Now, let me start with just a small disclaimer- I'm just an Army medic and a nursing student, so I don't claim to be an expert on this. I do have a little understanding, but if there's anyone who is more informed, you're welcome to add on or let me know of any parts I may have messed up! Thanks!
After dealing with unexplained, sporadic hamstring pain throughout portions of last season, John Brown's pain returned this season, prompting his doctors to run multiple blood tests. These tests diagnosed Brown with being a carrier of Sickle Cell Disease.
Being a carrier is also referred to as having the Sickle Cell Trait, or SCT. SCT occurs when one of your parents passes on the trait, meaning one of Brown's parents also has SCT, but probably was completely unaware. How? Well its simple.
Full blown Sickle Cell Disease is when a person's red blood cells are deformed, and resemble a crescent moon, or a sickle (image below). But Sickle Cell Trait is different.
People with SCT often have a majority of regular blood cells, with a few sickle cells sprinkled in. These sickle cells cause no problems, and people with SCT can lead ordinary lives. But there are a few complications.
Intense heat, intense exercise, high altitudes, and extreme dehydration can sometimes cause these normal red blood cells to change and deform into the sickle cell shape. These sickle cells do not flow as efficiently, and as they rush through the bloodstream, they can collide and tangle up with each other, leading to a partial blockage, which reduces blood flow to the muscles.
This lack of circulation to the muscles leads to "ischemic rhabdomyolysis", which is the rapid breakdown of muscles which are starved for blood.
This logjam and breakdown is not only painful, but it is very dangerous. Think of red-lining your Ford Pinto down the I10 but your engine is not getting enough coolant or oil.
It's going to tap out real soon, and has a real possibility of permanent damage. Same here. These muscles are being stressed and worked but lack nourishment, causing them to literally break apart.
The most notable example of this was in 2006, when a Rice defensive back collapsed while running 16 one hundred yard sprints. He died the following morning, eventually leading the NCAA to pass a mandate, requiring Division I college athletes to be screened unless they provide prior test results or sign a waiver declining the test.
Now, before you start fearing the worst, now that John Brown (and the team) is aware of his condition, it is easily managed. Hydration, important enough in this Arizona heat, is even more critical. Also, now that he is aware, he can stop when he begins to feel the signs, rather than just attributing it to cramps or normal muscle pain. Ryan Clark and Tevin Coleman are both notable players with SCT who can play and contribute at a high level.
John Brown will likely miss this Sunday's showdown with the Seahawks, as his body recovers from "hopefully" the last time he red-lines that Ford Pinto of his. Once he is 100%, I don't expect any more complications, as the team and Brown will be more prepared and can properly manage this new diagnosis, as the team eyes a late season run towards NRG Stadium in Houston.