Normal Pressure Hydrocephalus (NPH)
Normal pressure hydrocephalus (NPH) is a cerebrospinal fluid circulation disorder, usually seen after age 60, presenting with a triad of gait disturbance, cognitive decline, and urinary incontinence. It is one of the treatable causes of dementia, and selected patients may benefit from shunt surgery.
Última atualização: 2026-06-07
Definition
Normal pressure hydrocephalus is a communicating (non-obstructive) type of hydrocephalus in which the brain's ventricles enlarge while cerebrospinal fluid (CSF) pressure remains largely within normal limits on measurement. It is classically recognized by the Hakim triad: gait disturbance, cognitive decline (dementia-like), and urinary incontinence. Because it is one of the treatable causes of dementia, early diagnosis is important.
Causes and Risk Factors
A substantial proportion of cases are idiopathic (primary) NPH of incompletely understood cause and associated with advanced age. Secondary NPH may develop after prior subarachnoid hemorrhage, head trauma, meningitis, or brain surgery. The underlying mechanism is not fully clarified; proposed theories include impaired CSF absorption, increased pulsatile CSF flow, and reduced brain compliance.
Symptoms
Gait disturbance is the first and most prominent symptom in most cases; a small-stepped, broad-based, 'magnetic' gait with feet seeming stuck to the floor and difficulty turning is typical, and falls are common. Cognitive decline usually manifests as slowing of attention, planning, and psychomotor speed, with memory less affected than in Alzheimer disease. Urinary incontinence progresses from urgency to loss of control. The symptoms may occur together or individually.
Diagnosis
On brain MRI the ventricles are enlarged while the surface sulci are not markedly widened; the combination of an enlarged Sylvian fissure with narrowed high-convexity sulci (the DESH sign) raises the likelihood of NPH. CSF removal tests are used to support the diagnosis and predict the chance of benefit from shunting: removing a quantity of CSF by lumbar puncture and measuring gait (tap test), or external lumbar drainage over several days. The differential diagnosis includes Alzheimer disease, Parkinson disease, and vascular dementia.
Treatment
The principal treatment for NPH is placement of a ventriculoperitoneal (VP) shunt, which diverts excess CSF to the abdominal cavity. Adjustable (programmable) valves are preferred because pressure can be set externally after surgery as needed, allowing management of over- or under-drainage. Patients with a positive tap test or drainage test have higher response rates. Physical therapy and rehabilitation support postoperative recovery.
Prognosis
In suitable patients, the most evident improvement after shunting is in gait; urinary incontinence and cognitive symptoms may also improve to varying degrees. Improvement is usually gradual over weeks to months. Response is better in patients with a short symptom duration, prominent gait disturbance, and positive tests. Because complications such as shunt-related subdural collection, infection, and shunt malfunction can occur, regular follow-up is required. Outcomes are individual and none can be guaranteed.
Referências
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:438-447.
- Winn HR, ed. Youmans Neurological Surgery. 6th ed. Saunders; 2011:495-514.
- Nakajima M, Yamada S, Miyajima M, et al. Guidelines for management of idiopathic normal pressure hydrocephalus (third edition). Neurol Med Chir (Tokyo). 2021;61(2):63-97.
Este artigo é informativo e não substitui um exame médico. As decisões de diagnóstico e tratamento são individuais.