optic neuropathy 1

Question 1

how many retinal ganglion cell axons make up the optic nerve?

Answer 1

1-1.5 million

Question 2

what are the 4 anatomical segments and sizes of the optic nerve?

Answer 2

 4 anatomical segments
 Intraocular: 1 mm
 Intraorbital: 25 mm
 Intracanalicular: 10 mm
 Intracranial: 16 mm

Question 3

vascular insult

Answer 3

intraocular

Question 4

muscle engorgement/tumors

Answer 4

intraorbital

Question 5

fractures and sinus inflammation

Answer 5

intracanalicular

Question 6

pituitary gland and circle of willis

Answer 6

intracranial

Question 7

where are the cell bodies of retinal ganglion cells?

Answer 7

ganglion cell layer

Question 8

is the optic nerve covered by meninges?

Answer 8

yes

Question 9

what supplies the optic nerve prelaminar?

Answer 9

SPCA (peripapillary choroidal vessels); branch of opthalmic artery; branch of internal carotid

Question 10

blood supply of lamina cribrosa

Answer 10

SPCA, circle of zin haller

Question 11

blood supply of retrolaminar

Answer 11

branches from CRA, branches from pial vessels

Question 12

blood supply of choroid

Answer 12

SPCA

Question 13

what determines papillaedema?

Answer 13

bilateral optic nerve head swelling due to raised intracranial pressure

Question 14

how can we tell difference b/w NV and shunts?

Answer 14

angiofluorescence; shuts do not leak and NV does

Question 15

3 conditions that can cause collaterals/shunts

Answer 15

 Optic nerve sheath meningioma
 CRVO
 Chronic glaucoma

Question 16

 VA loss
 RAPD
 Dyschromatopsia
 VF defect
 Reduced contrast sensitivity
 +/- normal optic disc appearance 
 Abnormal VEP

Answer 16

optic nerve dysfunction

Question 17

2 types of optic neuritis

Answer 17

 Typical: demyelinating optic neuritis

 Atypical: systemic infectious/inflammatory causes

Question 18

5 hallmarks of typical optic neuritis

Answer 18

 Primary demyelination of the optic nerve
 - Autoimmune: antibodies attack myelin sheath
 Sudden VA loss
 -Progresses over 1 week
 -Improvement begins by 1 month
 Pain on EOMs: 90% of patients
 +/- RAPD
 Dyschromatopsia: usually worse than VA

Question 19

 Retrobulbar: 2/3
 Age: 18-46; average 32 years
 77% female
 Laboratory testing unnecessary

Answer 19

typical optic neuritis characteristics

Question 20

 Diffuse: 48%
 Altitudinal/arcuate/nasal step: 20%  Central/centrocecal: 8%
 Other:16%
Bottom line: predilection for central 30o, but any pattern is possible

Answer 20

optic neuritis VF abnormalities

Question 21

 Numbness in hands
 Problems with bladder control
 Pulfrich phenomenon: altered perception of moving objects
 Stereo-illusion of swinging pendulum
 Perceived depth due to relative difference in signal timings
between the two eyes
 Uthoff sign
 Worsening of neurologic symptoms with increased body temperature

Answer 21

optic neuritis associated symptoms

Question 22

 Better understanding of relationship between ON and MS
 Sponsored by NEI
 Clinical trial of corticosteroid therapy for ON
 Conducted between 1988-1991

Answer 22

optic neuritis treatment trial (ONTT)

Question 23

 Patients presented with typical unilateral acute optic neuritis
 3 treatment arms
 IV methylpredinisolone 250mg QID x 3 days, followed by
oral prednisone 1mg/kg/day x 11 days
 Oral prednisone 1mg/kg/day x 14 days
 Oral placebo x 14 days

Answer 23

ONTT

Question 24

ONTT RESULTS

Answer 24

 High dose IV steroids accelerated visual recovery
 Oral steroid treatment alone increased rate of recurrence of ON
 IV steroids reduced risk for development of MS after initial attack of ON for 2 years – no benefit after 2 years
 Typical ON: no underlying systemic or infectious etiology, therefore no need for bloodwork
 Brain MRI extremely useful in identifying patients who are at higher risk for developing MS

Question 25

 ONTT 15 year follow-up  294 subjects from original 457 cohort (65%) -most had good VA  No significant difference in visual function among 3 treatment arms  QOL measurements lower in patients with worse vision and associated neurologic deficits from MS

Answer 25

longitudinal optic neuritis study (LONS)

Question 26

 15 year overall risk: 50%  75% in women  Initial MRI most predictive risk factor  0 lesions: 25%  1 lesion: 60%  3+ lesions: 78%

Answer 26

LONS: risk for developing MS after ON

Question 27

 White race  Family history of MS  Ill-defined neurologic complaints  Pervious episode of acute optic neuritis

Answer 27

LONS: other risk factors for MS

Question 28

whats typical of optic neuritis?

