User:Delldot/p&si

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Primary and secondary brain injury are ways to divide the injury processes that occur in brain injury. Primary injury, which occurs during the initial insult, results from displacement of the physical structures of the brain, whereas secondary injury occurs gradually and may involve an array of cellular processes.[1] Primary and secondary injuries occur in other types of trauma as well, such as spinal cord injury. traumatic brain injury (TBI)

Primary injury includes contusion, damage to blood vessels, and axonal shearing, in which the axons of neurons are stretched and torn.[1]

Secondary injury is an indirect result of the insult. It occurs in the hours and days following the primary injury and plays a large role in the brain damage and death that results from TBI.[2] Unlike in most forms of trauma a large percentage of the people killed by brain trauma do not die right away but rather days to weeks after the event.[3] In addition, rather than improving after being hospitalized as most patients with other types of injuries do, about 40% of people with TBI deteriorate.[4] This is often a result of secondary injury, which can damage even neurons that were unharmed in the primary injury. It occurs after a variety of brain insults including subarachnoid hemorrhage, stroke, and traumatic brain injury and involves metabolic cascades.[5]

Secondary injury can result from complications of the injury.[1] These include ischemia (insufficient blood flow); cerebral hypoxia (insufficient oxygen in the brain); hypotension (low blood pressure); cerebral edema (swelling of the brain); raised intracranial pressure (the pressure within the skull); and changes in the blood flow to the brain.[1] Other secondary insults include hypercarbia (excessive carbon dioxide levels in the blood) and acidosis (excessively acidic blood).[6]

Secondary excitotoxicity, free radical

Contents

[edit] Secondary injury details

ion flux, energy needs, hyperglycolysis, lactate production, mismatch between metabolic demand and supply. insufficient energy -> mptp but this is way too much detail.

[edit] Diffuse axonal injury

In diffuse axonal injury, though some axons are torn at the time of injury, most axonal separation is a result of secondary injury processes which occur afterwards.

[edit] Prevention

Since primary injury occurs at the moment of trauma and is over so rapidly, little can be done to interfere with it other than prevention of the trauma itself.[1] However, since secondary injury occurs over time, it can be prevented in part by taking measures to prevent complications such as hypoxia. Furthermore, secondary injury presents opportunities for researchers to find drug therapies to limit or prevent the damage. Since a variety of processes occur in secondary injury, any treatments that are developed to halt or mitigate it will need to address more than one of these mechanisms.[5]

[edit] References

  1. ^ a b c d e Scalea TM (2005). "Does it matter how head injured patients are resuscitated?", in Valadka AB, Andrews BT: Neurotrauma: Evidence-Based Answers To Common Questions. Thieme, 3–4. ISBN 3131307811. 
  2. ^ Sullivan PG, Rabchevsky AG, Hicks RR, Gibson TR, Fletcher-Turner A, Scheff SW (2000). "Dose-response curve and optimal dosing regimen of cyclosporin A after traumatic brain injury in rats". Neuroscience 101 (2): 289–95. PMID 11074152. 
  3. ^ Sauaia A, Moore FA, Moore EE, et al (February 1995). "Epidemiology of trauma deaths: A reassessment". J Trauma 38 (2): 185–93. PMID 7869433. 
  4. ^ Narayan RK, Michel ME, Ansell B, et al (May 2002). "Clinical trials in head injury". J. Neurotrauma 19 (5): 503–57. doi:10.1089/089771502753754037. PMID 12042091. 
  5. ^ a b Marion DW (2003). "Pathophysiology and treatment of intracranial hypertention", in Andrews BT: Intensive Care in Neurosurgery. New York: Thieme Medical Publishers, 52–53. ISBN 1-58890-125-4. Retrieved on 2008-06-08. 
  6. ^ Andrews BT (2003). "Head injury management", in Andrews BT: Intensive Care in Neurosurgery. New York: Thieme Medical Publishers, 125. ISBN 1-58890-125-4. Retrieved on 2008-06-08. 

primary in a non-trauma context???

talk about secondary injury in other tissues???