The effects of a traumatic brain injury (TBI) are pretty clear – problems with memory, headaches, and emotions – but what's unclear is the underlying pathological causes for those symptoms. According to new research led by researchers at the National Institutes of Neurological Disorders and Stroke (NINDS), those underlying pathological causes may actually involve more extensive blood vessel damage than previously known. These findings could help target better treatment of these common injuries.
The study, "Traumatic microbleeds and vascular injury," was published Oct. 13 in the journal Brain, and was a collaborative effort between the Uniformed Services University of the Health Sciences (USU), the National Institutes of Health (NIH), the University of Maryland, and the Cold Spring Harbor Laboratory.
TBI sustained in sports or battlefield can have fatal or lasting effects, but until now it's been unclear how these symptoms develop pathologically. Therefore, the researchers sought to better understand the pathological mechanisms that cause these symptoms by examining the brains of hundreds of patients very soon after injury using high-resolution imaging techniques. They looked, specifically, at traumatic microbleeds – where trauma left a physical imprint on the brain that appeared as dark lesions on MRI scans, according to Dr. Lawrence Latour, the study's lead author and researcher at NINDS.
Of the study's 439 patients with acute TBI (less than 48 hours after injury), about 30 percent had evidence of traumatic microbleeds (blood vessel injury). The traumatic microbleeds were also identified in 27 percent of mild, 47 percent of moderate, and 58 percent of severe TBI patients. They also found that traumatic microbleeds were seen in more than 25 percent of patients with mild TBI, suggesting that traumatic microbleeds are not exclusive to patients with moderate or severe TBI. Overall, blood vessel damage was much more widespread than expected in patients with TBI.
"These findings are also significant because of the presence of traumatic microbleeds was an independent predictor of outcome," according to Dr. Regina Armstrong, Director of Translational Research at the US Center for Neuroscience and Regenerative Medicine (CNRM) who also collaborated on the study. The researchers also found patients who had traumatic microbleeds were more than twice as likely to have disability as a result of their TBI upon follow-up at 30 and 90 days post injury.
This study is important to the general public, and especially the military, to help detect TBI and provide treatments to those at risk of prolonged symptoms. Future studies are needed to explore therapies targeting the effects of traumatic microbleeds in acute TBI, including TBIs that result from high-impact blast exposures. "
Dr. Regina Armstrong, Director of Translational Research at USU's Center for Neuroscience and Regenerative Medicine (CNRM)
Uniformed Services University of the Health Sciences (USU)
Griffin, A.D., et al. (2019) Traumatic microbleeds suggest vascular injury and predict disability in traumatic brain injury. Brain. doi.org/10.1093/brain/awz290.