Optic Neuropathies Flashcards
1
Q
what type of injury is most likely to occur in the intraocular section of the optic nerve?
A
vascular insult
2
Q
what type of injury is most likely to occur in the intraorbital section of the optic nerve?
A
muscle engorgement or tumors
3
Q
what type of injury is most likely to occur in the intracanalicular section of the optic nerve?
A
trauma/fractures and sinus inflammation
4
Q
what type of injury is most likely to occur in the intracranial section of the optic nerve?
A
pituitary gland and circle of willis
5
Q
what is the blood supply to the pre-laminar region?
A
short posterior ciliary artery
6
Q
what is the blood supply to the lamina cribrosa?
A
short posterior ciliary artery and circle of zinn haller
7
Q
what is the blood supply to the retro-laminar region?
A
branches of the central retinal artery and pial vessels
8
Q
what are the three conditions that can cause optic nerve shunt/collateral vessels?
A
optic nerve sheath meningioma, CRVO, and chronic glaucoma
9
Q
what are the hallmark signs of an optic neuropathy?
A
VA loss, RAPD, dyschromatopsia, VF defect, reduced contrast sensitivity, +/- optic disc appearance, and abnormal VEP
10
Q
what is typical optic neuritis?
A
autoimmune condition = primary demyelination of the optic nerve myelin sheath
11
Q
what is the pattern of VA loss in typical optic neuritis?
A
progresses over 1 week and improvement begins by 1 month
12
Q
what is the typical demographic for typical optic neuritis?
A
young adults (18-46), female > male, and no history of systemic disease
13
Q
what type of swelling does typical optic neuritis have?
A
2/3 of cases are retrobulbar
14
Q
what are the VF defects for typical optic neuritis?
A
any pattern is possible (diffuse is most common)
15
Q
what are 4 associated signs with typical optic neuritis?
A
numbness in hands, problems in bladder control, pulfrich phenomenon, and uthoff sign
16
Q
what did the optic neuritis treatment trial (ONTT) conclude?
A
high does IV steroids accelerated visual recovery, oral steroids alone increased rate of recurrence and IV steroids reduced risk of MS development for 2 years
17
Q
why is an MRI useful in patients who have typical optic neuritis?
A
it can identify patients who are at higher risk of developing MS
18
Q
what did the longitudinal optic neuritis study (LONS) conclude?
A
the initial MRI is the most predictive factor for developing MS after ON, the 15 year overall risk was 50% (females > males)
19
Q
what did the CHAMPS study conclude?
A
the medication Avonex (interferon therapy) reduced risk of development of MS and T2 lesions
20
Q
which medication for MS is oral and has CME as a side effect?
A
Gilenya - can cause CME 3-6 months after starting medication (need OCT at the start and after 4 months)
21
Q
what blood test is used to check for MS?
A
oligoclonal bands (immunoglobulins) present in CSF indicate inflammation in CNS (79-90% of MS patients have bands)
22
Q
what is atypical optic neuritis?
A
a systemic infection or inflammatory cause
23
Q
what is the presentation for atypical optic neuritis?
A
ages 50, bilateral, lack of pain, uveitis, retinal exudates/infiltrates, optic nerve swelling, hemorrhages, VA worsens past 1 week
24
Q
what is the most common symptom in typical optic neuritis?
A
90% has pain with EOM movements
25
what are the causes of atypical optic neuritis?
connective tissue disease (lupus, sjogrens, bechet), infectious (lyme, syphilis), infiltrative (sarcoidosis, cancer)
26
what is neuromyelitis optica (NMO) - Devic's syndrome?
unilateral or bilateral optic neuritis + inflammation of spinal cord (limb weakness)
27
what is the typical age for NMO?
average age is 39 (can affect children)
28
what causes NMO?
NMO antibodies (NMO IgG) target aquaporin 4 - NMO IgG is found in astrocytes and around the blood brain barrier
29
how is NMO different from MS?
