Introduction:
Swelling, also known as inflammation, is the body’s natural reaction to an injury. Edema refers to swelling which happens due to trapped fluid. Unlike edema seen in other parts of the body, edema present in the brain has serious complications. Swelling can either occur in a specific area or all over the brain. It is a life-threatening situation that can lead to permanent brain damage or death if not treated promptly.
What Is Cerebral Edema?
Cerebral edema is swelling that occurs in the brain, mostly as a result of traumatic brain injury (violent blow to the head or body). Swelling can occur anywhere in the brain, and it leads to increased pressure inside the skull. This pressure is known as intracranial pressure or ICP. Cerebral edema can restrict the blood flow inside the brain. The blood contains oxygen needed for the functioning of brain cells. As a result of restricted blood flow, the brain cells get deprived of oxygen. This can destroy the brain cells or even cause them to die. Cerebral edema is a very serious condition, and if left untreated, it may lead to death.
What Are the Causes of Cerebral Edema?
The following are the causes of cerebral edema:
1. Traumatic Brain Injury (TBI): It is also called a head injury. A sudden injury damages the brain. The most common causes are road traffic accidents, falls, sports injuries, assaults (physical attacks), and being hit with or dashing against a heavy object. Generally, the impact of the injury causes the brain to swell. However, in severe cases, TBI can cause the skull to break, and the broken pieces may cut off the blood vessels inside the brain. This also can cause brain swelling.
2. Tumors: A brain tumor is an abnormal growth of cells inside the brain. The tumor inside the brain can press against its nearby areas. As a result, blood vessels present near the tumor may leak and can lead to swelling. The tumor may block the cerebrospinal fluid (fluid present in and around the brain and spinal cord) from flowing out of the brain, which can also be a cause of the swelling.
3. Infections: Infections caused by microorganisms like bacteria or viruses can lead to brain swelling. Encephalitis and meningitis are the two most common examples. Encephalitis is an infection caused by viruses (for example- herpes simplex virus and rabies virus) that cause brain swelling. Meningitis is the swelling of the layers covering the brain and spinal cord. A bacterial or viral infection causes it.
4. Ischemic Strokes: It is caused when the blood supply to the brain is disturbed by a blood clot. This results in arteries getting narrowed or blocked by fatty deposits, leading to decreased supply of oxygen and nutrients to the brain cells. This causes the brain cells to die, and swelling occurs.
5. Hemorrhagic Strokes: This occurs due to the sudden rupture of a blood vessel inside the brain. The blood pools up, and the pressure inside the brain increases. This may be due to head injuries, certain drugs (cocaine), and uncontrolled high blood pressure.
6. High Altitudes: Researchers believe that cerebral edema can occur at high altitudes (when an individual spends more than 48 hours at a height above 4000 feet). This can be associated with acute mountain sickness, which is caused due to decreased air pressure and low oxygen levels seen at high altitudes.
What Are the Symptoms of Cerebral Edema?
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Severe and constant headaches.
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Nausea (urge to vomit) and vomiting.
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Sudden mood changes (anger, anxiety, or depression).
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Difficulty in speaking.
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Seizures (sudden uncontrolled movement in the brain, which causes changes in behavior and movements of the patient).
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Neck pain or stiffness.
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Loss of vision.
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Loss of consciousness.
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Lack of coordination (unsteady body movements and walking style).
How Can Cerebral Edema Be Diagnosed?
1. Physical Examination:
The doctor checks if the patient shows any signs of headache, unconsciousness, problems in vision, and responsiveness. Any signs of altered mental status or fixed and dilated pupils are checked.
2. Computed Tomography (CT) Scan and Magnetic Resonance Imaging (MRI):
If cerebral edema is present, a CT scan will show the following:
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Visible areas of low density (indicates an increased amount of air or water present in the brain).
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Loss of white or gray matter differentiation. Gray matter is a tissue within the brain that receives information and regulates outgoing information. White matter is a group of nerve fibers that transmits signals to other parts of the brain and body. In some cases, CT also reveals the cause of edema.
If cerebral edema is present, MRI will show the following:
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Increased signal changes in the brain show signs of prolonged compression of the spinal cord and signs of tumor progression.
3. Blood Tests:
Blood tests are done to identify the cause of the swelling. Blood sugar levels, carbon monoxide levels, and serum electrolytes (low serum sodium can cause brain edema) are checked.
How Is Cerebral Edema Treated?
1. Medications: The administration of pain reliever drugs to make the patient comfortable. Medications to decrease swelling and prevent blood clots are also given.
2. Positioning of the Patient: The hospital bed is kept elevated at an angle of around 30 to 45 degrees. This is to keep the head of the patient in an elevated position because the pressure inside the brain increases when the head is kept flat. A peaceful environment with low lighting is provided to the patient to avoid agitation.
3. Osmotherapy: Swelling of the brain causes excess fluid to accumulate. Osmotherapy is a technique used to draw out the excess amount of fluid from the brain. The osmotic agents (agents used to draw water from the tissues and increase the volume of blood), like mannitol and high salt saline, are used in this procedure. This procedure helps to reduce the swelling and pressure inside the skull.
4. Hyperbaric Oxygen Therapy: The patient is provided with oxygen through a respirator (a device used to protect the patient from inhaling hazardous particles and gases) or chamber to ensure that blood has an adequate amount of oxygen in it.
5. Hypothermia: This is a method that is still under research. In this method, body temperature is lowered, which reduces the brain’s metabolism and decreases swelling.
6. Ventriculostomy: This is an invasive method that is used to drain fluid from the brain. The doctor makes a small incision in the skull, and a tube is inserted to draw out the fluid. As a result, the pressure inside the brain subsides.
7. Surgery: In severe cases of cerebral edema, surgery may be required. Generally, it is of two types:
- Decompressive Craniectomy: A part of the skull is removed to relieve the intracranial pressure (pressure inside the skull).
- Removing or Repairing the Source of Swelling: Removing a tumor or repairing a damaged artery or vein.
Conclusion:
Cerebral edema is a serious condition that can cause permanent damage to memory. It may even lead to death if left untreated. Hence, if any side effects are observed after an accident, physical assault, or while undergoing treatment for any infection, immediate consultation with the doctor to start treatment immediately should be done.
