Saturday, December 21, 2019

Cerebral Edema (Brain Swelling) - Types, Symptoms, Causes and Treatment

Cerebral edema, also known as brain swelling, is the excess accumulation of fluid in intracellular or extracellular spaces of the brain, causing an increase in pressure known as intracranial pressure. 
Cerebral edema is one of the most dangerous diseases that may affect humans. So we find many of us frightened by the severity of the health complications that result from it, which may radically affect the patient's life. 
So let us take a comprehensive look at cerebral edema in terms of causes, symptoms, methods of diagnosis and treatment.


Cerebral edema or brain swelling - Everything you need to know about Brain Swelling

Cerebral Edema (Brain Swelling) - Types, Symptoms, Causes, Diagnosis, and Treatment

What is Cerebral Edema?

Cerebral edema, also known as brain swelling, is a serious and life-threatening condition that occurs as a result of fluid accumulating inside the brain, which increases the size of the brain. 
Because the brain is confined to the cranial box, so any increase in the volume of fluid inside the brain raises intracranial pressure, which reduces blood flow to the brain and weakens the supply of the brain with oxygen. 
Cerebral edema is sometimes difficult to treat and leads to permanent damage.


Types of Cerebral Edema

Vasogenic edema: The most common type occurs as a result of a breakdown of the blood-brain barrier due to trauma or external injury.

Cytotoxic/ionic/cellular edema: The blood-brain barrier remains healthy, but there is a defect in the brain cells that makes it unable to produce energy properly.

Interstitial/hydrocephalic edema: Interstitial/hydrocephalic edema is caused by hydrocephalus.

Osmotic / hypostatic edema: Osmotic edema occurs as a result of a loss of osmotic balance between the blood plasma and the visceral tissue of the brain, which promotes the accumulation of fluid within the brain.

Hydrostatic edema: Hydrostatic edema occurs as a result of a loss of the ability to regulate blood circulation within the brain.

Cerebral Edema or Brain Swelling: All you need to know

Brain swelling has many names:
  • Brain edema
  • Cerebral edema
  • Elevated intracranial pressure
Intracranial Pressure (ICP)
Intracranial pressure (ICP) is the pressure that is formed in the component parts of the skull: the brain, blood vessels and cerebrospinal fluid (CSF). 
Intracranial pressure is equivalent to the pressure of the cerebrospinal fluid that can be measured by a lumbar puncture. 
The normal CSF value is usually 8 mm Hg, or 110 mm h2o (80 - 180 mm h2o). This value is variable and is related to several factors, such as body and head position, heart and respiratory activity, effort, pressure in the veins and pain stimuli.

The skull resembles a solid, closed box. Therefore, any increase in the size of any of its components causes an increase in intracranial pressure.


Elevated Intra - Cranial Pressure (EICP)
Elevated Intra - Cranial Pressure (EICP) or Intracranial hypertension, is a medical condition that requires urgent treatment, usually with severe effects.

High pressure is not governed by a direct relationship with the change in volume. 
The increase in the size of one of the brain’s chambers, up to a certain extent, does not cause an increase in pressure, due to the mechanisms of adjustment and compensation found in the brain and the elasticity of the different tissues. 
However, if this limit is exceeded, any slight increase in size causes a sharp increase in intracranial pressure.

High intracranial pressure may have dangerous consequences, due to a decrease in the perfusion pressure in the brain, to the point where the blood supply to the brain cells is interrupted.

Low intracranial pressure: intracranial pressure may be lower than normal due to cerebrospinal fluid leakage as a result of a hole in the covers of the brain, spontaneously or as a result of shock (for example, after a lumbar puncture). 
The most prominent symptom of this condition is a headache that gets worse when standing up. 
Diagnosis is made if low pressure is detected in the lumbar puncture examination and then confirmed by magnetic resonance imaging (MRI) that shows (by dye) highlighting the brain envelopes with the indicated Gadolinium.


