Hydrocephalus: causes, types and treatments

Cerebrospinal fluid is a substance of great importance for the maintenance of the brain. It is a vital element to keep nerve tissue floating, Cushioning possible blows, maintaining the pressure level and electrochemical balance of the nervous system, helping to keep their cells nourished and eliminating the waste generated by their functioning.

With a life cycle that begins with its synthesis in the lateral ventricles and ends with its reabsorption into the bloodstream, cerebrospinal fluid is continuously synthesized, generally maintaining a constant balance between the amount of this liquid substance that is being synthesized. and who is absorbed. However, this balance can be altered, causing serious problems with excess or fluid deficiency. This is the case with hydrocephalus.

Hydrocephalus: its typical symptoms

Hydrocephalus is a disorder in which, for various reasons, excess cerebrospinal fluid appears, inflate the cerebral ventricles and / or the subarachnoid space and producing a high level of pressure on the rest of the brain material against the skull or between different brain structures.

Hydrocephalus is a problem that, if left untreated, can be fatal, especially if the areas of the brainstem that regulate vital signs are under pressure. The pressure exerted on different parts of the brain will produce a number of symptoms which may vary depending on the parts being pressed. In addition to this, the subject’s age and tolerance to CSF ​​also affect the onset of certain symptoms.

However, some of the more common symptoms are headache, nausea and vomiting, double or blurred vision, problems with balance and coordination during movement and walking, drowsiness, irritability, stunted growth and intellectual disability if it occurs during the period of neurodevelopment, alterations in consciousness or changes in personality or memory

In newborns who do not yet have the bones of the skull completely closed, it is typical to observe vomiting, convulsions or a tendency to look down. Sometimes, in addition, hydrocephalus can produce macrocephaly, which is an exaggerated enlargement of the head in which the meninges and bones are squeezed.

the causes

There are many possible causes of excessive cerebrospinal fluid, but it can generally be considered to be due to two groups of possible causes. Hydrocephalus usually occurs either when the normal flow of cerebrospinal fluid is blocked at any given time, or when the balance between synthesis and absorption of this substance is upset, Either because too much is secreted or because it cannot be reabsorbed by the blood.

But these hypotheses can be reached in very different ways, whether it is congenital or acquired hydrocephalus. Some of the causes can be deformities such as spina bifida or that the spine does not close before birth (a problem known as myelomeningocele), as well as genetic type difficulties.

Throughout the development of life, situations can also occur that eventually cause this problem. Traumatic brain injury that causes internal bleeding (Eg in the subarachnoid space) can cause blockage of fluid flow. Tumors that pinch or squeeze the pathways through which cerebrospinal fluid circulates are another possible cause. Some infections, including meningitis, can also affect the normal flow of this substance.

Hydrocephalus subtype

Hydrocephalus is a problematic and very dangerous medical condition for the life and normal functioning of human beings. This disorder can be congenital, in which it appears as a consequence of prenatal situations such as malformations, genetic predisposition, trauma or intoxication in the fetal or acquired phase during childbirth or at a later point in the life cycle.

The problem itself is in all cases too much cerebrospinal fluid. which induces different problems due to the pressure caused in the brain, but depending on the cause, they can find different types of hydrocephalus.

1. Communicate hydrocephalus

We call hydrocephalus communicating this situation in which it occurs a blockage after cerebrospinal fluid leaves the ventricles. In other words, the problem is not in the ventricles, through which the cerebrospinal fluid normally circulates, but the cause is an alteration of the parts of the arachnoid that connect to the blood vessels.

2. Obstructive or non-communicating hydrocephalus

Obstructive is the type of hydrocephalus in which the problem can be found in the fact that the ventricles or the ducts that connect them are impaired and do not allow proper flow. This type of hydrocephalus is one of the most common, Being particularly frequent that the reason is in an aqueduct of Silvio (conduit that communicates the third and fourth ventricles) excessively narrow.

