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KMK Ocular Disease > 9 - Cornea3 > Flashcards

9 - Cornea3 Flashcards

1
Q

Biggest risk for any corneal ulcer

A

Contact lens wear

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2
Q

Bacterial keratitis

-epidemiology/hx

A

Most common etiology for infectious keratitis

  • esp CLS wear
  • consider all corneal infection bacterial until proven otherwise
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3
Q

Bacterial keratitis

-pathophys

A

Most common microbes: PSEUDOMONAS AERUGINOSA*, staph epi/aureus, h. flu, moraxella cararrhalis
*pseudo aur = most common gram(-) pathogen in severe bacterial keratitis; thick, green mucopurulent discharge, fast - can perforate in 48h

Most bacteria require an epi defect to invade
-exceptions: CNHL (corney, neisseria, haemophilus, listeria)

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4
Q

Bacterial keratitis

-signs/symp

A

Signs: INFECTIOUS ULCER (stromal infiltrates + overlying epi defects)

Symp: SEVERE PAIN + AC rxn, red eye, photophobia, decr vision

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5
Q

Describe an infiltrate

A

Sign of immune system attacking an antigen via antibodies
-without overlying epi defect is immune-mediated, not a sign of infection

Infiltrates start in the stroma, are signs of immune system attacking or over-reacting

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6
Q 
Bacterial keratitis
-corneal infiltrates/ulcers
—infectious corneal ulcer
—sterile corneal ulcer
—sterile infiltrate
A

ICU: rare, fluoro staining area RATIO 1:1, MOD-SEVERE PAIN, mild AC rxn, DIFFUSE INJECTION

SCU: common, fluoro staining area RATIO <1:1, less pain/injection

SI: will NOT STAIN with fluoro (no overlying epi defect), multiple lesions with mild pain, sectoral injection, no AC rxn

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7
Q

Fungal keratitis

  • epidemiology/hx
  • pathophys
A

Most common type of corneal ulcer after injury, esp vegetable matter

Candida: pts with CHRONIC corneal disease (dry eye, herpes keratitis, esposure k) or IMMUNOCOMPROMISED
-recall: candida is part of normal flora, won’t harm unless compromised

Aspergillus + Fusarium: VEGETABLE MATTER TRAUMA

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8
Q

Fungal keratitis

  • culture
  • signs/symp
A

Sabouraud’s agar

Signs:

  • Candida: similar app as bacterial corneal ulcer
  • Aspergillus/Fusiform: epi defect with UNDERLYING GRAY-WHITE INFILTRATE WITH FEATHERY EDGES and possible surrounding SATELLITE INFILTRATE
  • possible anterior chamber rxn, hypopyon

Symp: pain, photophobia, tearing, decr vision

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9
Q

Acanthamoeba keratitis

  • epidemiology/hx
  • pathophys
A

Rare parasitic infection
Assoc with poor cls hygiene

Common protozoa in soil, water, human mouth
Compromise of corneal epi -> invade
Infections progress slowly, often mis-dx

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10
Q

Acanthamoeba keratitis

  • culture
  • signs/symp
A

HEAT-KILLED E COLI CULTURE

Signs:

  • early: punctate/pseudodendritic epi defect, SEVERE PAIN OUT OF PROPORTION TO SIGNS
  • late: radial keratoneuritis (corneal nerve inflammation), patchy anterior stromal infiltrates -> gradually progress to RING ULCER

Symp: blur, pain, minimal discharge

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11
Q

Herpes simplex virus

-epidemiology/hx

A

DNA virus
Young pts, previous episodes and/or cold sores

Primary exposure: children 6mo-5yr, usually ASYMPTOMATIC

Recurrent infections: reactivation of latent infection in trigeminal ganglion, TRIGGER (stress, sun, fever, immunosuppression)

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12
Q

Herpes simplex virus

-pathophys

A

Tissue damage via:

  • direct invasion from virus
  • neurotrophic mechanism
  • immune-system response
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13
Q

Herpes simplex virus

-signs/symp

A

Signs: DECR CORNEAL SENSITIVITY
-primary exposure: blepharitis and/or conjunctivitis
—B: focal vesicular lesion w/ crusting on lids/periorbita
—C: acute unilateral follicular, watery discharge, preauricular
-recurrent infection: 1) epithelial dz 2) neurotrophic k 3) stromal dz 4) endotheliitis/disciform keratitis

Symp: pain, redness, serous discharge, tearing, photophobia, decr vision

  • other possible findings:
  • acute unilateral anterior granulomatous uveitis
  • trabecultis
  • ARN
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14
Q

3 things that happen when the cornea is touched

A

Blink
Lacrimation
Miosis

*last 2 = PNS

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15
Q

Herpes simplex virus: recurrent infection

-epithelial disease

A

Corneal vesicles (SPK)

Ulcers:

  • dendritic: most common presentation, rose bengal (borders) + fluoro staining (center)
  • geographic: similar to dendritic but wider - irregular with scalloped borders, assoc with previous use of TOPICAL STEROIDS
  • marginal: at margin of limbus
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16
Q

Herpes simplex virus: recurrent infection

-neurotrophic keratopathy

A

CN V1 issue (nasociliary)
Unique because etiology is not immune-mediated or infectious
Ulcers typically inferior, oval in app, smooth borders

17
Q

Herpes simplex virus: recurrent infection

-stromal disease

A

Worst because of neovascularization
Accounts for 20-48% of recurrent ocular HSV disease