Answer 28

2/3 are retrobulbar

Question 29

```  Severe disc swelling  No pain  Disc or peripapillary hemorrhage  Retinal exudates  NLP vision  Male sex ```

Answer 29

LONS: low risk for MS

Question 30

 In typical ON, make clinical diagnosis  Obtain MRI of brain and orbits with gadolinium  Treatment: high dose IV steroid x 3 days; oral prednisone taper x 11 days  Refer high-risk patients to neurologist  Abnormal brain MRI

Answer 30

LONS recommendations

Question 31

 Randomized, double-blind, placebo controlled, multicenter study  383 subjects enrolled from 1996-1998  Study group received weekly Avonex injections  Inclusion criteria  18-50 year old  First occurrence of isolated, well-defined demyelinating event  Abnormal unenhanced brain MRI

Answer 31

controlled high risk subjects avonex MS prevention study (champs)

Question 32

 Primary: development of CDMS -Avonexreducedriskby44% -35%chanceofdevelopingMSwhileondrug -50%chanceofdevelopingMSonplacebo  Secondary: effect of treatment on MRI findings (subclinical MS) - FevernewandenlargingT2lesions  67%fewerenhancinglesions

Answer 32

champs endpoints

Question 33

 Brain MRI (T1, T2, Gadolinium)  Assess for subclinical disease  Identify high-risk patients  Interferon therapy in high-risk patients

Answer 33

champs recommendations

Question 34

 Treatment available that alters development and/or course of CDMS after first demyelinating event  MRI not necessary to diagnose optic neuritis, but required to determine who is at greatest risk for MS  OD’s must be able to promptly diagnose optic neuritis  Order MRI  Refer to neurology for treatment initiation

Answer 34

indication of champs

Question 35

```  Avonex (interferon beta-1a)  Rebif (interferon beta-1a)  Betaseron (interferon beta-1b)  Copaxone (glatiramer acetate)  Tysabri (natalizumab)  Novantrone (miloxantrone)  Gilenya: first oral medication ```

Answer 35

types of MS TREATMENT

Question 36

WHAT eye finding can MS lead to?

Answer 36

macular edema

Question 37

 Proteins in blood serum  AKA immunoglobulins  When present in CSF, indicate inflammation of the CNS  79-90% of patients with MS have permanently observable oligoclonal bands

Answer 37

oligoclonal bands

Question 38

what does optic neuritis atypical require?

Answer 38

labwork

Question 39

```  Age: 50 years  Bilateral  Lack of pain  Anterior/posterior uveitis  Retinal exudates/infiltrates  Severe optic nerve swelling  Hemorrhages  VA continues to worsen past 1 week  Recurrence within short interval or during steroid taper ```

Answer 39

optic neuritis atypical

Question 40

```  Bloodwork  CBC with differential  ESR  CRP  ACE  FTA-Abs  ANA  Chest X-Ray  MRI  Lumbar Puncture ```

Answer 40

optic neuritis atypical

Question 41

 Connective tissue disease  Lupus  Sjogren’s  Bechet’s  Infectious  Viral  Bacterial: Lyme, syphilis  Infiltrative  Sarcoidosis  Cancer: lymphoma, leukemia

Answer 41

other causes of optic neuritis (secondary)

Question 42

 NMO antibodies (NMO IgG) target aquaporin 4  Channel for water transport across astrocyte cell membrane  NMO IgG found in astrocytes around blood brain barrier  Inflammatory demyelination results in necrotic damage of white and grey matter

Answer 42

neuromyelitis optica pathophys

Question 43

```  AKA Devic’s Syndrome  Unilateral or bilateral optic neuritis  Myelitis: inflammation of the spinal cord  At least 2 of the following  Contiguous spinal cord lesion > 3 vertebral segments on MRI  Brain MRI non-diagnostic for MS  Positive NMO IgG serology ```

Answer 43

neuromyelitis optica

Question 44

 Can affect children, but median age of onset is 39  Relapsing (80-90%) or monophasic  Treatment: immunosuppressive therapy  IV steroids  Azathioprine  Rituximab

Answer 44

neuromyelitis optica

Question 45

 Focal inflammatory disorder of spinal cord  80% present with numbness and paresthesias  1/3 complete recovery, 1/3 moderate disability, 1/3 severe disability  May progress to MS

Answer 45

transverse myelitis

Question 46

 Postinfectious encephalomyelitis  Fever, nausea, vomiting, positional vertigo  Typically children s/p viral infection or immunization  MRI: extensive lesions (basal ganglia, thalamus)  Tx: high dose IV steroids for 3-5 days, oral taper for 4-6 weeks

Answer 46

acute disseminated encephalomyelitis (ADEM)

Question 47

what makes the nerve head pink?

Answer 47

prelaminar vascular supply