Recurrent Isolated Sixth Nerve Palsy in Relapsing-Remitting Chronic Inflammatory Demyelinating Polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated sensory and motor demyelinating polyneuropathy that typically presents as a relapsing-remitting or progressive disorder. Cranial neuropathies infrequently occur in association with other more typical symptoms of CIDP.

We report a case of CIDP with recurrent isolated sixth nerve palsy. Her physical examination showed a right sixth nerve palsy and absent deep tendon reflexes as the only indicator of her disease. Magnetic resonance imaging revealed thickening without enhancement of the trigeminal and sixth cranial nerves. Nerve conduction study (NCS) revealed a sensory and motor demyelinating polyneuropathy with conduction block and temporal dispersion in multiple nerves consistent with CIDP. Cerebrospinal fluid demonstrated albuminic-cytologic dissociation. She had a remarkable response to intravenous immunoglobulin and remains asymptomatic without any additional immunomodulating therapy.

Isolated cranial neuropathies can rarely occur as the sole manifestation of relapsing-remitting CIDP. The profound demyelination found on NCS in this case demonstrates that there can be a dramatic discordance between the clinical and electrodiagnostic findings in some patients with this disorder.