Case Report: CASPR2-associated autoimmune encephalitis with NF155 Antibody-positive autoimmune nodopathies: a rare case with hyponatremia onset

This case report contributes to the literature by documenting a rare co-occurrence of CASPR2-associated autoimmune encephalitis and NF155 antibody-positive AN, with a unique presentation of hyponatremia. The findings underscore the importance of considering autoimmune etiologies in patients presenting with hyponatremia and neurological symptoms. Moreover, the favorable response to B-cell depletion therapy suggests a potential treatment option for similar cases. The main take away is the need for heightened clinical suspicion and comprehensive diagnostic evaluation in patients with complex neurological presentations, to facilitate timely diagnosis and appropriate management.