3. Hydrocephalus ex-vacuide

Ex-vacuide hydrocephalus occurs when, for some reason, a loss or decrease in brain mass or density has been caused. Faced with this loss, usually due to the death of neurons following trauma, bleeding or neurodegenerative processes such as dementia, the ventricles have more space available inside the skull, which eventually dilates them (filling of cerebrospinal fluid) until it occupies the available. space. It is therefore about a type of passive hydrocephalus, Which does not correspond to an alteration of the normal functioning of the cerebrospinal fluid.

4. Normotensive hydrocephalus

A subtype that occurs particularly in the elderly, this type of hydrocephalus appears to be due to poor reabsorption of cerebrospinal fluid, in a manner similar to communicating hydrocephalus. However, in this case, even if the amount of liquid is excessive, the pressure at which it circulates is practically normal (Hence its name).

The fact that it usually occurs in older people and the symptoms it causes are similar to those typical of dementia processes (memory loss, walking problems, urinary incontinence, slowing down and loss of cognitive function) means that ‘it is often not detected. , which makes processing difficult.

Treatments applied in these cases

Prompt action in hydrocephalus is essential to prevent the problem from causing further difficulty. It should be noted that the cerebrospinal fluid does not stop secreting and that the blockage or deregulation of the flow can cause the areas where the fluid is in excess to stop the swelling and cause more and more injuries and swelling. damage. this class of complications.

While treating the cause of hydrocephalus is necessary and the treatment of this factor will depend on the cause itself (if it is due to an infection, inflammatory process or tumor, there will be different ways to treat the case), the first thing to do is to eliminate excess liquid in if to avoid further damage.

The treatments used in these cases they are surgical in nature, The most applied being the following.

extracranial shunt

One of the most applied treatments in these cases, the extracranial shunt, has a relatively easy to understand operation: it involves removing excess fluid from the cranial cavity and sending it to another place in the body where it is does not produce alterations, usually any of the cerebral ventricles or the blood system. The basic procedure is to place a catheter between the zone from which the transfer is to be made to the area where the flow is to be redirected, by placing a valve that regulates that the drainage is neither insufficient nor excessive.

Although this is the most common and widely used treatment, it should be noted that for some reason the drainage stops working, the problem will reoccur, so this resolution could only be temporary. That is why even while performing this intervention, it is still necessary to investigate the causes that caused hydrocephalus and treat them as much as possible. It is currently used less and less, preferring other treatments.

Endoscopic ventriculostomy of the third ventricle

This intervention is based, like the previous one, on the creation of a drainage path allowing the elimination of excess liquid. However, in this case it would be an internal and endogenous drainage path, Producing a small opening in the third ventricle that would allow excess fluid to drain into the blood (where it would naturally end). This is usually one of the most effective and reliable types of intervention.

Choroid plexus cauterization

If the problem with hydrocephalus is caused because the cerebrospinal fluid is too synthesized or not reabsorbed quickly enough, one treatment option is cauterization or removal of some of the areas that make it. .

This way, cauterization of some of the choroid plexuses that secrete cerebrospinal fluid (Not all of them, because renewal of it is necessary for the proper functioning of the brain) will reduce the speed at which the flow circulates. It is generally used in conjunction with a ventriculostomy. However, it is one of the most invasive forms of intervention.

Bibliographical references:

  • Kinsman, SL; Johnston, MV (2016), Congenital anomalies of the central nervous system. A: Kliegman, RM; Stanton, BF; Saint-Geme, JW; Schor, NF (ed.). Nelson Handbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier ;: chap. 591.
  • Rosenberg, Georgia (2016). Cerebral edema and cerebrospinal fluid circulation disorders. A: Bradley, WG; Daroff, RB; Pomeroy, SL; Mazziotta, JC; Jankovic, J. (ed.). Bradley: Neurology in Clinical Practice. 7th ed. Philadelphia, by: Elsevier Saunders; 88.
  • Zweckberger, K .; Sakowitz, OW; Unterberg, AW et al. (2009). Intracranial pressure-volume relationship. Physiology and pathophysiology Anesthesiologist. 58: 392-7.

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