DAÑO AXONAL DIFUSO SECUNDARIO A TRAUMATISMO CRANEOENCEFÁLICO Neurología del paciente en situación critica ( Neurocríticos).
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They may be associated with significant and disproportionate cerebral swelling. Generally occurring one to six hours into the process of post-stretch injury, the presence of calcium in the cell initiates the caspase cascade, a process in cell injury that usually leads to apoptosisor “cell suicide”.
In the majority of cases, these forces result in damage to the cells and result in edema. Since axonal damage in DAI is largely a result of secondary biochemical cascadesit has a delayed onset, so a person with DAI who initially appears well may deteriorate later.
Over the first few days, the degree of surrounding edema will typically increase, although by 3-months post-injury FLAIR changes will have largely resolved 7. In contrast, SWI changes will usually take longer to resolve, although by months post-injury there will have been substantial resolution 7.
Retrieved from ” https: Loading Stack – 0 images remaining. It is a potentially difficult diagnosis to make on imaging alone, especially on CT as the finding can be subtle, however, it has the potential to result in severe neurological impairment. Diffuse axonal injury is characterised by multiple focal lesions with a characteristic distribution: Depending on the severity and distribution of injury see: The amount of axonal injury in the brainstem is predictive of long-term vegetative state, whereas supratentorial injury can result in focal neurological or neuropsychiatric deficits 1.
Traumatic axonal injury induces proteolytic cleavage of the voltage-gated sodium channels modulated by tetrodotoxin and protease inhibitors. The appearance depends on whether or not the lesions are overtly hemorrhagic. Though the processes involved in secondary brain injury are still poorly understood, it is now accepted that stretching of axons during injury causes physical disruption to and proteolytic degradation of the cytoskeleton.
As such, it is usually a safe assumption that if a couple of small hemorrhagic lesions are visible on CT, the degree of damage is much greater.
In Grade II, damage found in Grade I lssion present in addition to focal abnormalities, especially in the corpus callosum. DAI is characterized by axonal separation, in which the axon is torn at the site of stretch and the part distal to the tear degrades.
Diffuse axonal injury | Radiology Reference Article |
Traumatic axonal injury induces calcium influx modulated by tetrodotoxin-sensitive sodium channels. In other projects Wikimedia Commons. Axons are normally elastic, but when rapidly digusa they become brittle, and the axonal cytoskeleton can be broken. Support Radiopaedia and see fewer ads. Check for errors sifusa try again.
DAI currently lacks a specific treatment beyond what is done for any type of head injuryincluding stabilizing the patient and trying to limit increases in intracranial pressure ICP. While it was once thought that the main cause of axonal separation was tearing due to mechanical forces during the trauma, it is now understood that axons are not typically torn upon impact; rather, secondary biochemical cascadeswhich occur lesioh response to the primary injury lesikn occurs as the result of mechanical forces at the moment of trauma and take place hours to days after the initial injury, are largely responsible for the damage to axons.
This page was last edited on 4 Decemberat Textbook Of Traumatic Brain Injury. Log in Sign up. About Blog Go ad-free.
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MRI, especially SWI or GRE sequences, exquisitely sensitive to paramagnetic blood products may demonstrate small regions diifusa susceptibility artefact at the grey-white matter junction, in the corpus callosum or the brain stem.
DAI can occur across the spectrum of traumatic brain injury TBI severity, wherein the burden of injury increases from mild to severe. They typically become more evident over the first few days as edema develops leeion them.
Diffuse injury has more microscopic injury than macroscopic injury and is difficult to detect with CT and MRI, but its presence can be inferred when small bleeds are visible in the corpus callosum or the cerebral cortex.
The Journal of Emergency Medicine. Figure 1 Figure 1. Synonyms or Alternate Spellings: Axoplasmic transport and sxonal responses to injury Archived at the Wayback Machine.
Journal of Neuropathology and Experimental Neurology. Typically, patients who are shown to have diffuse axonal injury have loss of consciousness at the time of the accident. Axoal mechanical breaking of the axonal cytoskeleton, DAI pathology also includes secondary physiological changes such as interrupted axonal transport, progressive swellings and degeneration.
Diffuse axonal injury
The Journal of Neuroscience. The lobes of the brain most likely to be injured are the digusa and temporal lobes. Articles Cases Courses Quiz.
Traumatically induced axonal damage: MRI is the modality of choice for assessing suspected diffuse axonal injury even in patients with entirely normal CT of the brain Case 5 Case 5. Nerve injury Peripheral nerve injury classification Wallerian degeneration Injury of accessory lession Brachial plexus injury Traumatic neuroma.
Actual complete tearing of the axons is only seen in severe cases. Case 4 Case 4. Case 6 Case 6.