Memantine Treatment for Neuropsychiatric Symptoms in a Patient With Probable Idiopathic Normal Pressure Hydrocephalus

A Case Report

Masahiko Takaya

Disclosures

J Med Case Reports. 2013;7(94) 

In This Article

Abstract and Introduction

Abstract

Introduction: Patients with idiopathic normal pressure hydrocephalus often show neuropsychiatric symptoms besides the triad of 'classic' symptoms. Memantine has been reported to have positive effects on the neuropsychiatric symptoms of patients with Alzheimer's disease and patients with dementia with Lewy bodies. We administered memantine to a Japanese patient with probable idiopathic normal pressure hydrocephalus, hoping that this treatment would have positive effects on the neuropsychiatric symptoms of his idiopathic normal pressure hydrocephalus.

Case presentation: An 80-year-old right-handed Japanese man was diagnosed as having probable idiopathic normal pressure hydrocephalus and showed neuropsychiatric symptoms as well as the triad of classic symptoms of idiopathic normal pressure hydrocephalus. We treated our patient with memantine by increasing, decreasing, and then again increasing the dose of memantine. We evaluated his neuropsychiatric symptoms using the Neuropsychiatric Inventory at baseline, after the dose was increased to 20mg/day, after the dose was decreased to 5mg/day, and after the dose was increased again to 15mg/day. We simultaneously evaluated the triad of symptoms and conducted neuropsychological tests. In addition, we evaluated the psychological distress of our patient's caregiver using the Zarit Caregiver Burden Interview.

Conclusions: Memantine had positive effects on the neuropsychiatric symptoms of our patient with idiopathic normal pressure hydrocephalus. Although none of his triad of classic symptoms, including cognitive abilities, improved, the psychological distress of our patient's caregiver improved.

Introduction

Normal pressure hydrocephalus (NPH) is characterized by a progressive neurological syndrome accompanied by a triad of symptoms: gait disturbances, cognitive impairment, and urinary dysfunction.[1] NPH is diagnosed as idiopathic NPH (iNPH) if a patient has no causative antecedent disease. Diagnosis and treatment of patients with iNPH has gained popularity, and shunt surgery is believed to be a very effective treatment for such patients.[2] However, there is no evidence to indicate whether shunt surgery is effective in the management of NPH.[3] Moreover, patients with iNPH or their caregivers do not necessarily desire surgical treatment or shunt surgery. In such cases, an attending psychiatrist often initiates psychotropic agents when a patient shows neuropsychiatric symptoms.

In addition to the triad of symptoms, neuropsychiatric symptoms are observed in patients with NPH.[4] The neuropsychiatric characteristics of patients with iNPH have been evaluated using the Neuropsychiatric Inventory (NPI)[5] and compared with those of patients of Alzheimer's disease (AD).[6]

Various neuropsychiatric symptoms such as delusions, agitation, anxiety, and apathy are usually observed in patients with iNPH.[6] Memantine, an N-methyl-D-aspartate receptor antagonist, has significant effects on behavioral and psychological symptoms of dementia in patients with AD.[7] Because dementia with Lewy bodies (DLB) has some pathological and biochemical similarities to AD, pharmacological intervention with memantine might provide similar benefits for patients with DLB.[8] We hoped that memantine would therefore have similar effects on a patient with iNPH.

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