optic neuropathy 3 Flashcards by Christie Wong

who are the great masqueraders?

syphilis, lyme, sarcoid

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!  Progressive onset
!  Vision loss and central VF involvement
!  Dyschromatopsia
!  APD
!  +/- optic nerve edema
!  +/- optic nerve pallor

compressive optic neuropathy

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2 types of non neoplastic

thyroid eye disease

aneurysim

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aneurysms arteries

ICA, anterior cerebral, ophthalmic artery

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2 types of neoplastic

intracranial and optic nerve

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3 types of intracranial neoplastic

! Sphenoid wing meningioma
! Pituitary adenoma
! Metastases

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2 types of optic nerve neoplastic

! Optic nerve sheath meningioma

! Optic nerve glioma

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” F>M(3:1)
“ Fourth decade
“ Pallor, optic nerve collateral vessels, gradual VA loss
“ Metastasis rare; damage due to compression of adjacent structures

! Optic nerve sheath meningioma: adults

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” 75% before age 20
“ 50% have NF1
“ Benign course in children; high mortality in adults

! Optic nerve glioma: children

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significant difference of gliomas in children over adults

benign in kids, but high mortality in adults

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” F>M
“ 4th-5th decade
“ 10-15% of all primary intracranial neoplasms
“ 10% of healthy population has pituitary abnormality detected by MRI
“ Slow growing epithelial tumor
“ Hyperpituitarism

Pituitary Adenoma: adults

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3 types of hyperpituitarism

! Cushing syndrome: excessive cortisone
! Acromegaly (adults), gigantism (children)
! Prolactinoma: amenorrhea, galactorrhea, infertility

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Optic nerve is vulnerable to _____ at many points along its anatomic course

Optic nerve is vulnerable to injury at many points along its anatomic course

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name the 4 optic nerve zones

” Optic disc/laminar zone
“ Intra-orbital zone
“ Intra-canalicular zone
“ Intra-cranial zone

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” Optic nerve avulsion
“ Forceful backward dislocation of optic nerve from scleral canal
“ Caused by extreme pressure from blunt force

laminar injury

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3 mechanisms of intraorbital trauma

! Penetrating FB
! Displaced fracture or bone fragment
! Compression by hematoma

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3 appearances of intraorbital trauma

! Variable depending on location
! CRAO: direct injury to CRA
! Disc edema

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whats the most common type of trauma?

intracanalicular trauma

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” Most common location
“ Occurs with or without fracture
“ Usually d/t frontal/maxillary blunt trauma
“ Optic nerve appears normal initially; pallor develops 4-6 weeks later
“ Direct injury: damage from bone fragments
“ Indirect injury

intracanalicular trauma

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3 types of indirect injuries

! Tearing of pial blood vessels

! Shearing of axons ! Edema

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! VA typically poor immediately following trauma
! + RAPD
! Visual field defects

intracanalicular trauma

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3 types of visual field defects of intracanalicular trauma

” Altitudinal/arcuate
“ Central, paracentral, centrocecal
“ Useful in documenting return of vision or progression of VF loss

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” CT of orbits best: fractures, bone fragments, orbital/optic
nerve hematomas

! Radiologic studies

” Mega dose corticosteroids: decrease edema
“ Optic nerve decompression
! Elective procedure
! If deterioration or no improvement in vision
! If hematoma or bone fragments

management for intracanalicular trauma

bacteria infectious ON

" Bartonella henselae " TB " Treponema pallidum " Lyme

" HZV " Measles " Mumps " Chickenpox

viral infectious ON

who is susceptible to fungus infectious ON

immunocompromised pts

" Mucormycosis extending from sinusitis | " Cryptococcal meningitis (AIDS patients)

fungi infectious optic neuropathy

toxoplasma, toxocara

parasite infectious optic neuropathy

! Sudden or gradual VA loss in one/both eyes ! +/- fever, lymphadenopathy ! +/- RAPD ! Optic disc typically swollen ! +/- macular edema " Aka stellate neuroretinitis " Inflammation of ONH results in secondary leakage and exudation around macula ! +/- anterior uveitis/vitritis/vasculitis

infectious on

" Transmission: scratch by infected cat " Children develop febrile illness few weeks after exposure to a kitten " Sysemic symptoms: fever, malaise, general adenopathy " Visual symptoms start 2-3 weeks after systemic symptoms resolve " Fundus evaluation ! Mild optic disc edema ! Macular edema " Prognosis: very good with or without treatment

