Unconsciousness:
How “awake” a person is can be measured by the Glasgow Coma Scale/Score (GCS) as seen below.
This tool shows how “alertness” or “arousability” is a gradient and is determined by eye opening, verbal, and motor response. So what causes comas and what is the GCS of each cause of a coma?
Sleep: Think about someone who is asleep. They may have their eyes closed until you make a sound or you may have to “shake” them awake. Their GCS would be 13-14. This is pretty much normal.
Alcohol: Think about someone who is very drunk. Maybe they won’t open their eyes until you apply a little pain, they are a little confused about where they are, but they still will obey simple instructions, “like raise your arm so I can take off your shirt idiot”. Their score would be 12. If they are so drunk, they can only moan and will only pull away from painful stimuli, their score would be 8. We sometimes call this being “out cold”.
Medications: People who are sedated medically with a breathing tube are usually somewhere between 7-8: they will open their eyes to pain, withdraw their hand from painful stimuli or even swat the source of the pain away, but they can’t speak (because they have a breathing tube in place). As a side note, you can be completely awake with a breathing tube in place. In that case your GCS would be 11, because you can obey commands, open your eyes spontaneously, but can’t speak. Most people are in this state right before the breathing tube is taken out, so they are aware and very eager to get it out. On the opposite end, we may have you completely paralyzed and on a breathing tube. If someone is paralyzed medically, like during surgery or when critically ill, their GSC will be the lowest possible, which is the same as if you were dead: 3. Certain drugs, like ketamine, make people act “loopy”. We use these drugs when we want people to relax, but still obey simple instructions and answer simple questions. We call this “conscious sedation”, and their GCS is usually somewhere between 13-14.
Infections and Diseases of the Brain, also called encephalitis, can affect the brain in any number of ways. People usually lose verbal responses first: acting confused, using inappropriate words, or incomprehensible sounds. Eye opening will be affected next and motor very last. These diseases are some of the only states in which you will see motor scores of 2 or 3, which are very concerning signs of brain abnormalities.
Low Oxygen States: I’m talking about when someone is losing a massive amount of blood, have infections of the blood, severe anemia, or are dehydrated. “Shock” is any time the heart is not able to pump enough blood/oxygen and severe or “decompensate” shock affects level of consciousness. Unlike what you hear on TV, “shock” is not an emotional state triggered by trauma, but a medical emergency referring to dysfunction of the heart. Level of consciousness will decrease in the same way it would for encephalitis: verbal response first, then eye opening, then motor response. As a side note, fainting is also usually caused by low oxygen states which are extremely transient. People who faint usually wake up within seconds, and if they don’t it is very concerning.
Seizures: For sake of completeness, I’ll throw this in there. People having seizures will usually have abnormal movements, which puts them in the 4-5 GCS range.
Traumatic Brain Injuries: I know this is what y’all actually care about. Let’s talk about getting hit in the head. Whether it is a punch, sports injury, car accident, or fall, hitting your head is BAD. If the injury is minor, people may “lose consciousness” for a couple of seconds. This usually means the person has a concussion and may have memory loss of the seconds to minutes before and after the injury as well as mild confusion. Their GCS is almost always 14. As a side note, it is an old wives' tale that you shouldn’t let people sleep after a concussion. Sleep is necessary for healing of the brain and is absolutely A-OK. A medical professional may tell you to make sure you can wake a family member up every few hours, because they are looking for signs of a more serious problem called “hemorrhagic stroke”.
Hemorrhagic Stroke: So, what about more severe injuries that may cause bleeding in the brain? Well, surprisingly, their GCS is also usually a 14, sometimes a 12-13. They will be wide awake, but maybe a bit confused. They may have trouble finding words or only capable of grunting. People just don’t stay unconscious very well. At least at first. The idea that you get “knocked out” by a blow to the head, just isn’t a thing, but if someone suffers a brain bleed, the blood will fill up the immovable skull and push the brain to the side, eventually causing decreased level of consciousness.
As an example, my sister witnessed my brother-in-law fall from a ladder four years ago. She actually told me that she perpetuates the myth all the time that trauma to the brain causes unconsciousness by telling people that he was “in a coma” for two weeks after the injury and wouldn’t wake up. What actually happened was that immediately after the fall he was on the ground, in pain, eyes wide open, bleeding from the head, flaying wildly, panicked, grunting, and moaning (GCS 12) until first responders arrived and medically sedated him while simultaneously putting in a temporary airway. He was medically sedated through surgery which removed a flap of his skull to allow space for the brain to expand while he bled. However, after they took him off sedation about a week later, he failed to wake up, because the pressure inside his brain was still too high. This is called increased intracranial pressure or ICP, and most definitely can cause people to be anywhere from 3-14 on the GCS. As a side note, although he eventually regained full motor and speech functions, he lost critical thinking skills and impulse control due to his brain injury. And he is “THE LUCKY ONE”.
In conclusion, brain injuries are no joke, but the effects are often delayed or subtle. We can’t just hit someone in the head, expect them to “stay down”, and then expect them to be ok in a few hours. I think I’ve said this before on the forum, but if you watch boxing matches, boxers don’t stay down because they are unconscious. They do it because they are in pain. Boxing is brutal, fighting is brutal, and the old “pinch the neck like a ninja trick” isn’t a thing. Unless it’s magic... then ignore everything I’ve said and do what you want. You have my blessing! 🥰