Neuromyelitis optica phenotype associated with therapy-responsive acute peripheral neuropathy

Case report. A 51-year-old Hispanic woman with a history of Churg-Strauss syndrome (in remission for 20 years)–associated mesangial glomerulonephritis and end-stage renal disease with a recent renal transplant and previously cured cytomegalovirus (CMV) infection who was on a tapering dose of tacrolimus presented with sudden onset of lower extremity numbness. Symptoms progressed to complete paraplegia and sensory loss over 24 hours. The following day, ascending paresis extended to bilateral upper extremities, with high thoracic sensory level and complete blindness. Initial MRI revealed contrast enhancement of bilateral prechiasmatic optic nerve as well as T2 hyperintensities involving the central gray matter of the entire spinal cord with associated edema. CSF analysis documented neutrophilic pleocytosis (182 neutrophils per mm) and increased total protein level (142 mg/dL) without oligoclonal banding. Bacterial, fungal, and mycobacterial cultures from the CSF were negative, as was PCR for CMV, Epstein-Barr virus, herpes simplex virus, human herpesvirus 6, and varicella-zoster virus. Serologic autoimmune assessment, including onconeuronal, anti-neutrophil cytoplasmic antibody, and other rheumatologic, Lyme, and aquaporin-4 (AQP4) antibody testing, was negative. Moreover, testing for sarcoidosis and HIV antibody was unrevealing. Nerve conduction studies (NCS) performed 2 weeks after symptom onset documented severe reduction in compound motor action potential amplitudes (worse in the lower extremities), ,10% slowing of distal latencies but not conduction velocities, and mildly slowed upper extremity f-wave latencies. Sensory nerve action potentials were pathologically reduced in the lower extremities (table). Needle examination (EMG) showed active, severe denervation changes in lower extremity muscles and less severe changes in upper extremity muscles. Subsequent GM1, GM2, GD1a, GD1b, and GQ1b ganglioside antibody testing was negative. The patient was diagnosed with concurrent clinically definite neuromyelitis optica (NMO) phenotype and acute axonal polyradiculoneuropathy with primarily axonal features. The patient was treated initially with methylprednisolone followed by 5 cycles of plasma exchange, with minimal improvement in upper extremity muscle strength and sensation despite repeat MRI showing partial resolution of the previously seen lesions. Subsequently she received 4 weekly cycles of IV rituximab therapy. Follow-up at 7 and 14 months demonstrated normal strength in her upper extremities with decreased reflexes, and she was able to walk with use of a walker. Moreover, the patient regained complete right eye vision with improved left eye vision (20/400), clinically consistent with a monophasic process. Repeat NCS/EMG at 7 months revealed improvement, and at 14 months NCS were normal and EMG was significantly improved (table). Repeat AQP4 antibody testing was negative at 7 months posttreatment.