Paediatric neuromyelitis optica: Clinical, MRI of the brain and prognostic features
Absoud M., Lim MJ., Appleton R., Jacob A., Kitley J., Leite MI., Pike MG., Vincent A., Wassmer E., Waters P., Woodhall M., Hemingway C., Palace J.
© 2015, BMJ Publishing Group. All rights reserved. Background: Neuromyelitis Optica (NMO) is a severe and rare inflammatory condition, where relapses are predictive of disability. Methods We describe a national paediatric NMO cohort's clinical, MRI, outcome, and prognostic features in relation to Aquaporin-4 antibody (AQP4-Ab) status, and compared to a non NMO control cohort. Observations: Twenty NMO cases (females=90%; AQP4-Ab positive=60%; median age=10.5yrs) with median follow-up=6.1yrs were compared to a national cohort sample of known sequential AQP4-Ab negative first episode CNS acquired demyelination cases (n=29; females=55%; all AQP4-Ab negative; median age=13.6yrs). At presentation, 40% NMO cases had unilateral optic neuritis (ON); 20% bilateral ON; 15% transverse myelitis (TM); 15% simultaneous TM&ON; 10% Acute disseminated encephalomyelitis. At follow up, 55% had a clinical demyelinating episode involving the brain; 30% of cases had abnormal brain MRI at onset and 75% by follow up. NMO brain scan lesions compared to controls were large (>2 cm), acute lesions largely resolved on repeat imaging, and often showed T1 hypointense lesions. Mean time to relapse=0.76yrs (95% CI 0.43-1.1yrs) for AQP4-Ab positive vs 2.4yrs in AQP4-Ab negative cases (95% CI 1.1-3.6yrs). In AQP4-Ab positive cases, 10/12 had visual acuity<6/60 Snellen in ≥1 eye (0/8 AQP4-Ab negative), and 3 AQP4-Ab negative cases were wheelchair-dependent. Conclusions: In children, NMO is associated with early recurrence and visual impairment in AQP4-Ab positivity and physical disability in AP4-Ab negative relapsing cases. Distinct MRI changes appear more commonly and earlier compared to adult NMO. Early AQP4-Ab testing may allow prompt immunomodulatory treatment to minimise disability.