Normal pressure hydrocephalus (NPH) is a chronic type of communicating hydrocephalus whereby the increase in intracranial pressure (ICP) due to accumulation of cerebrospinal fluid (CSF) becomes stable and that the formation of CSF equilibrates with absorption. The ICP gradually falls but still maintains a slightly elevated level and the CSF pressure reaches a high normal level of 150 to 200 mmH₂O. Because of this equilibration, patients do not exhibit the classic signs of increased intracranial pressure such as headache, nausea, vomiting, or altered consciousness. It is often misdiagnosed as Parkinson's disease, Alzheimer's disease, and senility due to its chronic nature and its presenting symptoms [see below]. The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) is a detailed description of known diseases and injuries. ... The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) is a detailed description of known diseases and injuries. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... Intracranial pressure, or ICP, is the pressure of the brain, Cerebrospinal fluid (CSF), and the brains blood supply within the intracranial space. ... Intracranial pressure, or ICP, is the pressure of the brain, Cerebrospinal fluid (CSF), and the brains blood supply within the intracranial space. ...

Clinical manifestations

NPH may exhibit the classic triad of urinary incontinence, wide-based ataxic gait, and dementia. Urinary incontinence is the involuntary excretion of urine from ones body. ... Ataxia (from Greek ataxiā, meaning failure to put in order) is unsteady and clumsy motion of the limbs or trunk due to a failure of the gross coordination of muscle movements. ... For other senses of this word, see dementia (disambiguation). ...

• Gait disturbance is usually progressive, due to expansion of the ventricular system, particularly at the level of the lateral ventricles, leading to traction on the sacral motor fibers that run in this region. Often, this takes on the form of unsteadiness and impaired balance, especially on stairs and curbs. Weakness and tiredness may also be part of the complaint, although this is very vague. The gait may represent that in Parkinson's disease, with short shuffling steps and stooped, forward-leaning posture, but there is no rigidity or tremor.

• Dementia is predominantly frontal lobe in nature, with apathy, dullness in thinking, and slight inattention. Memory problems are usually the main problem, which can lead to the misdiagnosis of Alzheimer's disease. The dementia is thought to result from traction on limbic fibers that also run in the periventricular region.

• Urinary incontinence appears late in the illness, consisting of increased frequency and urgency. Ultimately, the patient may exhibit "frontal lobe incontinence," where he becomes indifferent to his recurrent urinary symptoms.

Diagnosis

Diagnosis of NPH is usually first led by a lumbar puncture, followed by the evaluation of clinical response to removal of CSF. This can be followed by a CT, MRI, or radionuclide cisternography. A patient undergoes a lumbar puncture at the hands of a neurologist. ... CAT apparatus in a hospital Computed axial tomography (CAT), computer-assisted tomography, computed tomography, CT, or body section roentgenography is the process of using digital processing to generate a three-dimensional image of the internals of an object from a large series of two-dimensional X-ray images taken around... This article or section does not cite its references or sources. ...

• Lumbar puncture is usually the first step in diagnosis and the opening pressure measured carefully. In most cases, CSF pressure is usually above 155 mmH₂O. Clinical improvement after removal of CSF (20 to 30 mL or more) has a high predictive value for subsequent success with shunting.

• CT scan may show enlarged ventricles without convolutional atrophy.

• MRI may show some degree of transependymal egress of water surrounding the ventricles.

Treatment

NPH may be relieved by surgically implanting a ventriculoperitoneal shunt to drain excess cerebrospinal fluid to the abdomen where it is absorbed. Once the shunt is in place, the ventricles diminish in size in 3 to 4 days, regardless of the duration of the hydrocephalus. Most patients who have continued success with such shunts usually only have two of the three triads (excluding incontinence). In medicine, a shunt is a device designed to drain excess cerebrospinal fluid from the brain and carry it to other parts of the body. ...

External links

• About NPH
• Normal Pressure Hydrocephalus
• eMedicine: NPH