Cerebral perfusion pressure (CPP)
Cerebral perfusion pressure (CPP) is the difference between the blood pressure in the arteries of the brain (arterial pressure- MAP) and the intracranial pressure (ICP) on these arteries, which determines the transfer of oxygen and metabolites from the blood to the brain cells.

In a healthy brain, there is a special mechanism that regulates the flow of blood (Autoregulation) and maintains a continuous flow regardless of the level of blood pressure, by changing the degree of resistance in the walls of blood vessels. 
This mechanism may be malfunctioned by the disorder caused by high intracranial pressure, which makes the brain more sensitive to changes in blood pressure.

In contrast, hypertension lowers the ischemic stroke, creating a life-threatening condition for the brain.
 Another dangerous consequence of high intracranial pressure is the risk of herniation, i.e. pushing the content of brain tissue from one of the compartments in the skull, where the pressure is high, to another compartment where the pressure is low. 

This is through narrow openings in the covers of the brain or the base of the skull, along with increased pressure and damage to vital areas of the brain.
The increase in the size of any of the internal components of the skull, due to various reasons, may cause intracranial hypertension:


Cerebrospinal Fluid (CSF)
Cerebrospinal fluid is a clear, colorless liquid around your brain and spinal cord. 
CSF is a total volume of about 150 ml, running in cavities inside (chambers) and around the brain and spinal cord (in cisterna subarachnoidalis). 
CSF helps protect the brain from shocks, in regulating metabolic activity and removing exudate. 
The fluid is absorbed in the upper area of the brain surface into the vast sinuses, through microscopic villi called Arachnoid villi.

The delicate balance between fluid production, on the one hand, and its absorption, on the other hand, maintains its constant quantity. 
The amount of fluid may increase significantly, causing high pressure inside the skull, as a result of the following:

1. Increased CSF production - a very rare phenomenon, because the normal ability to absorb CSF is greater than the ability to produce it.

2. Disorders of cerebrospinal fluid (CSF) circulation - caused by bile duct obstructions as a result of birth defects, infection, bleeding or increased growth, or any compressive growth elsewhere nearby. 
The fluid produced accumulates in the chambers above the site of the blockage, causing them to swell and increase in size, which increases intracranial pressure. 
This condition is called obstructive hydrocephalus and requires, in addition to removing the obstruction cause, treatment for fluid drainage (Shunt), i.e. placing a tube from the side chamber, passing through the subcutaneous canal and up to the abdominal cavity, to drain the fluid.

3. Cerebrospinal fluid absorption disorder caused by a blockage in Arachnoid Villi due to inflammation, contamination or bleeding in the cerebrospinal fluid or due to an unknown cause as a result of age, the formation of cerebral edema is non-obstructive.

4. Increased cerebral blood volume: Arterial capillaries in the brain are sensitive to a change in the concentration of gases in the blood. 
An increase in the partial pressure of carbon dioxide, or a sharp decrease in the partial pressure of oxygen due to breathing problems, will lead to its expansion and an increase in the amount of blood (and pressure) in the brain. 
A sharp rise in blood pressure can disrupt the mechanisms of autoregulation and high pressure within the skull, coinciding with the occurrence of hypertensive encephalopathy.

An increase in the volume of venous blood in the brain can be caused by a blockage of the drainage system from venous sinuses, as a result of thrombosis or a foreign body airway obstruction (FBAO (tumor, fracture) or increased central venous pressure transferred to the veins of the brain.

5. Increase in brain size: This phenomenon includes the main factors of intracranial hypertension:

1. Operations occupying space in the cranial cavity: tumor, sinus formation, bleeding, an abscess. The pressure increases due to the increase in size without additional space in the skull. This occurs due to obstruction of the cerebrospinal fluid (CSF) leak or CSF absorption, due to blockage of venous sinuses or the formation of cerebral edema.

2. Brain tissue swelling due to fluid accumulation in it, due to a variety of injuries: stroke, blockage, swelling, bleeding, infection, inflammation, hypoxia, metabolic and toxic disorders, etc.


