Abstract 1). Introduction West Nile Virus (WNV) neuroinvasive disease (NID), including encephalitis, meningitis, myelitis, and acute flaccid paralysis, occurs in less than 1% of infected individuals, with increased risk and severity in older or immunocompromised adults. WNV-associated Guillain-Barré Syndrome (GBS) is rare, with an annual incidence of 0.6/100,000. We report a case of a patient with mantle cell lymphoma (MCL) on rituximab who developed progressive weakness and respiratory failure due to WNV-associated GBS. 2). Case Presentation A 63-year-old woman with MCL on rituximab presented with rapidly progressive bilateral weakness of all extremities for two days. She denied numbness, fever, headache, or recent travel. On arrival, she was alert, oriented, and hemodynamically stable. Motor strength was symmetrically reduced in all limbs, with intact reflexes, sensation, and cranial nerves. On day 3, she developed bulbar weakness and respiratory distress, requiring intubation. Differentials considered were CNS involvement due to MCL, GBS, or paraneoplastic syndrome.Blood work showed pancytopenia. Infectious workup, including WNV serologies and imaging, was unremarkable. On day 4, she developed fever, left facial droop, diminished reflexes, and shock. Cerebrospinal fluid (CSF) analysis showed albumin-cytologic dissociation but was negative for pathogens as well as WNV antibodies. Brain MRI showed scattered hyperintensities. Spine MRI revealed ventral cauda equina root enhancement, classically seen in GBS (Figure 1), and labyrinthine facial nerve enhancement, sometimes seen in the Miller Fisher variant. Paraneoplastic panels were negative. No clinical improvement was seen after five plasmapheresis sessions. Metagenomic sequencing of CSF (MSCSF) detected WNV RNA on day 12. Despite supportive care, her condition did not improve, and on day 15, the family decided to transition to comfort care. 3). Discussion This case emphasizes the diagnostic value of MSCSF in identifying CNS infections when conventional testing is inconclusive. Our immunocompromised patient presented with acute flaccid paralysis. Blood and CSF WNV serologies were negative, likely due to rituximab-induced immunosuppression. Ultimately, MSCSF detected WNV RNA, confirming neuroinvasive WNV infection-associated GBS. This highlights two key points: (1) WNV neuroinvasive disease should be considered in acute flaccid paralysis or GBS-like presentations in immunocompromised hosts.(2) MSCSF offers superior diagnostic value when standard CSF testing fails. This abstract is funded by: None
Asif et al. (Fri,) studied this question.