Bilateral abducens and facial nerve palsies as a localizing sign due to reduction in intracranial pressure after fourth ventriculoperitoneal shunting.

A trapped fourth ventricle often requires fourth ventriculoperitoneal shunting (4VP). Complications of this procedure include shunt blockage, infection, shunt migration, and overdrainage. Cranial nerve palsies are very rare after 4VP shunting and have been described with over drainage and brainstem distortion. We present an unusual case of bilateral abducens and facial nerve palsies after 4VP shunting after normalization of 4(th) ventricular parameters. Measurement of various brainstem angles presented us with a plausible hypothesis to explain the cranial nerve dysfunction.