INTERSTITIAL KERATITIS: infiltrate with DIFFUSE NV, an immune/“WESSLEY” ring, stromal thinning, scarring*

  • thought to result from ag-ab complement cascade
  • by definition: STROMAL INFLAMMATION WITHOUT PRIMARY INVOLVEMENT OF EPI/ENDO
  • stromal scarring = #2 cause of corneal blindness behind trauma
  • recall: 90% of IK cases are from congenital syphilis

NECROTIZING STROMAL KERATITIS: rare, from direct viral invasion, severe stromal inflammation with necrosis, corneal thinning/perforation

18
Q

Herpes simplex virus: recurrent infection

-endotheliitis

A

aka disciform keratitis

Secondary stromal edema due to IMMUNE REACTION within corneal endothelium

Disciform endotheliitis = most common form, FOCAL, DISC-SHAPED stromal edema overlying STELLATE KPs

Unlike IK, disciform is (-)stromal infiltrates, neovascularization

19
Q

Herpes zoster virus

-epidemiology/pathophys

A

VZV = initial invading organism

  • affects 95% of children by age 5
  • after initial infection, transported to trigeminal ganglia (and other cell bodies) where it becomes dormant

Reactivation can result from age*, trauma, neurodegeneration, immunosuppression
*if occurs in pt <50yo, consider a medical eval for immunosuppression

20
Q

Herpes zoster virus

-signs

A

Unilateral, follows dermatome

Pre-zoster: PRODROME of tingling, malaise, fever

Active-zoster: vesicular rash, may or may not form on lid margin -> blepharoconjunctivitis

Post-zoster: post-herpetic neuralgia, depression
-PHN: pain persisting BEYOND 1 MO after rash onset or resolution, most common complication of zoster
—severe PHN affects 7% of pts, leading cause of suicide in pts over 70

21
Q

Herpes zoster ophthalmicus

  • eyelid signs
  • corneal signs
A

Lid: trichiasis, ec/entropion, madarosis, poliosis

Cornea: occurs in 65% of pts

  • keratitis: punctate epithelial, anterior stromal, interstitial
  • PSEUDOdendritic keratitis (active = whole lesion stains)
  • endotheliitis
  • keratouveitis
  • keratopathy: neurotrophic, exposure
22
Q

Pseudodendrites

A

HSV keratitis starts with small, stellate lesions -> progress to pseudodendrites

  • tapered ends with NO TERMINAL BULBS
  • STUCK-ON app
  • ENTIRE LESION STAINS WITH RB (just edges in HSV)
  • does not stain well with fluoro (unlike HSV)
23
Q

Mooren’s ulcer

  • who
  • benign vs malignant
A

Rare
Older men (40-70)
No cls wear association

Benign (75%): elderly (70yoM), unilateral infiltrate, mild-mod symp, responds well to tx

Malignant (25%): younger, black males, bilateral, severe symp, responds poorly to tx, progresses relentlessly

24
Q

Mooren’s ulcer

-pathophy

A

Painful, progressive, chronic VASCULITIS of the limbal BVs -> ischemic necrosis + PERIPHERAL ULCERATIVE KERATITIS

Idiopathic, likely autoimmune
-assoc with HEPATITIS C

25
Q

Mooren’s ulcer

-signs/symp

A

Signs: UNILATERAL PERIPHERAL CRESCENT-SHAPED GRAY INFILTRATE -> progresses to ulcer CONCENTRIC TO LUMBUS with unique OVERHANGING EDGE
-may be self-limited or spread circumferentially and/or centrally

Symp: PAIN, often severe
-other: tearing, redness, photophobia, decr vision (irreg astig, iritis, central ulcer)

26
Q

Staph marginal keratitis

-pathophys

A

Common
T3 HS RXN to staph AUREUS: immune over-reaction to normal staph flora on the eye (STERILE ULCER)
-typically in pts with CHRONIC STAPH BLEPH
-recurrences are common

27
Q

Staph marginal keratitis

-signs/symp

A

Signs: multiple bilateral stromal infiltrates (esp 2/4/8/10 o’clock, where lid contacts limbus)

  • assoc phlyctenule, signs of bleph and/or acne rosacea
  • residual thinning, superficial NV, peripheral scarring

Symp: asymptomatic; acute photophobia, tearing, redness, decr vision

28
Q

Collagen vascular disorders

  • disorder examples
  • symp
  • corneal findings
A

RA, SLE
-also polyart nodosa, wegeners

Asymptomtic; significant pain, redness, decr in vision

Peripheral corneal thinning/ulcers
Uni or bilateral
May progress to encompass ENTIRE PERIPHERAL CORNEA
May be assoc with epi/scleritis, DRY EYE

29
Q

Corneal deposits

  • whorl keratopathy
  • fleischer’s ring
  • kayser-fleischer ring
A

WK: “Mr. Fabry whirls his CHAI-T”
-Fabry dz, Chloroquine, Hydroxychloroquine, Amiodarone, Indomethacin, Tamoxifen

FR: iron ring at base of keratoconus

KF: copper accum in pts with certain liver disorders, esp Wilson’s

30
Q

Corneal deposits

  • hudson-stahli line
  • stocker’s line
  • ferry’s line
  • band keratopathy
A

HS: iron deposits at junction b/w mid + lower third of cornea, common in elderly, no clinical significance

SL: iron deposits on leading edge of pterygium

FL: iron deposits on leading edge of filtering bleb

BK: Ca2+ deposites within Bowman’s layer (“swiss cheese pattern”)

KMK Ocular Disease (17 decks)

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