Hemianopic visual field defects in children with intracranial shunts: report of two cases

Intracranial shunts are commonly placed in children and frequently require replacement during the child's growing years. Severe signs of increased intracranial pressure often are the first indication of shunt displacement and malfunction. Subtle neuro-ophthalmic signs in children are usually overlooked. Two cases are described in which homonymous hemianopsia resulted from unsuspected movement of the shunt catheter in growing children. In one male patient, the catheter tip impaled the optic tract, and in the other male patient the shunt became embedded in the midbrain tegmentum and shunt failure led to compression of the posterior cerebral artery. In the presence of optic atrophy, papilledema may go unnoticed without serial examinations. This stresses the importance of detecting other early warning signs of shunt displacement and increased intracranial pressure, including visual field changes and subtle abnormalities of motility. Because early diagnosis and shunt revision may allow visual recovery, children with shunts should be followed with visual fields and serial disc photographs.