Highly Immunoresistant Acute Motor and Sensory Axonal Neuropathy With Concomitant Anti-NF155 Axonal Nodopathy: A Case Report.

Acute motor and sensory axonal neuropathy (AMSAN) is a rare, severe subtype of Guillain-Barré syndrome (GBS) associated with a poorer prognosis and greater resistance to standard immunotherapies. While immunomodulatory therapies are the traditional mainstay therapies for GBS and its variants, as autoimmune-mediated processes, refractory cases can present unique challenges. In addition, chronic inflammatory demyelinating polyneuropathy (CIDP) is a known persistent variant of GBS with its own wide array of variations, including neurofascin IgG4-positive axonal nodopathy, associated with an antibody that provides an additional layer of immunoprotection. This condition has been found in previously documented case series to require non-traditional immunoregimens. We present a unique case of a highly refractory AMSAN with concomitant chronic axonal motor and sensory axonal nodopathy with high multimodal immunotherapy resistance. This case illustrates the importance of considering neurofascin IgG4 in refractory subacute axonal nodopathies and, consequently, the potential role of empiric rituximab, while also highlighting the need for further research into B-cell-depleting therapeutic alternatives in resistant cases.