Optic Nerve Misc Flashcards
Optic neuropathy vs optic neuritis
According to ONTT - eye pain (usually worse with eye movement) in 92% of patients with optic neuritis; most eyes with optic neuritis (65%) have normal appearing optic nerves.
Optic neuritis - excellent VA Px (91% recover to 20/40)
AION: eye pain is very unusual, & AION always results in optic disc edema. Altitudinal visual field loss is characteristically seen in AION but is also seen in 15% of patients with optic neuritis so it is not a reliable distinguishing characteristic.
40% of non-arteritic-AION have VA < 20/200
60% of arteritis AION have VA < 20/200
Average time to nadir = 4.5 days Prognosis Good (VA >20/40 in 95% untreated)
Optic nerve drusen
Hyaline (proteinaceous) bodies in prelaminar optic nerve
75% bilateral
Caucasians
Inheritance? Sporadic or AD
Si/Sx:
progressive VF defects (80%): enlarged blind spot(MC), “NFL type”
CVNM
TVO (10%)
rare to have decreased central VA (work-up if present), NAAION
(Systemic) associated with?
Angioid streaks
Retinitis pigmentosa
Alagille’s syndrome
Diagnosis: B-scan: high reflectivity Autofluorescence FA: early blockage, late staining CT: calcification
no hyperemia of the disc, no hemorrhages, no exudates, and no obscuration of the retinal blood vessels
ONTT risk of MS development
based on the presence or absence of characteristic demyelinating white matter changes on MRI of the brain.
Eyes with peripapillary ON hemorrhages had a markedly reduced risk of developing MS vs. all eyes with optic neuritis
Information can be remembered as the “10/20/40/60 rule.”
10 years:
20% risk of MS with only Optic Neuritis (but w/o white matter lesions)
40% risk “ “ “ “ “without MRI findings
60% risk of MS with white matter lesions on MRI
OR @15 years:
~<20%/50%/75%
15-year risk of MS with MRI?
0 lesions: 16%
overall risk: 50%
1 or more lesions: 72%
PO prednisone increased recurrence
IV methylprednisolone recovered vision faster if treated in first 2 weeks,
IV methylprednisolone in patients with CNS plaques had fewer recurrences within first 2 years, but equivocal at 3 years
DDx for papilledema
DVST and brain tumor - so always order MRI/MRV
-esp for atypical demographic and patient with hypercoagulable risk factors
DVST often presents acutely with one or more of the following: headache, blurred vision, papilledema, transient visual obscurations, and unilateral / bilateral sixth nerve palsy.
Leber hereditary optic neuropathy (LHON).
Clinical case: optic neuropathy of the right eye with sudden loss of central VA, an APD, and optic disc swelling. However, unlike inflammatory optic neuropathies (e.g. optic neuritis), there is NO leakage on FA.
Males, 10-30y/o. acute, severe visual loss (< 20/200).
VF deficit?
Central or cecocentral (MC)
Fundus appearance? Hyperemia and elevation of optic disc Peripapillary telangiectasia Tortuosity of medium arterioles Retinal thickening Findings may precede visual loss May also appear normal
FA shows?
No leakage or staining of disc
2nd eye affected weeks - months later
Inheritance?
Mitochondrial DNA
MC= 11778. + 3460+14484 = 90% of all mutations
Treatment?
Coenzyme Q. avoid smoking/EtOH to decrease oxidative demand.
Prognosis: incidence of spontaneous partial recovery of VA up to 10%
Based on mutation type. 14484… = LAATE visual recovery (1=L, 4=A, 8=ate)
11778=HeLL (almost nobody escapes when they are in that mutation)
The rate of spontaneous late visual recovery in the 14484 mutation is about 65% as opposed to only 4% in the more common 11778 mutation.
Associated conditions?
Cardiac conduction abnormalities (WPW)
traumatic optic neuropathy (TON)
Traumatic optic neuropathy always presents with an APD.
TON can have mild to severe impairment of visual acuity and visual fields.
Usually the damage occurs in the retrobulbar portion of the optic nerve in the optic canal so there is no disc swelling visible on DFE.
Autosomal dominant optic atrophy (ADOA) aka Kjer’s dominant optic atrophy
Dominant optic atrophy (AD; OPA1 on ch3 in 60%*)
Most common hereditary optic neuropathy
Bilateral / symmetric
Insidious onset 5-10 yo but can present later
Mild vision loss, lose 1 line every 10 yrs
VA loss progresses until mid-teens, when it stabilizes (usually VA > 20/200)
TEMPORAL sectoral pallor of disc with thinning of
papillomacular fibers and demyelination of ON
cecocentral enlargement of blind spot +/- temporal depression
pathognmonic if present: ACQUIRED BLUE-YELLOW DYSCHROMATOPSIA (color defects almost universally present)
- different from Leber’s b/c earlier onset with very slow (moderate) visual loss
- assoc/w/cardiac pre-excitation syndrome, dystonia, cerebellar, pyramidal system demyelination
Vague FH of color blindness, progressive glaucoma, or poor vision of unknown etiology in close family members which supports the dominant inheritance (although may be a de novo mutation).
