About hydrocephalus

Hydrocephalus is a condition in which excess cerebrospinal fluid accumulates inside the brain

This condition may occur by itself or as a complication of a different brain disorder. In most cases, the term "hydrocephalus" is used for conditions in which the cerebral ventricles (chambers inside the brain filled with cerebrospinal fluid) are enlarged, but conditions also exist in which hydrocephalus cannot be determined on the basis of enlargement of the cerebral ventricles alone, and a diagnosis is then made by taking the overall condition of the patient into account. Hydrocephalus is categorized as "congenital" if it occurs as an inborn abnormality, or "acquired" if it arises after birth.

Cerebrospinal fluid and the cerebral ventricles

Cerebrospinal fluid is believed to function as a protective fluid that bathes the entire brain and spinal cord. It is a colorless, clear liquid that not only holds the brain suspended, softening the shock imparted by sharp movements of the head, but also acts to remove substances produced during the activities of parts of the brain. It is produced (from components of the blood) by a structure called the choroid plexus, which is found in the chambers (cerebral ventricles) that store the cerebrospinal fluid already present in the brain. This fluid is known to flow according to a specific pattern, circulating at a speed that means it is entirely replaced around three times a day.

The four ventricles within the brain comprise a structure linked together by separate channels, with cerebrospinal fluid generated inside, stored to some extent within the chambers, and circulating from chamber to chamber.

The cerebrospinal fluid that finally leaves the ventricles spreads out between the arachnoid membrane (one of the membranes that protects the brain) and the brain itself, and returns to the blood via absorption. Of course, cerebrospinal fluid also circulates around the spinal cord, which is connected to the brain.

Does hydrocephalus only affect children?

Hydrocephalus in children has been known for many years as a condition that results in enlargement of the head. The cranium is composed of a number of different bones joined together, but for some time after birth, these joints between the bones remain weak and soft. In children with congenital hydrocephalus and those who develop it while the joints between the cranial bones are still soft, pressure from the enlarged ventricles containing excess fluid can cause the cranial bones to be continuously pushed apart, resulting in the head becoming enlarged. Once the joints between the bones have become firm, the head will not enlarge, and this is also true for adults. Due to this characteristic, hydrocephalus is well known in children, but in fact it can occur at any age.

The best-known form of hydrocephalus in adults is called normal-pressure hydrocephalus (NPH) or idiopathic normal pressure hydrocephalus (iNPH). This occurs in older adults. A more detailed explanation of this condition is given in the section on "Normal-pressure hydrocephalus."

>> Normal-pressure hydrocephalus.

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