Concussion Side Effects May Cause Gastrointestinal Problems: Study

New research points to a strong link between the gut and brain, suggesting that individuals may experience harmful side effects in the gastrointestinal tract after a suffering a concussion or traumatic brain injury. 

In a study published in the November 2017 issue of the medical journal Brain, Behavior, and Immunity, researchers indicate that people who suffered a head injury or severe concussion, also often experience long-term changes to their gastrointestinal systems.

Researchers from the University of Maryland School of Medicine induced a moderate level traumatic brain injury (TBI) in some mice. They then examined changes in the mucosal barrier properties of the gastrointestinal system and colon and compared that to the mice without TBI.

The study focused on enteric glial cell response in the gut after brain trauma. Researchers also infected some mice with Citrobacter rodentium, a bacteria that causes similar symptoms in mice as E. coli does in humans.

The result indicate that there is a distinct, two-way link between traumatic brain injury and intestinal changes after a head injury, suggesting that brain injuries may contribute to increased infections in affected patients. Similarly, gut infections may worsen chronic brain damage.

Researchers noted that brain injuries in the mice triggered delayed long-term changes in the colon, making it more permeable after trauma and allowing harmful microbes to move from the intestine to other parts of the body.

According to the findings, people who experience a brain injury are 12 times more likely to die from blood poisoning, which is often caused by bacteria. They are also 2.5 times more likely to die of digestive system problems, compared with those without brain injuries.

Researchers said it is unclear exactly how concussions cause the changes to the gastrointestinal system, but it may be linked to the enteric glial cells. Those cells are specific to the gut. However, astroglial cells are similar, but are located in the brain. Researchers speculate both cells may become activated after brain injuries.

The cell activation was associated with brain inflammation. Among the mice who had the Citrobacter rodentium, their brain inflammation worsened. The mice who had a TBI also lost more neurons in their hippocampus, a brain region important for memory.

Traumatic Brain Injury Long-Term Effects

These findings are in line with other studies, which have shown brain trauma to have far reaching effects on memory and emotional response.

Prior research has shown traumatic brain injuries to have far reaching effects, both short term and later in life. A study published earlier this year linked TBI to increased risk of dementia later in life. It also increases the risk of developing Alzheimer’s disease.

Another study published in October indicated teens who suffered a head injury had a higher risk of developing multiple sclerosis later in life. That risk increased to 150% if they had suffered more than one head injury.

Researchers in this latest study said the gut-brain connection may be activated by brain trauma, which may trigger a vicious cycle between the two. In this case, brain injury causes gut dysfunction, then the gut dysfunction or subsequent infection has the potential to worsen the original brain injury by increasing post traumatic brain inflammation and tissue loss.

While prior research has shown that concussions have significant effects on the gut, this new study indicates a more direct link on how the two react with each other. This may also help explain why many people who suffer TBIs have increased incidence of systemic infections after the trauma.

The study’s authors called for more research on the gut-brain connection and how the two communicate.