RETINA - HEREDITARY RETINOPATHIES Flashcards
what are 8 types of hereditary retinal dystrophies?
- retinitis Pigmentosa
- stargardt disease
- Best’s disease
- progressive cone dystrophy
- gyrate atrophy
- familial dominant drusen
- von hippel-lindau disease
- Leber’s congenital amaurosis
what is retinitis pigmentosis (RP)?
it’s a group of inherited retinal disorders characterized by progressive photoreceptor (& RPE function) degeneration.
which is the most common hereditary retinal dystrophy?
retinitis pigmentosa
what is the average age of retinitis pigmentosa?
age 9-20
what causes (pathophysiology) RP?
cause by abnormal protein production that causes progressive loss of PR (rods + cones).
are cones or rods damaged first in RP?
rods
symptoms of RP?
Rods are affected first:
* Nyctalopia (hallmark)
* Mid-peripheral ring scotoma
* VF constriction
Cones are affected second:
* trianopic color vision defects
* progressive loss of central vision starting at age 20.
signs of RP? what is the classic triad?
Triad:
1. Attenuated vessels
2. Retinal bone-spicules pigmentation
3. Waxy optic disc pallor
Other signs:
* PSC (30-50%)
* macula signs: CME / ERM / RPE atrophy
* ERG - scotopic ERG is reduced
what is the work-up for RP?
- Mac OCT - standard of care
- ERG - scotopic will be reduced.
what systemic Dz is RP asscociated with?
Usher’s syndrome (congential hearing loss)
tx/managment for RP?
- vitamin A - slows progression.
- low vision consult
- acetazolamide - for macular edema (if present).
what 3 medication is c/i in RP?
- isotretinoin
- sildenafil
- vitamin E
what is stargardt’s Dz?
It’s characterized by a reduction of central vision with a preservation of peripheral vision.
female or males get stargardt’s more common?
M=F
whats the onset of stargart’s dz?
<20 y/o
what is the most common hereditary macular disease?
stargardt’s
what causes stargardt’s?
accumulation of all-trans retinal w/in the PR disc –> ultimately leads to toxic levels of A2PE which is hydrolyze to a highly toxic metabolite, A2E –> A2E accumulates as a component of lipofuscin in RPE –> this leading to degeneration of RPE & eventually PR b/c of lack of RPE supply.
symptoms of stargardts?
- Bilateral decrease central VA in the 1st- 2nd decade of life w/out previous subnormal vision & often out of proportion w/ fundus appearance.
- Color vison abnormalities - R/G deficiency
signs of stargardts?
- Early: pathognomonic pisciform flecks, yellowish flecks of lipofuscin scattered throughout the posterior pole & mid-periphery.
- Late: ring of atrophy in the macula.
- Late: pathognomonic “beaten bronze” appearance - macular lesion surrounded by yellow-flecks.
tx/managment for stargardt’s?
- Pt should avoid vitamin A - slows down accumulation of lipofuscin.
- DHA supplementation - may delay RPE & PR death
- UV sunglasses – for photophobia
- Low vision aids
what is best disease?
abnormal accumulation of material (lipofuscin) in the RPE.
what are symptoms of Best’s Dz?
signs are more severe than symptoms:
* Asymptomatic (75% better than 20/40 VA)
* Eventually mild decrease VA
what are the stages of Best Dz?
- Stage 1 pre-vitelliform
- Stage 2 vitelliform
- Stage 3 Pseudohypopyon
- Stage 4 vitelliruptive
- Stage 5 end-stage
what are the signs for each stage of Best’s Dz?
- Stage 1 - characterized by abnormal EOG (Arden ration < 1.8) with a normal fundus is an asymptomatic patient.
- Stage 2 - bilateral egg-yolk macular lesion appears.
- Stage 3 - the entire lesion can become absorbed w/ little to no effect on vision.
- Stage 4 - egg-yolk starts to break up and gives a “scrambled-egg” appearance. (Mild vision loss).
- Stage 5 - characterized by moderate to severe vision loss due to CNVM, hemorrhage, atrophy, & macular scarring.
pathognomonic sign for best dz?
- Pathognomonic - bilateral & progressive yellow, round, lesions filled w/ lipofuscin at the fovea (“egg-yolk”).
what is the work up for best dz?
- EOG - to Dx. Abnormal EOG
- ERG - will be normal
- Mac OCT - standard of care - will show lipofuscin accumulation in the RPE at fovea.
tx/managment for best dz?
No tx unless CNVM present:
* Anti-VEGF – Subfoveal.
* Laser photocoagulation – outside of the fovea.