CAT SCRATCH DISEASE

3 developmental anomalies of the ONH

hypoplasia dysplasia symptoms/signs

reduced number of axons

Hypoplasia

disorganized axons

Dysplasia

4 types of symptoms/sings of anomalies of the onh

" Reduced VA " VF loss " Color vision deficit " +/- RAPD

" Swollen " Atrophic " Unusual shape/size " Anomalous vasculature

appearance of anomalous nerves

! Patients unaware of reduced VA, or report longstanding reduction ! May have systemic abnormalities

anomalies of onh

3 types of systemic abnormalities due to anomalies of the onh

" CNS abnormalities " Endocrine dysfunction " Developmental delay

``` ! Unusual refractive errors ! Strabismus ! Amblyopia ! Ocular colobomas ! Hypertelorism ! Microphthalmos ! Aniridia ```

associated findings of anomalies of onh

``` ! Subnormal number of axons in the optic nerve ! Spectrum: mild to severe ! Fundoscopy " Small ONH " Double ring sign ! Reduced optic nerve function ! VA: normal to severe impairment ! Nystagmus if VA loss severe ! VF defects: altitudinal, arcuate, temporal depressions ```

ON hypoplasia

``` Insult to visual pathways before completion of development " Toxic " Infectious " Ischemic " Hereditary " Fetal alcohol syndrome " De-Morsier Syndrome ! Associated with developmental abnormalities of anterior midline brain structures " Mental retardation " Endocrine deficits ```

etiology of on hypoplasia

! Aka septo-optic dysplasia ! Disorder of early brain development " Optic nerve hypoplasia " Abnormal formation of midline brain structures (corpus callosum and septum pellucidum) " Pituitary hypoplasia ! Typically sporadic mutation, not inherited

de morsier syndrome

! Due to incomplete closure of the fetal fissure during prenatal development ! Excavation of disc may extend into retina and choroid ! May involve inferior iris and lens ! Commonly bilateral ! VF loss can mimic glaucoma

ON COLOBOMA

COLOBOMA will always be found where?

inferiorly --> b/c fissure closes inferiorly

! Small, partial coloboma ! Usually in infero-temporal aspect of ONH ! Stable arcuate VF defects may be present ! May lead to macular edema " 30% of patients " Usually in 4th decade ! Optic disc typically larger ! Peripapillary chorioretinal atrophy is common

ON pit

! Enlarged optic disc ! Large physiologic cup ! Bilateral or unilateral ! May appear pale: spread-out distribution of axons makes lamina cribrosa more visible ! Baseline VF recommended to r/o glaucoma

megalopapilla

! Dysplastic disc ! Excavated, funnel shape surrounded by elevated ring of chorioretinal pigmentary disturbance ! Unilateral; OD more common ! F>M ! No known hereditary pattern ! Associated with basal encephalocele " Deficit in skull floor allowing brain tissue to protrude outside of cranial cavity " Can lead to CSF leaks

morning glory syndrome

what are the 3 cardinal signs of morning glory syndrome?

" Cup is enlarged with deep depression and white tissue at the base " Raised annulus surrounds disc with variable amount of pigment " Retinal blood vessels emerge from disc in radial fashion, like spokes of a wheel

! Due to oblique insertion of optic nerve into the globe ! Typically oval in shape ! Scleral crescent often present ! Situs inversus: blood vessels directed nasally before sweeping temporally ! High myopic astigmatism with oblique axes ! VF loss has bitemporal appearance ! VA may be mildly impaired – probably due to mild refractive amblyopia

tilted disc (congenital anomaly)

! Small scleral opening ! Axons must squeeze through ! Little or no room for physiologic cup ! Slight elevation due to axonal crowding ! Indistinct margins can mimic papilledema ! Anomalous BV: multiple bifurcations, trifurcations

pseudopapilledema

Optic nerve drusen: hyaline bodies anterior to LC " Lumpy, scalloped appearance " 70% bilateral " AD inheritance " Cause prelaminar stasis of axoplasmic flow due to axonal crowding " VF defects possible: arcuate, can be progressive " B-scan " Autofluorescence

pseudopapilledema

whats one way to differentiate b/w pseudopapilledema and papilledema?

the vessels do not appear blurry in pseudopapilledema

``` ! Pseudoswelling greatest in central portions ! Vessels arise from central cone ! Anomalous bifurcations ! +/- SVP ! RNFL hemes uncommon ! Familial ```

pseudopapilledema

! Swelling greatest at edges with blurring of BVs ! Cup preserved in early stages ! Normal bifurcations ! No SVP ! RNFL hemes common ! No genetic component

papilledema

! 1% of population ! Extended proliferation of normal tissue ! Superficial bright opacification of retina ! Feathery appearance obscures underlying tissue ! May have VF defects

myelinated nerve fibers