特発性正常圧水頭症（iNPH）の診断

Diagnosis for Idiopathic Normal Pressure Hydrocephalus

Point

・『特発性正常圧水頭症（iNPH）診療ガイドライン第3版』（GL 2020）では，iNPHの診断を症候，画像所見とタップテスト判定を中核にし，シャント治療が有効な患者群を抽出している．

・GL 2020の診断アルゴリズムは，iNPHの症状に類似する疾患との鑑別プロセスが含まれていないため，アルゴリズムに含まれない検査は詳細な疾患病態や併存疾患の程度を捉える目的で実施される．

　In aging societies, idiopathic normal-pressure hydrocephalus（iNPH）has emerged as an important disease that can negatively affect the activities of daily living among the elderly. Evidence supporting diagnosis and treatment has accumulated and, in Japan, the third edition of the iNPH treatment guideline was published in 2020. Through the promotion of multi-facility research efforts in Japan, diagnosis of iNPH has been based on characteristic phenomena including gait disturbance, overactive bladder, cognitive impairment, and disproportionately enlarged subarachnoid space hydrocephalus（DESH）. In supplementary examinations, brain transformations associated with iNPH have been evaluated using modified magnetic resonance imaging methods. Moreover, studies aimed at elucidating the disease state in combination with biological information obtained from cerebrospinal fluid findings are in progress. However, the outcome prediction of shunt treatment for atypical iNPH（i.e., non-DESH iNPH）and coexisting nervous system abnormalities is also important. In these cases, determining indications for surgery is a particular challenge.