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