Veinitis is the inflammation of a vein. It can occur after an infusion or after an intravenous injection of an irritant, without necessarily having a bacterial infection.

Veinitis occurs when the lining of a vein is irritated. It is most often a superficial vein, located under the skin. This complication is therefore usually seen with the naked eye: the area around the puncture site becomes red, hot and painful, while the vein may appear hard and tight to the touch.

Venitis is a complication frequently encountered in drug addicts but also in patients who have had a medical infusion. Without an infection, the stung vein can be irritated by:

• the injected product : this is all the more true when the treatments administered are aggressive (chemotherapy, quinine, etc.). Sclerotherapy, which aims to remove a diseased vein by injecting a sclerosing product into it, can also cause venitis: instead of sclerosing and disappearing, the vein becomes hard and painful;
• the catheter itself : even if it has been stabilized on the arm by a bandage, it is difficult to prevent it from moving slightly, especially during prolonged infusions, which last several days, or during childbirth. However, the walls of the superficial veins are thin and fragile: they end up reacting. The longer the treatment, the greater the risk of inflammation;
• repetition of bites : the walls of the superficial veins being thin, they end up reacting to repeated trauma caused by needles or catheters. This is true for drug addicts, who then have to find other veins to prick, but also in case of long-term intravenous treatments. In the latter case, to overcome the problem, a new access route can be created artificially by a vascular surgeon: arteriovenous fistula in dialysis patients, central venous route, in a large vein in the thorax or neck in patients in chemotherapy, etc.

In case of associated fever, the inflammation may be doubled by a bacterial infection.

If it is painful, the venitis itself is not serious. It is even a frequent sequel to infusions, which may subside on its own. But she must be watched. 

Indeed, when the venous wall is inflamed, it is less flexible and the blood, which circulates less well, may have a tendency to coagulate, therefore to form a blood clot (or thrombus) liable to block the vessel. The inflammation then doubles as swelling of the vein, which is then felt like a hard cord under the skin. It is superficial venous thrombosis, or superficial phlebitis.

It is rare for the clot to dislodge, go to block another vessel downstream, especially in the lungs, and create an embolism.

During post-operative hospitalization, taking an anticoagulant normally limits the occurrence of such an event. However, this risk is not completely zero. As it is serious, patient monitoring will therefore be set up in the event of superficial venous thrombosis, to avoid it.

The inflammation usually resolves on its own within days of catheter removal, but tenderness to touch may persist for several weeks. While waiting for it to go away, this pain can be relieved with pain medication. The application of hot compresses to the sensitive area can also be recommended.

If the venitis occurs before the end of a treatment, and requires the catheter to be withdrawn prematurely, another vein should be sought for the placement of a new catheter. If all the veins are fragile but long-term treatment is needed, artificial access will be created. 

In patients with end-stage renal disease, the situation is even anticipated: before they reach the stage of dialysis, an arteriovenous fistula is created by a vascular surgeon between a vein and an artery, so as to create a vessel more resistant to puncture, with an artery wall but close to the skin. Likewise, for some chemotherapy drugs, a catheter can be placed directly into a large vein in the neck or chest, with thicker walls, for the administration of treatments. This last access will be removed after the last infusion.