NMO has more severe attacks, includes spinal cord, MRI is normal, no CSF oligoclonal bands, and usually has an autoimmune disease coexisting
30
what is transverse myelitis?
focal inflammatory disorder of the spinal cord - has numbness and paresthesias (peripheral limbs)
may progress to MS
31
what is acute disseminated encephalomyelitis (ADEM)?
post-infectious encephalomyelitis (fever, nausea, vomiting, vertigo)
typically children status-post viral infection or immunization
MRI = extensive lesions in basal ganglia and thalamus
32
what is non-arteritic anterior ischemic optic neuropathy (NAION)?
ischemic, non-inflammatory vascular insult to the pre-laminar and retro-laminar optic nerve (posterior ciliary artery involved)
33
what is the typical clinical presentation for NAION?
acute, painless VA loss (mild-severe), older patients (>55 and males>females) with cardiovascular risk factors, and a disc at risk (smaller)
34
what is the optic nerve appearance in NAION?
hyperemic edema (acute state), flame hemorrhages, +/- macular star and disc pallor develops 2-3 weeks after initial insult
35
what is the typical VF defect in NAION?
altitudinal
36
is NAION unilateral or bilateral?
starts unilateral - can become bilateral sequentially
37
what causes NAION?
chronic HTN causes an alteration in autoregulatory response - vasodilation fails with decreased BP and ischemia to PCA results in decreased optic nerve perfusion
38
what is the treatment for NAION?
monitor 2-4 weeks, if VA or VF is still worsening then needs additional work-up
39
what is arteritic ischemic optic neuropathy (AION)?
inflammation of elastic tissue in arterial walls in vessel occlusion and causes ischemia (systemic inflammatory condition of the medium sized vessels all over the body)
affects the ophthalmic artery
40
what is the typical demographic for AION?
65+, females > males, bilateral within 1-2 days, 50% have polymyalgia rheumatica
41
why is AION an ophthalmic emergency?
the whole eye looses blood supply and will result in complete blindness
42
what are some symptoms of AION?
severe VA loss, scalp tenderness, jaw claudication, mild fever, weight loss, arthralgias/myalgias
43
what are the signs for AION?
pallid optic nerve swelling, no hemorrhages, extensive cotton wool spots, preceded by episodes of TIA
44
what is the treatment for AION?
needs STAT IV steroids for 3-5 days, temporal artery biopsy, Labs: ESR and CRP
45
what is giant cell arthritis (CGA)?
systemic vasculitis of medium/large arteries, self-limiting but may persist for years, oral steroids protect surviving optic nerve
46
what do you have to rule out in patients with NAION under age 40?
DM, HTN, hyperlipidemia, elevated homocysteine, vasculitides (SLE, Wegener's), coagulopathy and perform blood work
47
what causes posterior ischemic optic neuropathy?
most commonly = post-surgical (especially long procedures with severe blood loss)
or a spontaneous cause (GCA, athersclerosis, radiation)
48
what are the symptoms of posterior ischemic optic neuropathy?
patient recovers consciousness and discovers poor VA in one or both eyes
49
what are the signs of posterior ischemic optic neuropathy?
initially the optic disc is normal - then pallor develops 4-6 weeks after (if there is - APD then suspect bilateral posterior cerebral artery infarction)
50
what is diabetic papillopathy?
a milder form of NAION in diabetic patients - the vision is typically unaffected
51
what is a hallmark sign of diabetic papillopathy (more than in NAION)?
hyperemic disc swelling with dilated pre-laminar vessels (will also see diabetic retinopathy - dot/blot hemorrhages)
52
what is papilledema?
optic nerve edema caused by raised intracranial pressure - need to confirm with lumbar puncture
53
what is stage 1 of papilledema?
very early = incomplete C-shaped peripapillary halo, no elevation, blurring of superior/inferior and nasal aspects and normal temporal disc
54
what is stage 2 of papilledema?
early = blurring or all borders, complete peripapillary halo (360), elevation of nasal border
55
what is stage 3 of papilledema?
moderate = increased ONH diameter, partial obstruction of vessels at disc margin, peripapillary halo with finger-like projections
56
what is stage 4 of papilledema?
