Cerebral edema is the medical term for brain swelling. By definition, it is an increase in the amount of water in the brain, according to Dr. Jeffrey Frank in "Principles of Critical Care." It can cause part of the brain to shift, which leads to increased pressure and areas in the brain without blood flow. Several diseases can cause cerebral edema.
Diabetic Ketoacidosis
DKA, or diabetic ketoacidosis, is a complication most commonly found in diabetes mellitus type 1. In diabetes mellitus, people have high levels of glucose in their bloodstream. In diabetes type 1, this is because they do not have the insulin to move glucose from the bloodstream into the cells. But cells need glucose for energy, so the liver makes glucose. This only increases the blood glucose levels even more. DKA is life-threatening and one complication is cerebral edema. Physicians do not yet agree why DKA is related to cerebral edema. In the August 2004 issue of "The Journal of Pediatrics," Dr. Nicole Glaser wrote that the results of her research group showed that cerebral edema is due to a breakdown between the barrier that normally exists between the brain and the bloodstream.
Subarachnoid Hemorrhage
The meninges is a membrane that covers the brain, and the arachnoid is one of the layers of the meninges. In a subarachnoid hemorrhage, blood hemorrhages below the arachnoid layer. Trauma to the head is the most common cause of this type of hemorrhage. Other causes include a ruptured aneurysm and abnormal blood vessels. An aneurysm is part of an artery that has increased in size due to a weakness in the arterial wall. Similar to the results that Dr. Glaser found in her research on DKA, Dr. Frank explains in "Principles of Critical Care" that the brain swells after a head trauma or hemorrhaging because of a change in the barrier that exists between the blood and the brain. Normally, the cells in the lining of the brain capillaries are very tightly connected to each other. Head trauma interferes with that tight connection. This results in fluids and proteins now being able to pass from the bloodstream into the brain tissue and causing edema.
Reye's Syndrome
Physicians are not sure yet what causes Reye's syndrome. They do know that some children develop this disease after having the flu or the chickenpox. Aspirin increases the risk of developing this disorder by approximately 35 times, according to Dr. Elizabeth Palumbo of the Pediatric Group in "The Merck Manual for Healthcare Professionals." The disease causes abnormalities in the liver and brain. Children can develop seizures and quickly go into a coma. They may also develop cerebral edema. As explained by Dr. Frank in "Principles of Critical Care," Reye's syndrome damages the nerve cells of the brain. Due to this damage, the cells hold onto sodium and water, which results in edema.
Brain Abscess
Several disorders can lead to a brain abscess including head wounds and infections, and infections that spread to the brain via the bloodstream, per Dr. Michael Jacewicz, professor of neurology at the University of Tennessee Health Science Center, writing in "The Merck Manual for Healthcare Professionals." Protozoa, fungi and bacteria can all cause brain abscesses. Inflammation develops in an area of the brain, an abscess then forms and edema develops around the abscess. Similar to the subarachnoid hemorrhage, the cerebral edema develops due to a change in the blood-brain barrier.
References
- "Principles of Critical Care"; Dr. Jesse Hall, Gregory Schmidt, M.D., Lawrence Wood, M.D., Ph.D.; 2005
- "The Journal of Pediatrics"; Mechanism of Cerebral Edema in Children with Diabetic Ketoacidosis; Dr. Nicole S. Glaser, et. al.; 2004
- The Merck Manual for Healthcare Professionals: Brain Abscess
- The Merck Manual for Healthcare Professionals: Reye's Syndrome
