Course and outcome of a voltage-gated potassium channel antibody negative Morvan's syndrome

Area of Science:

• Neurology
• Immunology

Background:

• Morvan's syndrome is a rare autoimmune disorder affecting peripheral nerves, central nervous system, and autonomic systems.
• It is typically associated with high serum voltage-gated potassium channel (VGKC) antibody titers.
• Previously, VGKC antibody positivity was considered a hallmark of Morvan's syndrome.

Observation:

• This report details a patient with Morvan's syndrome, myasthenia gravis, and a history of thymoma.
• The patient presented with clinical features consistent with Morvan's syndrome.
• Notably, serum VGKC antibody levels were undetectable in this patient.

Findings:

• The clinical presentation mimicked VGKC antibody-associated Morvan's syndrome.
• The patient did not respond to plasma exchange, a standard treatment for VGKC antibody-associated conditions.
• However, the patient showed a positive response to corticosteroid therapy.

Implications:

• This case challenges the notion that VGKC antibodies are essential for Morvan's syndrome diagnosis.
• It suggests alternative autoimmune mechanisms may underlie Morvan's syndrome.
• The findings support an autoimmune etiology for Morvan's syndrome, even in the absence of VGKC antibodies, and highlight corticosteroids as a potential treatment.