Introduction 

What is Thrombophlebitis? 

Thrombophlebitis is a medical condition where a blood clot develops within a vein, through a process known as thrombosis. A blood clot is when red blood cells bind together, which can block blood flow.¹ Blood clots are usually formed during inflammation, the body's natural response to injury from trauma or medical procedures.² Thrombophlebitis tends to occur after periods of minimal movement, so it frequently affects individuals who are pregnant, obese or under bed rest. There is a wide range of causes for this disorder, making it highly common. 

What are the outcomes of Thrombophlebitis? 

Blood clots tend to only last a couple of hours. However, blockages in the veins limit blood flow and could lead to side effects. For example, delaying seeking treatment for thrombophlebitis can lead to other conditions such as long-lasting pain (known as post-thrombotic syndrome) or vein scarring.

Thrombophlebitis is a sign of clotting issues and increases your chances of suffering from other related disorders such as a pulmonary embolism (blood clots within the lungs), which is a medical emergency. Medical assistance should be sought for thrombophlebitis as it can lead to more serious conditions or be an indicator of another disease. 

Diagnosing thrombophlebitis can encourage lifestyle changes or introduce medications to reduce the chance of further blood clots. 

Development of Thrombophlebitis

Thrombophlebitis can occur in any vein within your body. They are more likely to form close to the skin or between muscle layers.² These typically form in the lower portion of your body, such as your legs and different types of thrombophlebitis vary in where blood clots are likely to form. The arms, neck and pelvis are also common areas for blood clots to form.¹

Thrombophlebitis development consists of two key stages:

1. Inflammation of the vein: Also referred to as phlebitis, this is where the body sends immune cells to a site as a result of damage to the vein wall. This increases blood flow to the area for white blood cells to protect the site
2. Formation of a blood clot: Increased blood flow can cause blood cells to gather near the inflamed tissue and form a solid mass through aggregation

These two stages can be deciphered from the name thrombophlebitis which can be broken down into thrombo-, referring to a thrombus (blood clot), -phleb, referring to veins, and -itis, meaning inflammation.³

It is also hypothesised that blood clots can form first and trigger the onset of inflammation within the veins. 

Explaining the causes of Thrombophlebitis

Genetic mutations can alter the normal composition of blood and increase the chance of blood clots forming also known as hypercoagulable states. These can include deficiencies in antithrombin, protein C, protein S, and heparin cofactor II which are involved in regulating clotting. Mutations that affect blood clotting factors include factor V Leiden and the prothrombin gene. 

Lifestyle factors can also increase the chance of thrombophlebitis. Lack of movement or inactivity can decrease the circulation of blood within veins and lead to blood clots. This is likely in those who sit at desks for prolonged periods of time or long travel journeys, such as flights where movement is restricted. 

Individuals who are pregnant are likely to suffer from thrombophlebitis since it can increase substances in the blood that increase clotting. Pregnancy also reduces the ability of the body to break down clots known as fibrinolytic activity. 

Medications that include the hormones oestrogen and progesterone, such as oral contraceptives and hormone replacement therapy (HRT). These increase the concentrations of a protein (fibrinogen) that is involved in blood clot formation.²

Medical procedures involving the veins such as receiving medication through an intravenous line or catheter, can disrupt the vein. This can cause inflammation at the site, leading to thrombophlebitis. Trauma and injuries to veins cause thrombophlebitis in the same way. 

Key mechanism of Thrombophlebitis 

Virchow’s triad 

Rudolf Virchow was a scientist who researched blood clots and created the term ‘thrombosis.² He proposed there are three features that lead to thrombosis, known as the Virchow Triad.⁴ This theory summarises why thrombophlebitis occurs and identifies risk factors and groups at risk. This includes:⁴

Types of Thrombophlebitis

There are several different types of thrombophlebitis that range in seriousness and symptoms. The two main types include superficial thrombophlebitis and deep vein thrombosis. 

Superficial Thrombophlebitis 

This is when thrombophlebitis occurs within veins at the surface of your skin, typically within your legs and arms and occasionally the neck. This form of thrombophlebitis is less serious and resolves in 2-6 weeks. Females have a higher chance of developing superficial thrombophlebitis than men. It is common for superficial thrombophlebitis to form within varicose veins,² which are veins at the surface of the skin that are larger in size than normal and can be twisted. 

Symptoms of Thrombophlebitis

• Lumps you can see or feel under the skin
• Sweilling
• Reddened veins
• Fever

Risk Factors of Thrombophlebitis

• Trauma to site
• Receiving medical treatment through intravenous (IV) lines at the site

Treatments of Thrombophlebitis

• Using a warm compress to the site
• Wearing support stockings
• Taking painkillers such as ibuprofen or aspirin

In some cases, superficial thrombophlebitis can lead to other disorders such as deep vein thrombosis if the clot travels to a deeper vein. 

Deep Vein Thrombosis (DVT)

This is when thrombophlebitis occurs in veins deep below the skin, typically within the legs, thighs or pelvis. This form of thrombophlebitis is more serious and can be life-threatening. If the blood clot moves from its position in the vein and travels to the brain, lungs or heart it can cause a stroke, pulmonary embolism or heart attack, respectively. Adults over the age of 40 are at greater risk of developing deep vein thrombosis.

Symptoms of DVT

• Swelling
• Cramps
• Pain
• Red or purple skin
• Site is warm to touch 

Note that deep vein thrombosis, commonly referred to as DVT, can also present no symptoms, leading to it going undiagnosed and untreated. 

Risk Factors of DVT

• Heart failure
• Inflammatory bowel disease (IBD)
• Obesity
• Cancer
• Factor V Leiden 
• Prothrombin mutations 
• Family history of DVT⁶

Treatments of DVT

• Blood thinning medications (anticoagulants)
• Inferior vena cava filter (procedure that filters blood to catch the clot)
• Wearing compression socks 

Prevention

Thrombophlebitis can be caused by a range of different factors and reducing the exposure to some of these factors can lower the chances of developing thrombophlebitis. For example, DVT is estimated to affect 80 people per 100,000 every year. With the serious complications such as pulmonary embolism that can be caused by thrombophlebitis, individuals may choose to reduce their risks. 

This can include:

• Quitting smoking
• Increasing exercise and movement
• Reducing intravenous exposure (recreational drugs)³ 
• Blood thinners (anticoagulants), if you are at high risk of thrombophlebitis³

Summary

Thrombophlebitis is the formation of blood clots within veins as a result of inflammation, the body's natural healing response.^1,5 There are a range of genetic disorders, lifestyle choices, diseases and medications that are linked to increasing the chances of developing thrombophlebitis as these affect factors involved in the normal clotting process and blood flow. There are different types of thrombophlebitis which range in seriousness. Deep vein thrombosis (DVT) and superficial thrombophlebitis are the two main types and differ by the location of the veins they affect.² Individuals with symptoms of thrombophlebitis, such as pain in the legs, red veins and swelling, should seek medical advice. Thrombophlebitis can normally resolve itself but in some cases medication or procedures are required to limit blood clots, leading to life-threatening disorders.