Classification of Chronic Hydrocephalus in Adults: A Systematic Review and Analysis

BACKGROUND: Chronic hydrocephalus in adults (CHiA) includes all nonacute forms of hydrocephalus occurring in adulthood. It covers a spectrum of disorders. Some of these have relatively agreed on definitions, while others are less well characterized. The existing medical classification systems lack adequate structure and are neither clinically oriented nor easy to use, which severely hampers research and clinical care efforts. METHODS: A systematic literature review and data analysis were performed, focusing on the terms "adult hydrocephalus" and "classification," using the PubMed, Scopus, and Cochrane Library databases. Data on terminology, defiitions, patient demographics, symptom duration, and clinical presentations were extracted, analyzed, and compiled. A Delphi process was followed to define CHiA disorders. RESULTS: A total of 33 studies collectively used 48 terms to define various CHiA disorders. Different terms were used to describe similar conditions. CHiA disorders were found to be clustered into 7 distinctive clinical entities based on the clinical characteristics. CONCLUSIONS: An evidence-based new clinical classification for CHiA is suggested. Our review identified gaps in knowledge and areas for further research.