Source Guardian UK
Gabrielle Giffords shooting: Survival factors after gunshot wound to head
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If the victim survives the initial blood loss, the problem then becomes the increasing pressure inside the skull. "The blood supply to the brain reduces but also the blood which is coming out of the vessels causes pressure within this confined space of the skull," said Husain. "And, if the bullet itself goes through the brain structure, there is a massive inflammatory reaction, so you get a lot of swelling in the brain and that's another big cause for death."
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For the next few days, doctors will monitor the pressure in her skull and look for any other potential sources of increasing pressure. "The experience of intensive care is that things can suddenly take a turn for the worse without any warning. I would say that you'd have to wait at least a week before you're starting to become confident about the future. And that doesn't take into account the cognitive future. So far, we're just talking about survival."
The left hemisphere in most people is responsible for language, cognition and abstract thought. The back portion also contains the occipital lobe, where visual information is processed for the right-hand field of view. Any of these functions could be affected in the long term but doctors will not be able to assess these problems for several more weeks.
"Cognitive testing requires someone to be alert enough," said Husain. "It is unrealistic to talk about cognitive future either from looking at scans or seeing whether she can move her foot. I'd be far more guarded about that."
http://www.guardian.co.uk/world/2011/jan/10/gabrielle-giffords-shooting-gunshot-wound