Ped/genetic Cornea Flashcards
K crystals - bietti vs cystinosis
Corneal crystals in Bietti’s occur only at the LIMBUS and are diffuse in cystinosis.
CSCD (congenital stromal corneal dystrophy)
congenital stromal corneal dystrophy: diffuse cloudy of central cornea with whitish flakes. CLEAR PERIPHERAL CORNEA.
present at birth
non-progressive
AD, mutation in DECORIN gene (chr12)
“CSCD is decorous (decorin) - nonprogressive, spares periphery.”
Terriens
Thinning of the cornea
Top (starts superiorly) then spreads cicumferentially
Thirties (when age)
Transplant treatment if perf occurs
epi remains intact; fine pannus traverses area of K thinning. End of pannus = line of lipid deposition
generally u/L or asymmetrically bilateral
Terriens in kids
fuchs superficial marginal keratitis
Assoc/w/spontaneous hyphema in kids
xanthogranuloma, retinoblastoma, leukemia
young pt with recurrent dendrites
Tyrosinemia
AR
disease 2/2 a defect of tyrosine aminotransferase.
Dx: EXCESS level of tyrosine in the blood and urine but a NORMAL phenylalanine level in the blood.
Si/Sx: present with pseudodendrites (lesions are not completely devoid of epithelium with distinct margins as they are with an HSV dendrite). If you ever see a child with recurrent dendrites you should suspect tyrosinemia.
Rx: RESTRICT dietary tyrosine and phenylalanine. Doing this leads to a reduction in mental retardation.
Congenital glaucoma classic triad (Sx)
epiphora, photophobia, blepharosasm
Increased horizontal diameter: 9.5-10.5
CYP1B1 gene assoc
Mnemonic: little babies (congenital) use a sippy (CYP1B1) cup which looks like a BEE
Alkaptonuria:
Alkaptonuria: Al-capone will hunt you with an Assault Rifle [AR inheritance] and shoot you [dark pigmentation - like lead bullets].
You will be scared [urine and sweat patches are dark] and like an old man when he has finished with you [spinal disc degeneration].
To avoid him you need to smell danger [grey nasal cartilage] and keep an ear out for danger [grey ear lobes].
Megalocornea
nonprogressive and bilateral corneal disease
XR
histologically-normal corneas having horizontal diameters >13 mm.
Megalocornea patients can have glaucoma but not congenital glaucoma.
normal AL and deep AC in megalocornea–>minimizex the chance of angle closure glaucoma.
associated with Marfan syndrome.
Mnmemonic: MegaloK is X-rated, not PG-13. It is big, so assoc/w/Marfan’s. No angle closure for you!
Cornea plana
Cornea plana = flat cornea with a central corneal power of <43 D.
cornea curvature is similar to the adjacent sclera (pathognomonic finding)
Corneal plana is a common finding in other ocular abnormalities like sclerocornea and colobomas and can be associated with systemic syndromes like Ehlers-Danlos syndrome. Most isolated cases occur in Finnish individuals.
Both open and chronic-angle closure forms of glaucoma can be found in these patients.
Ehlers Danlos (Finnish pt) with CSCG (cornea plana, sclerocornea, colobomas, glaucoma). Also keratoglobus. Complete Plan: Sclera colors Glouchester (glaucoma)
Peters anomaly
catch phrase - “localized absence of corneal endothelium and Descemet’s membrane underneath a central corneal opacity.”
Other: lens-cornea touch, glaucoma, cataract, and microcornea.
It is generally inherited sporadically and is bilateral in 60% of patients. Coincidentally, 60% of these patients also have systemic problems including heart defects, hearing problems, and skeletal/facial abnormalities.
Mnemonic: Peter’s plus = Peter PAN has microK, cataract touching cornea, and glaucoma. He is fickle (sporadic). Rule of 60%: (60% bilateral, and 60% systemic prblms. He is heart-broken (heart defects) and doesn’t listen (hearing problems). Also looks funny (skeletal/facial abnormalities)
Microcornea
AD
clear cornea of normal thickness, but whose horizontal diameter < 10 mm.
typically hyperopic because flat corneas, therefore more prone to angle closure glaucoma. For those patients without angle closure glaucoma, still 20% (not 5%) of them will develop an open-angle glaucoma
MicroK -flat/angle closure. Little K so hyperopic
bilateral anterior lenticonus
bilateral anterior lenticonus = bilateral refractive amblyopia.
Lenticonus is generally posterior and unilateral.
When it is bilateral and anterior it is often associated with Alport’s syndrome. Alport’s syndrome is often associated with kidney disease.
Keratoglobus
very rare corneal ectasia which features a globular overall corneal curvature. Unlike keratoconus & PMD, the corneal is thinnest in the PERIPHERY and typically present at birth while the other two corneal ectasias occur in puberty or young adulthood and is frequently associated with corneal perforation and rupture
-strong association with Ehlers-Danlos syndrome type VI and blue sclera
also associated with flexible joints, bone fractures, deafness, and teeth abnormalities.
DDx: megalocornea (nml K thickness and contour) and congenital glaucoma (corneal edema and Haab’s striae)
Remember assoc/w/Ehler Danlos (which is also assoc/w/cornea plana)
Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease)
AD
telangiectasias of the conjunctiva, nasopharynx, GI tract, brain, and elsewhere.
Patients generally do not have bleeding from these abnormal vessels until adulthood. These fragile vessels in the conjunctiva can bleed with minimal eye rubbing. Patients may also have abnormal bleeding from blowing their nose or notice blood in their stool. They may also demonstrate an iron-deficiency anemia on normal blood work.
