When I was 15 my sister had an accident while sledding and suffered a concussion. Visiting her in the hospital was a rather surreal experience, with her failing with recognize me one minute then trying to hold a conversation about Russia the next. I could tell there was something unusual going on, but I didn’t have any inkling of all the things going on inside her brain at that moment. Of course I knew that getting hit too hard in the head was a bad thing, your brain could slosh around and there was no possible way that could be a positive thing, but it turns out that in the wake of a concussion there is a flurry of activity down at the molecular level.
The worst part of the story is that when you get a concussion, your brain gets leaky. It’s about as bad as it sounds. Your brain normally generates the electrical impulses it uses to function by swapping tiny concentrations of ions across cell membranes. After a concussion, the leaky cells let those ions out when they shouldn’t, resulting in random electrical pulses going all over the place. The neurons’ ion pumps go into overtime to try and get things under control, which uses up a lot of energy. Unfortunately the concussion also disrupts your cells’ normal energy generation, so instead of using oxygen as normal, they try to use anaerobic metabolism. This generates large amounts of lactate, which can shift the local pH. Among other things, this can make your cells even leakier. Eventually your brain can cope, but in the meantime you get headaches, confusion, and vomiting.
And the coping takes time. More time, in fact, than it takes for you to feel better. It can take over a month for things to get back to normal, and if there are any head injuries in that time, the effects can be catastrophic. It can result in second impact syndrome, in which the already damaged brain swells dramatically. This can be disabling or even fatal. In the absence of second impact syndrome damage can still be compounded, with enough damage resulting in chronic traumatic encephalopathy. In the past this was called dementia pugilistica or punch drunk syndrome, as it was commonly seen in boxers. CTE is a progressive neurodegenerative condition, resulting in brain atrophy, with symptoms and neuropathology similar to Alzheimer’s disease, including amyloid beta plaques and tau protein deposition.
While there’s no chance we could get our athletes off the field, we need to be aware of the dangers and what can be done to protect them. New rules are being put into place which help prevent some of the riskier maneuvers, and advanced helmets are being developed which minimize the force transferred to the athlete’s brain. At the risk of sounding rather older than my years, it’s good to have fun but there’s no reason we can’t be safe while we do it.
Concussions
