Normal pressure hydrocephalus occurs when there is an increase in intracranial pressure (ICP) due to an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can cause ventriculomegaly. 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. Measurements of CSF, therefore, are not usually elevated. Because of this equilibration, patients do not exhibit the classic signs that accompany increased intracranial pressure such as headache, nausea, vomiting, or altered consciousness. (Though some studies have shown pressure elevations to occur only intermittently). However, the enlarged ventricles put increased pressure on the adjacent cortical tissue and cause myriad effects in the patient. Although the exact mechanism is unknown, normal-pressure hydrocephalus is thought to be a form of communicating hydrocephalus with impaired CSF reabsorption at the arachnoid granulations. There are 2 types of normal pressure hydrocephalus: idiopathic and secondary. The term idiopathic means that it has no known cause. The secondary type of NPH can be due to a subarachnoid haemorrhage, head trauma, tumour, CNS infection, or a complication of cranial surgery. NPH may exhibit a classic triad of clinical findings (known as the Adams triad or Hakim's triad) of urinary incontinence, gait disturbance, and dementia (commonly referred to as "wet, wobbly and wacky" or "weird walking water").

http://purl.obolibrary.org/obo/ND_0000175

symptomatic hydrocephalus

NPH

Normal pressure hydrocephalus occurs when there is an increase in intracranial pressure (ICP) due to an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can cause ventriculomegaly. 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. Measurements of CSF, therefore, are not usually elevated. Because of this equilibration, patients do not exhibit the classic signs that accompany increased intracranial pressure such as headache, nausea, vomiting, or altered consciousness. (Though some studies have shown pressure elevations to occur only intermittently). However, the enlarged ventricles put increased pressure on the adjacent cortical tissue and cause myriad effects in the patient. Although the exact mechanism is unknown, normal-pressure hydrocephalus is thought to be a form of communicating hydrocephalus with impaired CSF reabsorption at the arachnoid granulations. There are 2 types of normal pressure hydrocephalus: idiopathic and secondary. The term idiopathic means that it has no known cause. The secondary type of NPH can be due to a subarachnoid haemorrhage, head trauma, tumour, CNS infection, or a complication of cranial surgery. NPH may exhibit a classic triad of clinical findings (known as the Adams triad or Hakim's triad) of urinary incontinence, gait disturbance, and dementia (commonly referred to as "wet, wobbly and wacky" or "weird walking water").

Alexander P. Cox

http://en.wikipedia.org/wiki/Normal_pressure_hydrocephalus

normal pressure hydrocephalus

ND:0000175

normal pressure hydrocephalus

http://purl.obolibrary.org/obo/ND_0000001