A clinical and radiological profile of neuromyelitis optica and spectrum disorders in an Indian cohort
Abstract
Background:
There is insufficient data on the clinical and radiological features of neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD) from India.
Objective:
The objective of the following study is to examine the clinico-radiological features of NMO and NMOSD in an Indian cohort.
Materials and Methods:
This retrospective study included 44 consecutive patients who (1) satisfied the 2006 Wingerchuk criteria for NMO (16 seropositive and 7 seronegative); or (2) had isolated or recurrent optic neuritis (ON) with seropositivity (n = 4); or (3) had isolated or recurrent myelitis with seropositivity (n = 17).
Results:
The female:male ratio was 7.8:1 with median age of onset 26.5 (range 8-72). Annualized relapse rate (ARR) was comparable across all groups (F [3, 40] = 0.938 and P = 0.431). Various presentations other than ON and myelitis were noted. All 40 patients with myelitis had spinal cord lesions involving ≥3 vertebral segments during the course of the disease. Cervicomedullary involvement was seen in 32.5% (13/40) patients. Brain magnetic resonance imaging was available for 40 patients; eight of these (20%) had brain lesions in locations described in multiple sclerosis (MS), 27.5% (11/40) had lesions at sites unusual for MS and 52.5% (21/40) had normal brain imaging.
Conclusion:
NMO and NMOSD patients in this cohort have comparable ARR regardless of clinical presentation, supporting the emerging trend of treating all patients with immunotherapeutic agents at an early stage. Varied presentations seen in NMO and NMOSD highlight the need for a high index of suspicion for NMO in demyelinating episodes not classical for MS.
Introduction
Neuromyelitis optica (NMO) is an inflammatory demyelinating, necrotizing disease of the central nervous system, with a predilection for the optic nerves and spinal cord. Clinical, radiological and immunopathological characteristics distinguish it from multiple sclerosis (MS). Classical NMO is defined by the revised diagnostic criteria set out by Wingerchuk et al. in 2006, which requires the presence of optic neuritis (ON) and myelitis, plus any two of: (a) Brain magnetic resonance imaging (MRI) not satisfying the McDonald criteria; (b) contiguous spinal cord MRI T2 lesions spanning three or more vertebral segments; (c) positive serology for NMO-immunoglobulin G (IgG) (anti-aquaporin-4 antibody).[1] Since the discovery of NMO-IgG as the pathogenic marker for NMO, various limited forms of NMO have also been recognized based on NMO-IgG seropositivity;[2] these constitute the neuromyelitis optica spectrum disorders (NMOSD).
Various studies on NMO from the pre-MRI era from India report that NMO comprised 9-24% of the demyelinating diseases in India.[3] However, very few studies have examined NMO in India after the adoption of the 2006 revised Wingerchuk criteria and there is insufficient data on the clinical and radiological features of NMO in India. In addition, there is very little data available on NMOSD in India. The objective of the present study was to examine clinical and radiological features of NMO and NMOSD, in an Indian cohort.
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