitis

A

must be broad spectrum → 4th gen fluoroquinolones

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38
Q

what microbial keratitis ulcers are central, with an infiltrate > 2mm & unresponsive to initial treatment

A

high-risk ulcers

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39
Q

when treating a microbial keratitis high-risk ulcer, what is the loading dose in office

A

5 qtt of 4th gen fluoroquinolone separated by 5 min each

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40
Q

what kind of antibiotics would you use for a high-risk microbial keratitis ulcer

A

fortified antibiotics → cephalosporins (G+) & aminoglycosides (G-)

  • cefalozin/cefuroxime/ceftazidime 50mg/mL q1h with vancomycin 50mg/ml or tobramycin 15 mg/ml qih
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41
Q

how would you apply the fortified antibiotics

A

alternate 1 qtt every 30 min in the affected eye

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42
Q

what infectious corneal disorder has:

  • insidious onset & growth
  • elicits significant inflammatory response w/ hypopyon
  • ocular signs are typically worse than symptoms
  • can lead to corneal perforation
A

fungal keratitis

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43
Q

what is a type of fungal yeast & how does it reproduce

A

candida → reproduce by budding

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44
Q

what are some types filamentous fungi & how does it reproduce

A

aspergillus & fusarium → grow by producing hyphae

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45
Q
  • chronic ocular surface disease
  • long-term use of topical steroids
  • CL wear
  • systemic immunosuppression
  • diabetes
  • injury with vegetable matter

these are all?

A

predisposing factors for fungal keratitis

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46
Q

which type of fungi is more common in fungal keratitis

A

filamentous

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47
Q

fungal keratitis with a dense yellow-white infiltrate is from which type of fungi

A

candida

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48
Q

fungal keratitis with:

  • yellow-white/grey infiltrate with fluffy margins
  • satellite lesions
  • feathery branch-like lesions
  • large infiltrates with possible small epithelial defect
  • anterior uveitis with hypopyon
  • can have bacterial hyperinfection

is from which type of fungi

A

filamentous

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49
Q

when should you culture for a fungal keratitis

A

prior to starting treatment

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50
Q

what media would you use for fungal keratitis

A

sabouraud/chocolate agar (allows labs to test for sensitivity of antifungal agents) → PCR

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51
Q

when should you perform a corneal biopsy for a fungal keratitis

A

if no improvement in 3-4 days of treatment

if no organisms grow on culture

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52
Q

what do you use to treat fungal keratitis until lab results arrive

A

antibiotic cover

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53
Q

what is the treatment regimen for topical antifungals & give some examples

A

q1h for 48hr → taper slowly when it improves
treatment required for 4-6 weeks
medications: natamycin 5%, amphotericin B

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54
Q

what do you use to reduce corneal thinning when treating fungal keratitis

A

doxycycline 100mg BID PO

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55
Q

can you use steroids to treat fungal keratitis

A

no

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56
Q

what infectious disorder is frequently misdiagnosed as herpes simplex keratitis in its early stages

A

acanthamoeba keratitis

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57
Q

who have an increased risk of acanthamoeba keratitis

A

CL wearers who:

  • swim in CLs
  • use tap water to clean CLs or CL cases
  • poor hygiene
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58
Q

signs:
- early → epithelial surface is irregular & gray
- formation of epithelial pseudodendrites
- limibitis with diffuse or focal stromal infiltrates
- stromal infiltrates enlarge & coalesce to form a ring

A

acanthamoeba keratitis

59
Q

what is a pathognomonic sign of acanthamoeba keratitis

A

perineural infiltrates (keratoneuritis)

60
Q

sequelae:
- scleritis
- slowly progressing stromal opacification & vascularization
- corneal opacification & melting

these are all sequelae of what infectious disorder

A

acanthamoeba keratitis

61
Q

how would you investigate to determine if it is acanthamoeba keratitis

A

culture, PCR, corneal biopsy

62
Q

what media would you use to culture acanthamoeba keratitis

A

non-nutrient agar w/ dead E. coli

63
Q

what is the treatment regimen for acanthamoeba keratitis

A

anti-protozoa treatment q1h & reduced when it improves

64
Q
  • polyhexamethylene biguianide 0.02%
  • chlorhexidine 0.02% q1h
  • brolene q1h

these are all what kind of treatment

A

anti-protozoa treatments

65
Q

many cases of acanthamoeba keratitis require?

A

corneal transplant

66
Q

when would you use an antibiotic to treat acanthamoeba keratitis

A

when there is a bacterial superinfection

67
Q

how do you manage the pain that comes with acanthamoeba keratitis

A

oral NSAID & cycloplegia

68
Q

can you use steroids to treat acanthamoeba keratitis?

