Hey guys. I’m Siobhan, a 3rd year medical resident. Today I’m gonna be telling you about James. He’s a 21 year old healthy university student, never had any medical issues. He’s active, but he is a bit of a picky eater. Ever since he was a kid, he didn’t like a lot of food textures. And so he ends up just really eating bread, french fries and Cheerios, but without the milk. One day walking home from class, he noticed that his calf was a bit sore and he figured he must have just strained it at the gym. But throughout the week it started getting more painful and swollen and then so painful that he couldn’t even touch it. So he decided to go to the emergency department. After waiting for a few hours, he was finally seen by the emergency doctor. The doctor noticed that his right calf was 4 centimeters bigger than the left one and it was very painful. So he ordered some blood work and an ultrasound of that leg and then James was diagnosed with a deep vein thrombosis: a blood clot in his leg. But why would a 21 year old get a blood clot? The most common thing in a young person who gets any kind of diseases is a genetic cause or genetic predisposition. So they tested him for all the common ones including factor v. Leiden, some antibodies like antiphospholipid antibody and everything came back normal, with the exception of a high MCB. Which just means that your red blood cells are larger than they should be. So he was started on a blood thinner and then sent home with appropriate followup with a thrombosis clinic and they specialize in blood clots. Over the next few months James started to notice that he was having trouble concentrating and his marks were actually starting to slip a bit. Plus he felt like his legs were a bit weaker and then sometimes he would get this numbness and tingling in his feet that would come and go. He didn’t think much of it, but then the symptoms started getting more frequent and he was worried that maybe this had to do with the blood clot. So he went back to the hospital. So there he was back in the emergency department. The emergency doctor found that his legs were actually weaker. They were 4/5 in strength on both sides and you would definitely expect a 21 year old healthy man to have 5/5 strength. Plus he wasn’t able to feel his feet as well as you’d expect. So the emerge doc ordered some bloodwork and then called the neurology team, the specialist in the brain, the spine and the nerves, to come down and assess James. And again his blood work looked good except for those large red blood cells which were even larger than they were 3 months ago when the neurology team came to assess James. They did a ton of different physical exam findings to try to figure out what was wrong. They watched him walking and then they noticed that he was lifting his feet higher than you’d expect off the ground. When they got him to stand with his feet together and close his eyes, he couldn’t keep his balance and was gonna wobble and fall over. And when they were testing his sensation, he couldn’t feel any vibration underneath the level of his knee and they couldn’t get any reflexes from his ankles. Putting all of these little pieces together, the neurologists felt pretty confident that this was a sensory nerve problem. So the nerves that run from the tip of the toes all the way through the spine and up to the brain to tell the brain what position is the foot in. Otherwise your brain actually doesn’t know what’s going on with your foot. Those are the fibers that were having trouble. So right now we’ve got red blood cells that are too big and sensory nerve fibers that aren’t working well. And there are a ton of different things that can cause both of those and we’ve gotta figure out what crossover, what condition can cause both of these signs and symptoms. So now we send off even more blood work. This time zeroing in on what we suspect: low thyroid, low vitamin b12 levels and evidence of chronic alcohol use. And what we find is incredibly low levels of vitamin b12. After waiting for a while, we finally get the results of James’ brain MRI and the results are shocking. His brain actually looks like it’s 40 years older than he is. We can see that there is brain atrophy, which means the brain actually looks smaller than it should, plus there are lesions in the white matter on both sides of the brain. All of this is consistent with severe vitamin b12 deficiency. Plus this explains why he was having so much trouble concentrating at school. It actually explains everything from the blood clot to the nerve problems. B12 is involved in making myelin, which is kind of like insulation that can go over the nerves and help it send signals really quickly over long distances like your leg. And when there’s damage, that’s when you can get the weakness and the sensation changes and that’s actually why James was lifting his feet so high off the ground. Because he wanted to slam it into the ground and actually feel something because the lack of sensation he had. Vitamin b12 is also involved in blood clotting, but it’s a little bit more confusing, so stick with me. So b12 helps to convert one protein into another protein, simple enough. But if you don’t have b12, this conversion doesn’t happen. So you end up with a lot more of this protein over here and that’s called homocysteine. It’s a normal protein, we all have it, it’s amino acid. But at high levels it can put you at risk for having heart attack, stroke and blood clots. So low vitamin b12 caused the blood clot, his decrease in concentration at school, the decreased sensation in his legs, the weakness and of course those large red blood cells. So great, we’ve got a diagnosis! But that’s not enough… We need to know: Why are his b12 levels so low? So there are actually a bunch of different causes of vitamin b12 deficiency. It can be related to absorption or autoimmune diseases, but in James’ case this is most certainly to do with his diet. So vitamin b12 is actually only found in animal products like meat, dairy, eggs. And if you’re not eating those things because either you don’t like them like James or because you’re vegetarian or vegan, it’s super important that you find other ways to get vitamin b12. There are some products where they fortify and put in b12. Or you can take a supplement, but you really want to stay healthy. The crazy thing is that the amount of b12 that’s fortified into different things like cereals is different in different countries based on regulations laws, things like that. So where I am or James is, it’s Canada. And we don’t have any b12 that’s put into cereals like Cheerios, whereas the US and UK hey actually add that in. So if you think about it… If James had actually lived in the US, this might not have happened. So luckily for James, he started getting vitamin b12 injections every day, then every week and then every month and slowly all of his symptoms went away within a couple of years. And since then he’s actually tried to go and seek psychological therapy and see if he could add in some more food into his diet. But despite his best efforts, he just couldn’t bring himself to do that. So he definitely will be on vitamin b12 pretty much forever. So be truthful: Did you think it was gonna be b12 that explained all of his symptoms or were you surprised? Let me know in the comments below or what you thought it was gonna be. Otherwise, I hope that you like this style of video. If you do, don’t forget to subscribe and I’ll be chatting with you in the next video. Bye for now!