Provide Amsler grid for self-check and RTC if any changes.
F/U – yearly exam or prn
what is progressive cone dystrophy?
progressive condition that only impacts the PR layer (predom the cones).
onset of cone dystrophy?
between age 20-40
symtpoms for cone dystrophy?
- Slowly progressive bilateral decrease in central vision
- Sever photophobia
- Sever color vision loss
- 20/400 by the 4th decade
signs of cone dystrophy?
- Early - normal fundus but abnormal cone function on ERG.
- OCT - PR layer missing.
- Late - central geographic atrophy with bull’s eye maculopathy.
- Vessel attenuation
- Deutan-tritan color defects
w/u for cone dystrophy?
- ERG - abnromal cone function
- mac OCT - missing PR layer
*
tx/mangement for cone dystophy?
No tx but mangement aimed to manage symptoms of photophobia:
* sunglasses or tinted CLs
F/U: 1 year
what is gyrate atrophy? what causes it?
- Bilateral chorioretinal degeneration due to a deficiency in the mitochondrial enzyme ornithine aminotransferase
what inheritance is gyrate atrophy?
AR
what is the onset of gyrate atrophy?
at the age of 10
deficiency in the mitochondrial enzyme ornithine aminotransferase leads to elevated levels of…
10-20x levels of ornithine in urine and blood
symptoms of gyrate atrophy?
- Nyctalopia
- Decreased vision.
- Constricted VF
signs of gyrate atrophy?
- Multiple, well-defined, scalloped areas of peripheral chorioretinal atrophy 360.
- Macula is spared until 4th – 7th decade.
- PSC
tx/managment for gyrate atrophy?
- restricted argine and protein in pt’s diet - prevents ornithine formation.
- vitamin B6 supplement
what is familial drusen?
retinal dystrophy characterized by early onset of macular and peripapillary drusen.
what inheritance pattern is familial dominant drusen?
AD
onset of familial dominant drusen?
before the age of 20.
symptoms of familial dominant drusen?
- asymptomatic or mild vision loss.
- when 40-50 y/o - pt might complain of significant vision loss.
signs of familial drusen?
- Mild cases: depicted by harmless, small, hard drusen located in the macular region.
- Moderate cases: characterized by multiple, large, soft drusen distributed throughout the entire posterior pole and the peripapillary region; this may occur after the 3rd decade.
- drusen may coalesce and form honeycomb appearance eventually turning to geographic atrophy.
- possible CNVM
tx for familial dominant drusen?
No tx unless CNVM present –
* Anti-VEGF – Subfoveal.
* Laser photocoagulation – outside of the fovea.
what is leber’s congenital amaurosis?
Hint: it is not the same as leber hereditary optic neuropathy.
it is a progressive AR rod-cone dystrophy
leber’s conenital amaurosis is the most common congenital cause of blindness in ___?
children
what 3 layers of the retina are loss in leber’s congenital amaurosis?
- PR
- Outer segments
- Outer nuclear layer
what are symptoms of lebers congenital amaurosis?
- roving eye w/in the first few months of life.
- blur vision
- color perception
- nyctalopia
- photophobia
signs of leber’s congenital amaurosis?
- reduced VA (20/40 - NLP)
- attenuated vessels
- chorioretinal atrophy
- pigmentary retinopathy
- yellow flecks
- nystagmus
- high hyperopia
- KCN
- keratoglobus
- PSC
tx for lebers cong amaurosis?
- no tx
- refer to low vision specialist
what is von hippel-lindau disease?
it is a genetic disorder in which non-cancerous tumors grow in multiple organs (parts of the body).
what are hemangioblastomas (aka capillary hemangiomas)?
benign tumors that arise from blood vessels which are secreting VEGF.
in what organs do hemangioblastomas form in von-hippel lindau dz?
- CNS (brain, spinal sord, cerebellum)
- retina
what inheritance pattern is von-hippel lindau disease?
AD
what are symptoms of von-hippel lindau Dz?
- asymptomatic or blurry visoin worse than 20/100 in affected eye
what are systemic signs of VHL Dz?
- CNS hemangiomas
tx for VHL Dz?
- No tx if asymptomatic - just observed.
- symptomatic - cryotherapy, PRP, argon laser, radiotherapy, surgical excision - to removed or minimize tumor.
what retinal condition are pts at risk with VHL dz?
Retinal detachment
what are ocular signs of VHL Dz?
- retinal capillary hemangioma - appears as an orange-red glob (ballooning) with a feeder vessel often located ST quad of peripheral retina. –> BV may leak exudates and blood.
- possible ERM
- retinal holes
- retinal detachment
- macular edema
