SEARCH RESULTS FOR: Diffuse-Axonal-Injury

Diffuse Axonal Injury

Diffuse Axonal Injury: Pathogenesis and Clinical Findings
Authors: Stephanie de Waal Reviewers: Braxton Phillips Shahab Marzoughi Gary Michael Klein* * MD at time of publication
Shear injury to small intracranial vessels
   Fall from height
High-speed motor vehicle accident
Blunt trauma
   Unrestricted head movement with impact
Rotational acceleration and/or deceleration forces applied to brain
    Shearing forces applied to white matter tracts of brain
Sphenoid bone causes shear injury to pituitary stalk
        Primary Axotomy
Shear force disconnects neurons at white-grey matter junctions
Secondary Axotomy
     Stretch injury to axons create mechanical damage to axon sodium channels
Uncontrolled sodium influx into neurons Reversal of sodium-
Shear injury to hypothalamo- neurohypophysial portal system
Intra-parenchymal Hemorrhage
  Panhypopituitarism (decreased production and secretion of pituitary hormones)
     Increased intracellular sodium creates increased osmotic pressure between extracellular and intracellular space
Water moves passively along osmotic gradient into intracellular space
Neuron swelling
Hemorrhagic lesion on MRI
calcium exchangers
Activation of voltage gated calcium channels
   Calcium enters the damaged neuron
Proteolytic activity increases with elevated intracellular calcium
Activated proteases cause delayed cytoskeleton damage Damage to neuron cytoskeleton impairs transport of axonal proteins Protein accumulates within axon creating bulb structure at the terminal Disconnection of axon terminal from adjacent dendrites and cell bodies
Diffuse Axonal Injury
Axonal bulbs on pathology
           Damage to cortical, subcortical, and brainstem white matter tracts leads to a constellation of symptoms
Post-traumatic seizures Damage to temporal lobe Damage to primary motor cortex Lesions in ascending reticular activating system impact consciousness
       Memory deficits Motor deficits
Coma & brain death
  Legend:
 Pathophysiology
Mechanism
 Sign/Symptom/Lab Finding
 Complications
 Published Sep 18, 2024 on www.thecalgaryguide.com