Foreign Affairs Writer, Toronto Star
On a dusty road near Kandahar, a Canadian soldier crawls from his bomb-battered vehicle as his bleeding colleagues are carried away on stretchers. Dizzy, his ears ringing, he dusts himself off and shakes his head in amazement that he has escaped injury.
Or has he?
"Everyone knows that traumatic brain injury is the leading cause of death and disability in both civilian and military trauma," says Canadian military trauma surgeon Homer Tien. "It takes a huge toll."
Since the days of World War II and Vietnam, protective body armour and medical treatment received by Western troops have brought a quantum leap in survival rates of wounded soldiers.
But researchers have found that even those who walk away from an explosion may be suffering from traumatic brain injury, which has been tagged "a silent epidemic" in the United States.
Military doctors have found that mild or serious brain injury is afflicting substantial numbers of soldiers who survive the ever more powerful bombs, or "improvised explosive devices," planted by militants in Afghanistan and Iraq .
This week, a presidential panel charged that the military health care system was no longer able to meet the demands of the contemporary battlefield — including the mounting number of traumatic brain injuries.
It recommended sweeping changes to upgrade treatment and benefits of affected veterans.
So concerned is the U.S. Congress that it has authorized $450 million for care and research into head injuries, whose treatment may cost millions more over the next few decades.
Up to January 2007, more than 2,000 brain injuries were recorded by the U.S. military. But doctors treating veterans from Iraq and Afghanistan say figures are several times higher.
Canada, which is just beginning to focus on the seriousness of the problem, is no exception.
In Afghanistan, among Canadians killed between February and July 2006, brain injury and bleeding were leading causes of death, according to a study by Tien and two Canadian forces colleagues.
But those who die, or suffer severe head injury, are easier to classify as brain-damaged than soldiers who walk away from the blasts.
"People who have experienced a mild head injury might not know at first, because of medical or tactical considerations," says Col. Jonathan Jaffin, acting commander for U.S. Army Medical Research and Materiel Command. "It is important for commanders to be aware of (those injuries) because it can have great bearing on a soldier's readiness to go back to active duty."
According to Walter Reed Army Medical Center in Washington D.C., which routinely evaluates combat casualties for brain injury, 59 per cent of those exposed to a blast are diagnosed with traumatic brain injury – 56 per cent moderate to severe, and 44 per cent mild.
As the bombs used to attack the troops in Iraq and Afghanistan pack bigger explosive punches, those numbers could escalate.
"A blast creates a sudden increase in air pressure by heating and accelerating air molecules, and immediately thereafter, a sudden decrease in pressure that produces intense wind," writes American physician Susan Okie in the New England Journal of Medicine.
Rapid pressure shifts can injure the brain, without any visible head wound. They can also cause fatal or damaging brain swelling, or drive fragments of metal through the skull. Specialists in battlefield medicine say it's the "invisible" or closed head injuries that are the most difficult to treat.
Brain swelling that results from car crash or sports injuries responds well to medication and surgical techniques. But the damage caused by explosions is a special challenge.
"When the sound wave moves through the brain it seems to cause little gas bubbles to form," neurologist P. Stephen Macedo told the Washington Post. "When they pop, it leaves a cavity. So you are littering people's brains with these little holes."
And, says Sunil Ram, an Ontario-based international security and defence analyst, "everyone in the blast zone is a potential casualty. When you look at Canadian casualties in Afghanistan, more than half of those who die are killed by IEDs. But depending on the munition and the environment, the blast wave is catching everyone within a 200- to 500-metre range."
Advanced body armour saves lives by protecting soldiers' bodies, says Dr. Ronald Glasser, author of Wounded: Vietnam to Iraq, in an essay in the Washington Post.
But he says, "neurologists worry ... at least 30 per cent of the troops who've engaged in active combat for four months or longer in Iraq and Afghanistan ... risk potentially disabling neurological disorders from the blast waves of IEDs and mortars, all without suffering a scratch."
Those who are worst hit may lose consciousness, or suffer seizures and convulsions. Moderately affected troops may experience vomiting, numbness in the arms and legs, and nausea.
But mild brain injuries can cause memory loss, sleep disturbances, confusion, dizziness and blurred vision – symptoms that zealous soldiers or their superiors might shrug off as unimportant. They may also be classified as psychological.
"Events that cause head injury are the same ones that cause post-traumatic stress disorder. And some people have components of both," says Jaffin.
Most mild brain injuries get better without treatment, he adds. But as with sports injuries, those who go back to their activities too soon risk more serious problems.
Victims of worse brain injuries need careful long-term care, which is costly and requires close monitoring and treatment of blast victims. In moderate as well as severe cases, the brain's attempts to heal itself can cause epilepsy, as it "miswires" neural circuits. In other cases, victims suffer personality changes that make them unable to lead a normal life.
Glasser, who treated soldiers wounded in Vietnam, contends that the real toll of war now goes far beyond the death count.
"The real risk to our troops is no longer the numbers of dead but the numbers ending up on orthopedic wards and neurosurgical units."
Even for those with milder head injuries, long term monitoring is crucial, says Tien. So is research on the effects of the trauma.
"The challenge is to find out about those who are further from the centre of the explosion," he says. "A blast wave hits and a soldier may be knocked unconscious for two seconds. Then he gets up and says `I feel great.' Even a CAT scan may be negative. But the question is, will he develop a problem in the future?"
http://www.thestar.com/News/article/240721