*OPA1 gene codes for a GTPase that appears to have a function in mitochondrial energy production and maintenance of mitochondrial membrane integrity.
Optic nerve enhancement
- MRI shows marked enhancement and slight thickening of the optic nerve sheath while the optic nerve itself shows very little enhancement.
- Optic nerve sheath enhancement can be seen in optic nerve sheath meningiomas and optic perineuritis (OPN). –inflammation of the meninges surrounding the optic nerve, OPN is a radiologic and pathologic diagnosis. ”
- acute presentation and pain with eye movement is suggestive of optic perineuritis.
OPN is generally considered on the spectrum of orbital pseudotumor because in many cases there is concomitant orbital inflammation and like orbital pseudotumor it is usually idiopathic inflammation. Additional known etiologies of OPN, however, include sarcoidosis, giant cell arteritis, lymphoma, Wegener’s granulomatosis, tuberculosis and syphilis.
OPN, can present like demyelinating optic neuritis (DON). In contrast to DON, however, OPN less commonly involves the central visual field, often occurs alongside other radiographic and clinical findings of orbital inflammation, and is exquisitely steroid responsive.
As we alluded to above, reasons to distinguish OPN from DON is that OPN: 1) Does not carry the same risk of future multiple sclerosis as DON; and 2) Requires a laboratory evaluation to rule-out other causes such as sarcoidosis, giant cell arteritis, lymphoma, Wegener’s granulomatosis, tuberculosis and syphilis.
Arteritic vs nonarteritic
Arteritic anterior ischemic optic neuropathy = often more visually-devastating than its non-arteritic counterpart with 60% of patients with less than 20/200 vision.
GCA damages vision by vasculitic occlusion of the posterior ciliary arteries that supply the optic nerve head and choroid; therefore, it is common to see “pallid” disc edema due to severe ischemia along with patchy choroidal filling on FA in the affected eye (and sometimes even the seemingly unaffected contralateral eye).
Optic disc swelling can make it difficult to judge a patient’s baseline cup-to-disc ratio in the affected eye prior to the ischemic event. Based on the fact that most people have symmetric optic nerves, a small cup-to-disc ratio in the contralateral eye is suggestive of non-arteritic anterior ischemic optic neuropathy in the affected eye.
MAR (melanoma associated retinopathy)
auto-antibodies to the TRPM1 cation channel
PION (posterior ischemic optic neuropathy)
2/2 hypoperfusion of posterior optic nerve.
2/2: Severe hypotension/hypovolemia +/- anemia 2/2 blood loss in major surgery (usually)
rarely 2/2 : GCA, lupus-associated vasculitis, VZV-realted vasculitis, polyarteritis nodosa.
Acutely: normal nerve. Optic pallor appears 6-8 weeks after PION
Associated with antibiotics (ethambutol, INH, sulfa) or chemo
Optic Disc Drusen associations
Higher rate of small ODD in pts with RP and PXE.
Usually affects whites (rare to have minorities)
Tuberous sclerosis
Yellow, mulberry-like astrocytic hamartomas lesion with occasional calcification
Associated with?
Tuberous sclerosis
NF (rare)
Septo-optic dysplasia (SOD) - de Morsier syndrome
faulty closure of embryonic ventral (fetal) FISSURE OF OPTIC STALK and cup
u/L or b/L ON hypoplasia
Associated with?
midline brain development abnormalities =
Absence of septum pellucidum
Hypothalamus & pituitary deficiency (usu. growth hormone deficiency)
Agenesis of corpus callosum
VA: near normal to severly impaired.
Nystagmus usually develops around 1-4 mo when pathways required for normal fixation typically mature
Work-up?
Get MRI and endocrine consult (GH is MC endocrinopathy)
MRI shows?
upside-down liberty bell sign
DDx of optic disc edema
ON edema = cessation of axonal transport
MC: pseudo/papilledema, ONeuritis, AION,
Somewhat common: CRVO, diabetic papillopathy
Uncommon: posterior uveitis, hypotony, malignant HTN, ON infiltration, Leber’s hereditary optic neuropathy
ONTT Rx
IV corticosteroid Rx (Methylprednisone 250 mg q6h x3 days) followed by PO prednsione 1 mg/kg/day x 11 days - less likely to have recurrence vs. PO prednisone alone
NASCET (North American Symptomatic Carotid Endarterectomy)
Pts with amaurosis fugax or hemispheric TIAs with 70-99% carotid stenosis benefited from CEA to reduce risk of future storke.
