Dana King explains how he was knocked down from the blast wave of an explosion. King served with the Marines in Afghanistan in 2001 in the first part of the United States fight against the Taliban. King was injured from a blast waves during his service and now has traumatic brain injury.

The kill zone was just a battlefield sprint away as Marine Sgt. Dana King felt one bomb after another drop. It was early 2002, and King was part of a mission to scour one of al-Qaida’s most important hideouts. Amid the firefights, ground troops guided coalition aircraft to their targets, which unleashed some of the biggest bombs in the American arsenal.

At times, King was only a few hundred yards from these targets. Over and over, he felt the blast waves ripple through his body. “The explosions came right at you,” he recalled. Over and over, he threw up, his body’s involuntary response to the blast waves’ punches. During the night, bombers dropped 1 million pounds of explosives around him.

Today, King has no visible scars from his time in combat. But his injuries are as real as any veteran hit by shrapnel. Instead of losing a limb, King lost functions in his brain that help him remember things, control his emotions and sometimes talk clearly.

He covers it up well. He said most people around him don’t know he’s suffering from the effects of a traumatic brain injury – don’t know the invisible battle with his disability that he wages every day.

And King is far from alone. Since 2000, more than 270,000 troops have been diagnosed with concussions and other traumatic head injuries. Experts say the numbers are likely much higher. A Rand Corp. study in 2008 put the number of brain-injured troops at more than 320,000, and that was two years before a massive surge in improvised explosive device attacks in Afghanistan.

As highlighted in Sunday’s Post and Courier, the military’s documentation and focus on the dangers of concussions was shaky until 2009, when commanders made traumatic brain injury issues a priority.

Traumatic brain injury “is the silent epidemic,” said Mark George, director of the Medical University of South Carolina’s Brain Stimulation Laboratory. “We’re just coming to grips with how much it might be affecting normal and abnormal behavior in society.”

The medical and social implications of these invisible wounds of war go far beyond the battlefields and accident scenes where they took place. A growing chorus of researchers says that repeated blows to the head change brain cells on a cellular level that make people more likely to develop neurological problems later in life, conditions similar to those found in punch-drunk boxers and football players who have had their bells rung too many times.

Many vets will turn for help to the Department of Veterans Affairs, which has spent tens of millions of dollars gearing up for a new wave of vets with injuries that are costly and difficult to diagnose. A study last year by the Congressional Budget Office found that treating patients for traumatic brain injuries costs four to six times greater than helping patients overcome post-traumatic stress.

Complicating things further: Symptoms of post-traumatic stress and traumatic brain injuries are often similar. Some veterans, including King, have both. And yet, though these invisible injuries are challenging to diagnose and treat, as King’s experience shows, they are even more difficult to ignore.

King’s journey to al Qaida’s lair began years before, when his father died. King was born in Myrtle Beach. His father was a TV repairman, inventor and Air Force veteran. “When I was 12, he might as well have been Superman.” That’s also when he found out his father had cancer.

His father died a few months later, and during a memorial service, King was handed an American flag. He promised himself and his father then that he would try as hard as he could to live up to his values. At age 17, his mother gave him permission to sign up with the Marines.

On Sept. 11, 2001, he learned that his then-wife was pregnant. A month later, he was in Egypt as part of a large military exercise, and a few weeks away from a secret mission to Afghanistan. The exercises in Egypt involved live ammunition, including an anti-tank weapon that’s one of the loudest in the military.

During the exercise, he was caught in the weapon’s blast zone and knocked over, like a lineman slamming into a quarterback.

“I was out of it for a while,” he said. He talked incoherently to a doctor; he had difficulty unloading his gun magazine. When someone approached him to take his gun, he reflexively grabbed it tight and refused to give it away. The next day, he felt a sudden rush of euphoria, a common effect after concussions.

But the doctor didn’t diagnose him with a concussion then, which as far as King was concerned, was just fine. He didn’t want to jeopardize his next assignment — dismantling one of al-Qaida’s command-and-control centers.

By January 2002, he was with about 50 Marines who joined Navy SEALs and other Special Forces in the Zhawar Kili cave complex in eastern Afghanistan.

The cave complex was a heavily fortified warren that had been used extensively in the Afghanistan war with Russia. It had an irrigation system to water trees, and tunnels and rooms that extended for hundreds of feet.

Working alongside Special Forces teams, King led men through villages and into the caves, where they found a trove of intelligence and eerie photos of President George W. Bush with blood running down his face and the Twin Towers burning. Taliban and al-Qaida fighters were scattered throughout the area, trying to pick off troops when they could. Since it was such a massive intelligence coup, a 10-hour mission turned into a nine-day search-and-destroy marathon.

