Pediatric optic neuritis: brain MRI abnormalities and risk of multiple sclerosis.

BACKGROUND: Optic neuritis is often the initial presentation of multiple sclerosis (MS). As established by the Optic Neuritis Treatment Trial, an abnormal baseline brain MRI is a strong predictor of MS after isolated optic neuritis in adults. However, the rate of conversion to MS after optic neuritis in children based upon brain MRI findings is unknown.

METHODS: We reviewed the medical records of children (<18 years) presenting with optic neuritis between 1993 and 2004 at the Children's Hospital of Philadelphia. Children with a history of demyelinating disease or prior optic neuritis were excluded. Symptoms, ophthalmologic findings, MRI findings, and clinical outcomes were recorded.

RESULTS: We identified 29 consecutive children with idiopathic optic neuritis. Eleven patients (38%) had white matter T2/FLAIR lesions in the brain (not including the optic nerves). Eighteen patients were followed for more than 24 months, and 3 of the 18 (17%) developed MS. All 3 patients had an abnormal brain MRI scan at their initial presentation of optic neuritis. None of the patients with a normal brain MRI scan at presentation developed MS over an average follow-up of 88.5 months. Patients with one or more white matter lesions on MRI were more likely to develop MS (3/7 vs 0/11, p = 0.04, Fisher exact test).

CONCLUSIONS: Children with brain MRI abnormalities at the time of the diagnosis of optic neuritis have an increased risk of multiple sclerosis. Larger collaborative studies are needed to further define the prognosis for childhood optic neuritis.