chapter  16
18 Pages

Normal Pressure Hydrocephalus

ByThomas A. Krefft, Neill R. Graff-Radford

Normal pressure hydrocephalus (NPH), also termed symptomatic hydrocephalus, may cause

dementia in up to 6% of patients (2) and thus not infrequently enters the differential diagnosis of

dementia. The diagnosis and treatment of NPH are problematic. The cardinal symptoms (gait

difficulty, cognitive decline, and incontinence of urine) are not pathognomonic for the diagnosis,

commonly occur in the elderly (3-5), and may be caused by multiple disease processes. Cerebral

ventricle size increases with age (6) and in common dementing illnesses such as Alzheimer’s

disease (AD) (7), so that ventriculomegaly is frequent in an older population. Current diagnostic

tests for NPH give both false positive and false negative results. Its surgical treatment carries

important short and long term risks. Finally, the cause or pathogenesis of many NPH cases is

unknown. This chapter will address the reasons why the diagnosis is difficult as well as the

differential diagnosis, features of the history, examination, and neuropsychological assessment in

NPH that may help clinicians with management. It also will discuss the radiological evaluation,

including computed tomography (CT), magnetic resonance imaging (MRI), cisternography and

single photon emission tomography (SPET), and special testing including lumbar puncture (LP),

continuous cerebrospinal fluid (CSF) drainage, CSF absorption tests, and CSF pressure monitoring.