Bilateral acute optic neuritis: prospective clinical, MRI, CSF, neurophysiological and HLA findings

Abstract

This paper presents the clinical picture and the results of a battery of tests performed in a prospective study of 30 patients (aged 15-53 years; 14 females) consecutively referred during a six-and-a-half-year period and suffering from bilateral acute optic neuritis (BAON) according to clinical criteria. Both eyes were affected within a time span of six weeks. Ten patients showed papillitis in one or both eyes. Causes of BAON other than clinically definite multiple sclerosis (CDMS), present in 12 patients, were carefully ruled out and all relevant blood tests were normal, having excluded two patients with Leber's optic neuropathy. Tissue typing showed HLA-DR15 in 12 patients. The proportion of abnormal results at onset was 14/27=52% (cerebral MRI), 23/30=77% (VEP), 11/27=41% (SEP), 10/24= 42% (biotesiometry), 8/20=40% (CSF oligoclonal bands), 10/26=38% (IgG-index), and 9/25=36% (CSF leukocyte count). One year from onset, 24 patients were reexamined; another two patients were followed clinically and with VEP only. Abnormal results were observed by MRI in 13/21=62%, by VEP in 21/26=81%, by SEP in 6/23=26%, and by biotesiometry in 9/24=38%. Five patients had developed CDMS. The visual acuity improved in one or both eyes in 19, remained unchanged in four, and deteriorated in three patients. The frequency of abnormal VEP, IgG-index, and oligoclonal bands was significantly lower in idiopathic cases than in patients with CDMS. Abnormal results tended to be less frequent when symptoms occurred simultaneously (n=15), suggesting simultaneous BAON to be more rarely a part of MS. Bilateral idiopathic cases seemed to show abnormal CSF, MRI, and VEP findings less frequently than unilateral cases.

Key Words:

• Optic neuritis
• multiple sclerosis
• magnetic resonance imaging
• evoked potentials
• immunoglobulin G