Pseudotumor cerebri med associations
vitamin A, tetracycline, cyclosporine, OCP, use/withdrawal of corticosteroids, nalidixic acid (fluroquinolone abx)
Systemic assoc: SLE, chronic respiratory insuffiency
Other: Whipple, Reye’s syndrome (swelling of liver/brain), Behcet’s, iron def
cavernous sinus-dural fistulae assoc
80% develop ocular HTN
25% develop ON cupping
20% VF deficits
GCA VA
VA < 20/200 in > 60% pts
ON glioma
aka: juvenile pilocytic astrocytoma
Path: Rosenthal fibers
Long, hair-like cells (pilocytic)
Most common primary ON tumor
CT/MRI: fusiform kinking
Frequently associated with? NF1 (AD; Ch 17) = 50% More common in? Children than adults Usually occurs in 1st two decades (90%)
Children: ~6 yo with visual defects, proptosis, stable nonprogressive course, good Px with noninvasive pilocytic astrocytoma
less common to see optociliary shunt vessels (as compared to ON meningiomas)
malignant gliomas of visual pathways (although rare) - occur more frequently in middle-aged adults than in children with rapid severe VA loss, with survival only 6-12 mo after Dx,
Histology: invasive malignant astrocytoma
no assoc/w/NF
ON meningiomas
2nd most common primary ON tumor
occur primarily in adults
3x more common in women, worse when PREGNANT
slowly progressive monocular VA loss
More common in NF2
orbital meningiomas present earlier than intracranial
meningiomas in youth assoc/w/NF
slightly higher incidence in NF-1 over general population (minority of ppl with both)
ON sheath or sphenoid wing
Path: Psammoma bodies
(whorls of calcium)
CT/MRI: tram-track sign (enhancement), calcification. ON appears hypodense with more dense peripheral ring.
Other findings? Optociliary shunt vessels Gaze-evoked amaurosis Vision loss over decades \+optociliary venous shunts, +/- TVOs,
Surgery if extend to chiasm
papillophlebitis
normal/near normal VA
no RAPD
normal color VA
VF testing: enlarged blind spot
fundus exam: retinal venous engorgement assoc/w/hyperemia ON edema
retinal hemorrhages extend to the equatorial region are common
form of incomplete CRVO - usually resolves spontaneously w/in 12 mo
Morning glory disc anomaly
Funnel-shaped staphylomatous excavation of the posterior fundus that incorporates the disc with the following 3 features:
(1) Surrounding RPE elevation
(2) central white core of glial tissue
(3) radiating abnormal blood vessels.
Unilateral
Female>male (2:1)
Associated with myopia
Causes what retinal problem? Serous RD (33%)
Associated with what systemic problem?
PHACE syndrome
Basal encephalocele (Occult, transsphenoidal)*
Moyamoya (chronic progressive cerebrovascular disease with bilateral stenosis or occlusion of the arteries around the Circle of Willis –> TIAs, strokes, and epilepsy. (may necessitate revascularization procedures to prevent ischemia)
CNS imaging (MIR/MRA) is MANDATORY: ~40% of patients may have vascular abnormalities.
- can see midline abnormalities (agenesis of the corpus collosum and pituitary abnormalities)
- associated with Neurofibromatosis Type 2.
VA often < 20/200 with RAPD and VF defect
*Brain tissue protrudes through bony defects in the cribriform plate and body of the sphenoid or ethmoid. Also assoc/w/ON hypoplasia, these can mimic nasal polyps on exam.
Ayptical optic neuritis
“atypical” situations include the presence of vasculitis or intraocular inflammation, massive disc edema with peripapillary hemorrhages, and/or severe vision loss.
DDx: lupus, sarcoid, or syphilis
Workup if atypical (lasting > 1 month)?
ANA, anti-DNA, VDRL, FTA-ABS, CXR, ACE, ESR
When does optic atrophy occur after the initial insult?
Optic atrophy does not occur in the acute phase of optic nerve or retinal damage but rather requires 4-6 weeks to appear. Optic atrophy will occur with significant damage, ranging from the retina to the lateral geniculate body, where the majority of retinal ganglion cells synapse.
Papilledema vs. ON edema from other causes
Both can have very similar appearance (hyperemia, hemorrhages, etc)
Generally, papilledema is bilateral and patients retain good visual function (central visual acuity, visual fields, and color vision) until late in the disease course regardless of how swollen the nerve appears. Optic disc edema from other causes often has prominent visual field and/or acuity deficits early in the disease course. In these instances, the visual field and acuity can be much worse than expected based on the optic nerve appearance.
