Diffuse Axonal Injury (DAI)
What Is It?
Diffuse axonal injury is a severe form of brain injury which occurs in some traumatic brain injury patients. Axons are the long processes of nerve cells which carry electrical impulses from one part of the nervous system to another. Billions of them traverse the brain and spinal cord, carrying information back and forth. They comprise a large part of what is considered the white matter of the brain.
During a traumatic injury, many forces are acting on the brain. These forces can cause twisting and shearing of the brain tissues. With enough twisting of the tissues, the long, delicate axons can tear or break. This axonal injury prevents the normal electrical impulses from passing down the axon normally. It is called diffuse axonal injury because generally when enough rotational and shearing force is created axons in many areas of the brain can be injured simultaneously. Therefore, in patients who suffer DAI, axonal damage can often be found throughout the white matter.
Because it can be so widespread in the brain, this form of injury can be one of the most devastating, leading to major and often permanent neurological disability.
What Types of Symptoms Are Typical?
Because DAI is diffuse, it does not generally cause specific, focal neurological symptoms. However, it can often contribute to a depressed level of consciousness, including traumatic coma
. Additionally, because axons in the central nervous system cannot re-grow, it can contribute to the long-term neurological disability these patients can experience following injury. While DAI can vary from more mild to severe, patients who have severe DAI often remain in coma or a persistent vegetative state.
How Is The Diagnosis Typically Made?
Diffuse axonal injury is most definitively diagnosed by microscopic analysis of brain tissue. However, this obviously requires brain tissue to sample. Clinically, the diagnosis is often suggested by imaging studies of the brain. In some cases, diffuse small areas of hemorrhage and swelling of the white matter can be seen on CT scan
. More reliably, the resolution of MRI scans
is better suited to the identification of injury consistent with DAI.
What Are Some Common Treatments?
The treatment of victims of traumatic brain injury is complex. Close neurological monitoring, surgery and control of intracranial pressure are just some of the standards of care. There is no specific treatment for diffuse axonal injury beyond that which is done for traumatic head injury in general.
The treatment of every patient with head injury is different and should be discussed with each patient's own personal physicians.
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This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.