Neuromyelitis optica and neuromyelitis optica spectrum disorder: Natural history and long-term outcome, an Indian experience

Sex ratio and age of onset in AQP4 antibody-associated NMOSD: a review and meta-analysis

BACKGROUND

Aquaporin-4 (AQP4) antibody-associated neuromyelitis optica spectrum disorder (NMOSD) is an antibody-mediated inflammatory disease of the central nervous system. We have undertaken a systematic review and meta-analysis to ascertain the sex ratio and mean age of onset for AQP4 antibody associated NMOSD. We have also explored factors that impact on these demographic data.

METHODS

A systematic search of databases was conducted according to the PRISMA guidelines. Articles reporting sex distribution and age of onset for AQP4 antibody-associated NMSOD were reviewed. An initially inclusive approach involving exploration with regression meta-analysis was followed by an analysis of just AQP4 antibody positive cases.

RESULTS

A total of 528 articles were screened to yield 89 articles covering 19,415 individuals from 88 population samples. The female:male sex ratio was significantly influenced by the proportion of AQP4 antibody positive cases in the samples studied (p < 0.001). For AQP4 antibody-positive cases the overall estimate of the sex ratio was 8.89 (95% CI 7.78-10.15). For paediatric populations the estimate was 5.68 (95% CI 4.01-8.03) and for late-onset cases, it was 5.48 (95% CI 4.10-7.33). The mean age of onset was significantly associated with the mean life expectancy of the population sampled (p < 0.001). The mean age of onset for AQP4 antibody-positive cases in long-lived populations was 41.7 years versus 33.3 years in the remainder.

CONCLUSIONS

The female:male sex ratio and the mean age of onset of AQP4 antibody-associated NMOSD are significantly higher than MS. The sex ratio increases with the proportion of cases that are positive for AQP4 antibodies and the mean age of onset increases with population life expectancy.

Utility of optical coherence tomography in patients of central immune mediated demyelinating diseases - A prospective study

Optical coherence tomography (OCT) is a non-invasive tool to measure thickness of various layers of retina. Recently, retinal nerve fibre layer (RNFL) and ganglion cell and inner plexiform layer (GCIP) thinning has been observed in OCT in patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), This study compared OCT profile, along with visual acuity (VA), color vision (CV), contrast saturation (CS) and visual evoked potentials (VEP) in two main cohorts of MS and NMOSD and with controls, during acute episode of optic neuritis (ON), at 3 and 6 months. We found that changes of ON were present in 75% of MS eyes and in 45% of NMOSD patients. Of these, subclinical involvement was present in 56.25% of MS eyes and only in 5% of NMOSD eyes suggesting frequent subclinical involvement in the former. Mean RNFL was 95.23 ± 15.53 in MS and 66.14 ± 43.73 in NMOSD after 6 months of ON episode. Thinning of NQ and IQ was observed in NMOSD eyes in the immediate period after ON attack. At 6 months relative sparing of RNFL in TQ was observed in NMOSD ON eyes and MS ON showed predilection for involvement of TQ.

Comparison of clinico-radiological profile, optical coherence tomography parameters, and outcome in MOGAD and Neuromyelitis optica spectrum disorder subtypes: A prospective observational study

Objectives

The objectives of the study were to compare the clinico-radiological profile, optical coherence tomography (OCT) parameters and outcome in Myelin Oligodendrocyte Glycoprotein-IgG-associated disorders (MOGAD) and Neuromyelitis Optica Spectrum disorder subtypes.

Materials and Methods

This prospective study involved collection of data regarding neurological assessment, neuroimaging, cerebrospinal fluid analysis, OCT parameters, treatment and outcome. Disease severity and disability were assessed using Expanded Disability Status Scale and modified Rankin scale. Patients were categorized into aquaporin-4 (AQP4+), MOGAD, and double negative (DN; both AQP4 and MOG negative).

Results

Among 31 patients included, 42% were AQP4+, 32.2% were MOGAD, and 25.7% were DN. The median age at onset was comparable (AQP4+ vs. MOGAD vs. DN = 28 years vs. 24.4 years vs. 31.5years; P = 0.31). Females predominated in AQP4+ compared to MOGAD group (76.9% vs. 30%; P = 0.02). Majority of patients (73.5%) had a relapsing course with a median of two (range = 1-9) relapses. Ninety-nine demyelinating events occurred: Transverse myelitis (TM) in 60/99 (60.6%), optic neuritis (ON) in 43/99 (43.4%), area postrema (AP) syndrome in 20/99 (20.1%), and optico-spinal syndrome in 10/99 (10.1%). ON was common in MOGAD than AQP4+ patients (58.6% vs. 32.1%; P = 0.03). Spinal cord and brain lesions on magnetic resonance imaging (MRI) were seen in 90.3% and 54.8% patients, respectively. A significantly higher proportion of AQP4+ patients showed longitudinally extensive transverse myelitis as compared to MOGAD group (69.2 % vs. 20 %; P = 0.04), specifically involving dorsal cord (92.3% vs. 50%; P = 0.02). MRI brain lesions, especially involving AP, was frequent in DN than MOGAD (47.1% vs. 6.9%; P = 0.003) and AQP4+ (47.1% vs. 18.9%; P = 0.03) patients. AQP4+ group showed significant nasal RNFL thinning on OCT (P = 0.04). Although 6-month good functional outcome was better in MOGAD than DN and AQP4+ (80% vs. 71.4% vs. 41.7%) groups, they were comparable (P = 0.13).

