Normal-pressure hydrocephalus

Normal-pressure hydrocephalus

Normal-pressure hydrocephalus (NPH) is a neurological disorder characterized by the triad of gait disturbance, dementia, and urinary incontinence, with normal cerebrospinal fluid (CSF) pressure. It is a type of hydrocephalus that typically affects older adults and can often be misdiagnosed as other neurodegenerative conditions such as Alzheimer's disease or Parkinson's disease.

Pathophysiology

NPH is caused by an imbalance between the production and absorption of cerebrospinal fluid, leading to an accumulation of CSF in the brain's ventricles. This results in ventricular enlargement, which can compress surrounding brain tissue and lead to the characteristic symptoms. Despite the enlarged ventricles, the CSF pressure remains within normal limits, hence the term "normal-pressure."

Symptoms

The classic triad of symptoms associated with NPH includes:

• Gait disturbance: Often the most prominent and earliest symptom, it is characterized by a broad-based, shuffling walk, similar to that seen in Parkinson's disease.
• Cognitive dysfunction: This can range from mild memory problems to more severe dementia-like symptoms, affecting daily activities and quality of life.
• Urinary incontinence: Patients may experience urgency, frequency, or a complete loss of bladder control.

Diagnosis

Diagnosing NPH can be challenging due to symptom overlap with other conditions. The following methods are commonly used:

• Clinical evaluation: Assessment of the symptom triad and medical history.
• Neuroimaging: Magnetic resonance imaging (MRI) or computed tomography (CT) scans are used to identify ventricular enlargement.
• CSF tests: A lumbar puncture or CSF tap test may be performed to assess symptom improvement after CSF removal.

Treatment

The primary treatment for NPH is the surgical insertion of a ventriculoperitoneal shunt, which diverts excess CSF from the brain to the abdominal cavity, where it can be absorbed. This procedure can lead to significant improvement in symptoms, particularly gait and urinary function.

Prognosis

The prognosis for patients with NPH varies. Early diagnosis and treatment can lead to substantial improvement in symptoms, but delayed treatment may result in irreversible damage. Regular follow-up is essential to monitor shunt function and manage any complications.

Also see

• Hydrocephalus
• Alzheimer's disease
• Parkinson's disease
• Ventriculoperitoneal shunt

Classification
External resources