Normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH), also called malresorptive hydrocephalus, is a form of communicating hydrocephalus in which excess cerebrospinal fluid (CSF) builds up in the ventricles, leading to normal or slightly elevated cerebrospinal fluid pressure. The fluid build-up causes the ventricles to enlarge and the pressure inside the head to increase, compressing surrounding brain tissue and leading to neurological complications. Although the cause of idiopathic (also referred to as primary) NPH remains unclear, it has been associated with various co-morbidities including hypertension, diabetes mellitus, Alzheimer's disease, and hyperlipidemia. Causes of secondary NPH include trauma, hemorrhage, or infection. The disease presents in a classic triad of symptoms, which are memory impairment, urinary frequency, and balance problems/gait deviations (note: use of this triad as the diagnostic method is obsolete; the triad symptoms appear at a relatively late stage, and each of the three can be caused by a number of other conditions). The disease was first described by Salomón Hakim and Raymond Adams in 1965. The usual treatment is surgical placement of a ventriculoperitoneal shunt to drain excess CSF into the lining of the abdomen where the CSF will eventually be absorbed. An alternate, less invasive treatment is endoscopic third ventriculostomy. NPH is often misdiagnosed as other conditions including Meniere's disease (due to balance problems), Parkinson's disease (due to gait) or Alzheimer's disease (due to cognitive dysfunction).