Conclusion

Nearly three-fourth of our patients showed a relapsing course, with TM being the most common clinical presentation. AQP4+ group showed female preponderance, frequent dorsal cord longitudinally extensive transverse myelitis, less frequent ON, and greater nasal RNFL thinning compared to MOGAD group. MRI brain lesions were more common in DN patients. All three groups exhibited good response to pulse corticosteroids and showed a comparable functional outcome at 6-month follow-up.

Approach to optic neuritis: An update

Over the past few years, there has been remarkable development in the area of optic neuritis. The discovery of new antibodies has improved our understanding of the pathology of the disease. Antiaquaporin4 antibodies and antimyelin oligodendrocytes antibodies are now considered as distinct entities of optic neuritis with their specific clinical presentation, neuroimaging characteristics, treatment options, and course of the disease. Similarly, there has been a substantial change in the treatment of optic neuritis which was earlier limited to steroids and interferons. The development of new immunosuppressant drugs and monoclonal antibodies has reduced the relapses and improved the prognosis of optic neuritis as well as an associated systemic disease. This review article tends to provide an update on the approach and management of optic neuritis.

Relapsing neuromyelitis optica in an adolescent girl

Early differentiation of neuromyelitis optica spectrum disorder (NMO-SD) from multiple sclerosis (MS) is of paramount importance as NMO-SD (especially relapsing variant) has more severe morbidity than MS. We describe a case of an adolescent girl who presented with repeated episodes of optic neuritis over a period of 4 years with normal brain MRI scans. She was treated initially as relapsing remitting MS, before showing clinical evidence of transverse myelitis (TM), and eventually being diagnosed as NMO-SD. Pulse intravenous methyl prednisolone along with immunosuppressive therapy led to remission of her disease. However, delay in diagnosis as NMO-SD led to visual disability in the left eye. Therefore, in young patients with recurrent optic neuritis and normal brain MRI, it may be prudent to get spinal MRI done to look for TM, even when asymptomatic. In addition, we should keep a low threshold for requesting aquaporin-4 antibody testing in these patients.

Relapse Patterns in NMOSD: Evidence for Earlier Occurrence of Optic Neuritis and Possible Seasonal Variation

Neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) show overlap in their clinical features. We performed an analysis of relapses with the aim of determining differences between the two conditions. Cases of NMOSD and age- and sex-matched MS controls were collected from across Australia and New Zealand. Demographic and clinical information, including relapse histories, were recorded using a standard questionnaire. There were 75 cases of NMOSD and 101 MS controls. There were 328 relapses in the NMOSD cases and 375 in MS controls. Spinal cord and optic neuritis attacks were the most common relapses in both NMOSD and MS. Optic neuritis (p < 0.001) and area postrema relapses (P = 0.002) were more common in NMOSD and other brainstem attacks were more common in MS (p < 0.001). Prior to age 30 years, attacks of optic neuritis were more common in NMOSD than transverse myelitis. After 30 this pattern was reversed. Relapses in NMOSD were more likely to be treated with acute immunotherapies and were less likely to recover completely. Analysis by month of relapse in NMOSD showed a trend toward reduced risk of relapse in February to April compared to a peak in November to January (P = 0.065). Optic neuritis and transverse myelitis are the most common types of relapse in NMOSD and MS. Optic neuritis tends to occur more frequently in NMOSD prior to the age of 30, with transverse myelitis being more common thereafter. Relapses in NMOSD were more severe. A seasonal bias for relapses in spring-summer may exist in NMOSD.

Aquaporin 4 Antibody in the Korean Patient with New-Onset Optic Neuritis

PURPOSE

To evaluate the prevalence of aquaporin 4 antibody (AQP4-Ab) in new-onset optic neuritis patients and investigate the characteristics of seropositive patients.

METHODS

Thirty-six women and six men with new-onset isolated optic neuritis were included in this study between January 2013 and December 2014. AQP4-Ab was detected and all blood samples were obtained prior to treatment and within one week from attack. The patients were sub-grouped into either a seropositive group or a seronegative group according to AQP4-Ab. Differences in age, gender, initial visual acuity, and final visual acuity between groups were analyzed.

RESULTS

Six (14.3%) of these patients (five women and one man) exhibited AQP4-Ab. There was no significant difference in mean age between study groups (positive group: 38.7 ± 11.5 years, negative group: 42.3 ± 14.7 years, P=0.548). Bilateral simultaneous involvement was more common in seropositive patients than in seronegative patients (occurred in two out of six seropositive patients and in one out of 36 seronegative patients, P = 0.007). With regards to poor visual outcome (worse than 1.0 LogMAR), seropositive patients exhibited more severe visual loss than seronegative patients. None of the seropositive patients exhibited myelitis symptoms during the follow-up period (mean follow-up period: 8-32 months).

CONCLUSION

The prevalence of AQP4 antibody was often detected in new-onset optic neuritis patients. In patients with bilateral involvement or poor initial visual acuity, the AQP4 antibody test should be considered.