Lecture 3a Optic Nerve Edema

Vitamin E acronym for optic nerve swelling

- Vascular

- Inflammation, infections

- toxic

- autoimmune

- metabolic

- inherited

- neoplastic

- endocrine

majority of clinical cases of optic nerve edema

- papilledema

- optic neuritis

- anterior ischemic optic neuropathy (AION)

Papilledema

- what is this?

- bilateral optic nerve edema , caused by elevated intracranial pressure (which increases pressure in subarachnoid space surrounding optic nerves)

- stagnation of venous outflow from retina/optic nerve results - results in obstruction/stasis of axoplasmic flow at lamina cribrosa btwn RGCs and LGN

AION/optic neuritis edema characteristic - is it bilateral or unilateral ?

unilateral optic nerve edema

optic nerve

- avg nerve diameter

- 1.5 mm

what is optic nerve made of ?

- 80% axons

- blood vessels and glial tissue are the rest of it

Blood sources for optic nerve

- CRA supplies superficial disc capillaries and NFL

- ophthalmic artery supplies orbital portion of optic nerve

- posterior ciliary artery supply pre-laminar, lamina cribrosa, post-laminar and peripapillary region

ONH venous drainage ?

- through CRV

what is optic nerve surrounded by ?

- subarachnoid space and CSF

majority of disc vessels are what ?

capillaries from venous side of circulation

why does occlusion of CRA not cause complete ischemia to eye?

b/c of posterior ciliary artery blood supply

CSF function

- cushion

- immune protection

Clinical changes as a result of papilledema are b/c of ...

- hypoxic, mechanical, vascular factors

how to measure CSF pressure ?

lumbar puncture

CSF/intracranial pressure normal ranges

- normal weight

- overweight

- in papilledema

- 100-200 mm H2O

- 25-50

- >200 to 550

Papilledema

- symptoms

- asymptomatic often until later stages

- VA unaffected until atrophic stages/mac edema

- VF enlarged blind spot

- transient vision loss lasting seconds associated with changes in posture

- HA

- diplopia

- dizziness

- nausea

- vomiting

Papilledema causes

- intracranial lesions

- obstruction of CSF being re-absorbed

- intracranial hemorrhage

- inflammation

- infection

- vascular disorders (HTN, CHF)

- pseudotumor cerebri

- toxic

- endocrine disorders

- hematologic disorders

- trauma

What is pseudotumor cerebri ?

symptoms

- idiopathic benign intracranial hypertension (increase of CSF) due to decreased CSF absorption/increase CSF formation

- most common in young women

- neck stiffness

- HA

- subjective puslatile intracranial noise from heartbeat

Papilledema diagnosing steps

- CT, MRI, lumbar puncture

Papilledema early signs

- blurring/swelling of peripapillary NFL

- blurring of disc margins

- disc hyperemia

- splinter flame shaped NFL hemorrhage

- optic nerve cupping

- loss of spontaneous venous pulsation

presence of spontaneous venous pulsation indicates what ?

normal intracranial pressure

Moderate papilledema signs

- increased disc hyperemia

- elevation of disc surface

- obscuration of BVs crossing disc

- thickening/opacification of NFL

- tortuosity

- CWS

- retinal hemorrhage

- optic nerve cupping lost

- Paton's lines (wrinkles) near disc

Severe papilledema signs

- lipid exudates

- marked disc elevation

- more of moderate signs

Chronic papilledema signs

- less disc hyperemia

- decrease in edema, CWS, hemorrhages

- atrophy of NFL begins (less swelling)

Atrophic papilledema signs

- reduction in edema, hemorrhages

- sheathing of retinal vessels

- optic nerve pallor

- optociliary shunt vessel formation

- viable NFL gone - less disc edema/NFL swelling

- VF peripheral constriction

- Foster Kennedy Syndrome - unilateral disc edema

Time course in papilledema

- within days to weeks possible

- following intracranial hemorrhage - 2-4 hrs

- resolution in weeks to months

what is the major threat of papilledema ?

blindness from irreversible optic nerve damage if treatment is delayed / inadequate

Optic neuritis (aka papillitis)

- what is this?

- localized inflammatory optic neuropathy typically from demyelinating plaque located within optic nerve, optic chiasm or optic tract , it's also associated with MS

Optic neuritis - idiopathic demyelinating optic neuritis (IDON)

- associated with what diseases ?

- what symptoms

- MS

- loss of vision rapid within week of onset

- ocular pain upon eye movement

Treatment for acute optic neuritis ?

- steroids

#1 thing to do after pt is diagnosed with optic neuritis ?

MRI scan -- abnormalities found in 50% of patients with ON

what risk of MS 10 yrs post optic neuritis

38%

Clinical characteristics of optic neuritis

- unilateral optic nerve edema (if anterior portion of nerve is involved)

- optic nerve appears normal if plaque is retrobulbar

- loss of vision rapid/progressive

- pain upon eye movement

- RAPD

- color desaturation

- VF defects

Anterior ischemic optic neuropathy (AION)

- result of ...

- affects what size arteries ?

- GCA or temporal arteritis - leads to insufficiency of vascular supply via posterior ciliary arteries to optic nerve

- med to small arteries

Anterior ischemic optic neuropathy (AION)

- signs

- acute unilateral painless loss of vision with nerve edema

- disc hemorrhage common

- optic nerve atrophy with pallor in inactive AION

2 types of AION ?

- NAION

- AAION

AAION - arteritic AION

- patient profile

- 70-80's, female, elevated ESR (sedimentation rate), GCA

NAION-non arteritic

- patient profile

- risk factors

- 40-60's, not GCA related

- systemic HTN, diabetes, smoking, episodes of systemic hypotension, small diameter optic nerves w/small cupping

NAION what is believed to be pathogenesis ?

- structural abnormality of optic nerve with crowding affect of tissue is believed to be associated with pathogenesis of this disorder

Management of AAION and NAION

- arteritic AION is ocular emergency, go on corticosteroids

- no treatment for NAION

AION/NAION clinical characteristics

- unilateral optic nerve edema - sectoral

- disc hemorrhages

- decreased VA

- RAPD

- color desaturation

- VF altitudinal defect

- optic nerve pallor in inactive disease

Posterior ischemic optic neuropathy (PION)

- associated with ...

- what results ?

- management ?

- spinal/cardiac surgery

- retrobulbar involvement - severe bilateral vision loss

- urgent neuro-ophthalmology referral

Pseudopapilledema

- causes of this ?

- persistent hyaloid tissue (Bergmeister's papilla)

- hyperopia - small optic nerves

- medullated nerve fibers

- drusen of optic nerve

Drusen of optic nerve

- explain what this is ?

- autosomal dominant disorder which affects 2% population

- calcified axoplasmic debris associated with small scleral canal

Drusen of optic nerve clinical characteristics

- yellowish glistening spheres on/within optic nerve

- nerves appear elevated full or swollen

- retinal vessels exit nerve centrally

- retinal vessels clearly visible crossing disc

- retinal vessels can have anomalous branching patterns in disc

- peripapillary region RPE can be irregular

- disc margins poorly defined

Drusen optic nerve diagnosis

- fluorescein angiography

- CT, MRI

- B scan