Questions:
36. In idiopathic demyelinating optic neuritis what percentage of cases have pain with eye movements?
37. In idiopathic demyelinating optic neuritis what percentage of cases is a spontaneous improvement is seen within several weeks?
38. In idiopathic demyelinating optic neuritis, what percentage of cases does visual acuity improves spontaneously to at least 20/40 at 6 months?
39. In idiopathic demyelinating optic neuritis, what is the overall risk of multiple sclerosis at 15 years?
40. In idiopathic demyelinating optic neuritis, what is the 15-year risk of multiple sclerosis if the brain MRI is normal?
41. In idiopathic demyelinating optic neuritis, what is the 15-year risk of multiple sclerosis if the brain MRI shows one T2-weighted ovoid > 3 mm in diameter, highly suggestive of multiple sclerosis?
42. In idiopathic demyelinating optic neuritis, what is the 15-year risk of multiple sclerosis if the brain MRI shows at least six T2-weighted white matter lesions suggestive of multiple sclerosis?
43. In a patient with optic neuritis and an abnormal MRI what percentage will not develop multiple sclerosis at 15 years of follow-up?
44. In idiopathic demyelinating optic neuritis, what can a lumbar puncture detect if the cause is multiple sclerosis?
45. In idiopathic demyelinating optic neuritis are oligoclonal bands in the CSF useful if the patient’s MRI has demonstrated findings consistent with multiple sclerosis?
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Questions with answers:36. In idiopathic demyelinating optic neuritis, what percentage of cases have pain with eye movements?
In > 90% of cases.
37. In idiopathic demyelinating optic neuritis, what percentage of cases is a spontaneous improvement is seen within several weeks?
In > 90% of cases. The absence of improvement should raise concern for another diagnosis.
38. In idiopathic demyelinating optic neuritis, what percentage of cases does visual acuity improves spontaneously to at least 20/40 at 6 months?
In > 90% of cases. The diagnosis should be reconsidered when the visual acuity does not improve to this level.
39. In idiopathic demyelinating optic neuritis, what is the overall risk of multiple sclerosis at 15 years?
50%.
40. In idiopathic demyelinating optic neuritis, what is the 15-year risk of multiple sclerosis if the brain MRI is normal?
23%
41. In idiopathic demyelinating optic neuritis, what is the 15-year risk of multiple sclerosis if the brain MRI shows one T2-weighted ovoid > 3 mm in diameter, highly suggestive of multiple sclerosis?
56%.
42. In idiopathic demyelinating optic neuritis, what is the 15-year risk of multiple sclerosis if the brain MRI shows at least six T2-weighted white matter lesions suggestive of multiple sclerosis?
74%
43. In a patient with optic neuritis and an abnormal MRI, what percentage will not develop multiple sclerosis at 15 years of follow-up?
At least 26% of patients with optic neuritis and abnormal brain MRI at baseline will not have developed multiple sclerosis after 15 years of follow-up.
44. In idiopathic demyelinating optic neuritis, what can a lumbar puncture detect if the cause is multiple sclerosis?
Oligoclonal bands in the CSF
45. In idiopathic demyelinating optic neuritis are oligoclonal bands in the CSF useful if the patient’s MRI has demonstrated findings consistent with multiple sclerosis
The information below is from Neuro-ophthalmology Illustrated-2nd Edition. Biousse V and Newman NJ. 2012. Thieme
8.4.5 Idiopathic Demyelinating Optic Neuritis
Idiopathic demyelinating optic neuritis is the most common acute optic neuropathy in persons under the age of 45. It is also the most common cause of optic neuritis and often the presenting sign of multiple sclerosis.
Characteristics
Idiopathic demyelinating optic neuritis is more prevalent in young women than men (3:1). It is unilateral (occasionally bilateral) and is characterized by acute to subacute onset (usually rapidly progressive over a few days), decreased visual acuity (variable) and color vision (usually pronounced), pain with eye movements (in >90% of cases), and exacerbation with heat or exercise (Uhthoff Phenomenon).
