Normal pressure hydrocephalus is also called adult onset hydrocephalus. It's the abnormal buildup of fluid, cerebrospinal fluid or CSF, within the brain’s cavities--also called ventricles. According to the National Institute of Neurological Diseases and Stroke, NINDS, this occurs due to an obstruction to the normal flow of CSF throughout the brain and spinal cord. Most of these cases are seen in people older than 60, according to the American Association of Neurological Surgeons. The AANS says that in most cases, the cause of normal pressure hydrocephalus is unknown. Several known factors are documented as causes of normal pressure hydrocephalus in the other cases.
Trauma and Surgery
Head trauma from falls, sports injuries or motor vehicle accidents could result in damage of structures in the brain and hemorrhage into the brain, with later development of normal pressure hydrocephalus. Subdural hematoma, developing after such trauma, is also a possible cause of normal pressure hydrocephalus. The AANS also mentions complications of intracranial surgery as a possible cause of normal pressure hydrocephalus.
Infections
Meningitis--an inflammation of the covering of the brain and spinal cord, the meninges, brought on by infections--is one of the possible causes of normal pressure hydrocephalus mentioned by the National Institutes of Health, NIH. The scarring that's a part of the healing process in meningitis can lead to the obstruction of CSF flow. Subdural abscesses and other intracranial infections can also lead to the development of normal pressure hydrocephalus later in life.
Brain Tumors
Brain tumors can obstruct the flow of CSF within the brain and spinal cord, leading to the development of normal pressure hydrocephalus. According to the American Cancer Society, ACS, ependymomas--brain tumors that arise from the cells lining the ventricles--are known for obstructing the flow of CSF within the ventricles. Other tumors elsewhere in the brain, such as meningiomas, oligodendrogliomas and astrocytomas, may also grow to compress the ventricles and obstruct the flow of CSF.
Other Possible Causes
Subarachnoid hemorrhage, a form of intracranial hemorrhage seen in disease states such as congenital intracranial aneurysms and severe hypertension, is mentioned by NINDS as a possible cause of normal pressure hydrocephalus. Other causes of intracranial hemorrhage--such as the use of blood thinners including warfarin, arteriovenous malformations and bleeding disorders--can also result in the development of normal pressure hydrocephalus.
