Main Causes Of Traumatic Brain Injuries And Why TBI Outcomes Are Different For Every Patient

In the United States, the most common causes of TBI include falls (35.2%), motorcycle and car accidents, automobile accidents involving pedestrians (17.3%) and assaults (10%) with or without a weapon. Athletics and sports also cause a lot of TBI. In the U.S., combat head injuries are also pervasive. Combat injuries combine blunt (closed head injuries), penetrating (with retained fragments, perforating, grooving the skull, tangential and cranial facial degloving) and blast-over pressure CNS injuries. Approximately one and a half million people suffer TBI annually in the United States. Fifty-two thousand people die, and 1.365 million people are treated and released, while another 275,000 people are hospitalized with moderate to severe symptoms. More than 30,000 children have disabled annually. The estimated cost of TBI annually exceeds $48 billion.

PRIMARY AND SECONDARY TRAUMATIC BRAIN INJURIES

The primary injury, caused at the moment of impact, can
involve a specific part of the brain, or it can affect the entire brain. The skull does not have to be fractured. The impact of the blow to the head might cause the brain to literally crash against the inside of the skull repeatedly as it moves back and forth. The impact can cause bruising, bleeding and tearing of nerve fibers.

Directly after the impact, symptoms might be absent. Often though, the condition of the patient can deteriorate very rapidly. At first, the patient might be confused. Memory and vision might be impaired, and dizziness and even unconsciousness might follow.
The brain often experiences delayed trauma. Swelling, when it occurs, can push the brain against the skull, and this might reduce the flow of blood and access to oxygen. Injuries resulting from trauma are classified as secondary injuries. The secondary injuries are very often more detrimental than the primary injuries were.

TBI ARE CLASSIFIED INTO THREE MAIN CATEGORIES, DEPENDING ON SEVERITY

Mild TBI (Concussions included) will, if at all, result in only brief loss of consciousness, and the patient will normally be awake – with eyes open. Symptoms might include a headache, disorientation, confusion, and loss of memory.

Moderate TBI will lead to loss of consciousness between twenty minutes and six hours. The patient will be sluggish and inert, but the eyes will open to stimulation. A degree of brain swelling or bleeding will present, and this will lead to sleepiness. But, the patient will be able to wake up when prompted.
Severe TBI leads to unconsciousness for longer than six hours. The eyes will respond to any stimulation and will not open.

WHY TBI OUTCOMES ARE DIFFERENT FOR EVERY PATIENT

The long-term impact of TBI is notoriously difficult to predict. One of the main reasons for this is the fact that every TBI is unique. The amount of force, the direction of the force, location of impact, the health and the strength of the patient, the speed and quality of the treatment of the injury, all these factors determine the severity of the long-term effects of a TBI to some degree.

Recent research (i) elucidated how the individual patient’s immune system and microbiota impact the severity of the TBI. Disruptions of the gut-brain axis appear to be partly responsible for ongoing TBI complications, and some suggested immune system treatment targets might improve future outcomes. The role of inflammation caused by the TBI is also under the microscope.

At best, predicting the outcome is a very complex and unchartered field in brain medicine. Because of the side effects caused by head injury, including some of the above-mentioned reactions inside the body, there might be a slight deterioration in the condition of brain cells over time, which may cause new symptoms or cause some of the long-term effects of TBI to become more severe.

According to McMillan, et al (ii) evidence is accumulating that TBI might trigger a persistent chronic disease with late deterioration - sometimes several years after injury. Studies show that up to 25% of all TBI survivors show functional deterioration between seven and thirteen years after injury, which might indicate that TBI could be the substrate for the induction of chronic: neurodegenerative processes.

Studies show that individuals who had a history of sick-leave or unemployment before their TBI suffered worse outcomes and had more problems with daily activities over the long-term than those fully employed with no history of frequent sick-leave. Studies also indicate that the longer the delay before discharge from intensive care and admission to rehabilitation, the worse the outcome was for the patient one year after injury. iii,iv

References:

i)McKee Celia A., Lukens John R. "Emerging Roles for the Immune System in Traumatic Brain Injury" Frontiers in Immunology, 7, 556 AND A. Houlden, M. Goldrick, D, et. al. Brain injury induces specific changes in the caecal microbiota of mice via altered autonomic activity and mucoprotein production. Brain, Behavior, and Immunity. 2016, 57, 10-20.
ii) McMillan TM, Teasdale GM, Stewart E. Disability in young people and adults after head injury: 12-14 year follow-up of a prospective cohort. J Neurol Neurosurg Psychiatry. 2012; 83:1086–91.
iii)Ulfarsson, T., “Predictors of long-term outcome after severe traumatic brain injury” Department of Clinical Neuroscience and Rehabilitation. Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, 2013
Iv) Leon Edward with Dr Anum Khan, “CONCUSSION, TRAUMATIC BRAIN INJURY, mTBI ULTIMATE REHABILITATION GUIDE: Your holistic manual for traumatic brain injury rehabilitation and care (Life After Stroke or TBI , Living with Hemiparesis)”