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OPTO3003 > W11 Retinitis Pigmentosa > Flashcards

W11 Retinitis Pigmentosa Flashcards

1
Q

RP description:

A

Group of disorders.
Inherited progressive rod/cone degeneration
Syndromic (35%) or non-syndromic (systemic assoc.)
Causes progressive central/peripheral vision loss

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2
Q

RP common gene:

A

AD: RHO at 3p22.1
10% mutation of (RhoPro23His) > “typical RP”
Mutation of cys-187-tyr > rapid degeneration
Mutation of thr-58-Met > slow mild sectoral

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2
Q

RP genetic description:

A

AR: 55% non-syndromic retain central vision till 60
AD: 40% best prognosis
X-linked recessive: rare, most severe. Blind by 40

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3
Q

Patho of RP mutations:

A

Mutation alters proteins for PR structure/phototransduction/visual cycle > altered rhodopsin/RPE function > signalling cascade > PR apoptosis

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4
Q

RP remodelling patho:

A

PR loss > RPE dysfunction >
RPE hyperplasia / inward migration (bony spicules)
Glial cell migration/proliferation (ON pallor)
PR loss > O2 consumption loss > BV attenuation
RPE degen. > BRB loss > intraretinal fluid leakage > macula edema

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4
Q

RP symptoms:

A

Nyctalopia: initial Rod loss
Peripheral loss: Tunnel vision from Rod loss
Photophobia: Rod/Cone loss > doubled recovery time for photopic stress
Photopsia: altered PR signals > peripheral shimmering

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5
Q

RP signs:

A

Bony spicules: interstitial pigment clumps
ON pallor: white/waxy from Gliosis/ganglion death
BV attenuation: PR loss > attenuation / CC atrophy
Macula oedema: BRB loss > leakage
ERM: Atrophy/BRB loss > proliferative vitreoretinopathy
Bulls eye maculopathy / PSC / Vit. Degen.

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6
Q

Syndromic RP types:

A

Syndromes associated with RP forms
Bassen-kornweig syndrome
Refsum disease
Kearns-Sayre syndrome
Bardet-Beidel Syndrome
Usher syndrome

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6
Q

Kearns-Sayre syndrome:

A

Sporadic mitochondrial DNA mut. > energy loss
Chronic progressive external ophthalmoplegia (EOM weakness) / ptosis
RP (macula salt/pepper)
Cardaic loss, dementia

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7
Q

Bassen-Kornweig syndrome:

A

AR mutation > lipoprotein def. > vit. Absorbtion loss
RP by 10y, reduced w/ vitamin supp.
Spinocerebellar ataxia (motion loss)
Acanthocytosis (thorny red BCs)

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7
Q

Refsum disease:

A

AR PEX7 mutation > enzyme PA hydrolase def. > Systemic phytanic acid accumulation
Infant RP (salt/pepper) w/mental loss, scaly skin
Low phytanic acid diet decreases progression

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8
Q

Atypical RP types:

A

Diseases related-to/forms-of RP
Cone-rod dystrophy
RP sine pigmento
Retinitis puncata albescens
Sector RP
Pigmented paravenous chorioretinal atrophy

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9
Q

Bardet-beidel syndrome:

A

AR mut. In BBS gene > cell cilia dysf. > signalling pathway loss
Polydactyly (extra appendage), HT/DM, obesity
Bulls eye maculopathy

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10
Q

Ushers syndrome:

A

Type 1 (75%): Deaf by 1y, RP in child
T2 (23%): adolescent hearing loss
T3 (2%): progressive / late deafness/RP
Salt/pepper pigment / cataract

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11
Q

Cone-Rod dystrophy:

A

Early RP sign
Poor central vision > late peripheral loss > nyctalopia

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11
Q

RP sine pigmento:

A

Rod loss wo/pigment
Bony spicules late development

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12
Q

Retinitis punctata albescens:

A

AD/AR variant
Peripheral white scatted dots w/ arterial attenuation
Gradual peripheral loss/nyctalopia

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13
Q

Sector RP:

A

AD variant
Typical pigment in inferior quadrant
Progresses throughout retina

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14
Q

RP management:

A

Ophthal reff. > electrophysiological/genetic testing
Low Vision Service reff. > Royal society of the blind > visual aids (service dogs, counselling, employment)

14
Q

Pigmented paravenous chorioretinal atrophy:

A

AD variant
Asymptomatic non-progressive
Bony spicules wo/vision loss

15
Q

Most common macular dystrophy:

A

Stargardt disease and fundus flavimaculatus (variations of same condition)
AD mutation in ABCA4 gene > rod OS metabolism dys. > ^RPE lipofuscin
VA 6/60
Round/pisciform yellow flecks on fundus

15
Q

BEST vitelliform macular dystrophy patho:

A

Second most common macular dystrophy
Bestrophin gene (BEST1) AD mutation on chromosome 11q13
Altered RPE BEST ion channel > ^metabolic by-product above RPE
^by-product size > CNV / geographic atrophy