marked = elevation of entire nerve head, near total obstruction of major blood vessels at the disc
57
what is stage 5 of papilledema?
severe = dome-shaped protrusion, obliteration of cup, total obscuration of blood vessels on the disc
58
why is papilledema a medical emergency?
need to rule out any intracranial masses with neuroimaging
59
what are the clinical features of papilledema?
bilateral, VF enlarged blind spot or arcuate, initial edema is on ONH periphery, and absent SVP
60
what are some symptoms of papilledema?
headache, transient visual obstructions, pulsatile tinnitus, diplopia (CN6 palsy)
61
what is the order of the diagnostic work-up for papilledema?
MRI first to rule out structural lesion - then lumbar puncture
lab tests for inflammation/infection
62
what are the two most common mechanisms of increased ICP in papilledema?
increased brain volume (tumor, hemorrhage, trauma) and decreased CSF drainage (hydrocephalus, meningitis, venous sinus thrombosis)
63
what are the two least common mechanisms of increased ICP in papilledema?
increased CSF production and decreased skull volume
64
what are the medical causes for pseudotumor cerebri?
COPD, malignant HTN, sleep apnea, and renal failure
65
what are the medication causes for pseudotumor cerebri?
tetracyclines, excessive vitamin A, steroids, and birth control pills
66
how does a venous obstruction cause psuedotumor cerebri?
either with a central venous sinus thrombosis or jugular venous thrombosis
67
what are the signs and symptoms for idiopathic intracranial hypertension (pseudotumor cerebri - unknown cause)?
headache, nausea, vomiting, transient visual obstructions, and papilledema
all lab work and MRI results must be normal
68
what is the LP opening pressure in idiopathic intracranial hypertension (IIH)?
greater than 25 cmH20 with normal CSF composition
69
who typically gets IIH?
triple F = fat, fertile, females
70
what are the treatments for IIH?
weight loss = 6% reduction results in papilledema resolution
| Acetazolamide = first line of medical treatment
71
what are the causes of unilateral optic nerve edema - papillitis?
papillophlebitis, diabetic papillopathy, CRVO, NAION, AION, infiltrative and infectious
72
what is papillophlebitis?
very similar to CRVO - patients are typically young and healthy, etiology is unknown but suspected inflammation of the retinal vessels, resolves in 3-6 months
73
what can cause infiltrative optic neuropathy?
(one or both nerves) = leukemia, lymphoma, breast/lung/bowel metastases, and sarcoid
patients usually have a known malignancy
74
what are the 2 types of compressive optic neuropathies that are non-neoplastic?
thyroid eye disease (EOMs choke off optic nerve) and aneurysm (ICA)
75
what are the 3 neoplastic intracranial causes of compressive optic neuropathies?
sphenoid wing meningioma, pituitary adenoma, and metastases
76
what are the 2 neoplastic optic nerve causes of compressive optic neuropathies?
optic nerve sheath meningioma and optic nerve glioma
77
who typically gets a pituitary adenoma?
females > males, 40-50 years old
78
what are the hyperpituitarism symptoms caused by a pituitary adenoma?
cushing syndrome (excessive cortisone - moon face, obesity, hirsutism), acromegaly, and prolactinoma (amenorrhea, infertility, gynecomastia)
79
what is the typical VF defect in a patient with a pituitary adenoma?
bitemporal hemianopsia
80
who typically gets an optic nerve sheath meningioma?
females > males, usually in 4th decade
| metastasis is rare
81
who typically gets an optic nerve glioma?
children (75% before age 20) and 50% have NF1
| benign course in children (low mortality) and causes significant VA loss
82
what type of traumatic optic neuropathy can occur at the optic disc/laminar zone?
optic nerve avulsion - forceful backward dislocation of optic nerve from the scleral canal
83
what type of traumatic optic neuropathy can occur at the intraorbital zone?
penetrating FB, displaced fracture or bone fragment, compression by hematoma
usually see CRAO and disc edema
84
what type of traumatic optic neuropathy can occur at the intracanalicular zone?
