I’m about to summarize what I usually teach over 8 1 hour nursing visits, so yeah, this is going to be a long post.
A blood clot happens when any one of a number of things goes wrong with the clotting system in your blood.
A blot clot is a scab, like when you skin your knee, only it’s inside you and usually a lot smaller. We want blood to clot sometimes, like when you get cut. We don’t want it to clot other times, like when it’s still all inside your blood vessel. We don’t want it to clot there because it runs the risk of being pushed along with the flowing blood until it reaches a teeny tiny blood vessel where it won’t fit, and it blocks the vessel like a cork in a bottle. Then whatever is downstream of that block doesn’t get blood supply, and lacks oxygen and stews in its own waste products.
If the clot is just sitting there stuck to the blood vessel wall, it’s called a thrombus. The condition or action of having a body which makes a thrombus is called thrombosis. If it happens in a big vein in your leg (where they often start), it’s called deep vein thrombosis.
Once it starts to move, the clot is called an embolus. If it gets stuck somewhere, that’s called an embolism. Often people refer to it as a thromboembolism, and I refrain from whacking them with sticks because I love humanity. Thromboembolism is more properly the condition of thrombosis + embolism. Don’t worry about it, you don’t need to know that part.
If the embolus gets swept along until it gets stuck in a blood vessel going to your brain, you can have a stroke. If it gets swept along until is gets stuck in a blood vessel going to your heart, you can have a heart attack. If it gets swept along until it gets stuck in a blood vessel going to your lungs, you can have a pulmonary embolism. These are all Bad Things. And yes, they can all hurt. They can also all not hurt. Pain is not a good way to diagnose a thrombus or an embolus, but it does often tell us where we need to start looking.
A thrombus/embolus can sometimes be diagnosed by using a kind of ultrasound called a Doppler ultrasound. Painless and non invasive, but it doesn’t “see” all of them. Sometimes they use contrast dyes injected into the vein and then x-rays or CT scans - this won’t let you see a thrombus/embolus itself, but it will let you see where blood is being blocked and not getting through anymore.
There are a lot of steps involved in making clots, and any one of them can go wonky and create inappropriate clots. If your doctors know which step in the process is acting up, they can choose which drug to give you, because the drugs work on different steps in the process. But most of the time, they don’t know exactly which step is broken, and they don’t care. There are four common tried-and-true and one new and exciting drugs which work on almost everyone. All of them require some amount of dose fiddling to make sure you’re not likely to get a clot you don’t want, while still being able to make a clot when you do need one and don’t suffer excessive bleeding.
Aspirin. We’ve all heard about low dose aspirin therapy. Some people get put on full dose aspirin therapy. Aspirin inhibits platelets from sticking together, which is one of the steps in clot formation. There is no antidote to aspirin if you take too much and start bleeding.
Plavix. Plavix also inhibits platelets from sticking together, but it does it slightly differently than aspirin. Plavix has an unfortunate side effect of killing white blood cells, so it can make you more likely to get infections or have trouble fighting off infections. It also interacts with a ton of other drugs. There is no antidote to Plavix if you take too much and start bleeding.
Heparin/low-molecular weight heparin/Lovenox. This is an injection into the subcutaneous tissue (the fat) under the skin. It’s usually given in the stomach, but it can also be given in the back of the arm, the thigh, the shoulder…anywhere you can give insulin, you can give heparin. Heparin blocks something called thrombin, another step in clot formation. There is an antidote to heparin if you take too much and start bleeding.
**Coumadin **(brand name)/**warfarin **(generic). Warfarin blocks Vitamin K, which is needed to make several different clotting factors, another step in clot formation. It’s taken by mouth, and takes several days to kick in. While you’re on it, you need frequent testing (as much as twice a week for the first month or two, and monthly once your body gets used to it) to test how long it takes your blood to clot when compared to someone not on warfarin. This test is called a PT/INR, or just INR. If your INR is too low, you need more warfarin and you’re at risk for a clot. If the INR is too high, you need less warfarin, and you’re at risk for a bleed. Vitamin K in your diet can affect the dose you need. They used to tell people to avoid Vitamin K if you’re on warfarin, but now they suggest simply keeping your diet consistent in the level of Vitamin K week to week. If you eat leafy greens, eat about the same amount of leafy greens/bananas/other foods high in Vit K every week, and they can match the dose of warfarin to the amount of Vitamin K in your diet. What you don’t want to do is eat no leafy greens this week and go on a collards binge next week. The extra Vitamin K won’t be blocked by your warfarin dose, and you may develop a clot. There is an antidote to coumadin if you take too much and start bleeding. (I have an 8 week lesson plan just on warfarin therapy, but this will do for now.)
Pradaxa. This is the new and exciting one. It works by inhibiting thrombin directly. It doesn’t require frequent blood tests, you can eat all the Vitamin K you want and it’s an oral drug. There is no antidote to Pradaxa if you take too much and start bleeding.
Because all of the oral drugs take a few days to reach effective levels in your body, doctors often order heparin/lmw heparin/Lovenox right away while you start taking one of the oral meds, and then take you off of it when the oral medication is working. This is called “Bridge Therapy” or “Bridging” for short. Later on if you need surgery, or even extensive dental work, your doctor will tell you when to stop taking your oral medication a few days before (if possible) and may want to “Bridge you” with heparin until a few days after the surgery when you can resume your oral medication. This provides the best protection against clots, while also providing the best prevention of excessive bleeding during or just after surgery.
So, if you have a clot, you need to be under a doctor’s care (which is sounds like you are) and you need to take your medication as directed and make sure you understand the risks (bleeding) and benefits (fewer clots) and when to stop taking it (when your doctor tells you to.) You also need to tell every medical professional you ever see - doctors, nurses, pharmacists, dentists, paramedics - that you’re on anticlotting therapy, because it’s really, really important that they know that.
Whew! Any questions? 