Diffuse Axonal Injury
Concussion is the most minor and the most common type of Traumatic brain injury.jpg)
(TBI). Technically, a concussion is a short loss of consciousness in response to a head injury, but in common language the term has come to mean any minor injury to the head or brain. Traumatic brain injury (TBI), a form of acquired brain injury, occurs when a sudden trauma causes damage to the brain. TBI can result when the head suddenly and violently hits an object, or when an object pierces the skull and enters brain tissue.
Shaken baby syndrome is a type of inflicted traumatic brain injury that happens when a baby is violently shaken. A baby has weak neck muscles and a large, heavy head. Shaking makes the fragile brain bounce back and forth inside the skull and causes bruising, swelling, and bleeding, which can lead to permanent, severe brain damage or death. Shaken Baby Syndrome is commonly used to explain how diffuse axonal injury (DAI) occurs. Diffuse Axonal Injury is injury over a more widespread area. Diffuse axonal injury isn’t the result of a blow to the head. Instead, it results from the brain moving back and forth in the skull as a result of acceleration or deceleration. Unlike a local injury: think gunshot wound. In addition to being one of the most common types of brain injuries, it’s also one of the most devastating.
Testing includes:
- · Magnetic Resonance Imaging (MRI)—This test uses magnets, radio waves, and a computer screen to show detailed cross-sections of the brain. This is the preferred test for diagnosing diffuse axonal injury.
- · CT Scan—This test uses an x-ray machine and a computer monitor to show detailed images of the interior of the brain. CT scans may results in false negatives, so can’t be relied on to give definitive results when it comes to diffuse axonal injury.
- · Evoked Potentials—Commonly called the SSEP, BAER, and VEP, these tests look at the visual, auditory, and sensory pathways in the brain.
- · Electroencephalogram (EEG)—This test measures the electrical activity in the brain
- · Positron Emission Tomography (PET) – This test measures the metabolism in the brain.
Of patients with DAI, 80% demonstrate multiple areas of injury on computed tomography (CT) scans.
Classically, DAI has been considered a primary-type injury, with damage occurring at the time of the accident. Research has shown that another component of the injury comprises the secondary factors (or delayed component). Disruption causes local axonal transport impairment and, since the axons are injured, secondary swelling occurs. Complete detachment occurs and retraction bulbs form over a period of time after the injury.
This is very important since many physicians evaluate patients in the Emergency Room who appear cognitively intact but later go on to diminished levels of cognition. That is why hospitals give patients presenting with any hit to the head or head injury signs and symptoms a “Head Injury Checklist” on discharge. This protects the hospital in the case of a patient going on to develop head injury symptoms. Patients are instructed to watch of dizziness, fatigue and vomiting. But rarely is one discharged from a hospital aware of the latent problems or likely to follow up.
In the law, those who defend against claims of traumatic brain injury want to focus on the hospital discharge as proof that there was no “real injury.” It is important to understand the science and medicine of traumatic brain injury. You can always read more about traumatic brain injury by visiting my Brain and Spine Injury Law Blog or Titolo Law Office website.
