World Thrombosis Day is observed on October 13, every year to increase global awareness of thrombosis, and educating people about its causes, risk factors, symptoms, diagnosis and evidence-based prevention and treatment.

Eyes are usually considered as the windows to the mind. Hence, this year the theme of World Thrombosis Day is ‘Eyes Open To Thrombosis’ which campaigns to draw attention of health care professionals, the general public and policy makers on the significance of building awareness on the often overlooked and misunderstood condition of thrombosis. The campaign is said to encourage people to not wait until tomorrow and open their eyes to thrombosis today.

Although deemed as a major blood disorder and a cause of millions of deaths, people are still unaware of this health anomaly. This article aims to discuss the different types of thrombosis to help highlight the different risks associated with this disorder that people can face and ultimately help save lives.

What Is Thrombosis?

Thrombosis is a type of blood disorder which arises due to the formation of a blood clot within a blood vessel hindering the free flow of blood throughout the circulatory system. When a blood vessel (a vein or an artery) is damaged, the body triggers the platelets (thrombocytes) and fibrin to reach the damaged site and form a blood clot to prevent further blood loss. But, sometimes even when a blood vessel is not injured, blood clots may form in the body under certain conditions.

A clot, or a piece of the clot, formed without any injury, that breaks free and begins to travel around the body is known as an embolus. The embolus can block the blood vessel and inhibit or limit the flow of blood and lead to serious health problems. The blood clot can even travel to distant places and organs including the heart or brain and can even cause a heart attack or a stroke.

Types Of Thrombosis

Thrombosis is chiefly categorized depending upon the type of blood vessel affected and the precise location where the embolus arises or travels to. It is normally of two main types.

Venous Thrombosis:

When the embolus arises in any of the veins, it is known as Venous Thrombosis. Veins usually carry the blood away from the heart to the surface of the body. Hence, the blood flow within the veins is much slower than that of the arteries increasing the likelihood of blood clots. This sudden clot in the blood generally leads to congestion in the affected part of the vein.

Venous Thrombosis is further sub-divided into the following types:

Superficial Vein Thrombosis (SVT):

When the blood clot happens in a vein close to the surface of the body, it is defined as Superficial Vein Thrombosis. These veins can often be noticed bulging on the surface of the skin and usually helps in keeping the body cool. The thrombus can be felt by witnessing a slightly hardened area or reddening of the affected part. Although, they are not as severe as DVT, however, the condition can become chronic if the clot enters a deep vein through perforator veins.

Deep Vein Thrombosis (DVT):

Deep Vein Thrombosis is a chronic medical condition, wherein the blood clot or thrombus forms in one or more of the veins located deep inside the body, usually in the veins of the pelvis, thigh or lower leg. The thrombus formation can be fatal as in certain cases, it can break free from the deep vein, travel through the bloodstream and ultimately end up in different parts of the body, where it can block proper blood flow causing more chronic conditions. Common symptoms of DVT include; redness, swelling and warmness in the affected area.

Also Read: Deep Vein Thrombosis: Causes, Symptoms And Treatment

Pulmonary Embolism (PE):

Pulmonary Embolism arises when the blood clot that has happened somewhere travels through the blood stream to the lungs. It can block the flow of blood in the lungs, limiting the oxygen supply to the various other organs. If the clot is large, it can be fatal.

Femoral Vein Thrombosis (FVT):

In this case, the clot happens in the long vein of the thigh. Although, it usually doesn't cause characteristic symptoms, but sometimes one can notice some swelling, redness, or pain in the affected area of the leg. FVT can arise due to several factors including post- surgical recovery, while you're on bedrest, or if you sit for a long time, consumption of birth control pills, or if you have been diagnosed with DVT in the past.

Renal Vein Thrombosis (RVT):

RVT is a type of thrombosis which usually occurs in the veins that drain blood away from the kidneys. They chiefly reduce the ability of the kidneys to clean and filter the blood, increasing the risk of further clots. It is more common in men and usually affects people above the age of 40. RVT can occur due to several factors including kidney transplants, nephritic syndrome, cancer, and blunt trauma to the lower back or abdomen.

Portal Vein Thrombosis (PVT):

Portal vein thrombosis usually happens when the clot arises in the hepatic portal vein, which can lead to portal hypertension and diminishing of the blood supply to the liver. It usually happens as an underlying symptom of another disease such as cirrhosis, pancreatitis, diverticulitis or cholangiocarcinoma.

Paget-Schroetter Syndrome (PSS):

Paget-Schroetter syndrome, also known as upper extremity DVT (UEDVT) is a rare type of DVT, wherein the blood clot arises in the axillary vein or subclavian vein of the arm. The condition usually affects young, healthy individuals who play sports and uses the upper arms a lot, as in the case of swimming and baseball. The frequent use of the arm squeezes the muscles around it, causing a blood clot. Symptoms are usually characterized by swelling, chest pain, and a blue color in the affected part. PSS can get complicated if it's not treated right away.

Budd-Chiari Syndrome

This type of thrombosis involves a clot that blocks the hepatic vein obstructing the outflow of the blood from the liver. It can be recognized by symptoms like abdominal pain, ascites and enlarged liver or hepatomegaly.

Jugular Vein Thrombosis

In this type of venous thrombosis, the clot usually happens in the jugular vein and can arise as a result of intravenous drug use, infection or malignancy. If not treated on time, it can often lead to pulmonary embolism, systemic sepsis, or papilledema.

Cerebral Venous Sinus Thrombosis (CVST):

CVST is a rare form of stroke wherein a clot in the brain stops blood from draining out and back to your heart. Symptoms can range from headache, abnormal vision, weakness of the face and limbs on one side of the body or seizures.

Cavernous Sinus Thrombosis (CST):

It is a type of CVST, where a blood clot can form in a vein that runs through the space behind your eye sockets. It usually happens due to infections that spreads from the eyes, nose or teeth or head injury. Common symptoms include swollen, irritated eyes, double vision, etc.

Arterial Thrombosis (AT):

Arterial thrombosis is a type of thrombosis where the blood clot or thrombus arises in any of the arteries. It usually affects the blood supply and leads to damage of the surrounding tissues supplied by that artery. In most cases, an arterial thrombosis happens due to a rupture of atheroma (a fat-rich deposit in the blood vessel wall), and is therefore commonly referred to as atherothrombosis. Arterial embolism occurs when clots migrate downstream, and can affect different organs.

Arterial Thrombosis is further divided into:

Thrombotic Stroke:

When a blood clot obstructs the blood flow in one of the brain's arteries, limiting the supply of blood and oxygen to the brain, that part of the brain starts to die causing a stroke. A thrombotic stroke can happen due to ischemia, thrombus, embolus (a lodged particle) or hemorrhage (a bleed).

Also Read: World Stroke Day: 5 Myths And Facts About Stroke

Myocardial Infarction (Heart Attack):

When the arteries in the heart get clogged with a sticky fat called plaque, a clot may arise on the plaque which could cut off blood flow to the heart causing tissue death (infarction) or heart attack. This usually happens due to ischemia or obstruction of the coronary artery leading to an insufficient supply of oxygen to the heart muscles.