The brain edema it is the accumulation of fluid between brain cells. As a consequence, this causes an increase in intracranial pressure. It can arise from multiple causes, such as strokes, injuries, bacteria, viruses, tumors, poisoning, or certain drugs.
This condition can quickly cause serious damage, and even lead to death. However, it can be easily detected with some neuroimaging technique, such as magnetic resonance imaging..
If diagnosed early, it can be treated with drugs, ice, and removing excess fluid. Occasionally, surgical procedures must be used to remove intracranial pressure (ICP).
The skull is a thick bone that protects our brain effectively. However, it offers little space when the brain becomes inflamed. Pressure in the brain prevents blood from flowing properly, depriving it of the oxygen it needs to function.
At the same time, the lack of space blocks other fluids in our brain, such as cerebrospinal fluid, which further worsens inflammation. Some brain cells may also be affected or die.
On the other hand, the swelling can occur in specific places or cover the entire brain. This depends on the causative factor.
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Brain edema has a multitude of causative factors. Undoubtedly, it is a response of the brain and a consequence of some type of damage or primary alteration. The causes of brain edema can be:
They arise from a blood clot or a blockage in the blood vessels in or near the brain. In this way, the brain cannot receive the necessary blood and oxygen, so the cells of this organ begin to die..
Brain edema can also appear when blood vessels break anywhere in the brain. As the blood is filtered, the body's response causes an increase in intracranial pressure.
High blood pressure is the most common cause of cerebrovascular accidents, although it can also be due to injuries, medications and malformations present from birth.
It is a sudden damage to the brain from physical contact, such as the rapid acceleration or deceleration of the head.
The most common causes of traumatic brain injury are falls, traffic accidents, hitting objects, etc. The initial injury can cause a swelling in the brain.
It may also be that the broken pieces of the skull break the blood vessels anywhere in the head. The body's response to injury can aggravate inflammation by preventing fluids from leaving the brain..
It is an infection that causes inflammation of a layer that covers and protects the nervous system, the meninges. Meningitis appears due to the action of bacteria, viruses and some medications.
Encephalitis is the inflammation of brain tissue produced by an infectious process. It usually arises from various viruses, and can be spread by insect bites.
It is an infection caused by a parasite that frequently affects individuals who have problems with their immune system. It can be spread by contact with affected animals or contaminated food.
Brain edema can also occur in other infections such as cysticercosis and tuberculosis.
It consists of an accumulation of pus that occurs between the dura mater and the arachnoid layer, one of the layers that make up the meninges.
It appears due to the action of bacteria derived from serious ear infections, head injuries, surgeries in this area or infections in the blood. It can be derived from meningitis.
Tumors also cause brain edema. The development of the tumor involves a proliferation of cells that press certain areas of the brain involved. Thus, the circulation of blood and cerebrospinal fluid is interrupted..
It is a condition in which the liver becomes infected quickly and another must be transplanted. It is produced by different viruses and infections that also damage the nervous system.
Reye's syndrome is a brain inflammation caused by viral infections or by acetylsalicylic acid treatment. It is accompanied by progressive liver disorders.
The entry of these substances into the body is very dangerous, since they can cause brain damage (and, therefore, brain edema).
That is, when the sodium concentration in the blood falls. It seems that the body tries to reach an osmotic balance and compensate for the lack of sodium, causing the entry of water into the cells. This ultimately causes worse results, producing brain edema..
When high altitudes are reached (above 2000 meters), cerebral edema can occur. It is usually associated with acute mountain sickness or high altitude cerebral edema (ACE) or high altitude (ECGA).
Your progress can lead to death if you do not immediately descend to lower areas. This happens due to a lack of dioxygen in the blood, which is known as hypoxia..
Brain edema can also appear after the bite of certain reptiles and marine animals.
Different types of cerebral edema have been defined according to the existing damage.
In the 1960s, Igor Klatzo began the study of cerebral edema. He laid the foundations for the current classification thanks to his experiments on animals. In 1970 he published a study in the Stroke Magazine in which he divided edema into vasogenic and cytotoxic.
Through deeper studies, especially those of Fishman, a new category was added, called interstitial. This classification has made it possible to differentiate the molecular mechanisms of cerebral edema, and has facilitated the strategies for its treatment..
The types of brain edema are described below:
It refers to the influx of fluid and solutes into the brain due to an increase in vascular permeability. That is, there is a breakdown of the blood-brain barrier. Thus, the components of the blood plasma pass from the intravascular space to the extracellular space through the capillary walls..
This is the most common type of edema. The swelling is usually greater in white matter than in gray matter..
Vasogenic edema is associated with brain tumors, as well as inflammatory lesions and head trauma. However, in the latter, the three different types of edema can occur..
There are several subtypes of vasogenic edema; hydrostatic brain edema, cancer brain swelling, and high-altitude brain swelling.
In hydrostatic edema, there is pressure in the capillaries of the brain and an accumulation of fluid in the extravascular area.
In cancer brain edema, cancer glial cells increase the release of vascular endothelial growth factor (VEGF). It is a protein that stimulates the division of endothelial cells, those that make up blood vessels. In addition, it increases vascular permeability. This results in the weakening of the blood-brain barrier..