On Jan. 3, 2002, coalition forces struck the area with B-1B bombers, F/A-18 Hornets and AC-130 gunships. They dropped bunker-buster bombs and 15,000-pound “daisy cutters.” Forces on the ground helped guide the bombers. The bombers were so accurate, the Marines and Special Forces sometimes were within a football field of al-Qaida targets.

“I wasn’t in the kill radius (where casualties are likely), but I was definitely in the casualty radius,” King recalled. He threw up as the bomb blasts went through him, ordering his men to stay back. The fighting left him battered, and when the mission was over, he slept for a day and a half. In a recommendation for the Navy and Marine Corps Achievement medal, supervisors said King helped destroy “al Qaida’s most extensive and important command and control center, terrorist training camp and munitions storage facility.”

King knew his brain and body had taken a beating. At first, he found it difficult to do paperwork. Later, he had trouble remembering things. He was honorably discharged from the Marines in 2006, and according to his release summary, had “proven himself to be an exceptional leader and a sound tactical leader.”

As a civilian, King held jobs as a police officer, worked at Home Depot and at Brookgreen Gardens. But the symptoms worsened. His marriage dissolved. He stammered. He frequently misplaced his wallet. Sometimes he put bottles of milk in the cupboard, or do other things that left friends and family baffled. “My son would say, ‘Dad, the eggs are in the oven again.’”

In 2008 he went to see Michael Horner, a clinical neuropsychologist at the Ralph H. Johnson VA Medical Center in Charleston. Horner and his colleagues diagnosed him with post-traumatic stress and a traumatic brain injury. King learned about the complexities of post-traumatic stress and brain injuries, how the hypervigilance associated with post-traumatic stress sometimes amped up his stress levels, which then triggered memory and communication problems.

Early in the long Iraq and Afghanistan wars, the military and the VA were unprepared to handle the waves of troops with post-traumatic stress and traumatic brain injuries headed their way. “The veterans’ mental health system was simply overwhelmed by the influx,” a 2009 report by Iraq and Afghanistan Veterans of America found.

Not that brain injuries were anything new. “Brain injuries have been a consequence of war for thousands of years,” said David Cifu, the Veterans Health Administration national rehabilitation program director. But as IEDs became the insurgents’ weapons of choice in the early years of the Afghanistan and Iraq wars, the VA and Defense Department scrambled to build new clinics and learn more about TBI and its effects.

Where the VA had four TBI clinics 10 years ago, it now has more than 100, including one at Charleston’s Johnson VA center. Spending on clinical TBI work rose from $16 million in 2007 to $51 million last year. Spending on TBI research was a paltry $3 million in 2007. Last year it was more than $30 million.

Locally, the VA in Charleston and its clinics from Myrtle Beach to Savannah have given advanced TBI screening tests to nearly 900 vets since 2007. Of those, 237 were formally diagnosed with traumatic brain injuries.

Horner, the clinical neuropsychologist who worked with King, takes a cautious approach to the overall problem, noting that most studies about mild traumatic brain injuries, whether from blasts or other events, show that most people with mild TBI heal without any long-term health problems. He worries that the problem will become “over-pathologized” and unnecessarily stoke fears.

Others disagree. “There’s overwhelming evidence that mild TBI can lead to permanent damage,” said Lee Goldstein, a Boston University medical researcher who studied the effects of blast waves. One study found that the effects of blast forces can cause damage similar to what’s found in the brains of punch-drunk boxers.

Goldstein said he resists using the term “mild” to describe traumatic brain injuries. “It invalidates people’s horrific experiences, which may have been life-changing.”

George, the MUSC researcher, said scientists are still full of questions about traumatic brain injuries and their long-term effects. Researchers still don’t know whether several small concussions cause the same damage as a single severe blow. “We’re just now coming to grips with how traumatic brain injuries are affecting normal and abnormal behavior in society.”

Since his diagnosis, King has devised strategies to remember things. He has an iPod that helps him keep track of tasks. To exercise his brain, he took classes at Horry Georgetown Technical College. He said he reads everything from scientific papers to the classics. He works at the VA’s clinic in Myrtle Beach, and in his off-hours he does martial arts. He recently organized the Veterans Beard & ‘Stache Beach Bash, a beard and mustache contest.

He said it’s important for veterans with TBI to talk to their employers about their injuries. Without that dialogue, it’s easy for an employer to misunderstand why you forgot something or made a seemingly obvious mistake on a form.

Brain injuries are considered a disability under the Americans With Disabilities Act, which prohibits employers from treating employees differently under most circumstances. The least helpful thing people can offer people with traumatic brain injuries is advice. “You get some people who say, ‘Oh, just write things down. Make a list.’ Everyone has a quick fix, but there isn’t one.”

King said that despite his injuries, he has no regrets about his time in the military, especially his missions in Afghanistan. “I went over there so others wouldn’t have to,” he said. “The best thing people can do is just to show some patience.”