What is Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg)?
Deep Vein Thrombosis, often shortened to DVT, is a serious condition that can cause severe illness and even death. The complications from DVT can vary, from slowing down blood flow in a vein (venous stasis) to blocking a lung artery (pulmonary embolism). DVT happens when a clot forms in one of the body’s deep veins. Understanding this condition is crucial as it remains a major health concern.
What Causes Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg)?
Virchow’s triad outlines the three main factors that increase the risk for developing a deep vein thrombosis (DVT). These factors are slowed or erratic blood flow, abnormalities in blood clotting, and damage to blood vessels. Other common risk factors for DVT include cancer, recent surgery, staying still for long periods of time, estrogen therapy (particularly when combined with smoking), having had a DVT or pulmonary embolism (PE) before, and a strong family history of the condition.
Risk Factors and Frequency for Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg)
Deep vein thrombosis (DVT) is a frequent health issue. It’s seen in primary care offices, urgent care clinics, and hospitals. The exact number of people it affects isn’t known, but it is diagnosed in about 80 out of every 100,000 patients. In fact, one out of every 20 people will develop a DVT at some point in their lifetime.
- About 600,000 people are hospitalized each year in the U.S. because of a DVT.
- DVTs are more likely to occur in people over the age of 40.
- Men and African Americans are more likely to develop a DVT.
Signs and Symptoms of Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg)
Deep Vein Thrombosis (DVT) is a medical condition that involves the formation of a blood clot in one of the deep veins, typically in the leg. When diagnosing DVT, it’s helpful to take note of certain characteristics from a person’s medical history that can increase their risk of this condition. These risk factors may include a previous cancer diagnosis, the use of external estrogen therapy, recent surgery, smoking, a prior history of DVT, lack of physical movement, old age, history of blood clotting disorders, and other health comorbidities. People with DVT often experience symptoms like swelling and discomfort in one leg. It’s also important to ask about potential symptoms of Pulmonary Embolism (PE), such as chest pain, breathing difficulties, and fainting. A physical examination usually reveals swelling of one extremity, warmth and discomfort over the affected vein, and occasionally, a palpable “cord” at the site of the DVT.
- A history of cancer
- Use of external estrogen therapy
- Recent surgery
- Smoking
- Prior history of DVT
- Lack of physical movement
- Old age
- History of blood clotting disorders
- Other health conditions
- Swelling and discomfort in one leg
- Possible symptoms of PE: chest pain, shortness of breath, fainting
- Swelling of one extremity
- Warmth and discomfort over the affected vein
- A potential palpable “cord” at the DVT location
Testing for Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg)
If you come to the doctor with a possible Deep Vein Thrombosis (DVT), an assessment tool known as the Pulmonary Embolism Rule-Out Criteria (PERC) or the Wells Criteria may be used. These tools help your doctor determine the likelihood of your condition and decide the next steps for diagnosis and treatment. If you fit the PERC criteria, you may not need any more tests. Otherwise, if you don’t meet the PERC criteria and are considered low-risk according to the Wells Criteria, a blood test called a D-dimer might be suggested. This test is great at detecting DVT, but it’s not very specific – meaning it can show a positive result for other conditions as well. Doctors resort to this test often for low-risk patients whose symptoms don’t point towards other diseases that could cause a false positive result.
There are various imaging techniques used to check for DVT including diagnostic ultrasound, vascular studies, CT venograms, and at-hand ultrasound (POCUS). POCUS is very handy in emergency cases, helping doctors quickly rule in or rule out DVT, reducing the visit duration, and is especially useful in settings where around-the-clock ultrasound isn’t available. Doctors usually perform a 2-point compression exam in two regions with the highest chance for DVT. A recent suggestion is to perform a series of compression tests as it could significantly help improve the diagnosis accuracy without consuming extra time.
The POCUS procedure starts with the patient lying on their back, legs bent like a frog’s. The patient is then slightly tilted head-up to make the veins clearer. A high-frequency probe is placed on the area of the groin. The femoral vein, where DVT is common, can be seen just below the groin area. Pressure is applied to the vein, and if it completely collapses, it signifies the absence of a DVT. This method is repeated along the femoral vein.
Next, the process moves to the back of the knee or the popliteal region. While turning out the leg and bending the knee, the probe is applied t the crease behind the knee, where the popliteal vein resides. Pressure is applied and observation made for vein compression just like before. This constitutes the two-region technique.
If no DVT is detected, the process may be repeated one to two weeks after just to be sure that no small DVT has now grown bigger. In some cases, the D-dimer test may be repeated instead. Routine lab tests are also usually performed to assess blood clotting function, blood cell counts, and kidney performance.
Treatment Options for Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg)
There are a variety of treatments for deep vein thrombosis (DVT, a blood clot in a deep vein). The first decision to be made is whether the patient needs to be hospitalized or can be released with prescription blood thinners. Many factors come into play when making this decision, including the patient’s ability to reliably take their medication, insurance concerns, reliability of follow-up appointments, kidney function, other health conditions, other medications, fall risk, and the patient’s overall health status.
The usual treatment involves the use of a medicine called heparin or a similar drug called low-molecular-weight heparin, and then transition to a medication called warfarin. This approach often requires a hospital stay, but in certain healthcare settings, it might be managed without hospitalization. There are also newer blood thinning drugs that directly inhibit a substance called thrombin, but the decision to use these should be tailored to the individual patient’s needs.
Inferior vena cava (IVC) filters, devices placed in a large vein to catch blood clots and stop them from reaching the lungs, have been used in the past to reduce the risk of blood clots traveling to the lungs. However, it’s unclear from current research whether IVC filters actually prevent these potentially fatal complications, so use of these devices is decreasing. Nonetheless, they may still be used in specific situations.
What else can Deep Venous Thrombosis of the Lower Extremity (DVT of the Leg) be?
When doctors are diagnosing deep vein thrombosis in the lower leg (a blood clot in the leg), they need to consider other conditions that can cause similar symptoms. These include:
- Images indicating a Baker’s cyst (a fluid-filled sac behind the knee)
- Images suggesting Budd-Chiari syndrome (a rare liver disorder)
- Cellulitis (a skin infection)
- Edema (swelling) caused by dependency, like standing or sitting for long periods
- Heart failure
- Liver disease
- Pulmonary embolism (a blood clot in the lung)
- Kidney failure
- Septic thrombophlebitis (a blood clot with inflammation and bacterial infection)
- Nephritic syndrome (kidney disease causing blood in urine, high blood pressure and swelling)
Including all these possibilities helps ensure the doctors come to an accurate diagnosis.
