Failure to Recognize a Lumboperitoneal Shunt During Emergency Evaluation: A Diagnostic Pitfall in Traumatic Acute Subdural Hematoma

Abstract Lumboperitoneal (LP) shunts are not visible on routine brain computed tomography (CT), making their recognition dependent on prior history or medical documentation. We report a case in which failure to recognize the presence of an LP shunt placement at emergency triage precluded early consideration of valve adjustment in a patient who developed catastrophic brain herniation after minor head trauma. A 69-year-old woman with an LP shunt for normal pressure hydrocephalus developed a left acute subdural hematoma (ASDH) after a minor fall. The LP shunt history was not identified during the initial emergency evaluation. Emergency craniotomy was performed for ASDH with transtentorial herniation. Postoperative imaging revealed Duret hemorrhage and the Kernohan-Woltman notch phenomenon. The presence of the LP shunt became known only after surgery, at which point the valve pressure was emergently adjusted. The patient regained consciousness over 1 month but had persistent left hemiplegia and severe disability at 18-month follow-up. LP shunt catheters are not visible on routine brain CT and may not be reliably identified from surgical scars alone. This case illustrates a critical diagnostic pitfall: unrecognized LP shunt placement prevented early consideration of valve adjustment as an adjunct to emergency decompression. Incorporating the presence of an LP shunt history into emergency triage protocols and encouraging patients to carry written shunt information are simple measures that may help prevent similar delays.