Atypical case of Morvan's syndrome

Morvan's syndrome is a rare neurological condition characterized by the combination of neuromyotonia, autonomic instability and encephalopathy, associated with auto-antibodies against voltage-gated potassium channels. We report a patient with an initial presentation suggestive of typical Guillain-Barré syndrome (GBS), who later developed clinical and laboratory features compatible with Morvan's syndrome. Several months after resolution of the neurological symptoms, as well as disappearance of the characteristic anti-leucine-rich, glioma inactivated 1 (anti-LGI1) antibodies, the patient presented with episodes of fever of unknown origin, during which the antibodies became positive again, suggesting the possibility of a relapse. In this case, both the GBS-like symptoms at presentation and the isolated episodes of fever of unknown origin during follow-up are atypical, and may suggest the presence of an additional, yet unknown antibody.