Optic Neuritis

Optic Neuritis
SYMPTOMS Ocular symptoms: Rapid vision loss (can vary from 20/20 to NLP), Orbital pain especially with eye movement (precedes vision loss 90% of the time and typically lasts 3-5 days), Loss of color vision (typically worse in severity than vision loss), Decrease in contrast sensitivity
Systemic symptoms: May experience neurological symptoms such as Weakness and numbness in extremities and Uhthoff sign
SIGNS Typically unilateral
Optic nerves will often appear normal (occurs in about 2/3 of cases)
Can also present with Optic nerve edema, Optic nerve hyperemia, Loss of the cup, Blurring of the optic disc margins, Thickened and edematous retinal nerve fiber layer, Obscurations of the small vasculature at or around the optic nerve, Opacification of the retinal nerve fiber layer, Loss of sharp light reflexes around the optic disc, Splinter retinal hemorrhages, Cotton wool spots
Ultimately there will be optic nerve pallor following resolution of optic neuritis or if optic neuritis is chronic
WORK-UP Cranial nerve testing, Pupils (decrease in direct light response and an APD in the eye with optic neuritis), EOMs, Color vision (typically abnormal), Visual field (variable field loss that can be central, nasal, altitudinal, or a general constriction), Red cap test (reduced color brightness on side of optic neuritis), Blood pressure evaluation (in order to rule out malignant hypertension), Slit lamp examination, Dilated retinal exam, Fundus photos, OCT, Visual evoked potential (decrease in amplitude and increase in latency on side of the optic neuritis)
OCT (Optic nerve analysis with EDI and RNFL analysis): *Elevation of the neuroretinal rim thickness *Smooth optic nerve contour *Elevation of the optic disc with involvement of the retinal nerve fiber layer with a smooth, hill-like appearance *Anterior displacement of the Bruch's/RPE complex especially near the Bruch's membrane opening *Presence of peripapillary hyper-reflective ovoid-mass like structures (PHOMS) which represent bulging optic nerve axons *Presence of subretinal fluid (presence of “lazy V sign” especially at the Bruch’s membrane opening) *Thickening of the of the RNFL with typically the nasal side being > 86 microns, temporal side being > 97 microns, superior side being > 149 microns, and inferior side being > 165 microns (Nasal RNFL thickening has the greatest specificity and sensitivity) *Subretinal hyporeflective space between the optic disc and Bruch's membrane opening (SHYPS) is >464 microns (Findings seen on the OCT will be more mild than what is typically seen in papilledema)
TREATMENT Refer to a neuro-ophthalmologist/ER STAT for additional testing and treatment
Treatment involves high dose intravenous steroids as well as treating the underlying cause of the optic neuritis
FOLLOW-UP After resolution of optic neuritis, patient should be followed-up every 4-6 months
ADDITIONAL LAB | TESTS Testing will typically be ordered through the neuro-ophthalmologist/ER: MRI of the brain and orbits with and without contrast
If optic neuritis has an atypical presentation, the following will need to be ordered: MRI of the brain and orbits with and without contrast, Lumbar puncture, Chest X-ray, ACE, NMO IgG, Anti-Mog, FTA-ABS and RPR, ANA, CBC with differential, ELISA, ESR with C-reactive protein
ETIOLOGY Typically idiopathic optic nerve inflammation
Inflammatory optic neuropathy that can be caused by demyelinating disease such as multiple sclerosis or Devic’s disease
Atypical presentations can be secondary to autoimmune disease such as sarcoids or infections such as lyme disease
DIFFERENTIAL DX Ischemic optic neuropathy, Papilledema, Infiltrative optic neuropathy, Diabetic papillopathy, Hypertensive optic neuropathy
NOTES Often, optic neuritis is the initial presenting sign of multiple sclerosis
The profile of a typical patient with optic neuritis is a young female
Visual recovery typically occurs about 90% of the time and within 1 month
OCT will go from showing swelling of the RNFL to thinning of the RNFL as optic atrophy develops
Signs of an atypical optic neuritis include the following: Patient is male, Bilateral loss of vision, Orbital pain that typically persists for more than 2 weeks, Presence of a mild iritis and/or vitritis, Bilateral optic nerve edema, Extensive peripapillary splinter retinal hemorrhages, Star-shaped macular exudates, No visual recovery within 1 month
Optic Neuritis: MRI of the brain (axial cut) showing periventricular white matter lesions associated with multiple sclerosis https://webeye.ophth.uiowa.edu/eyeforum/cases/159-optic-neuritis.htm
Posted in Ocular Conditions, Optic Nerve