What causes brain damage? There are several things that cause brain damage. These can be traumatic injury, poison, stroke, tumor, or lack of oxygen.
The brain weighs about 1.5 kg on average and contains over 100 billion nerve cells. It uses 20% of the body’s energy, which is more than any other organ. Obviously, without the brain, we cannot function. Brain damage can lead to death or it can lead to a person falling into a coma or a persistent vegetative state. This is where the person is awake but not cognitively aware.
So, what causes brain damage? Causes of brain damage are divided into two different categories: traumatic injuries and acquired injuries. Let’s look at traumatic injuries first. They are caused by some kind of physical trauma to the brain. An external force impacts the head and causes the brain to move around in the skull, or it directly impacts the brain.
In an impact, such as in a car accident, something hits one side of the head. This is called the primary injury. The brain then crashes backwards and forwards against the sides of the skull as the head is knocked about by the initial blow. This causes bleeding, bruising, and nerve fibers can get torn. The primary injury can be fatal, depending on the severity of the impact. However, if it isn’t fatal, the secondary injury can be. One of our body’s responses to injury is to swell the flesh around the injured site. This response causes the brain to swell. In most parts of the body, swelling is not a problem, but in the brain there is nowhere to move because the space inside the skull is limited. The brain presses against the skill and cuts off the supply of blood, which cuts off the supply of oxygen to the brain. Unless this is dealt with quickly, it can be fatal.
Different parts of the brain are responsible for different tasks. Traumatic brain injury can damage the pathways that the brain sends signals along. The axons that pass the electrical charge between neurons no longer work and the signals cannot be passed. Sometimes, the cognitive part of the brain can shut down, but the brainstem functions continue to work. The brainstem functions are things like breathing, circulating blood, and swallowing. The cognitive functions such as communicating, thinking, and purposeful movement are lost.
The second category of brain damage is caused by acquired injuries. These are things like a stroke, tumors, lack of oxygen, or an infection in the brain.
A stroke causes brain damage because the blood supply to the brain is suddenly cut off. A blood clot travels from the heart and either lodges in the blood vessels in the neck that supply blood to the brain, or in the brain itself. This cuts off blood to the brain and parts of the brain start to die. Without blood, the brain cannot get any oxygen and without oxygen, the brain cannot make any energy from glucose, and without energy, the brain cells die. Similar to a traumatic injury, after the stroke, the brain starts to try to heal and begins to swell. This can often cause more damage than the original stroke. Strokes cause brain death in certain parts of the brain because the blood clots block certain blood vessels.
Brain tumors can cause brain damage because they grow into the brain and compress parts of it. The pressure inside the skull increases and parts of the brain can cease functioning. A brain infection can cause brain damage in a similar way. Meningitis is an infection of the brain caused by bacteria. It infects the brain, and the membranes swell up, pressing on the spinal cord and parts of the brain.
Lack of oxygen can cause brain damage in the whole brain in the same way that a stroke can cause brain damage in a portion of it. I the oxygen to the brain is cut off for long enough, the brain will be unable to metabolize glucose and it will start to die. Even if the oxygen supply comes back, it may be too late, and parts of the brain may already have died. This is one of the reasons you die if you bleed to death.
There are many things that can cause brain damage, but our brains do have an incredible ability to heal themselves. Neuroplasticity is where the brain can make new pathways if old ones are destroyed. Our brains can relearn how to do tasks in different ways. However, that of course depends on the extent of the brain damage. And this is what I learned today.
https://www.ncbi.nlm.nih.gov/books/NBK279302/
https://en.wikipedia.org/wiki/Persistent_vegetative_state
https://www.mayoclinic.org/diseases-conditions/traumatic-brain-injury/symptoms-causes/syc-20378557
https://www.healthline.com/health/brain-damage
https://www.shepherd.org/patient-programs/brain-injury/about/causes
https://www.flintrehab.com/how-does-the-brain-repair-itself-after-a-traumatic-injury/
https://www.verywellhealth.com/how-does-a-stroke-cause-brain-damage-3146287
https://www.hopkinsmedicine.org/health/conditions-and-diseases/bacterial-meningitis
https://www.spinalcord.com/blog/what-happens-after-a-lack-of-oxygen-to-the-brain