A

no

69
Q

an enveloped double-stranded DNA virus

A

herpes simplex virus (HSV)

70
Q

which type of HSV is above the waist (facial, oral, labial)

A

type 1

71
Q

which type of HSV is a genital infection & is rarely transmitted to eye

A

type 2

72
Q

when does primary infection of HSV occur & how

A

in childhood via droplet transmission

73
Q

which HSV infection may develop dermatitis & conjunctivitis

A

primary infection

74
Q

what can induce HSV reactivation & prolferation

A

stressors like fever, hormonal changes, UV radiation, trauma, psychological stress

75
Q

in a recurrent infection of HSV, the pattern of disease depends on

A

site of reactivation

76
Q

what are the risk factors for severe disease in recurrent HSV infection

A

atopy
immunodeficiency
immunosuppression
topical steroids

77
Q

these ocular manifestations are from what infectious disorder?

  • dermatitis
  • keratitis
  • blepharitis
  • conjunctivitis
  • uveitis
  • retinitis
A

HSV

78
Q

in HSV, what are the more common forms of keratitis

A
  • epithelial (80%)

- stromal (15%)

79
Q

what ocular manifestation in HSV causes elevated IOP

A

trabeculitis

80
Q

what ocular manifestations occur in the epithelium with a live HSV virus

A
  • dendritic ulcer

- geographic ulcer

81
Q

what ocular manifestations occur in the stroma with a live HSV virus

A

necrotizing keratitis

82
Q

what ocular manifestations occur in the anterior chamber with a live HSV virus

A

keratouveitis

83
Q

an immune reaction of the HSV virus in the stroma causes

A

immune keratitis

84
Q

an immune reaction of the HSV virus in the endothelium causes

A

disciform keratitis

85
Q

an immune reaction of the HSV virus in the anterior chamber causes

A

keratouveitis

86
Q

this presentation is indicative of what infectious disorder?

  • clear vesicles on erythematous skin base
  • crust & self-heal
  • may cause follicular conjunctivitis
A

HSV dermatitis

87
Q

what is the management for HSV dermatitis

A
  • warm/cool soaks
  • antibiotic treatment
  • topical antiviral
88
Q

in HSV dermatitis, when would you use a topical antiviral

A

if eyelid margin is involved

89
Q

this presentation is indicative of what infectious disorder?

  • bulbar conjunctival injection & chemosis
  • palpebral conjunctival follicles
  • palpable preauricular node
A

HSV conjunctivitis

90
Q

how do you manage HSV conjunctivitis

A
  • topical antivirals

- artificial tears

91
Q

mild anterior uveitis (grade 1 cells in AC) is present in which ocular manifestation of HSV

A

HSV epithelial keratitis

92
Q

a classic dendritic ulcer is indicative of which ocular manifestation of HSV

A

HSV epithelial keratitis

93
Q

in a dendritic ulcer, NaFl stains ______ & Rose Bengal stains ______

A

NaFl → body of ulcer

Rose Bengal → terminal bulbs

94
Q

which infectious corneal disorder is the most common corneal infection in the US

A

HSV epithelial keratitis

95
Q

which HSV ocular manifestation is caused by reactivation of the virus after a primary oral-labial infection

A

HSV epithelial keratitis

96
Q

when performing a clinical exam for HSV epithelial keratitis, what are you testing for

A

symmetry/asymmetry between the eyes

97
Q

in HSV epithelial keratitis, when do you test for corneal sensitivity

A

before instillation of drops

98
Q

in HSV epithelial keratitis, why do you check IOP

A

to check for trabeculitis

99
Q

which topical medication do you use to treat HSV epithelial keratitis & what are the 2 drugs

A

steroids → trifluridine (Viroptic) & ganciclovir gel (Zirgan)

100
Q

what medication CANNOT be used for HSV epithelial keratitis

A

steroids

101
Q

what oral medication do you use to treat HSV epithelial keratitis & what is the dosage

A

acyclovir (Zovirax) → 400mg 5x/day 7-10 days (therapeutic dose)

102
Q

which HSV ocular manifestation causes the most severe morbidity

A

HSV immune stromal keratitis

103
Q

when does HSV immune stromal keratitis occur & why

A

usually after a previous episode of HSV epithelial keratitis

antibody-complement cascade against retained viral antigens in the stroma

104
Q

mid-deep stromal infiltrate w/ intact epithelium that leads to deep stromal vascularization & scarring is indicative of which HSV ocular manifestation

A

HSV immune stromal keratitis

105
Q

which type of medications & which drug do you use to treat HSV immune stromal keratitis

A

topical steroid → prednisolone 1% 6-8x/day w/ long taper (at least 10 weeks)
oral prophylactic antiviral cover → acyclovir 400mg BID during steroid use

106
Q

why do you have to add an oral antiviral cover when using a topical steroid for HSV immune stromal keratitis

A

if only given the steroid → epithelial dendrite can develop

107
Q

which HSV ocular manifestation is a cell-mediated immune reaction to viral antigens

A

HSV endothelial/disciform keratitis

108
Q

which HSV ocular manifestation results in acute onset of diffuse stromal edema

A

HSV endothelial/disciform keratitis

109
Q

these symptoms are indicative of which HSV ocular manifestation:

