Acquired infantile abducens palsy associated with anti-GM2 antibodies

Anti-ganglioside antibodies have been associated with acquired neuropathies, including Guillain-Barré syndrome. We describe a case of acute abducens nerve palsy acquired 2 weeks after symptoms of upper respiratory tract infection and rash in a 6-month-old. Elevated anti-GM2 ganglioside immunoglobulin M antibodies were detected in the serum. The palsy slowly improved over time, although eventually surgical intervention was required. Elevated anti-GM2 immunoglobulin M antibodies have previously been reported in Guillain-Barré syndrome variants involving sensory and cranial neuropathies, but never in isolated unilateral cranial nerve VI mononeuropathy. Anti-ganglioside antibodies may play a role in the pathogenesis of postinfectious isolated abducens palsy in young children.