Meaning of thrombophlebitis: The name splits into three parts, clot, vein and inflammation, and all three are present at once in the affected segment.

Definition of thrombophlebitis

Thrombophlebitis is inflammation of a vein caused by a clot forming inside it. The clot irritates the vessel wall, which becomes red, warm, tender and firm along the line the vein follows, often feeling like a cord under the skin. It can affect a vein lying just beneath the surface or one running deep within a limb.

How thrombophlebitis is built

thrombo phleb itis thrombophlebitis
  • thromb/o Combining form · Greek clot, clotting
  • phleb/o Combining form · Greek vein
  • -itis Suffix · Greek inflammation

A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.

Does it matter which vein is involved?

Superficial veinDeep vein
What is seenA visible red, tender cord under the skinOften nothing on the surface; swelling and aching of the whole limb
Usual triggerA drip, a catheter, an injected irritant, or varicose veinsImmobility, surgery, or a tendency of the blood to clot
Main concernDiscomfort, and spread toward the deep systemA fragment breaking free and lodging in the lungs

Involvement of a deep vein is usually called deep vein thrombosis rather than thrombophlebitis, and it is the more dangerous of the two because deep veins drain straight toward the heart and lungs. Superficial disease is often described as minor, and usually it is, but that is not absolute. A superficial clot in the long vein of the thigh can extend upward into the deep system where the two join, so its position along the blood vessel matters as much as the fact that it is superficial.

What makes a clot form in a vein?

Three conditions, and most cases involve more than one. Blood moving slowly is the first, which is why long immobility, a plaster cast, a long journey or a hospital stay all raise the risk. Damage to the smooth lining of the vein is the second, and this is what a drip, a central line, an injected irritant or an injury supplies. Blood that clots too readily is the third, whether inherited, or acquired through pregnancy, hormone treatment, active cancer, obesity or an inflammatory illness. A blood clot forming in a vein for no evident reason at all is the pattern that prompts a look for an underlying cause.

When is superficial involvement not minor?

In two situations in particular. The first is the extension already described, where the clot reaches the junction with a deep vein. The second is a pattern of episodes appearing in one vein, settling, then appearing in another, sometimes in unusual sites. Migrating inflammation of this kind has a long recognized association with cancer that has not yet been found, particularly of the pancreas, and is treated as a signal rather than a local problem.

Used in a sentence

The patient developed thrombophlebitis of a superficial vein following prolonged intravenous catheter placement.

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Good to know

Superficial thrombophlebitis is generally less concerning than deep vein involvement, but a superficial clot near the junction with a deep vein can extend into it, so location matters alongside the superficial or deep label.

Word origin

Where “thrombophlebitis” comes from

Formed from thrombo-, Greek for clot, phleb-, meaning vein, and -itis, meaning inflammation.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.