Putaminal hemorrhage potentially attributable to over-drainage of cerebrospinal fluid following ventriculoperitoneal shunt surgery in moyamoya disease: A case report.

Background: Rebleeding is a prognostic factor in hemorrhagic moyamoya disease (MMD). This report describes a case of cerebrospinal fluid over-drainage from a ventriculoperitoneal (VP) shunt after an intraventricular hemorrhage that may have contributed to a putaminal hemorrhage. Case Description: The patient was a 51-year-old woman with a prior intraventricular hemorrhage and moyamoya diagnosis who had not undergone revascularization surgery and was neurologically stable. She was readmitted in August 2023 with recurrent intraventricular hemorrhage and underwent shunt placement for hydrocephalus. Three weeks later, she developed a massive putaminal hemorrhage and required an emergency craniotomy. The narrowing of the ventricles before the hemorrhage suggested over-drainage. Rapid reduction in intraventricular pressure may have collapsed the fragile collateral vessels and led to the hemorrhage. Conclusion: VP shunt placement for hydrocephalus in patients with MMD following intraventricular hemorrhage necessitates careful management of shunt pressure settings. Given the fragile condition of collateral vessels in MMD, aggressive reductions in shunt pressure should be avoided. Instead, gradual and controlled adjustments are recommended to minimize the risk of over-drainage and subsequent hemorrhagic complications. Regular imaging, such as frequent computed tomography scans, is essential to monitor ventricular size and guide cautious pressure modulation.