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CORNEA ANOMALIES > CORNEAL DYSTROPHIES > Flashcards

CORNEAL DYSTROPHIES Flashcards

1
Q

list general characteristics of corneal dystrophy

A

bilateral, symmetric, and have no neovascularization

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2
Q

list 1 anterior corneal dystrophy?

A

Epithelial basment membrane dysrophy (EBMD)

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3
Q

what is the most common anterior corneal dystrophy?

A

EBMD

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4
Q

what causes EBMD?

A
  • Basal epithelial cells secrete an excessive amount of basement membrane that leads to thickening of the basement membrane and causes weak hemidesmosomes formation –> this causes corneal epithelial cells to be trapped beneath the basmement membrane and prevents them from progressing anteriorly.
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5
Q

symptoms of EBMD?

A
  • Asymptomatic – unless central corneal is involved then they will have blurry vision.
  • Epiphora
  • Severe pain if RCE.
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6
Q

signs of EBMD?

A
  • Map – irregular islands of thickened, gray, hazy epithelium.
  • Dot – Dot-like (microcystic) epithelial lesions.
  • Fingerprint – Whorled/concentric lines that look like fingerprints.
  • Negative staining with NaFl.
  • Possible RCE – due to the lack of hemidesmosome between basal epithelial cells.
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7
Q

tx for anterior and stromal corneal dystrophies?

A
  • ATs
  • If RCE – Abx + ATs + bandage CLs
  • if central scarring – consider phototherapeutic keratectomy (PTK), lammellar keratoplasty (DALK), superficial keratectomy, or penetrating keratoplasty (PK).
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8
Q

what are 3 types of stromal corneal dystrophies?

A
  1. macular dystrophy
  2. granular dystophy
  3. lattice dystrophy
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9
Q

which sotrmal dystophy is autosomal dominant and which are autosomal recessive?

A

AD = granular dystophy & lattice dystrophy
AR = macular dystrophy

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10
Q

which stromal corneal dystrophy is most visually disabling?

A

macular dystrophy

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11
Q

what causes macular dystrophy?

A
  • It occurs due to an error in Keratan sulphate (GAG) metabolism  that leads to an accumulation of GAGs
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12
Q

signs of macular dystrophy?

A
  • Central anterior stromal haze 
  • Greyish white, dense, focal, poorly delineated spots –>
  • Irregular corneal surface (due to stromal deposits) –>
  • Increased in lesion size & stromal haze –>
  • Increasing opacification involving full thickness stromal limbus-to-limbus.
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13
Q

what stains macular dystrophy?

A

stains with Alcian Blue

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14
Q

what age does macular dystrophy occur?

A

ages 3-9

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15
Q

what is the most common stromal corneal dystrophy & which is the least?

A
  • most common = granular dystrophy
  • least common = macular dystrophy
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16
Q

what are the 2 types of granular stromal corneal dystrophy?

A
  • type 1 = Characterized by amorphous hyaline deposits w/in stroma that stains bright red with Masson trichrome.
  • type 2 = Characterized by amorphous hyaline & amyloid deposits w/in stroma that stains with Masson trichrome & Congo red.
17
Q

signs of granular dystrophy?

A

Type 1 signs (in order):
* Small, white, sharply demarcated deposits in the central anterior stroma.
* Gradual confluence
* Hazing of intralesional space

Type 2 signs:
* Superficial fine opacities that appear like rings, disc, stars, or snowflakes.
* Deeper linear opacities – like lattice dystrophy.

18
Q

what is lattice dystrophy?

A

accumulation of amyloid deposits in the anterior stroma.

19
Q

lattice dystrophy stains with?

A
  • Stains with Congo red
20
Q

signs of lattice dystrophy?

A
  • Anterior stromal glassy refractile dots which coalesce into refractile branching lines (amyloid deposits).
21
Q

which anterior and stromal dystophy have RCE and how often do they occur?

A
  • EBMD - frequently
  • macular dystophy - occasionally
  • granular dystophy - rare
  • lattice dystophy - common
22
Q

what is the pneumonic to remember types of depositis and staining associated with stromal dystophies?

A

Marilyn Monroe Always Gets Her Men in LA County:

M = Macular dystophy
M = Mucopolysaccharide deposits
A = Alician Blue
G = Granular dystrophy
H = Hylaline deposits
M = Masson Trichrome
L = Lattice
A = Amyloid deposits
C = Congo Red

23
Q

what are 2 types of posterior corneal dystrophies?

A
  1. Posterior polymorphous corneal dystrophy
  2. Fuch’s endothelial corneal dystrophy
24
Q

what is posterior polymorphous corneal dystrophy (PPMD)?

A
  • It is characterized by excessive proliferation & migration of of Descemet & endothelial cells.
25
Q

what age does PPMD occur?

A

age 20-30

26
Q

signs of PPMD?

A
  • Hallmark = vesicular lesion – that can also appear as linear & band-like (train-track lesions), or mix.
  • corneal edema
  • Angle closure glaucoma – from peripheral anterior synechiae.
27
Q

tx for PPMD?

A
  • same as anterior and stromal dystophy + treat increased IOP.
28
Q

what is Fuch’s Endothelial Dystrophy?

A

characterized by progressive endothelial cell loss (hallmark) due to excess descemet’s membrane.

29
Q

symptoms of Fuchs?

A
  • Blurry vision – vision is worse in the morning b/c there is an accumulation of fluid in the cornea while sleeping (stromal swelling)
  • Pain – if bullous keratopathy
30
Q

what are the signs for each stage of Fuch’s?

A
  • Stage 1 – initial manifestation of the disease is central corneal guttae.
  • Stage 2 – Decreased endothelial cell density associated with pleomorphism & polymegathism & stromal edema causes a fine gray haze (<500cells/mm^2).
  • Stage 3 – characterized by bullous keratopathy, which is epithelial microcyst that can coalesce to form large intra & interepithelial cystic spaces or bullae which can lead to epithelial erosions & fingerprint lines –> painful.
  • Stage 4 – characterized by avascular subepithelial fibrosis & scarring between the epithelium & Bowman’s membrane.
31
Q

what is the min cell count needed to prevent corneal edema?

A
  • A min of 500-700 cells/mm^2 are required to prevent corneal edema
32
Q

tx for Fuch’s?

A
  • Hypertonic saline solutions (Muro 128) gtts or ung – for stromal edema.
  • ATs & bandage CLs – for epithelial bullae or RCE.
  • DSAEK / DMEK – for severe cases.
33
Q

are posterior corneal dystophies associated with RCE?

A
  • NO!!
34
Q

what inheritance are posterior corneal dystophies?

A

AD

35
Q

why does stromal edema occur in fuch’s?

A

endothelial cell count is too low which leads to compromised endothelial pump mechanism.

CORNEA ANOMALIES (6 decks)

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