optic neuropathy 4 Flashcards
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
how to detect autosomal dominant optic atrophy vs nutritional/toxic?
ask for family hx
! Investigations: commercial gene test for the main mutation of the OPA1 gene
“ Different mutations exist
“ Gene encodes for mitochondrial protein
“ Genetic defect causes mitochondrial dysfunction
“ Equal M/F prevalence
! Treatment: low vision aids
! Prognosis: stable after adulthood
autosomal dominant optic atrophy
how do we differentiate autosomal dominant optic atrophy vs lebers?
lebers will have more men affected
what is optic atrophy?
end result of any kind of insult to the optic nerve
what do we make probable diagonosis off of?
” Pattern of optic nerve pallor
“ Pattern of VF loss
“ History of vision loss
temporal pallor relates to what?
nutritional/toxic dominance
central cecal vf patterns relates to what?
toxic nutritional
rapid vision loss?
think ischemic/inflammatory
slow vision loss
toxic, compressive, inherited
cupping without pallor
glaucoma
# Hereditary optic neuropathy # Nutritional deficiency # Atypical optic neuritis # Optic nerve glioma
children demographics
# Typical optic neuritis # Nutritional optic atrophy # Toxic optic neuropathy # Leber’s hereditary optic neuropathy # Traumatic optic atrophy # Optic nerve sheath meningioma # Infectious optic neuropathy (syphilis, TB, Lyme)
young adult demographics
# Ischemic optic neuropathy # Toxic optic neuropathy # Nutritional optic neuropathy # Optic nerve sheath meningioma # Infectious optic neuropathy (syphilis, Lyme, TB) # CRVO
older adults >50 demographics
family history
# Dominant optic atrophy # Leber’s hereditary optic neuropathy (males)
past ocular history
# Prior trauma # Retinal disease # Surgery
whats common after surgery?
ischemic on
medical history
# Prior malignancy # Severe blood loss # Spine or cardiac surgery # Known systemic/demyelinating/infectious/inflammatory disease
medication history
# Ethambutol (TB) # Isonazid (TB) # Amiodarone (cardiac arrhythmia)
# Acute onset # Optic neuritis # Ischemic optic neuropathy # CRVO # Subacute onset # Compressive # Toxic/nutritional # Traumatic
temporal onset of visual loss
unilateral vision loss
# Typical optic neuritis # NAION # Compressive # Traumatic
bilateral vision loss
# Toxic/nutritional # Hereditary # Atypical optic neuritis # AION
pupils
# RAPD: present in unilateral or bilateral asymmetric optic neuropathy # Absent in bilateral symmetric optic neuropathy
pattern of vf loss
# Altitudinal: NAION # Bitemporal: parasellar lesions # Hemianopic: ischemic/compressive # Centro-cecal: toxic/nutritional/DOA
# Inflammatory # Autoimmune # Infectious
anterior/posterior segment inflammation
# Ischemic # Inflammatory # Infectious
retinal vascular abnormalities
# Diffuse pallor: non-specific # Temporal pallor: # Dominant optic atrophy # Toxic/nutritional optic atrophy # Bow-tie pallor: optic tract lesion Optociliary shunt vessels: # CRVO # Optic nerve sheath meningioma # Chronic glaucoma
disc appearance
# Inflammatory: ESR, CRP, ANA, RF, chest X-ray # Infections: PPD, RPR-VDRL, FTA-Abs, Lyme titers, chest X-ray # Nutritional/toxic: B1, B6, B12, folate, heavy metal screen
bloodwork
if etiology of optic nerve pallor remains ambiguous after thorough history and exam
neuroimaging
