Acute Isolated External Ophthalmoplegia: Think of Anti-GQ1b Antibody Syndrome

Acute-onset ophthalmoplegia is a perplexing diagnosis in a young child. When the full-blown picture of ophthalmoplegia, ataxia, and areflexia is evident, the diagnosis of Miller-Fisher syndrome (MFS), a variant of Guillain-Barre syndrome (GBS), is almost certain. However, the same is not true for isolated external ophthalmoplegia as it is etiologically heterogeneous. Only anecdotal case reports of childhood-onset acute ophthalmoplegia exist in the literature. Adult series suggest that acute onset external ophthalmoplegia is often immune-mediated and is secondary to anti-GQ1b antibodies. We present a 30-month-old boy with acute-onset bilateral external ophthalmoplegia with highly elevated serum anti-GQ1b antibodies. The child had a rapid and complete recovery with intravenous immunoglobulin. A review of all published cases of childhood anti-GQ1b antibody syndrome was performed. The case highlights that anti-GQ1b antibody syndrome should be considered even in young children with acute-onset external ophthalmoplegia. The disease has a favorable prognosis. The majority improve on conservative management. Treatment with steroids or IVIG may be considered in some after weighing the risks and benefits.