Pearls
There is a strong association between optic neuritis and multiple sclerosis. Most patients with multiple sclerosis eventually have visual loss from optic neuritis. Many patients with acute isolated optic neuritis eventually develop multiple sclerosis.
Patient Evaluation
The examination should include the following:
● RAPD (if unilateral or asymmetric)
● Funduscopy:
○ Normal (two-thirds of cases) or swollen (one-third of cases) optic nerve head
○ Normal macula and retina (no exudates, no hemorrhages)
○ Optic disc pallor (only if at least 4–6 weeks after onset or if there has been a previous episode of optic neuritis)
● Visual field test:
○ Often central scotoma (diffuse depression on Humphrey visual field test)
In >90% of cases, spontaneous improvement is seen within several weeks; the absence of improvement should raise concern for another diagnosis. Risk of multiple sclerosis (▶Fig. 8.9) should also be assessed.
Pearls
In >90% of patients with typical acute idiopathic demyelinating optic neuritis, visual acuity improves spontaneously to at least 20/40 at 6 months. The diagnosis should be reconsidered when the visual acuity does not improve.
Association between Idiopathic Demyelinating Optic Neuritis and Multiple Sclerosis
Patients diagnosed with idiopathic demyelinating optic neuritis are at high risk of subsequent development of multiple sclerosis after an isolated attack of idiopathic optic neuritis (as high as 74% at 15 years). Initial MRI helps to stratify the risk of multiple sclerosis (as per the Optic Neuritis Treatment Trial):
● The overall risk of multiple sclerosis at 15 years is 50%.
● If the brain MRI is normal, the 15-year risk of multiple sclerosis is 23%.
● If the brain MRI shows one T2-weighted ovoid>3mm in diameter, highly suggestive of multiple sclerosis, the 15-year risk of multiple sclerosis is 56%.
● If the brain MRI shows at least six T2-weighted white matter lesions suggestive of multiple sclerosis, the 15-year risk of multiple sclerosis is 74%.
A lumbar puncture may detect oligoclonal bands in the CSF of patients with idiopathic demyelinating optic neuritis. However, it provides additional information only when the brain MRI is normal (an abnormal brain MRI is the strongest predictor of multiple sclerosis in a patient with optic neuritis).
To determine the prognosis for multiple sclerosis in patients with typical acute isolated optic neuritis, the only test definitely indicated is an MRI scan of the brain with contrast. Other tests are sometimes obtained (vary with patient characteristics and centers), for example, MRI of the orbits with contrast and fat suppression, lumbar puncture for CSF oligoclonal bands, blood tests (syphilis testing and ACE level for sarcoidosis), NMO antibodies, and chest radiograph.
The spontaneous visual prognosis is good without treatment.
Treatment of idiopathic acute optic neuritis should consider the following:
● Intravenous methylprednisolone (250 mg, every 6 hours for 3 days) followed by oral prednisone (1 mg/kg/d for 11 days, then tapered over 3 days):
○ Hastens the rate of visual recovery by about 2 weeks but does not change the final extent of visual recovery
○ May help alleviate the pain○ Delays neurologic symptoms and signs from multiple sclerosis for 2 years but does not change the risk of multiple sclerosis after 2 years
● Oral prednisone (1 mg/kg/d) should not be prescribed
○ No beneficial effect on recovery of vision or risk of multiple sclerosis
○ Doubles the risk of recurrent optic neuritis (in the Optic Neuritis Treatment Trial)
● Disease-modifying agents decrease the risk of subsequent neurologic symptoms and signs related to multiple sclerosis and should be considered in selected high-risk patients (those with typical idiopathic optic neuritis and white matter lesions highly suggestive of demyelinating disease on brain MRI).
Pearls
1. Treatment with intravenous methylprednisolone hastens visual recovery, but it does not change the long-term prognosis of patients with acute isolated optic neuritis.
2. In the Optic Neuritis Treatment Trial, treatment with oral prednisone 1 mg/kg/d alone doubled the risk of recurrent optic neuritis and should not be prescribed to patients with acute isolated optic neuritis.
Reference: 1. Neuro-ophthalmology Illustrated-2nd Edition. Biousse V and Newman NJ. 2012. Thieme
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