24,070views
00:00 / 00:00
de completadas
de completadas
2024
2023
2022
2021
normal pressure hydrocephalus p. 536
In normal pressure hydrocephalus, hydrocephalus can be broken down into “hydro” which means water and “cephalus” which means head.
Hydrocephalus, which is also termed as “water on the brain”, is an excessive buildup of cerebrospinal fluid within the brain.
Even though the pressure on lumbar puncture is expected to be increased, in this case, it’s normal, which is why it’s termed as “normal pressure” hydrocephalus.
Let's start with some relevant anatomy. The brain has four interconnected cavities in the brain called ventricles, and each one contains a structure called a choroid plexus.
The choroid plexus is made up of ependymal cells which produces cerebrospinal fluid - a fluid that helps provide buoyancy and protection, as well as metabolic fuel for the brain.
Highest up, are two C-shaped lateral ventricles that lie deep in each cerebral hemisphere.
The two lateral ventricles drain their cerebrospinal fluid into the third ventricle, which is a narrow, funnel-shaped, cavity at the center of the brain.
The third ventricle makes a bit more cerebrospinal fluid and then sends all of the cerebrospinal fluid to the fourth ventricle via the cerebral aqueduct.
The fourth ventricle is a tent-shaped cavity located between the brainstem and the cerebellum.
After the fourth ventricle, the cerebrospinal fluid enters the subarachnoid space, which is the space between the two inner linings of the brain - the arachnoid and pia mater.
Now, the arachnoid mater protrudes into the outermost covering, called dura mater, at various points.
Normal pressure hydrocephalus is a condition characterized by ventricular enlargement, without an increase in cerebrospinal fluid pressure on lumbar puncture. Cerebrospinal fluid (CSF) accumulates slowly and gradually in the ventricles, causing them to dilate. Ventricular dilation restores the CSF pressure to the normal level, hence the normal findings on lumbar puncture.
People with normal pressure hydrocephalus present with urinary incontinence, gait disturbances, and dementia. The excess amount of CSF can be temporarily drained through a lumbar puncture, but the long-term management is a surgical procedure called a ventriculoperitoneal shunt, in which a tube is inserted into one of the ventricles of the brain and directed to the abdomen, where the excess CSF can be absorbed.
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.