Deep vein thrombosis

Health encyclopaedia - Alphabetical Topic List

| A |

| B |

| C |

| D |

| E |

| F |

| G |

| H |

| I |

| J |

| K |

| L |

| M |

| N |

| O |

| P |

| Q |

| R |

| S |

| T |

| U |

| V |

| W |

| X |

| Y |

Blood clotting is an essential protection against severe loss of blood from injury to veins or arteries. Without it we should all be in serious trouble. But blood is only supposed to clot when it is outside a blood vessel. Clotting within an artery or vein is always abnormal and is often dangerous.

The word â€˜thrombosisâ€™ means clotting of blood within an artery or a vein. A deep vein thrombosis (DVT) is a clot occurring in the large veins of the legs that lie in amongst the muscles. There is another set of veins lying just under the skin.

In a deep vein thrombosis, a long, soft, snaky blood clot forms, usually attached at one end. It may become very large before it breaks loose into the bloodstream. If it does come loose, it will be carried quickly by the movement of blood into the larger leg veins. From there it will be carried up into the largest vein of the body and into the right side of the heart, then into the main branches of the arteries to the lung, where it will impact, blocking the blood flow. This is called pulmonary embolism or PE and is a common cause of sudden, unexpected death. When PE is severe it causes the lungs to collapse and heart failure.

Blood clots in superficial veins in the legs below the knee (phlebitis) are much less serious and usually easily treated with drugs.