Medical Definitions

Medical Definitions*

Acquired Hydrocephalus - Resulting from an outside factor; not inherited nor congenital

Aqueductal Stenosis - A blockage or narrowing of the path from the third to the fourth ventricle

Arachnoid Granulations - Protrusions of the arachnoid membrane of the brain. The arachnoid villi (or granulations) are very similar to a one-way valve, as they allow the CSF to drain from the subarachnoid space into the superior sagittal sinus, where it can be reabsorbed into the blood system

Benign External Hydrocephalus - (Also referred to as External Hydrocephalus.) An accumulation of CSF found on the outside of the brain, which usually presents itself at birth or soon thereafter. The child's head size will increase, but scans show no internal problems in the ventricles or pathways. The condition corrects itself within about 18 months of age (of the child)

Cerebrospinal Fluid (CSF) - The water-type fluid that bathes the brain and spinal cord

Cisterns – Closed spaces that serve as reservoirs at the base of the brain that bathe the surfaces of the brain and spinal cord, and then is absorbed into the bloodstream

Communicating Hydrocephalus - A type of hydrocephalus where the pathways and the ventricular system are not obstructed, however, the problem appears to be that of re-absorption of the used CSF

Congenital Hydrocephalus - A child diagnosed in utero or at the time of birth as having hydrocephalus

Diagnosis - Identification of a disease or disorder by a physician

Distal - (Catheter) - The catheter connected to the shunt valve and directed to the point where the CSF can drain and be re-absorbed

Encephalocele – A hole in the bony covering of the spinal cord through which portions of the brain, spinal cord or meninges may herniate

Endoscopic Third Ventriculostomy - A surgery in which a hole is punctured in the floor of the third ventricle. This allows a new pathway for the CSF to be absorbed by the body

Hydrocephalus - is derived from the Greek words "hydro" meaning water and "cephalus" meaning head. As its name implies, hydrocephalus is a condition in which the primary characteristic is excessive accumulation of fluid in the brain.

Intraventricular Hemorrhage (IVH) - A bleed within the ventricular system of the brain (also referred to as a brain bleed)

Lateral Ventricles - There are two, one on each side of the brain

Lumbar Tap - (Also called Lumbar Puncture and/or a Spinal Tap) The insertion of a hollow needle to remove some of the CSF either for pathological testing (i.e. for infection), or to relieve some pressure and see if the patient improves

Lethargic - Drowsy inactive reluctance or inability to move or respond to stimuli

Meningitis – An infection of the lining of the brain

Non-Communicating Hydrocephalus - Hydrocephalus that is caused by an obstruction in the flow of the CSF

Normal Pressure Hydrocephalus - Type of hydrocephalus, where the ventricles are enlarged but there is no obstruction in the ventricular system. The cause appears to be that the CSF is not being absorbed

Papilledema - is swelling of the optic disk, which is part of the optic nerve

Prognosis - Probable outcome of a disease

Programmable Shunt - Type of shunt where the physician can raise or lower the amount of CSF taken from the brain

Proximal (Catheter) - A catheter that is placed in the ventricle of the brain

Reservoir - Part of the shunt where the CSF is stored and then released periodically

Revision - When an operation is needed to replace part or all of the shunt

Shunt - A tube implanted in the cranium to balance the flow of cerebrospinal fluid;  used in the treatment of hydrocephalus

Spina Bifida – A condition that is present at birth which can affect the development of the back bones, spinal cord, surrounding nerves, and the fluid- filled sac

Subarachnoid - Space where CSF travels over the surface of the brain and the spinal cord

Tesla - Unit of measurement to determine the strength of a magnet

Urinary Incontinence - Inability to hold urine in the bladder.

Valve - Which controls how much CSF is taken from the brain

Ventricles - Four chambers of the brain that produce the CSF - lateral ventricles (2), one on each side of the hemispheres which then flows into the third ventricle, which is located in the center of the brain, and onto the fourth ventricle, which is located in the lower back of the skull

Ventriculo-Artial (VA) Shunt - Type of shunt where the distal catheter tip lies in the right atrium of the heart. This allows the CSF to enter the bloodstream directly

Ventriculo-Pleural Shunt - Type of shunt where the distal catheter is located in the pleural space that surrounds the lungs

Ventroperitional (VP) Shunt - Type of shunt where the distal catheter is located in the lower part of the abdomen

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