- Normal pressure hydrocephalus (NPH)
- Hydrocephalus is an abnormal buildup of cerebrospinal fluid (CSF) in the brain. The fluid (the CSF) is often under increased pressure which can compress and damage the brain. Normal pressure hydrocephalus (NPH) is a specific form of hydrocephalus which is due usually to a gradual blockage of the CSF drainage pathways in the brain. NPH is an unusual cause of dementia which can occur as a complication of brain infection or bleeding (hemorrhage). In some patients no predisposing cause can be identified.In patients with NPH, although central cavities of the inner brain (the ventricles) enlarge, the pressure of the CSF remains within normal range. NPH is characterized by gradual loss of memory loss (dementia), balance disorder (ataxia), incontinence of urine and a general slowing of activity. Symptoms progressively worsen over weeks. In some patients, an improvement of symptoms is noted immediately after removal of spinal fluid with lumbar puncture. Hydrocephalus, in general, can arise before birth or any time afterward. It may be due to many causes including a birth defect, hemorrhage into the brain, infection, meningitis, tumor, or head injury. Most forms of hydrocephalus are the result of obstructed CSF flow of normal cavities called ventricles in the center of the brain. With birth defects, physical obstruction of CSF flow in the ventricular system is usually the cause of the hydrocephalus. Hydrocephalus is a commonly associated with the birth defect spina bifida (meningomyelocele). What is termed "hydrocephalus ex-vacuo" occurs when there is damage to the brain caused by stroke or injury, and there may be an actual shrinkage of brain substance. Although there is more CSF than usual, the CSF pressure itself is normal in hydrocephalus ex-vacuo. In old age or persons with Alzheimer's disease, the entire brain may shrink and the CSF fills up the space created by the shrinkage. This is not due to hydrocephalus or related to it. The signs and symptoms of hydrocephalus depend upon the age of the person: In infants the most obvious sign of hydrocephalus is usually an abnormally large head. This occurs because of the constant outward pressure on the brain and skull from the hydrocephalus during the development and growth of the head. (That is one reason a baby's head should be measured at every well-baby visit). Symptoms of hydrocephalus in an infant may include vomiting, sleepiness, irritability, an inability to look upwards, and seizures. In older children and adults, there is no head enlargement from hydrocephalus, but symptoms may include headache, nausea, vomiting and, sometimes, blurred vision. There may be problems with balance, delayed development in walking or talking, and poor coordination. Irritability, fatigue, seizures, and personality changes such as an inability to concentrate or remember things may also develop. Drowsiness and double vision are common symptoms as hydrocephalus progresses.
Medical dictionary. 2011.