Rapid catastrophic neurologic deterioration following large Lumboperitoneal shunt adjustment in a patient with IIH.

Lumboperitoneal (LP) shunts are increasingly used for cerebrospinal fluid diversion in idiopathic intracranial hypertension (IIH), but their complication profile may be unfamiliar to emergency physicians compared to those associated with ventriculoperitoneal shunt malfunction. We present a case of fatal cerebral and cerebellar herniation following a large programmable LP shunt valve adjustment in a patient with an intact cranium. Despite the initial CT scan that was read normal, patient rapidly deteriorated while boarding in the ED. Repeat CT was consistent with cerebral and cerebellar herniation, likely secondary to overdrainage-induced paradoxical intracranial hypertension. A high index of suspicion should be maintained for any neurologic complaints following valve reprogramming, even if initial imaging is reassuring; an expedient neurosurgery engagement may be warranted. Familiarity with LP shunt failure complication profiles will be of increasing importance for emergency physicians.