Junior Seau's death again highlights risks of repeated concussions, head injuries

New England Patriots linebacker Junior Seau (AP)

The apparent suicide of former NFL player Junior Seau Wednesday evening has again highlighted the long-term risks of concussions and repeated brain injuries.

Seau, who played as a linebacker for the San Diego Chargers and New England Patriots, died of what authorities believe was a self-inflicted gunshot wound to the chest.  His family and friends told the press they were “stunned and shocked.”

Seau’s death is yet another in a string of former NFL players who have committed suicide – including Terry Long of the Pittsburgh Steelers, Andre Waters of the Philadelphia Eagles, and Dave Duerson of the Chicago Bears.

Duerson, who also shot himself in the chest, specifically requested that his brain be donated to science so researchers could study the damage repeated concussions had had on his brain.  The researchers from Boston University's Center for the Study of Traumatic Encephalopathy who conducted the brain autopsy found evidence that Duerson suffered from chronic traumatic encephalopathy, or CTE.

CTE is a is a progressive degenerative disease that is caused by repeated head injuries.  People with CTE may have symptoms such as dementia, headaches, tremors, confusion, aggression and depression.

According to reports, the Boston center has already requested to examine Seau’s brain as well. Though there is little documentation that Seau had a history of concussions, it is difficult to discount the idea that he may have suffered from CTE like Duerson, according to one sports trauma expert.

“It’s a strong possibility,” Dr. Kevin Crutchfield, director of the Comprehensive Sports Concussion Program for LifeBridge Health at Sinai Hospital in Baltimore, Md., told FoxNews.com.  “No one will be surprised if he comes back markedly positive for the tau protein [which is indicative of CTE].  That is what we would expect to find.”

Professional-level athletes are the largest demographic who suffer from CTE because of the repeated blows to the head they take during practice and games.  Seau, as a lineman, would have taken a hit with every snap of the ball, according to Crutchfield, who did not treat Seau.

“Even if he never told anyone about a concussion – and it was a lot less typical to report them back then – he likely took multiple hits,” Crutchfield explained.  “It’s not so much about suffering one big blow, but multiple hits over time.”

“Also, with a lot of athletes, if you ask them how many times they have a headache at the end of a game, you’d be shocked at the number who have a rip-roaring headache after playing that they don’t understand where it came from.”

CTE impacts mental and emotional health by disrupting the balance of neurochemicals in the brain.  When a person suffers a concussion, Crutchfield explained, it incites a release of glutamine, which in turn disrupts the brain’s potassium and sodium channels.  In addition, an influx of calcium to the nerve cells shut down the mitochondria, which supply energy to the brain.  This causes the brain to go into “energy failure.”

“You need energy for the brain to balance back out and for neurotransmitters to stay in balance,” Crutchfield said.  “And so that’s what leads to depression, because depression is a neurochemical imbalance.  It’s common in brain injuries to suffer injury-related depression because of the unbalance of chemicals.”

When the injuries are suffered repeatedly over time, it becomes more and more difficult for the brain to recover from the imbalance, and the condition can potentially become permanent or even worsen over time, according to Crutchfield.

Athletes and others who have reached this point need constant follow-up and adjustment of medication and treatment to grapple with the condition.

“The problem is, older retired players are out of the limelight…and people don’t watch them closely enough,” Crutchfield said.  “Retired players need to have periodic psychological assessment because they do get depressed.”

“[Seau’s] case was tragic,” he added.  “In my heart, I do believe [his problems] would have been picked up on had he been screened.  His doctors may have not been able to do anything about the CTE, but certainly would have been able to address depression or suicide ideation and risk.”

Crutchfield said this most recent case of a former athlete taking his own life shows there is a need to do depression scales and assess suicide risks in all athletes, from professional level to children, who suffered from head injuries.

The Associated Press contributed to this report.