*most common location
usually due to frontal/maxillary blunt trauma (occurs with or without fracture)
can be direct (damage from bone fragments) or indirect (tearing of pial vessels and shearing of axons)
85
what will the optic nerve look like in an intracanalicular zone trauma?
appears normal initially - pallor develops 4-6 weeks later
86
what imaging do you order and what is the treatment for traumatic optic neuropathies?
CT of orbits
| mega dose corticosteroids or optic nerve decompression (if poor VA)
87
what are the 3 great masqueraders?
syphilis, lyme, and sarcoid
88
what is the most common cause of infectious optic neuropathy?
bacteria is most common cause
syphilis, lyme, TB and bartonella are most common
(can also be treponema pallidum)
89
how does bartonella heneselae (cat scratch disease) usually present?
fever, malaise, adenopathy
VA symptoms start 2-3 weeks after systemic symptoms resolve
mild disc edema + macular edema
90
what are some viral causes of infectious optic neuropathy?
HZV (more common), measles, mumps, chickenpox
91
what are some fungi causes of infectious optic neuropathy?
typically in immunocompromised patients
| mucormycosis or cryptococcal meningitis
92
what are some parasite causes of infectious optic neuropathy?
toxoplasma and toxocara
93
what are the two conditions that present with macular edema (aka stellate neuroretinitis)?
infectious optic neuropathy and malignant hypertension
94
what are some signs and symptoms of developmental anomalies of the optic nerve?
reduced VA, VF loss, color vision deficiency, less likely to have RAPD because it will probably affect both nerves
all anomalies are stable or non-progressive
95
what are some associated findings with developmental anomalies of the ONH?
CNS abnormalities, endocrine dysfunction, developmental delays, strabismus, amblyopia, ocular colobomas, hyperelorism, microphthalmos and aniridia
96
what is optic nerve hypoplasia?
a subnormal number of axons in the optic nerve
| characterized by a small optic nerve with a double ring sign
97
what causes optic nerve hypoplasia?
insult to visual pathways before completion of development = toxic, infectious, ischemia, hereditary, fetal alcohol syndrome, De-Morsier syndrome
98
what can optic nerve hypoplasia be associated with?
developmental abnormalities of anterior midline brain structures (mental retardation and endocrine deficits)
99
what is De-Morsier syndrome (aka septo-optic dysplasia)?
disorder of early brain development (3 parts)
optic nerve hypoplasia
abnormal formation of midline brain structures (corpus collosum and septum pellucidum)
pituitary hypoplasia
**typically cause by sporadic mutation
100
what causes an optic nerve coloboma?
incomplete closure of the fetal fissure during prenatal development (defect is always inferior - may include retina, choroid, iris or lens)
commonly bilateral
101
what is the VF defect seen with optic nerve colobomas?
arcuate defect
102
what is an optic nerve pit?
small, partial coloboma
usually inferior-temporal aspect of ONH
they have a larger optic disc
may lead to macular edema in 4th decade
103
what is megalopapilla?
enlarged optic disc and large physiologic cup - same number of axons but they are spread out
104
what is morning glory syndrome?
a dysplastic disc (disorganized axons)
| excavated funnel shape, surrounded by elevated ring of chorioretinal pigmentation
105
who typically gets morning glory syndrome?
females > males
unilateral and OD is more common
no hereditary pattern
106
what is morning glory syndrome associated with?
basal encephalocele - deficit in skull floor, allowing brain tissue to protrude outside the cranial cavity, CSF leaks
107
what are the 3 cardinal signs of morning glory syndrome?
1. cup is enlarged with deep depression and white tissue at base
2. raised annulus surrounds disc with variable amount of pigmentation
3. retinal blood vessels emerge from disc in radial fashion (like spokes on a wheel)
108
what is tilted disc syndrome?