  • gradual onset of vision blur
  • photophobia & halos around lights
A

HSV endothelial/disciform keratitis

110
Q

these clinical findings are indicative of which HSV ocular manifestation:

  • stromal & epithelial edema confined to central cornea
  • large granulomatous KPs underlying edema
  • folds in Descemet’s membrane
  • elevated IOP
  • reduced corneal sensation
A

HSV endothelial/disciform keratitis

111
Q

how do you treat HSV endothelial/disciform keratitis

A
  • topical steroid w/ slow taper

- antiviral cover: acyclovir 400mg 5x/day for 7-10 days → then prophylactic dose

112
Q

which HSV ocular manifestation can occur in isolation or in association w/ HSV epithelial, stromal, or endothelial

A

HSV keratouveitis

113
Q

these signs are indicative of which HSV ocular manifestation:

  • acute trabeculitis → increased IOP
  • anterior chamber reaction
  • possible hypopyon
A

HSV keratouveitis

114
Q

what is a possible sequelae of HSV keratouveitis

A

transillumination defect of the iris

115
Q

how do you treat HSV keratouveitis

A
  • topical steroid w/ slow taper

- prophylactic antiviral cover

116
Q

which HSV ocular manifestation is the end result of repeat attacks of HSV keratitis causing damage to corneal nerves resulting in decreased corneal sensation

A

HSV neurotrophic keratitis

117
Q

decreased corneal sensation in HSV neurotrophic keratitis results in what

A

decreased tear production & blink rate

118
Q

where is HSV neurotrophic keratitis located & its appearance

A

ulcer is interpalpebral w/ smooth borders

119
Q

how can you treat HSV neurotrophic keratitis

A
  • aggressive lubrication
  • tarsorrhaphy
  • amniotic membrane
  • Oxervate (recombinant human nerve growth factor)
120
Q

HEDS I & II found that prophylactic dose of acyclovir does what

A

significantly reduces incidence of recurrent epithelial & stromal keratitis

121
Q

HEDS recommendation is for which HSV ocular manifestation

  • initial episode → no prophylactic therapy
  • 1+ episode → treat active ulcer first → oral therapy for 1 yr
A

epithelial disease

122
Q

HEDS recommendation is for which HSV ocular manifestation

  • initial episode: oral therapy for 1 yr
  • 1+ episodes: treat active ulcer first → oral therapy for at least 2 years
A

stomal disease

123
Q

what is the primary & secondary infection of VZV

A
  • primary → chickenpox (varicella)

- secondary → shingles (herpes zoster)

124
Q

reactivation of herpes zoster is most commonly along which dermatomes

A

thoracic & lumbar

125
Q

reactivation of herpes zoster in which dermatome is next most common & what is it called

A

trigeminal dermatome → herpes zoster ophthalmicus

126
Q

acute shingles (herpes zoster) skin lesions manifest in what way

A

strictly respect midline

127
Q

which branch of the trigeminal nerve dose reactivation of HZV affect more often & which branch of that is most commonly involved

A

V1 → frontal nerve

128
Q

when nasociliary nerve is involved in reactivation of VZV, what is the sign called

A

Hutchinson’s sign

129
Q

frontal nerve innervates which structures

A

forehead, upper eyelid

130
Q

how can you distinguish Hutchinson’s sign

A

vesicular eruption on tip of nose

131
Q

what ocular structures are involved in Hutchinson’s

A

sclera, cornea, iris, ciliary body, choroid

132
Q

most is the most common ocular manifestation of HZO

A

epithelial keratitis

133
Q

which ocular manifestation of HZO has pseudodentrite mucus plaques caused by swollen epithelial cells

A

HZO epithelial keratitis

134
Q

how can you differentiate HZO epithelial keratitis vs HSV epithelial keratitis

A

HZO epithelial keratitis has no terminal bulbs

135
Q

which HZO ocular manifestation is usually mild & responsive to topical steroid treatment

A

HZO stromal keratitis

136
Q

what happens to the iris from HZO

A

iris atrophy

137
Q

what is the treatment for herpes zoster

A
  • oral antiviral within 72 hours of maculopapular rash onset → acyclovir 800mg PO 5x.day x 7-10 days
138
Q

if the oral antiviral is taken within the 72 hours of the herpes zoster rash, what does it reduce the risk of

A

postherpetic neuralgia

139
Q

what can you use to treat herpes zoster in its active phase if it is severe & what does it do

A

oral steroid → reduces scarring & pain

- prednisone 60mg PO x 4 days → taper

140
Q

VZV Varivax is given to which age group & what does it do

A

given in childhood → prevents chickenpox & future shingles

141
Q

VZV Zostavax is given to which age group and what does it do

A

pts 60+ years → 50% reduced risk of shingles for 5-8 years

142
Q

VZV Shingrix is given to which age group and what does it do

A

pts 50+ years → prevents herpes zoster & postherpetic neuralgia

143
Q

if HZV has a bilateral presentation, what should you consider

A

atopy (allergies), thymoma, immunocompromised

Anterior Segment (37 decks)

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