15
Q

Forms of macula dystrophy:

A

Stargardt disease / fundus flavimaculatus
BEST vitelliform macula dystrophy
Sorsby fundus dystrophy
X-link juvenile retinoschisis
AD drusen

16
Q

BESTs disease stages:

A

Pre-vitelliform stage
Vitelliform stage
Pseudohypopyon stage
Vitelliruptive stage
Atrophic stage

16
Q

Stargardt disease and FFM signs:

A

Present 10-20yo w/ central vision loss
Mottled/metal macula > bulls eye maculopathy/atrophy
Pisciform (fish shape) flecks on fundus

16
Q

BEST disease first 3 stages:

A

Pre-vitreliform: abnormal EOG
Vitrelliform: vitrelliform lesion (yellow drusenoid PED) at macula 6/18
Pseudohypopyon: weight of material > inferior PED development

17
Q

BEST 4/5th stage:

A

Vitrelliruptive: lesion disruption (scrambled egg) 6/60
Atrophic: chorioretinal atrophy at macula > retina thinning > scarring ^6/60

18
Q

Sorsby fundus dystrophy patho:

A

Rare macula dystrophy
AD mutation in TIMP3 > altered inhibition of MMP-3 > by-product buildup in RPE
Characteristic yellow drusen-like deposits along arcades

18
Q

Sorsby fundus dystrophy signs:

A

Presents from 30y
Nyctalopia, metamorphopsia, altered colour vision
Exudative macula degeneration from 50y

19
Q

X-link juvenile retinoschesis signs:

A

Present by 10y w/secondary nystagmus/strabismis
Vision stabilises by 20, then degrades after 50
Peripheral retinoschisis in 50% Px

19
Q

X-link juvenile retinoschisis patho:

A

RS1 gene mutation > altered retinoschisin protein secretion from PRs > poor cell-cell adhesion > NFL splitting
Characteristic spoke wheel splits in macula

20
Q

Autosomal dominant drusen:

A

EFEMP1 gene mutation > RPE matrix protein loss > drusionoid deposits
AMD by 20
Increasing drusen at macula > confluence > geographic atrophy/CNV by 50

20
Q

CSNB patho:

A

Congenital stationary night blindness is a group of inherited retinal dystrophies affecting PR/bipolar/phototransduction cascade
Loss of retinal signalling > vision loss / fundus changes / altered ERG

21
Q

Lebers congenital amaurosis signs:

A

Blindness soon after birth > roving eye, nystagmus, photophobia
Low pupil light reflex
Arteriolar narrowing
Salt/pepper retinopathy > severe pigmentation
Systemic association w/deafness, epilepsy

21
Q

Lebers congenital amurosis patho:

A

Severe AR rod-cone dystrophy in kids
Mutation in RPE65, CRB1, CEP290 > altered phototransduction cycle
Characteristic Franceshetti’s oculodigital sign of eye rubbing > keratoconus/deep set eyes

21
Q

CNSB symptoms:

A

Nyctalopia w/poor light-dark adaptation
Photophobia, strabismus, nystagmus
Varied fundus: pigmented, scattered dots
ERG shows low red response, normal cone

22
Q

Retinal dystrophy management:

A

Ophthal refferal > Electrooculography / Electroretinography / gene testing
Genetic counselling (family)
Low vision aids (dogs)
Gene therapy for RPE65 can improve prognosis

22
Q

Electrophysiological testing:

A

Evaluate RPE / retina function
International Society for Clinical Electrophysiology of Vision developed guide for:
Full-field/Pattern/Multifocal electroretinogram (ERG/PERG/mfERG)
Electrooculogram (EOG)
Cortical-derived visual evoked potential (VEP)

23
Q

Electroretinography:

A

Electrodes placed on cornea / lower lids
20m Dark adaptation > 0.01/3/10 cd.s.m^-2 flash
10m light adaptation w/ bg luminance 30 cdsm > 3.0 cdsm flash at 3/30 Hz

24
Q

Assessment of electroretinography:

A

DA 0.01: Rod / rod-bipolar
DA 3/10: Rod / Cone (rod dominance)
LA 3 / 30Hz flicker: Cone / cone-bipolar

25
Q

Electroretinogram waveform:

A

A-wave: PR function (rod/cone for DA/LA)
Oscillating potentials: amacrine cells
B-wave: bipolar (rod/cone for DA/LA)
C-wave: RPE (requires functioning PRs)

26
Q

Pattern electroretinogram:

A

Asses macula via alternating high-contrast checkboard stimuli

27
Q

Multifocal electroretinogram:

A

Display of small hexagons evaluate localised function and disease progression

28
Q

Electrooculogram:

A

Measures RPE by 15m DA followed by 15m LA (100cdsm)
Ratio between dark trough and light peak is called Arden ratio
Represents function of RPE/PR complex

29
Q

Visual evoked potential:

A

Electrodes on scalp note ON and visual cortex response to checkerboard patterns
Useful in non-verbal Px

OPTO3003 (18 decks)

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