Central brain herniation in shunted Dandy Walker cyst.

INTRODUCTION: Dandy-Walker Syndrome (DWS) is a constellation of congenital anomalies of the central nervous system consisting of cerebellar vermis hypoplasia or agenesis, cystic dilatation of the fourth ventricle, enlarged posterior fossa, and a high tentorium. Hydrocephalus is a common occurrence in DWS and its treatment varies between shunting-ventriculoperitoneal or cystoperitoneal or both, endoscopic cyst fenestration, and third ventriculostomy. Chronic cerebral herniation is a known complication of treatment in DWS; however, we present an unusual case of central brain herniation. CASE REPORT: A 2 year old boy with shunted DWS presented with status epilepticus. Initial CT brain scan showed no increase in ventricle or cyst size; however, tapping the shunt reservoir did not yield any CSF prompting a shunt revision. Postoperatively, he was very slow to wake and subsequently experienced an episode of fixed pupils and extensor posturing. MRI brain demonstrated severe herniation of both thalami through the tentorium.
CONCLUSION: This child had chronic central brain herniation (CCBH) secondary to the shunting of his cyst. To our knowledge, this is the first case of CCBH following treatment of DW cyst.