1313. Low-Pressure Hydrocephalus: A Case Series and Systematic Review

Authors: Michael Bradley Keough, MD, PhD; Albert Isaacs, MD; Geberth Urbaneja, MD; Mark Hamilton, MD (Edmonton, Canada)

Introduction: Low-pressure hydrocephalus (LPH) is a rare phenomenon marked by symptoms of raised intracranial pressure and ventriculomegaly despite intracranial pressures below the normal range. LPH poses significant challenges as it is often refractory to standard interventions. We present a case series and systematic review of LPH to better characterize this paradoxical syndrome and provide viable treatment options. Methods: All LPH cases managed at the Foothills Medical Center and Alberta Children’s Hospital, Canada between 1997 and 2017 were reviewed. EMBASE and MEDLINE databases were searched for all published cases since its initial description in 1994. All cases that met inclusion criteria were pooled with our series and a descriptive data analysis was performed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was followed. Results: There were 42 cases from our institution and 111 retrieved from the literature. The age of patients ranged from 2 months to 78 years, with similar representation of males and females. The most common etiologies for hydrocephalus were tumors (40%), hemorrhage (40%), and congenital causes (12%). The majority of patients (58%) had previously undergone ventriculoperitoneal shunt insertion before presentation of LPH. Adjunctive treatments included head of bed elevation and neck wrapping to increase brain turgor. Surgical interventions included extraventricular drainage with heights set below zero until definitive therapy with shunt insertion or endoscopic third ventriculostomy. The majority of patients (63%) returned to baseline level of functioning. Conclusion: LPH is a variant of hydrocephalus that occurs secondary to several etiologies and is challenging to treat as it often is not recognized and does not initially respond to CSF shunting. With early recognition, careful negative height extraventricular drainage and implementation of adjunctive measures, the syndrome may be reversed to permit definitive therapy. Further studies are needed to understand the mechanistic triggers and pathophysiology of LPH.