Thursday, January 17, 2008

The ticking time bomb - TBI

At last count the number of Canadian combat vehicles which were disabled in explosions involving suspected improvised explosive devices (roadside bombs) is three in the last week. On Wednesday seven Canadian soldiers were wounded in two separate incidents. On Tuesday one trooper was killed and another wounded. On the weekend, four soldiers were wounded.

In all of the attacks the wounded soldiers were evacuated to hospital. Following a short period of observation a good number of the soldiers were released, their wounds having been declared "minor". On Wednesday for example, six of the seven troops evacuated to hospital were quickly released. It may be that their physical wounds were not significant; but that doesn't account for other wounds which are not as visible as torn flesh and broken bones.

What often goes unnoticed, except to the affected individual, and perhaps relatives and close friends, is an injury which isn't clearly visible to either medics accompanying patrols or doctors in a field hospital: Traumatic brain injury (TBI).

Conventional TBI is easily diagnosed, although the effects can be difficult to understand and manage. The skull is penetrated by the shrapnel of a blast and the removal of bits of metal, dirt, rock, etc. become a surgical procedure.
Such injuries (referred to as ballistic trauma) are “conventional” TBIs; they are easy to diagnose, because the shrapnel fragments leave entry wounds, and can be treated in a standard way: foreign bodies are removed from the brain, and the patient is given a type of drug called a calcium channel blocker, such as Amlodipine or Nifedipine, to prevent further damage to injured neurons. Diuretics may then be administered intravenously to prevent further swelling and, in extreme cases, a craniectomy can be performed. This surgical procedure, which involves the removal of a part of the skull, allows continued swelling while preventing the swollen region of the brain from coming into contact with the skull, which would otherwise cause more damage.
As difficult as those wounds are to treat, at least the medical community is able to recognize them. The problem occurs when there is no visible wound.
Troops with closed head injuries show no external signs of injury, and appear to be normal. And, if they have sustained other obvious external injuries, the medics treating them may neglect to test for neurological damage. Subtle personality changes that may occur as a result of such injuries would only be noticed by relatives or close friends who know the patient well, and other symptoms could take years to develop. The effects of such injuries may therefore go unnoticed for years or even decades. The difficulty in diagnosis is further compounded by the fact that many of the symptoms of closed head injuries overlap with, or sound similar to, those of post-traumatic stress disorder (PTSD).
The forces of a blast (illustrated here) have differing effects on different individuals depending on their proximity to the explosion. Someone within range of the primary blast-wave is quite likely to suffer injuries and even those who had injuries in the lower extremities were showing clear signs of TBI. However, the effects of the secondary and tertiary blasts also seem to be having a lasting effect.
Neurologists affiliated with the U. S. military now estimate that up to 30% of troops who have been on active duty for 4 months or longer (in both Iraq and Afghanistan) are at risk of some form of disabling neurological damage. This is partly based on the knowledge that closed head injuries far outnumber the penetrative head injuries on which official statistics are based. So, while official figures put the number of U. S. troop casualties in Iraq and Afghanistan at 22,600 (as of November 2006), there may be up to 150,000 already suffering from TBI.
The Journal of Neuropsychiatry reached the following conclusion:
An earlier study found that veterans with post traumatic stress disorder who had been exposed to blast had EEG abnormalities and attentional difficulties consistent with mild TBI. Thus, the limited clinical evidence to date suggests a similar range of neuropsychiatric impairments as seen with other traumas (e.g., accidents, assaults). In many cases, TBI clearly resulted from secondary and/or tertiary blast injuries.
Which goes back to those soldiers being injured in the proximity of an exploding IED.

Minor injuries?

I don't think so.

Main and Central has some information on a new US TBI resource.

H/T Colin by email.

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