The Lasting Impact of Concussions

Throughout week of October 27 in my neurochemistry class, we explored and discussed a very common brain injury that most people have heard of called a concussion. Recently, concussions have been given a lot more attention in sports because of research that has found them to be more severe than previously thought. Research has shown that concussions have the potential to have negative long term effects on the brain. Especially in contact sports, such as football and hockey, trainers and medical professionals are using a lot more care and being more cautious when treating them than was previously used. Sustaining numerous concussions have been linked with Alzheimer’s disease and CTE, so it is important to understand the symptoms and the pathophysiology in the brain, which I will hopefully explain clearly throughout this blog.
Concussion, also known as mild traumatic brain injury, mTBI, is a biomechanically induced neurological injury, which results in mental status alteration, such as confusion or amnesia. A concussion may or may not involve a loss of consciousness. Common clinical symptoms of concussions include impairments of memory and attention, headache, unsteadiness, and in rare circumstances, severe brain injury. Symptoms are also categorized into early and late symptoms. Early symptoms include headaches, dizziness, nausea, vomiting, and lack of awareness. Later symptoms include persistent headaches, sleep disturbance, reduced concentration and attention, memory impairment, and irritability. Sustaining multiple concussions is associated with more severe symptoms, longer recovery times, and also an earlier onset of age-related memory disturbances and dementia.
In order to understand concussions more thoroughly, it is important to know what happens in the brain to induce the symptoms that are associated with concussions. There are a variety of things that take place in the brain following a traumatic injury, which is called a neurometabolic cascade. It is pretty complex, but I will try to explain it effectively using simple terms. Inside the brain, depolarization and initiation of action potentials are the first things that take place. This causes the release of excitatory neurotransmitters, which leads to a massive efflux of potassium and an imbalance of ions. An imbalance of ions within the brain leads to increased ATP production, which comes in the form of increasing glycolysis. Lactate then accumulates in the cell, which eventually leads to oxidative metabolism and apoptosis. These two processes have a variety of negative impacts on the brain following a concussion.
Important to the pathophysiology following a concussion are the two alteration in glucose metabolism. They include hyperglycolysis and oxidative dysfunction. Hyperglycolysis basically means excessive glycolysis being carried out inside the brain. Following a concussion, there is an imbalance of ions within the cell. In order to restore the imbalance, the activation of sodium potassium pumps is needs, which requires an increase in ATP levels. In order to obtain more ATP, an increase in glycolysis takes place. Another thing that happens following a concussion is the activation of NMDA receptors, which causes an influx of calcium into the brain. Calcium ions accumulate in the brain, which leads to oxidative dysfunction and can have negative effects on the brain and cause the symptoms that are associated with concussions. Being an athlete, it has been very interesting learning about and discussing the various effects of concussions. Throughout my athletic career, I have witnessed numerous teammates experience concussions, but I didn’t have much knowledge about them. I have thoroughly enjoyed learning about what actually happens inside my teammates’ brains.