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HomeHealth articlesdiffuse axonal brain injuryWhat Is Diffuse Axonal Injury?

Diffuse Axonal Brain Injury - Causes, Symptomatic Complications, Diagnosis, and Treatment

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Diffuse axonal injury is a traumatic injury where a sudden jerk to the brain causes shearing of nerve connections, causing coma, death, or permanent disability.

Written by

Dr. Jayasree S

Medically reviewed by

Dr. Prakashkumar P Bhatt

Published At November 4, 2022
Reviewed AtApril 18, 2023

What Is Diffuse Axonal Brain Injury?

It is a type of traumatic brain injury caused by a rapid shifting of the brain inside the skull due to sudden jerky movements. It is one of the most common and devastating types of traumatic brain injury. It is also one of the major causes of unconsciousness and persistent vegetative state after severe head trauma. Diffuse axonal injury occurs in about half of all cases of severe head trauma, and it is the reason for primary damage in concussion cases. Unlike brain trauma, which occurs due to direct injury and deformation of the brain, diffuse axonal injury is a result of the traumatic shearing force that occurs when the head is rapidly accelerated or decelerated.

What Are the Causes of a Diffuse Axonal Injury?

Vehicle accidents are the most frequent cause of diffuse axonal injury. It can also occur as a result of child abuse, such as shaken baby syndrome. The major cause of damage in diffuse axonal injury is the disruption of axons, which are the long extensions of nerve cells through which they communicate with each other. With severe acceleration, deceleration, or rotation movements at the time of trauma, the nerve tissues tend to slide over each other, stretching the axons apart.

The damages are microscopic and mostly occur at the junction of white and gray matter inside the brain. When axons are harmed, the nerves will not be able to communicate with each other or function as a unit. This leaves the affected individual functionally disabled or in a state of coma. Hence, the swift backward and forward movement of the brain inside the skull is what triggers a diffuse axonal injury. This can occur due to the following:

  • High-speed car accidents and motorcycle accidents.

  • Falls, especially those that cause rapid whipping motion of the head.

  • Violent physical attacks.

  • Sporting injuries.

  • Shaken baby syndrome, or child abuse.

What Are the Predicted Outcomes Following a Diffuse Axonal Injury?

The most frequent outcome of a diffuse axonal injury is a coma, and over ninety percent of patients with severe damage never regain consciousness. Those who do wake up afterward often remain significantly disabled. It can occur in every degree of severity, from very mild to moderate to very severe. A concussion may be a milder type of diffuse axonal injury. But a person suffering a diffuse axonal injury may have mental and physical limitations and may often depend on others to perform basic tasks. Based on severity, the injuries are grouped into three as:

  1. Grade One - Mild diffuse axonal injury with microscopic changes in the brain.

  2. Grade Two - Moderate diffuse axonal injury with gross lesions (involving corpus callosum).

  3. Grade Three - Severe diffuse axonal injury (involving corpus callosum and brainstem).

What Are the Chief Symptoms of Diffuse Axonal Injury?

Loss of consciousness is the prevailing symptom in individuals with severe injury. In mild diffuse axonal injury, the patient may have a concussion disorder associated with other signs such as:

  • Headache.

  • Dizziness or loss of balance.

  • Drowsiness or fatigue.

  • Disorientation or confusion.

  • Nausea and vomiting.

  • Show trouble with sleeping or sleeping for longer than normal.

How Is a Diffuse Axonal Injury Diagnosed at the Hospital?

Like every other head injury event, individuals affected by diffuse axonal injury should be brought to the hospital for immediate care. Informing the doctor about the event of trauma helps assume the level of impact and severity of trauma. To assess the brain damage and functional status of the patient, one may conduct the following studies:

  • Glasgow Coma Scale (GCS) Evaluation - A study to measure the severity of brain injury involving eye-opening, verbal response, and motor response (response to touch, pressure pain, and more). Where a score of thirteen to fifteen indicates mild injury, nine to twelve is moderate injury, and below eight shows severe traumatic brain injury.

  • Imaging Studies - Because damage to the brain is microscopic, diagnosis of diffuse axonal injury with computed tomography (CT) scan may be difficult. However, a well-established magnetic resonance imaging (MRI) method called diffusor tensor imaging is used. This procedure provides a detailed view of the brain and more.

What Is the Treatment for a Diffuse Axonal Injury?

The affected individual should be put under a basic life support system if the trauma is severe. Reducing any swelling in the brain is the first course of action needed in the case of diffuse axonal injury. If this is delayed, it may cause further brain damage. Severe diffuse axonal injury has a likelihood of a vegetative state or death in the majority of cases. One may choose:

  1. Surgery to stop bleeding inside the brain and remove large blood clots.

  2. Steroids or anti-inflammatory drugs may help reduce swelling in some individuals.

  3. Lab tests and spinal tapping may help identify signs of bleeding and chemical changes indicating nerve injury.

In mild to moderate cases, rehabilitation is possible. Depending on the individual, a recovery program may include the following:

  1. Physical therapy.

  2. Occupational therapy.

  3. Speech therapy.

  4. Recreational therapy.

  5. Counseling.

  6. Adaptive equipment training.

What Are the Initial Steps to Take With a Closed Head Brain Injury?