```
due to oblique insertion of the optic nerve into the globe - nerve typically looks oval shaped
a scleral crescent is usually present
situs inversus (blood vessels go nasal before going temporal)
```
109
what does the VF look like in tilted disc syndrome?
bitemporal appearance
110
what is pseudopapilledema?
small scleral opening - axons must squeeze through, slight elevation of nerve, anomalous blood vessels and indistinct margins (but no obstruction of vessels)
111
what is optic nerve head drusen?
hyaline bodies anterior to the lamina cribrosa -can cause pseudopapilledema
lumpy/scalloped appearance
112
what causes optic nerve head drusen?
AD inheritance
| 70% bilateral
113
what are the VF defects seen in optic nerve head drusen?
arcuate - can be progressive
114
what are myelinated nerve fibers?
extended proliferation of normal tissue - benign
feathery appearance obscures underlying tissue
1% of population
115
what type of vision loss is seen with nutritional or toxic optic neuropathy?
painless, slowly progressive, bilateral, symmetric and ranges from 20/50-20/200 (never worse than 20/200)
116
what are the exam findings for nutritional or toxic optic neuropathy?
temporal ONH pallor, centro-cecal VF, no RAPD (bilateral) and dyschromatopsia
117
why are the B vitamins essential?
they are required for normal RBC formation, repair of tissues and cells and synthesis of DNA
118
what does vitamin B1 (thiamine) do? what causes a deficiency?
converts carbohydrates into glucose
| deficiency = chronic alcoholics, poor diet, liver disease
119
what does vitamin B6 do?
helps with serotonin, NE, myelin formation
120
what does vitamin B9 (folate) do?
critical for cell growth and metabolism, works with B6 and B12 to control homocysteine levels
121
what does vitamin B12 do? what causes a deficiency?
critical for RBC formation and nerve function
| deficiency = pernicious anemia
122
what medications can cause toxic optic neuropathy?
anti-TB medications (ethambutol and isoniazid) and some cancer chemotherapies
123
what substances can cause toxic optic neuropathy?
lead, methanol, tobacco, alcohol (not directly)
124
what is Leber's hereditary optic neuropathy?
caused by a mutation in the mitochondrial genome (maternally inherited) - there is a decrease in ATP production in the optic nerve and results in degeneration of retinal ganglion cells
125
when does Leber's hereditary optic neuropathy occur?
mutation is present at birth - manifests in early adulthood (25-35)
males > females
126
what type of VA loss is seen with Leber's hereditary optic neuropathy?
acute VA loss in one eye (severe) - fellow eye is involved 2-4 weeks after
may be triggered by alcohol/tobacco or nutritional deficiencies
127
what is the VF defect seen with Leber's hereditary optic neuropathy?
central or central-cecal scotoma
128
what does the optic nerve look like with Leber's hereditary optic neuropathy?
initially hyperemic and pallor develops a few weeks later
| dilation of peripapillary retinal vessels (makes nerve appear swollen - but does not leak on FA)
129
what is the management for Leber's hereditary optic neuropathy?
genetic counseling, electrocardiogram, limit tobacco and alcohol
No FDA approved treatment - may try oral idebenone (stimulates ATP in brain)
130
what is autosomal dominant optic atrophy (aka Kjer's DOA)?
most common inherited optic neuropathy
bilateral, symmetric, slowly progressive central VF loss (central-cecal)
VA loss begins in childhood (4-10) then stable at 20/200
females = males
131
which neuropathies have acute onset? which have sub-acute?
```
acute = optic neuritis, ischemic optic neuropathy, CRVO, trauma
sub-acute = compressive, nutritional/toxic
```
132
which neuropathies are unilateral? bilateral?
```
unilateral = typical optic neuritis, NAION, compressive, trauma
bilateral = toxic/nutritional, hereditary, atypical optic neuritis, AION
```
133
which neuropathies have altitudinal VF defects?
NAION
134
which neuropathies have bitemporal VF defects?
parasellar lesions
135
which neuropathies have hemianopic VF defects?
ischemic or compressive
136
which neuropathies have central-cecal VF defects?
toxic, nutritional, DOA
137
which neuropathies have temporal pallor?
DOA, toxic, nutritional
138
which neuropathies have bow-tie pallor?
optic tract lesions
