A Case of Insidious Onset Seronegative Neuromyelitis Optica Spectrum Disorder (NMOSD)
Ayatalla Ahmed1, Rachael Cella1, Qingli Hu1, Daniyal Asad2, Mohammed El-hunjul2
1University of Connecticut, 2Hartford Healthcare
Objective:
NA
Background:
NMOSD is an immune-mediated progressive demyelination disorder of the CNS that primarily affects females in their late 30s with prevalence up to 10 per 100,000 in the general population. About 73-90% of NMOSD patients are seropositive for aquaporin-4 antibodies (APQ4-Ab), a highly sensitive tool. However, seronegative cases may lead to diagnostic delays.
Design/Methods:
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Results:

A 56-year-old female with hyperlipidemia presented with a 1-week history of progressive headache and right eye vision loss. MRI revealed right optic pre-chiasmatic and orbital segment neuritis. She received a 3-day course of IV steroids with modest symptom improvement. Seven years later, she developed intermittent dizziness, gait instability, persistent hiccups, nausea, & vomiting. During hospitalization, she experienced right palm numbness with a sensory level at T5. MRI suggested a possible cerebellar vermis infarct, prompting stroke workup and dual antiplatelet therapy.  

Three weeks later, she developed diffuse facial paresthesia, and a repeat MRI showed enhancement of the dorsal brainstem, 4th ventricle, and internal auditory canal, findings atypical for subacute stroke. APQ4 and MOG antibodies were negative. CSF analysis showed 9 nucleated cells (98% lymphocytes), IgG index of 0.60, protein of 16 mg/dL, glucose of 68 mg/dL, and negative oligoclonal bands. She was treated with a 5-day course of pulse steroids, improving her hand and foot numbness.

A week later, she had a recurrence of bilateral lower extremity numbness, with significant improvement following plasmapheresis. Long-term treatment with rituximab was planned. Despite negative APQ4 antibodies, the patient met clinical criteria for NMOSD.

Conclusions:
This case demonstrates the NMOSD progression in an older patient who presented with unrelated neurological issues over several years. A thorough neurological history is imperative for diagnosing seronegative NMOSD, and it should remain high on the differential for patients who have core clinical features of optic neuritis, area postrema syndrome, and transverse myelitis.
10.1212/WNL.0000000000212053
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