Inflammation of the Superficial Veins in Dogs

Inflammation of veins is also known by its medical term phlebitis.  Superficial phlebitis implies that the condition affects the veins that are located closest to the skin as opposed to deep inside the body.

The inflammatory process occurs as a response to trauma or irritation of the vein.  Inflammation of the vein will cause vascular narrowing and thickening, swelling of endothelial cells, and can be a catalyst for thrombus (clot) formation. 

The condition is most commonly associated with placement of an intravenous catheter and improper catheter care.  It is estimated that 20-80% of hospitalised patients receiving intravenous fluid therapy will develop some form of inflammation to the vein.

Inflammation of the superficial veins is a common complication in dogs receiving intravenous fluid therapy.  Inflammation is usually local to the peripheral vein and the condition has a good prognosis.

Superficial phlebitis appears as localised inflammation.  Common symptoms displayed include:

• Superficial reddening of the skin
• Swelling of the vein and skin
• Veins that stand out
• Skin area that is tender to touch
• Warmth of the skin over the inflamed vein 

If the inflammation has progressed, the body will also display systemic signs of infection such as:

• Purulent discharge
• Fever
• Lethargy

Inflammation of the superficial veins in dogs is caused by inflicted trauma.  Trauma and bacterial penetration of the vein will cause an inflammatory response from cells resulting in vasoconstriction, coagulation, and an increase in vascular permeability.

Conditions with similar symptoms of phlebitis include hypersensitivity of the skin, superficial skin injury, and subcutaneous inflammation. History of trauma to the vein is an important diagnostic clue for the veterinarian.

The principal diagnostic test used to diagnose phlebitis is the Doppler test.  The Doppler monitor is used to determine patency of the vein and blood flow as well as taking a measurement of blood pressure.  Other diagnostic tests that may be used include bacterial culture, blood work, and less commonly phlebography and ultrasonography.

A bacterial culture can be useful to determine the type of foreign bacteria that is present in the vein.  Samples for bacterial culture can be collected if there is discharge present around the venipuncture or intravenous catheter site.

Blood panels are performed to determine any spread of systemic infection.  If a systemic infection is present, blood values will display an increased number of white blood cells and potential platelet abnormalities.

Ultrasonography and phlebography (imaging of the vein) can help to assess patency, character, and blood flow in the vein.  These methods not commonly used in general practice.  Phlebography requires the use of a contrast so is invasive and has increased patient risk, while specialised venous ultrasonography is less invasive but has limited availability. 

The initial response for treating phlebitis is to remove the irritating stimulant (most likely an intravenous catheter) that caused the inflammation.  Minor cases of phlebitis will usually heal spontaneously on their own while cases where inflammation has progressed may require antibiotics, topical treatment, and wound care.

 Wound care involves topical physical therapy over the venipuncture site and aims to reduce inflammation, promote blood flow, and stimulate tissue repair.  Common methods include moist compresses and hydrotherapy.  Moist compresses should be warmed before application over the venipuncture site.  Hydrotherapy is a popular mode of physical therapy to promote circulation and repair.  Low level light therapy, also known as photobiomodulation, is also becoming increasingly common and works by activating stem cells for faster healing.  These techniques have relatively low risk.

In cases where systemic infection is evident, antibiotic therapy will be required.  Antibiotics may be oral or injectable, however topical antibacterial ointments over the venipuncture site are contraindicated as they do not adequately reduce infection and can contribute to the development of antibiotic-resistant bacteria.  In cases of severe inflammation, anti-inflammatory medications may be used as well.

Blood volume replacement or fluid infusion may be required in order to avoid thromboembolism due to stagnant blood flow.  Any new catheters that are placed will require proper care for the aseptic technique as well as continual monitoring for adequate blood flow, adverse reactions, and pain.

After initial treatment in the clinic, continual monitoring of the inflamed vein will be required at home.  Owners will need to watch for an increase in swelling or tenderness around the venipuncture site as well as signs of infection such as discharge or fever (which can indicate systemic infection spread).

There are no specific environmental, feeding, or activity changes necessary.  Physical therapies to alleviate pain and promote circulation such as therapeutic massage may be implemented at home as long as the appropriate techniques have been demonstrated by the veterinary care team.

Superficial phlebitis has a good prognosis.  Inflammation of the vein will usually improve a few days after the irritating cause has been removed, however it can take several weeks for any superficial lumps to dissipate and pain to cease.