Frontotemporal dementia as a comorbidity to idiopathic normal pressure hydrocephalus (iNPH): a short review of literature and an unusual case

V E Korhonen,E Solje,R Vanninen,A M Remes,V Leinonen,N M Suhonen,T Rauramaa

doi:10.1186/s12987-017-0060-7

Abstract

Behavioural variant frontotemporal dementia (bvFTD) and idiopathic normal pressure hydrocephalus (iNPH) are neurodegenerative diseases that can present with similar symptoms. These include decline in executive functions, psychomotor slowness, and behavioural and personality changes. Ventricular enlargement is a key radiological finding in iNPH that may also be present in bvFTD caused by the C9ORF72 expansion mutation. Due to this, bvFTD has been hypothesized as a potential comorbidity to iNPH but bvFTD patients have never been identified in studies focusing in clinical comorbidities with iNPH. Here we describe a patient with the C9ORF72 expansion-associated bvFTD who also showed enlarged ventricles on brain imaging. The main clinical symptoms were severe gait disturbances and psychiatric problems with mild cognitive decline. Cerebrospinal fluid removal increased the patient’s walking speed, so a ventriculoperitoneal shunt was placed. After insertion of the shunt, there was a significant improvement in walking speed as well as mild improvement in cognitive function but not in neuropsychiatric symptoms relating to bvFTD. Comorbid iNPH should be considered in bvFTD patients who have enlarged ventricles and severely impaired gait.

Highlights

Idiopathic normal pressure hydrocephalus is a progressive neurodegenerative disease that has three core symptoms: gait disturbance, cognitive impairment, and urinary incontinence [1]
This is the first report of a response to a shunt in a patient with genetically, pathologically, and clinically confirmed Behavioural variant frontotemporal dementia (bvFTD)
In Idiopathic normal pressure hydrocephalus (iNPH) gait improvement is the most prominent, frequent, and usually the earliest sign of response to a shunt compared to improvements in urinary incontinence or cognition [21]

Summary

Introduction

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive neurodegenerative disease that has three core symptoms: gait disturbance, cognitive impairment, and urinary incontinence [1]. Patients with iNPH may show partial or full expression of this triad of symptoms as well as impaired frontal executive function [2]. *Correspondence: ville.leinonen@kuh.fi; ville.leinonen@uef.fi 1 Department of Neurosurgery, Kuopio University Hospital, P.O. Box 100, 70029 KYS Kuopio, Finland Full list of author information is available at the end of the article identified in neuropathological studies and studies using frontal cortical biopsies in iNPH [6,7,8].

Results

Conclusion