optic neuropathy 4 Flashcards
(52 cards)
all congenital anomalies are stable (T/F)
T
*except for ON drusen
what does congenital mean?
some sort of insult as they were developing; anomaly
what does hereditary mean?
actual genetic mutation; we may have it isolated or not
Vision loss " Painless " Slowly progressive " Bilateral " symmetric " VA ranges from 20/50 – 20/200
nutritional optic neuropathy
Exam findings " Temporal ONH pallor " Centro-cecal VF defects: papillomacular bundle dropout " No RAPD " Dyschromatopsia
nutritional optic neuropathy exam findings
what converts carbs into glucose
vitamine B1 (thiamine)
” Helps with serotonin, norepinephrine, and myelin formation
vitamin B6
” Critical for cell growth and metabolism
vitamin B9 (folate)
” Critical for RBC formation and nerve function
vitamin B12
” Chronic alcoholics
“ Poor diet and liver disease
“ Excess carbohydrate load consumes high amounts of B1
vitamin B1 (thiamine) deficiency
” Pernicious anemia: decrease in RBC due to poor
absorption of B12
“ GI surgery: B12 absorption impaired
vitamin B12 deficiency
” Poor nutrition
“ Poor absorption of thiamine (B1) and B12
“ Improvement with vitamin supplementation
alcoholism
” Synergistic optic nerve toxicity
tobacco alcohol amblyopia
how to determine toxic vs hereditary?
bloodwork and history
Management: address nutritional deficit
“ Lab studies: CBC with differential, B1, B6, B12, folate,
RPR-VDRL, Lyme
“ Early intervention may improve or restore vision
“ ERG to r/o rod-cone dystrophy
management of nutritional on
treatment for nutrion on
” B12 injections (q1mo x few months, then q3mo)
“ Multivitamins
medication for toxic optic neuropathy
Medications
“ Anti-TB meds: ethambutol, isoniazid
“ Some cancer chemotherapy agents
” Lead
“ Methanol
“ Tobacco
“ Alcohol: no direct toxic effect; causes nutritional optic neuropathy
substance ingestion causing toxic ON
! AD
! AR
! X-linked
! Mitochondrial
hereditary ON
! Mutations in mitochondrial genome
“ Code for crucial components of energy metabolism
“ Results in degeneration of retinal ganglion cells
“ 90% have one of three mutations of mitochondrial DNA
! Maternally inherited
“ Sperm does not contribute mitochondrial DNA
! Mutation present at birth, but manifests in adulthood
! Begins in ages 25-35
! M:F = 4-5:1
lebers hereditary ON
whats mitochondria responsible for?
atp
! Acute vision loss in one eye “ Severe vision loss
! Fellow eye involved in 2-4 weeks
! Precipitating factors unknown
“ May be triggered by alcohol/tobacco abuse or nutritional deficiency
! VF loss: central or cecocentral scotoma
! Optic nerve: initially hyperemic, then pale
“ Dilation of peripapillary retinal vessels
“ Optic nerve does not leak on FA
lebers hereditary on
Management
“ Rule out other causes: neuroimaging, laboratory tests
“ Genetic counseling once genetic mutation has been identified
“ Electrocardiogram: may have associated cardiac conduction deficits
“ Advised to limit tobacco and alcohol intake
“ No FDA approved treatment
! Oral administration of idebenone
“ Enters brain to stimulate ATP formation in mitochondria
! Gene therapy
managment for leber’s hereditary on
! Aka Kjer’s DOA
! Most common inherited optic neuropathy
! Bilateral, symmetric, slowly progressive central VF loss
! Vision abnormalities begin in childhood (4-10 years)
“ VA ranges from 20/30-20/200
! Tritan color vision defect
! Incomplete penetrance common: may not elicit strong family
history
! Fundus: NFL defect in papillomacular bundle
autosomal dominant optic atrophy