Objective:
The main objectives of this case study are to (1) re-iterate the importance of generating a differential diagnosis in the context of a patient's clinical status and neurologic exam when objective laboratory and imaging findings do not accurately resemble the clinical picture and (2) to demonstrate how the use of Rituximab may alter the outcomes of cerebrospinal fluid studies.
Background:
A 65-year-old female with a past medical history of NMO presented with two weeks of worsening diffuse weakness, nausea, vomiting and chills. Neurologic exam was notable for significant weakness in the bilateral upper extremities throughout and bilateral proximal lower extremities. MRI spine indicated patchy mild T2 hyperintensities scattered in the spinal cord from T2 - T5 and an enhancing lesion at T6. She was diagnosed with NMO relapse. She has been treated with Rituximab every 6 months since her diagnosis without prior breakthroughs. Her last dose was 4 months ago. She received 5 days of high-dose IV steroids, however, she continued to worsen clinically with further weakness and developed hypophonia. Broad serum and CSF infectious, neoplastic and autoimmune studies were obtained as the patient's weakness did not localize with her imaging findings. This initial work up was within normal limits outside of elevated total nucleated cells (143, 98% lymphocytes) on CSF analysis. EMG was performed and within normal limits as well. She was initiated on plasma exchange therapy and remained without improvement. Repeat CSF studies were obtained given her continued clinical worsening and were positive for West-Nile virus. Her initial CSF analysis was presumptively a false negative in the setting of her chronic rituximab use. She received supportive care and her strength gradually improved with extensive physical therapy.