From the Guidelines
Normal pressure hydrocephalus (NPH) is a neurological condition characterized by an abnormal buildup of cerebrospinal fluid in the brain's ventricles, despite normal pressure readings during spinal tap testing. It typically affects older adults and presents with a classic triad of symptoms:
- difficulty walking (gait disturbance)
- urinary incontinence
- cognitive decline or dementia. The condition occurs when cerebrospinal fluid is not properly absorbed, causing the ventricles to enlarge and put pressure on surrounding brain tissue. Diagnosis involves brain imaging, with MRI head without IV contrast or CT head without IV contrast being usually appropriate for the initial imaging 1. This is because these procedures are equivalent alternatives, providing the necessary clinical information to effectively manage the patient’s care 1. The primary treatment for NPH is surgical placement of a shunt, typically a ventriculoperitoneal (VP) shunt, which diverts excess cerebrospinal fluid from the brain to another part of the body where it can be absorbed. Early diagnosis and treatment are crucial, as NPH is one of the few potentially reversible causes of dementia, with many patients showing significant improvement in walking, bladder control, and cognitive function after shunt placement. Without treatment, symptoms typically worsen progressively over time. Key aspects of NPH management include:
- Prompt recognition of symptoms
- Accurate diagnosis through imaging and clinical evaluation
- Timely surgical intervention to prevent further decline and improve quality of life.
From the Research
Definition and Characteristics of Normal Pressure Hydrocephalus
- Normal pressure hydrocephalus (NPH) is a reversible disorder characterized by gait impairment, subcortical dementia, and urinary urgency and incontinence associated with impaired cerebrospinal fluid circulation and ventriculomegaly 2.
- NPH is a clinical triad of gait disturbance, dementia, and urinary incontinence combined with radiographic findings of ventriculomegaly and laboratory findings of normal cerebrospinal fluid pressures 3.
- The disorder is characterized by a triad of symptoms: gait disturbance, dementia, and urinary incontinence 4.
Diagnosis and Treatment
- Early diagnosis increases the rate of success to treatment, making accurate diagnosis and identification of responders to treatment important 3.
- Treatment with shunt surgery is most likely to increase mobility, and may also improve dementia and urinary symptoms 2.
- The treatment of choice is cerebrospinal fluid diversion with a shunt 4.
- The CSF tap test (CSF-TT) can be used to evaluate gait characteristics in patients with idiopathic NPH and investigate the effect of the CSF-TT on gait 5.
Pathogenesis and Clinical Features
- Hydrocephalus is an abnormal accumulation of cerebrospinal fluid (CSF) in the cerebral ventricles, usually caused by impaired absorption of the fluid into the bloodstream 6.
- The clinical features of normal pressure hydrocephalus include sustained ventricular dilatation despite normal VCSFP, increased periventricular fluid content, and localized periventricular white matter damage 6.
- NPH is estimated to be the cause of about 5% of cases of dementia and is one of the few reversible causes of dementia 3.