Immediate medical attention is the first priority. Seek medical help without delay. And till help arrives, do not try to move the injured individual, as this may aggravate the existing damages. When paramedics arrive, inform them about the details of the accidents and the possibility of sustaining a brain injury. Stabilizing the injuries in the best possible manner is the first step, followed by means of rehabilitation. The affected individual may need elaborate lifestyle modifications and support for their dear ones to recover to the maximum possible potential.


Among the injuries reported from car accidents, falls, and assaults, a significant percentage of individuals belong to the diffuse axonal injury category. The reason is that such accidents always involve rotational forces or severe deceleration. Though a great number of affected individuals may not regain consciousness, those who wake up require rehabilitation. The traumatic brain recovery program involves a team of doctors, nurses, and specialists, including physical, speech, occupational and recreational therapists. Complete recovery may be possible in very mild cases.

Frequently Asked Questions


Can a Person Recover From Diffuse Axonal Brain Injury?

Some patients can recover from a diffuse axonal injury. However, recovery is not guaranteed. The recovery depends on various factors, like the severity and location of the injury, the type of treatment taken, etc.


Is Diffuse Axonal Injury a Critical Issue?

Diffuse axonal injury stands for a kind of traumatic brain injury that is severe. Patients affected by it suffer from an array of neurological deficiencies that hinder their physical and mental abilities.


What Is the Prediction After Diffuse Axonal Injury?

In severe diffuse axonal injury cases, a vegetative state or death occurs mostly. However, in mild to moderate cases, rehabilitation is an option, which depends on the individual's condition and may include different therapies.


Why Does Diffuse Axonal Injury Occur?

Diffuse axonal injury mainly occurs due to road traffic accidents involving accelerating and decelerating motions exerting shear forces on the brain's white matter tracts and tearing their axons.


What Are the Consequences of Diffuse Axonal Injury?

Diffuse axonal injury causes the tearing of the brain's axons because of the brain injury's shifting and rotation inside the skull. It results in a coma or injury to several brain parts.


Can MRI Detect Diffuse Axonal Injury?

MRI (magnetic resonance imaging) is the main investigation option for diagnosing diffuse axonal injury, even for those with normal brain CT (computed tomography) and suffering from an unexplained neurological deficiency followed by head trauma. Lately, MRI has been the preferred choice for diagnosing and treating it.


What Is the Incidence of Diffuse Axonal Injury?

Diffuse axonal injury is the most prevalent and severe of all traumatic brain injuries. It is also the leading reason for unconsciousness and continued vegetative state due to severe head trauma and is seen in half of its cases. It may also cause primary damage that results in a concussion.


What Does Grade 3 Axonal Injury Mean?

Grade 3 axonal injury is a severe form of diffuse axonal injury that presents with Grade 2 injury findings associated with brainstem focal lesions and tissue tear hemorrhages. It may lead to an instant coma with a change in posture and an incomplete recovery.


Are Diffuse Axonal Injury and Concussion the Same?

Concussion and diffuse axonal injury are different conditions. When LOC (level of consciousness) post-head trauma occurs for less than six hours, it is called a concussion, whereas, in a diffuse axonal injury, the LOC lasts for six hours or more.


What Does a Shearing Brain Injury Mean?

A shearing brain injury is one of the types of traumatic brain injury (TBI) that generally occurs due to rotating forces that destroy the white and gray matter connections.


What Are the Three Different Traumatic Brain Injuries?

The three different types of traumatic brain injuries are:

- Concussion: It is a type of head injury that may lead to instant awareness or alertness loss, ranging from a few minutes to hours following the trauma.

- Skull Fracture: It is the breaking of the skull bone due to a head injury.

- Intracranial hematoma (ICH).


What Causes Shearing Injuries in TBI?

As the brain jolts against the skull's sides, it causes shearing injuries. The internal lining, tissues, and blood vessels get torn, leading to the brain’s internal bleeding, bruising, or swelling.


Which Is the Most Prevalent Traumatic Brain Injury?

A concussion is counted as the most common TBI. A concussion usually occurs because of the quick movement of the head or body back and forth, as seen in a car crash, a sports injury, or a head blow. Generally, concussions are considered mild TBIs as they are not life-threatening.


What Are the Various Traumatic Brain Injury Types?

The following are the common forms of traumatic brain injury:

- Coup-contrecoup brain injury.

- Concussion.

- Diffuse axonal injury.

- Brain contusion.

- Second impact syndrome.

- Penetrating injury.

- Shaken baby syndrome.

Dr. Prakashkumar P Bhatt
Dr. Prakashkumar P Bhatt



diffuse axonal brain injury
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