Symptoms of Cerebral Edema

Cerebral edema is difficult to diagnose, but the presence of some symptoms and signs helps the doctor in the diagnosis process, such as:
  • Headache
  • Dizziness
  • Nausea
  • Vomiting
  • Numbness
  • Loss of muscular nervous coordination
In severe cases, the patient may notice symptoms such as:
  • Mood changes
  • Memory loss
  • Vision loss
  • Low heart rate
  • High blood pressure
  • Difficulty speaking
  • Difficulty moving
  • Neck pain
  • Micturition Reflex
  • Unconsciousness
  • Epileptic seizures
Symptoms of cerebral edema vary depending on the severity of the swelling and the underlying cause. 
Dilated fundus examination (DFE) shows the presence of papilledema. For children, the Fonticuli cranii are swollen and the cranial sutures may separate.


Causes of Cerebral Edema

There are several reasons for cerebral edema such as:

Brain injuries: such as direct hits to the head may cause damage to the brain. Severe injuries can lead to fractures of the skull bones. The bone fragments resulting from the fractures may lead to a rupture of the blood vessels, leading to cerebral edema.

Ischemic stroke: Some cases of stroke lead to the occurrence of edema, especially if the cause of a stroke is a decrease in the amount of oxygen delivered to the brain, which leads to the death of brain cells and swelling as a result of the injury.

Brain hemorrhage: A brain hemorrhage is a type of stroke that occurs when the blood vessels in the brain rupture and leak. This leads to bleeding in or around the brain and causes inflammation and an increase in intracranial pressure (ICP).

Infections: Some bacteria are able to cause inflammation and swelling in the brain, especially if left untreated.

Brain tumors: the presence of tumors creates additional pressure on the brain causing swelling.

Other causes of cerebral edema: Other causes such as carbon monoxide (CO) poisoning, common hiking injuries, venomous animal bites, viral infections, and some medications.

Diagnosis of Cerebral Edema

Diagnosing cerebral edema is somewhat difficult and a challenge for the attending physician, but by referring to symptoms and using some techniques, a correct diagnosis can be made. 
Some of the common procedures that doctors use to diagnose cerebral edema include:

Clinical examination of the patient to show the symptoms they complain about.
Neurological examination to identify the extent and locate idiopathic edema.
Computed tomography (CT)  scan to locate the swelling and identify the extent.
Magnetic resonance imaging (MRI) of the head to locate edema.
Blood tests may help to determine the cause of cerebral edema.


Treatment of Cerebral Edema

Cerebral edema is a life-threatening condition so you need to monitor the patient's condition in the intensive care room. 
Early diagnosis and treatment are necessary to save a patient's life. Often the primary cause must be treated quickly, using various medications to reduce the amount of water in the brain and to produce cerebrospinal fluid. 
The treatment aims to restore blood and oxygen flow to the brain while reducing the swelling that occurs at the same time. 
The most common cerebral edema treatment options may include:

Medications: Medications work to reduce swelling and remove thrombus such as warfarin which thins the blood and reduces the chances of blood clots. A thrombus is a blood clot which closes the blood vessels and reduces blood flow and oxygen to the brain. 

Osmotherapy: Osmotherapy is a technique that pulls water out of the brain cells, which leads to the removal of swelling and blood clots, stimulates blood circulation to the brain and reduces intracranial pressure. 
This is done by using osmotic solutions such as mannitol and hypertonic saline.

Hyperventilation: Hyperventilation aims to cause the patient to release more gas than he inhales and reduces the concentration of carbon dioxide in the bloodstream and reduces intracranial pressure.

Hypothermia: This type of treatment involves lowering the body temperature, which can reduce the metabolic activity of the brain and thus reduces swelling.

Surgery: Surgery may include removing part of the skull and repairing the damage, such as ruptured blood vessels. Severe cases of cerebral edema (such as caused by tumors) may require surgery to reduce intracranial pressure.

Ventriculostomy: The ventriculostomy process aims to withdraw fluid from the brain by causing a hole in the skull and inserting a tube to aspirate the fluid.

By: Mahtab Alam Quddusi


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