Management of idiopathic normal pressure hydrocephalus (iNPH) - a retrospective study

Background: Normal pressure hydrocephalus (NPH) is communicating hydrocephalus characterised by normal intraventricular pressures. It presents with the triad of gait impairment, cognitive decline, and urinary incontinence. The term idiopathic normal pressure hydrocephalus (iNPH) is used in cases where the etiology is unknown. The aim of this study was to assess the prevalence and management of iNPH in our institution.Method: This was a retrospective study carried out at a tertiary health care center. Retrospective case series analysis was conducted using the existing electronic medical record data (2009-2017) on patients with hydrocephalus.Results: Forty-two (6.7%) patients with iNPH were identified, mean age 71.5 ± 8.8 years, 21 male (mean age 71.5 ± 9.3 years) and 21 female (mean age 71.5 ± 8.5 years). Ataxia was recorded in 39, symptoms of dementia in 31, and urinary incontinence in 29 patients. Forty patients were treated surgically by placing a ventriculoperitoneal (VP) shunt. One of the two patients treated by endoscopic third ventriculostomy (ETV) was subsequently treated by placing a VP shunt due to clinical deterioration. Significant improvements were noticed in cognitive and urinary symptoms, in the triad symptom sum score on the Japanese NPH scale, as well as in Evans' index and callosal angle (CA) on brain MRI (p < 0.05). Significant positive correlation was found between age and gait disturbance (Spearman's rho = 49.86% p = 0.0017), age and incontinence (Spearman's rho = 35.22%, p = 0.0351), age and triad symptom sum score (Spearman's rho = 44.67%, p = 0.0056), female gender and dementia (Spearman's rho = 34.94%, p = 0.0367), and among all three variables on the Japanese NPH scale (p < 0.0001).Conclusions: Treatment of iNPH with VP shunt showed significant improvement. A properly designed study is required to address the efficacy of ETV in the treatment of iNPH.