As for high-altitude cerebral edema, as mentioned above, it occurs when the person is at high altitudes. The hypoxia it causes leads to a leakage of capillary fluid.
It refers to inflammation at the cellular level. Thus, glial cells, neurons, and endothelial cells can swell. This generates the intracellular accumulation of fluid due to the interruption of the activity of ion pumps in the cell membrane..
Cytotoxic edema tends to affect gray matter more than white matter.
It is seen mainly in hydrocephalus and appears when the flow of cerebrospinal fluid is obstructed. This increases intraventicular pressure (in the ventricles or cavities of the brain).
Finally there is a leakage of cerebrospinal fluid into the brain. Specifically, it penetrates between the cells of the white matter.
Cerebral edema represents an approximate 80% increase in the fluid content of the brain. The symptoms of this condition vary and depend on the cause and the level of severity. Generally, they occur suddenly, and consist of:
- Headaches.
- Nausea and vomiting.
- Dizziness.
- Neck pain and / or excessive stiffness.
- Vision loss or vision changes, such as blurred vision.
- Difficulties in walking and changes in gait.
- Memory disturbances, having difficulty remembering certain events.
- Difficulties speaking.
- Irregular breathing.
- Seizures.
- Loss of consciousness, leading to coma in the most severe cases.
It is not always easy to recognize the symptoms of brain edema. Above all, when they are mild they can be confused with multiple other clinical conditions. First of all, it is essential to carry out a neurological examination; In this, reflexes, gait, speech and memory will be examined.
If brain edema is suspected, a brain scan is needed to confirm the diagnosis. For example, a CT scan of the skull may be done. Thanks to this test, the location and size of the inflammation can be identified. When the damage is focused, an abnormal hypodense signal is detected.
The tomography is not exact to differentiate a vasogenic edema from a cytotoxic one. However, it allows the underlying cause to be identified.
Magnetic resonance imaging (MRI), a neuroimaging test that more clearly reflects edema, can also be used. In addition, it allows to know what type it belongs to.
Blood tests are also helpful in identifying causes of inflammation.
Depending on the factor that has caused the cerebral edema, one treatment or another will be followed. Milder cases such as altitude sickness or mild brain damage can be resolved in a few days. However, in most cases, treatment should be more immediate and prolonged..
It is very important that this condition is diagnosed and treated promptly and appropriately. Without treatment, severe sequelae or death may occur.
The main goal of treating cerebral edema is to ensure that the brain receives sufficient blood and oxygen. In parallel, reduce inflammation and treat underlying causes.
To achieve them, it is necessary to combine different types of treatment that are explained below.
It consists of providing oxygen through a respirator or other means. The goal is to ensure that the blood contains enough oxygen. This technique should be carefully monitored by blood gas analysis and a chest x-ray..
This can help reduce inflammation of the brain. It involves placing ice on certain areas of the body. However, it is not always used because it is difficult to perform this technique correctly..
It is the fastest and most effective way to decrease water in brain tissues. It consists of the intravenous injection of osmotic agents that lower intracranial pressure. Thus, the viscosity of the blood is decreased and blood flow is increased. Mannitol is the most widely used osmotic agent.
The osmotic effect can be increased through the use of diuretics. Furosemide is generally used.
These drugs are effective in lowering intracranial pressure in vasogenic edema..
Barbiturates are sedative drugs that also serve to lower intracranial pressure. They act mainly by reducing brain metabolism.
However, not all professionals recommend its use. For example, in patients with traumatic brain injuries, it reduces pressure, but does not improve clinical outcome.
There is also no clear evidence to demonstrate its effectiveness in treating lesions caused by tumors, intracerebral hemorrhage or ischemic stroke..
Barbiturates are not widely used today because they can cause blood pressure drop and lung failure.
Surgery may be indicated when there are serious effusions in which the life of the patient is threatened.
Temporary ventriculostomy prevents complications and can save the life of the patient. It consists of a drainage of the excess fluid through a small incision in one of the cerebral ventricles.
Decompressive craniectomy may also be chosen. It involves the removal of a part of the skull to reduce pressure, increasing the available space.
On the other hand, it can intervene at the source of the inflammation. In this way, surgical procedures are performed to treat the damaged artery or vein..
In severe cases of hydrocephalus, ventriculoperitoneal shunt can be used. This technique allows excess fluid to pass through a small tube and travel into the abdominal cavity..
When intracranial pressure increases, certain general measures should be taken:
- Elevation of the patient. The position of the patient should be controlled, raising his bed between 15 and 30 degrees to promote cerebral venous drainage. This allows the cerebrospinal fluid to travel to the spinal space. The head must be in a position where the neck vein is not compressed.
- Other factors that contribute to increasing pressure must also be controlled. For example, hypercapnia (high concentration of carbon dioxide), hypoxia, hypertemia (high body temperature).
As well as acidosis, hypotension or hypovolemia (circulation of less amount of blood through the body).
- It is necessary to restrict fluid intake to avoid hypotension, as well as avoid solutions that include glucose.
- Blood pressure must be under continuous monitoring. Since, when cerebral edema occurs, systemic arterial pressure rises as a compensatory phenomenon.
For this, blood pressure measurements can be applied. For example, administer vasopressor medications such as adrenaline and norepinephrine. Isotonic solutions can also be administered.
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