Effects of intravenous methylprednisolone on outcome in MRI-based prognostic subgroups in acute optic neuritis

Abstract

Treatment of acute optic neuritis with steroids has been shown to hasten visual recovery without affecting the final degree of recovery. However, MRI-clinical studies indicate that patients with long optic nerve lesions, particularly those that involve the nerve within the optic canal, may have a worse prognosis for recovery of vision. Partly because such lesions could lead to swelling and subsequent ischemic optic nerve damage, steroids could have a selective beneficial effect on this subgroup of patients. The present randomized trial was designed to test this possibility. Sixty-six patients with acute optic neuritis received IV saline or IV methylprednisolone. The clinical, psychophysical, electrophysiologic, and MRI outcomes were assessed after 6 months. Patients with short lesions presented earlier than those with long lesions (involving three or more 5-mm-thick slices of any part of the optic nerve, as well as its intracanalicular portion), and lesion length was significantly less in patients presenting within a week of onset of symptoms. Lesions also tended to lengthen during follow-up in individual patients. Treatment did not limit lesion length in either the long or short lesion subgroup and had no significant effect on final visual outcome. We conclude that steroids do not improve visual outcome or lesion length in patients with acute optic neuritis.

Visual Acuity in Acute Optic Neuritis Studied with Contrast Enhanced MRI

“…11 The mean length of the optic nerve that enhanced was 13.5 mm, which is nearby the 10mm reported by 10 and 17.5mm reported by Dunker Weigand (1996) 4 using STIR. STIR signal more or equal to 17mm usually occurred in patients with a longer duration between the onset of visual loss and performing the MRI (Kapoor et al, 1998). 5 But in our case patients with gadolinium enhancement more than 17mm had duration of visual loss prior to the MRI which was similar to the patients with shorter affected segments.…”

“…Fat supressed gadolinum enhanced MRI appears to be more useful for detecting acute optic neuritis than STIR because STIR can also be abnormal in previously affected optic nerves 10 . Also, STIR has a lower sensitivity since only 77 (Dunker and Wiegand, 1996) 4 to 81 10 to 89% (Kapoor et al,1998) 5 of optic nerves affected within 30 days have demonstrable lesions. The MRI method used in our study will be beneficial in separating patients with optic neuritis and disc swelling from non-arteritic AION with some pain in the affected eye (Swartz et al, 1995).…”

“…Other authors have suggested that the length and location of abnormal enhancement of optic nerve affected by optic neuritis on MRI are associated with the degree of visual loss and might predict visual outcome. 3,4,5 In most cases if clinical criteria are strictly applied (Optic Neuritis Study Group, 1991) MRI is not required to diagnose optic neuritis however patients with non-arteritic AION or acute compressive neuropathy (tumor/aneurysm) or posterior scleritis may be difficult to distinguish from optic neuritis. In such cases MRI will prevent misdiagnosis.…”

Time to steroid treatment in severe acute optic neuritis

“…The possible mechanism for the steroid treatment effect may involve a suppression of the inflammation associated with acute ON, which in turn may limit the neuronal damage and accelerate visual function recovery (Beck et al., 1992; Kapoor et al., 1998; Sellebjerg, Nielsen, Frederiksen, & Olesen, 1999). This is supported by the current study's observation that nontreated patients experienced an early reduction in the pRNFL thickness and a delayed improvement of visual acuity and color mixing.…”

Quantitative Evaluation of Signal Intensity of Magnetic Resonance Images in Optic Neuritis

“…There have been improvements in the MRI techniques to detect optic nerve lesions in patients with acute optic neuritis since Johnson et al [1] introduced the excellent results with the MR STIR method. Evaluations were based on signal abnormalities, such as the signal intensity [3], the enlargement of the nerve width [11], the length and the position of the lesion [3,6,[12][13][14]. The precise measurement of the size and length of optic nerve lesions is considered unreliable because of the oblique placement of the optic nerve in the coronal plane.…”