Because neurologic disability in NMO is intimately linked with disease exacerbation, it is critical for physicians to recognize and treat patients as early as possible. To this end, the specificity of AQP4 antibodies for NMO has allowed physicians to identify affected individuals prior to their presentation with the complete diagnostic criteria. These NMO spectrum disorders include monofocal optic neuritis, longitudinally extensive transverse myelitis (LETM), recurrent optic neuritis, and unusual CNS demyelinating events. Given the pleiotropic presentation of NMO spectrum disease, it is important for the clinician to be aware of clinical, laboratory and radiographic findings that should prompt consideration and additional testing for findings suggestive of NMO. These are summarized in the table below.
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Isolated/Recurrent Optic Neuritis |
• Brain MRI inconsistent with MS or containing atypical white matter lesionsa And either • Poor visual recovery (< 20/200 Snellen Acuity) • Significant optic nerve atrophyb • Non-caucasian ethnicityc • Clinical History of – Transient weakness or numbness – Transient bowel or bladder issues • Positive Autoimmune Serologyd |
• NMO-IgGg • Cervical and Thoracic Spine MRIh • Antinuclear antigen serologyd |
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Transverse Myelitis |
• LETMe Or • Brain MRI inconsistent with MS or containing atypical white matter lesionsa And either • Non-caucasian ethnicityc • Clinical History ofo Transient or persistent vision lossf • Positive Autoimmune Serologyd |
• NMO-IgGg
• Ocular Coherence Tomography • Antinuclear antigen serologyd |
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Monofocal CNS Demyelinating Event |
• Brain MRI inconsistent with MS or containing atypical white matter lesionsa And either • Non-caucasian ethnicityc • Clinical History of – Transient weakness or numbness – Transient bowel or bladder issues – Transient or persistent vision lossf • Positive Autoimmune Serologyd |
• NMO-IgGg
• Cervical and Thoracic Spine MRI • Antinuclear antigen serologyd |
a Diffuse subcortical white matter lesions (enhancing or nonenhancing); “cloud-like” gadolinium enhancement; hypothalamic lesions; thalamic lesions; periacqueductal lesions; atypical appearing brainstem demyelination (Ito et al., 2009; Pittock et al., 2006)
b Greater than 15 microns of peripapillary retinal nerve fiber layer loss by optical coherence tomography (Ratchford et al., 2009)
c Japanese (Kira, 2003); Indian and Southeast Asians (Chopra et al., 1980; Lau et al., 2002); Afro-Caribbean (Papais-Alvarenga et al., 2002); Middle Eastern (Banwell et al., 2008); and Hispanic (Banwell et al., 2008)
d Antinuclear antibody (ANA); Anti–double-stranded DNA antibody; Extractable nuclear antigen (ENA); Sjogrens SS-A or SS-B (Javed et al., 2008; Weinshenker et al., 2006).
e Lesion extending over 3 segments or more (Wingerchuk et al., 2006).
f History of acute, painful vision loss.
g AQP4-positive serology (Jarius et al., 2008; Lennon et al., 2004)