Deep vein thrombosis (DVT) is a condition in which blood clots develop in different parts of the body. These clots are usually found in deep veins, such as those in the legs and arms. In rare cases, they may be found in the abdomen and lungs. People with DVT can experience a wide range of symptoms, including swelling and pain. DVT can lead to secondary conditions such as pulmonary embolism if left untreated.

Symptoms
Deep vein thrombosis is often observed in the veins of the legs and arms; however, a large number of individuals with this condition may not experience common symptoms. Some may experience mild symptoms, so the condition can go unnoticed. In a few cases, individuals experience severe symptoms that could lead to pain and affect their day-to-day functioning. Here are a few of them:

Swelling in the arm or the leg (this symptom can be sudden)
Veins in the particular area may seem larger or inflamed
Pain in certain areas of the arm or leg
Changes in the temperature of the swollen areas
Discoloration or redness of the skin
Pain in the abdomen and flank (observed when the blood clots affect the veins deep in the stomach and the core area)
Seizures can be a rare symptom
Sudden and severe headaches

Many people may not be able to detect deep vein thrombosis until the clots move from their arms and legs into the lungs or other parts of the body. When they move to the lungs, the clots can lead to symptoms such as chest pain, shortness of breath, and even blood while coughing. One may also feel dizzy and lightheaded. If one notices any such symptoms, it is important to get in touch with a healthcare professional immediately. This can help them get the emergency care and treatment they need.

Causes
The exact causes of deep vein thrombosis remain unclear, however, anything that affects the flow of blood and prevents it from moving freely can lead to a blood clot in the veins. One of the main causes of this condition is the damage caused to a vein during surgery. Other causes of DVT include inflammation or damage to the veins due to injuries or infection. While the precise triggers of vein thrombosis are not known, experts have found that a few factors can increase one’s risk of developing this condition. These factors include:

Age: Studies have found that those over the age of 60 are more prone to developing this condition. That said, DVT can affect anyone at any age.

Little to no movement: Lack of movement means that there is no contraction of muscles in the arms and the legs. These contractions are important as they promote blood flow in the body. Staying still for too long can increase the risk of blood clots and DVT.

Surgery: Surgery and injury can damage the veins, and damaged veins can result in an increased risk of blood clots.

Pregnancy: During pregnancy, one can experience a rise in blood pressure. This can pose a threat as it can lead to an increased risk of developing blood clots. This heightened risk of developing DVT and blood clots may also continue for six weeks after the child is born.

Oral contraceptives: Studies have shown that oral contraceptives and hormone replacement therapies can increase the risk of blood clots and make individuals prone to developing deep vein thrombosis.

Heart diseases, genetics, cancer, and family history can also be risk factors for the condition. In most cases, it is difficult to pinpoint the exact cause. Experts believe such conditions can result from a combination of personal health or genetics and environmental factors.

Diagnosing deep vein thrombosis
Various tests can help with the diagnosis of deep vein thrombosis. One of the most commonly used tests is the duplex venous ultrasound. This test is completely non-invasive and easily accessible. The ultrasound waves show the flow of blood in the body and even any present blood clots. The technician applies pressure to the arms and legs during the procedure. If this test does not yield conclusive results, doctors may suggest other testing and imaging methods. For instance, venography is an invasive test that is used to diagnose DVT. This is carried out by injecting a special dye into the neck or groin. This shows the doctor if there are any blood clots that are fully or partially blocking any of the veins. Doctors may also use an MRI or a CT scan to test for vein thrombosis.