Concussion: What is going on in my brain?
A concussion is like redirecting every flight to only a few airports due to poor weather – expect headaches, complaints, and delays.
Your brain is like looking at a flight route map of every flight (axon) and every airport hub (cell body) all at once.
Imagine every airplane was housed within every airport across the world, and each airport was equivalent to a brain cell or neuron. There are approximately 44,000 airports in the world. To get the number of brain cells in an average human brain, multiply the number of airports in the world by 2 million (roughly 88 billion neurons).
A concussion is like redirecting every flight to only a few airports because of poor weather. Bad weather is analogous to the mechanism of injury in a concussion. The bad weather causes planes to get redirected to only a few airport hubs. These hubs experience a disruption to their normal state and increased operational demands. The amount of demand depends on how bad and widespread the weather (injury) is. In the case of a concussion, or mild traumatic brain injury (mTBI), the weather is bad enough to cause rerouting of airline traffic to some airports, however the airports won’t cease all outbound flights.
A concussion is a mild traumatic brain injury, although subjectively the symptoms may feel much worse. A concussion is an acceleration or deceleration injury, and can be caused by either a direct or indirect blow to the head.
The weather can also physically damage structures such as the airplanes and airports.
In the brain, axons, cell bodies, bones, and blood vessels can all be potentially damaged after the initial injury. Trauma to the head causing a rotational force within the brain is thought to lead to more severe axonal injury.
HELP: Energy Crisis
The inner operations of the airport – including data centers, employees and employers – are in overdrive trying to correct the problem.
In the brain, the cellular processes are affected. After the initial injury, there is a massive loss of potassium from the cell and an influx of calcium ions. ATP-dependent ion pumps work on overdrive, trying to return the cell to a state of balance or homeostasis. They do this by regulating ion channels, controlling the movement of calcium, sodium and potassium ions. This process demands energy. In the brain, glucose is the source of energy and is delivered in the blood. However, after injury, vasospasm of blood vessels occur and cerebral bloodflow is reduced.
Airport employees need help (glucose) because of increased demands, but they don’t have the necessary support in place (cerebral blood flow) to deliver that help. Increased demands and inadequate staff lead to communication problems. As a result, there is an increase in the stress levels of employees and customers. They get agitated.
In the brain, reduced blood flow prevents the delivery of adequate glucose to the ATP-dependent ion pumps. Reducing cerebral blood flow is the body’s way of protecting the brain from massive swelling, but there are consequences to this protective mechanism. Cerebral excitation, or agitation, occurs through the release of the neurotransmitter glutamate. As with stress, a small amount is okay but a large amount of glutamate is unhealthy; in the brain, it is toxic.
COMMUNICATION: Altered neurotransmission and inflammation
With all this chaos going on, there is a change in communication. Customers are wondering what is going on, when they can be rescheduled, rebook flights, how long, etc. Employees are trying to handle the inquiries, attempting to communicate with each other and with the bosses to deal with the situation and coordinate their efforts. This communication ménage-a trois is disjointed, haphazard and inefficient.
The same processes occur within the brain. Altered communication leads to the outward expression of clinical symptoms – fatigue, memory impairment, dizziness, etc.
Everyone at the airport is irritated, stressed and complaining.
This altered state is the equivalent of an inflammatory response in the brain.
ANOTHER INJURY: Second Impact Syndrome
What if another issue grounded or rerouted more airplanes to even fewer airports while the first issue was still being resolved? The problems would be compounded with the potential to be catastrophic. It can shut down everything.
In human terms, it can get worse and can even be fatal. If another head injury occurs during this initial energy crisis, where a mismatch between cerebral blood flow and glucose metabolism is present, further metabolic changes occur. The brain can lose its ability to auto-regulate blood flow, resulting in blood vessel dilation and increased cerebral perfusion. This increase in cerebral blood flow causes the brain to swell, raising intracranial pressure. Increased pressure can cause cerebellar herniation, a potentially fatal condition that occurs when the brain is squeezed through the bottom of the skull. Although rare, this condition is called Second Impact Syndrome.
DETECTION: Imaging in concussions
Why can’t a concussion be accurately diagnosed with traditional medical imaging such as X-rays, MRI or CT scans? Continuing with our analogy, if we took a step back and looked at a satellite image of airports and airplanes globally, we would be unable to see the crisis unfolding within. We wouldn’t see the stress or communication problems between the customers, employers, and employees. We would unlikely pick up on the fact that airplanes have rerouted to fewer airports. We would just see airplanes in the air and airport buildings from above.
Standard imaging methods are not sensitive to the inner workings of the cell and of the metabolic crisis developing within. They focus on the macro level, whereas concussions affect the brain mostly on a micro level. Some of these details can be uncovered with specialized imaging equipment, but these are used mainly in research labs. However, progress is being made to find sensitive and specific methods of detecting concussion, from neuro-cognitive baseline testing to biomarker analysis.