Traumatic Brain Injury, often referred to as TBI occurs when the normal functioning of the brain is disrupted due to an impact on the head. This affects the cognitive abilities of the person as well as thinking and learning skills.
Most causes of TBI, according to health facilities with emergency departments occur as a result of a car crash, strikes made using blunt objects and falls. However, some indirect forces like shock waves felt in battlefields contribute to traumatic brain injury.
Health practitioners classify TBI as either mild, modest, or severe. This depends on how the patient reacts and how long the effects do last. Although most of these cases are treated as mild due to their low life-threatening chances, it’s worth noting that at times they can cause severe and extended effects.
But how is traumatic brain injury connected to dementia? A big number of aged people with a past case of TBI are prone to Alzheimer’s. The chances of developing this condition keep increasing on each hit on the head.
Read on to find how traumatic brain injury is associated with Alzheimer’s or dementia.
Pathological Relationship between TBI and Alzheimer’s Disease
Through different medical researches, it’s evident that some pathogenic mechanisms which involve proteins occur once there’s a brain injury. Chronic traumatic encephalopathy (CTE) is another condition that occurs to patients who were exposed to severe head injuries later in life. Anyone suffering from this condition can be identified with ease especially through mimicking, frontotemporal dementia (FTD), and Parkinson’s disease (PD).
Did you know that traumatic brain injury is a contributing factor to the blood-brain barrier (BBB) that causes the damage? Repeated head injuries that affect the brain lead to fast development of Alzheimer’s. This does not happen immediately, but the effect can be felt after some years.
Do all Head Injuries Result in Dementia?
It is not guaranteed that whenever a person experiences some form of head injuries will eventually succumb to dementia. Even though there’s no proof of strategies that might reduce the chances of getting dementia after a mild, severe or repeated TBI, you must understand that not everyone succumbs to dementia. As such, more studies should help in identifying links that can lead to dementia.
Disruption of Neurometabolic Processes
Physiological path damage caused by mild TBI leads to either acute or chronic neurological challenges. As such, the normal functioning of nerves that are responsible for the control of circuit function becomes disrupted. This type of damage ends up causing dementia.
Cerebrovascular Damage in TBI
Cerebrovascular damage (CVD) causes edema, hemorrhages, vasospasms, chronic inflammation, and alterations in the cerebral blood flow. The magnitude of this damage is determined as primary and secondary injury. Primary injury occurs due to mechanical destruction of the Blood Brain Barrier whenever a person experiences minimal stress forces. How does the secondary injury occur? These injuries result from alterations made in the cerebral blood clearance and flow. Also, they can take place when there is an activation of immune cells and slow metabolism.
Cerebrovascular damage has links to neuropathology together with amyloid-beta which are considered as causative agents of tau accumulation. This accumulation leads to abnormal inflammations and reduced Brain Blood Barrier resulting in dementia after some time.
Did you know that common conditions like diabetes, atherosclerosis, and high blood pressure increase your risks of dementia? These diseases cause significant damage to cerebral microvasculature, and when this happens, the affected person may succumb to dementia or Alzheimer’s.
Endothelial Damage in TBI and Alzheimer’s
In case of a traumatic brain injury, there are high chances that the endothelial cells might die and the BBI permeability might take place. The moment injury occurs to the endothelial cells, the normal functioning of your brain ceases. Therefore, proper maintenance of a functional BBB relies on endothelial cells structural support through tight junctions and associated proteins.
How Cerebrovascular Inflammation Relates to TBI and Dementia
Cases of Brain Blood Barrier lead to the inflammation of cerebrovascular. As such, the inflammatory responses become progressive, affecting the blood flow in the brain. From the inflammation effect and microbleeds, neurons, endothelial cells, and astrocytes die.
An inflammation that occurs after TBI is capable of raising the cytokine/chemokine levels in a matter of hours. If there are repeated cases of TBI, neuroinflammation can affect the neurovascular functionfor many years to come.
Impairment of Clearance Systems and AD
The main purpose of the clearance systems is to eradicate waste that is produced by cell metabolism from the brain cells. These systems include the glymphatic system, transportation across the BBB, and meningeal lymphatic vessels.
What happens when these systems fail? When a traumatic brain injury occurs, the mentioned systems start accumulating toxins in the brain leading to an insufficient oxygen supply. This causes inflammations that can lead to dementia or Alzheimer’s. In extreme cases, death can occur.
Mitochondrial Dysfunction
The first symptom that Alzheimer’s patient show is mitochondrial dysfunction. Damage in the mitochondrial enhances the accumulation of toxins in the brain hence causing dementia. Also, it is believed to cause microvascular dysfunction. More studies are ongoing to help determine how this dysfunction causes cell energy production failure.
Bottom Line
Alzheimer’s disease may occur as a result of traumatic brain injury. It is a progressive condition that can get worse with time. Just like all dementia cases, it affects the quality of life and shortens the lifespan of the affected persons. Therefore, it is important to seek immediate medical attention in case of a fall or hit.
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