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A blood clot is blood that becomes a solid instead of a liquid. It might form into a gel-like consistency.
Clotting is normally a good thing. Clots are the body’s way of protecting you from bleeding too much.
If you cut yourself or bump into something your body releases clotting factors (proteins) that travel to the injured area. The clotting factors work with your platelets to form a clot and stop the bleeding. It is like putting a bandage on from the inside. What you will see is a scab or a bruise.
Blood clots are a serious health issue if they occur in areas where they are not needed. Sometimes they happen in:
Blood clots can form in a blood vessel and stay there. They can form in arteries or veins.
This can happen by chance. Sometimes it happens if your child has a bad infection, specific illness, or as a side effect of having an IV with a larger catheter. Some people are more prone to these clots than other people.
Some people may get a clot without an illness or infection. This is called a spontaneous blood clot.
Veins and arteries are like one-way streets. When a blood clot forms it can make a roadblock. In a sense, the blood behind the clot gets caught in a traffic jam.
Sometimes, a small piece of a clot breaks away and moves through the blood vessel, usually to the lungs or brain.
This is a life-threatening event. But if it is going to happen, it will happen in the first few days or weeks after the clot forms.
If your child has a blood clot in an artery, it does not let the blood, which carries oxygen, get to the muscle or tissue beyond the clot. The clot acts like a barricade and will not let the blood get through.
When this happens the tissue beyond the clot can become damaged. The body’s tissue and muscles need oxygen to work correctly and to stay healthy.
A deep vein thrombosis is a blood clot in a large vein that is deep inside a muscle, usually in the legs.
If your child has a clot in a deep vein, it can prevent the blood from getting back to the heart. The blood gets trapped behind the clot and can make the area behind the clot swell and hurt.
A clot can damage the valves around it. If this happens the blood will flow backwards. It can cause more pain and swelling. It may lead to post thrombotic syndrome.
Post thrombotic syndrome (PTS) happens when the blood vessels are clogged, and valves are damaged from the clot. This means the valves do not close completely and blood flows backwards.
If this happens, the area (such as a leg) will swell and could be painful. The blood gets stuck or pools.
In the severe form, PTS can cause sores to form on the skin. These can be hard to heal.
PTS can be prevented or minimized by following these steps:
If your child has a blood clot, they will need to be on medicine to keep the clot from getting bigger or coming back if it is gone. The medicine also will help make the clot smaller. The treatment will help prevent PTS by keeping the remaining clot as small as possible.
The length of treatment and whether you continue medicine for the long term will depend on why your child developed the clot in the first place.
Your child’s care team can talk about this with you. Always follow the instructions given by your care team.
Your child’s care team will:
Your child has a greater chance of getting another blood clot within a few days to several months of the first one. But it still can happen later.
Treating the clot with medicine helps prevent it from coming back.
After your child has been treated for a clot for a period, the care team will want to see if it is bigger, smaller, or the same size.
They do this with an ultrasound test. Ultrasound lets the care team see a picture of the clot. Whatever size the clot is at this time is probably the size it will stay. Your child may need to stay on medicine to prevent other clots.
The longer your child has the clot the more attached it gets to the blood vessel wall.
After 2–4 weeks, it is unlikely that the clot will “break off” and move to another part of the body.
Reviewed: September 2022