Winter alert! Sudden leg swelling may breed a deadly "killer"

Swollen legs, swollen feet, foot pain, leg numbness, bulging veins on the legs, tenderness when touched... These seemingly common symptoms, if caused by venous disease, may lead to lower limb ulcers and even pulmonary embolism and sudden death if not treated in time. So, how does such a terrible situation happen? Let's talk about it in detail today.

Let’s look at a case first.

An 80-year-old man felt his left leg swell and calf pain for more than 10 days. He didn't take it seriously at first, thinking that it was normal to have some leg problems at an advanced age, and he didn't want to cause trouble for his children. As a result, he didn't come to the hospital until the swelling extended to the entire thigh and he couldn't walk.

The doctor at the hospital found that the patient's left lower limb was obviously swollen and cyanotic. Ultrasound examination showed that there was no blood flow in the superficial femoral and popliteal veins of the left lower limb, and deep vein thrombosis had formed . If not treated in time, it could lead to a fatal "pulmonary embolism" at any time. So leg swelling may be gestating a fatal "killer". So, what is deep vein thrombosis in the lower limbs, and how can it cause a fatal "pulmonary embolism"?

What is deep vein thrombosis in the lower extremities?

"Thrombosis" is easy to understand. It refers to a "plug" in the blood vessels that blocks the blood vessels and hinders the flow of blood in the blood vessels. How are the "plugs" in the blood vessels formed? For example, the human veins are like rivers, and the blood is like flowing water. The river water carries silt, which is like the blood cells in the blood, and the dam in the middle of the river is like the valve in the blood vessels, which can control the flow rate. If the water flow slows down and there is too much silt, it will easily lead to silt accumulation and block the river. Similarly, because the blood is thick with blood lipids and has many coagulation factors, the blood cells will gather and stick together, forming blood clots to block the blood vessels.

Most of the blood clots people often talk about refer to venous thrombosis, among which lower extremity venous thrombosis is the most common, accounting for 80% to 90% of all thrombosis types. In particular, people who have been bedridden for a long time, have undergone surgery or fracture trauma, have malignant tumors, take oral contraceptives, and are over 60 years old with hypertension, diabetes, stroke, obesity, and antithrombin deficiency often have their blood flow slowed down and the blood becomes viscous, making it easier for venous thrombosis to occur.

The veins in the lower limbs are divided into superficial veins and deep veins. The superficial veins are located in the superficial part of the legs and are easily visible to people. The deep veins are buried in the muscles and are relatively deep. Generally, the deep veins cannot be seen, but they are the main arteries for blood return to our lower limbs. As the name suggests, the concept of deep vein thrombosis in the lower limbs is that the blood in the deep veins of the lower limbs coagulates and stops flowing, causing blood congestion and thrombosis. This is what we often call deep vein thrombosis.

Clinically, deep vein thrombosis is mainly manifested by swelling, pain, tenderness, redness, edema, varicose veins, skin ulcers, and even "old leg rot". Over time, if not treated in time, it will spread to the superficial femoral vein in the thigh (Figure 1), followed by the large blood vessels in the pelvic cavity, the external iliac vein and the common iliac vein (Figure 2), and even develop to the inferior vena cava in the abdominal cavity (Figure 3). Once the thrombus breaks off and reaches the lungs with the blood flow, blocking the pulmonary artery, it will cause fatal pulmonary embolism in the patient, and the "pulmonary embolism triad" will appear, namely dyspnea, chest pain and hemoptysis. In severe cases, sudden death may occur at any time.

Figure 1: Femoral vein thrombosis

Figure 2: Pelvic venous thrombosis

Figure 3: Thrombus in the inferior vena cava

Deep vein thrombosis in the lower extremities: why is it a silent "killer "?

News such as "sudden death while surfing the Internet" and "sudden illness after playing mahjong all night and being sent to the hospital" are not uncommon on the Internet. This is often caused by the detachment of venous thrombosis. Because deep vein thrombosis of the lower limbs is a hidden disease, there are often no signs before the incident!

If a blood clot in the deep veins of the lower limbs breaks off and flows back to the lungs through the heart with the blood circulation, it will block the pulmonary artery and cause pulmonary embolism. Pulmonary embolism has an insidious onset, rapid progression, and a high mortality rate (90%-95%), and has become the third most common cause of vascular death after myocardial infarction and stroke.

This cannot be blamed on the patients themselves for not paying attention. The main reason is that deep vein thrombosis in the lower limbs may not have any clinical symptoms in the early stages. When the disease progresses to a certain extent, calf soreness, limb swelling, and persistent pain will occur, and the symptoms will worsen after activities. However, this symptom may also be ignored by the patient.

When the disease progresses to the point where thrombosis forms in the deep veins of the entire lower limbs, the body will open the superficial veins to compensate, and superficial varicose veins can often be seen. When deep vein thrombosis develops to the late stage, a corresponding systemic inflammatory response will occur.

What are the causes of deep vein thrombosis in the lower limbs?

The main causes of deep vein thrombosis in the lower extremities are as follows:

1. Due to age factors, decreased physiological functions, and the accumulation of bad living habits, the incidence of chronic diseases such as hypertension and diabetes has increased significantly. In addition, chronic inflammation, immune response and other factors have caused damage to the venous wall, which means that the inner membrane of the lumen is not smooth.

2. Blood stasis caused by various reasons, that is, there is resistance to blood return, such as obesity, high cholesterol levels and high blood viscosity.

3. The hypercoagulable state of blood can be understood as the blood is prone to coagulation.

Specifically, the following groups of people need to pay special attention to deep vein thrombosis in the lower limbs.

1. Long-term bedridden patients

2. Elderly people, especially those who are not active

3. People who travel long distances by plane or train

4. Pregnant women who take oral contraceptives for a long time

5. Postpartum pregnant women who are bedridden

6. Patients who are bedridden after surgery or trauma

7. Autoimmune diseases

8. Patients with advanced cancer

9. Obese people who don’t like to exercise

How to treat and prevent deep vein thrombosis in the lower limbs?

If you suspect you have deep vein thrombosis in your lower extremities, you should go to a regular hospital as soon as possible to find out the location or range of the thrombosis. If it is not very serious, such as peripheral thrombosis (small area), you can take oral medications, raise the affected limb, rest appropriately or wear elastic stockings to reduce edema.

When central thrombosis occurs (occurring in the main channel blood vessels, such as the iliac vein and femoral vein), the patient must be hospitalized in the company of doctors and nurses to receive more professional treatments such as anticoagulation, thrombolysis, and thrombus fragmentation, so as to avoid serious complications that affect our daily life in the future.

It is very important to learn how to prevent deep vein thrombosis in the deep veins of the lower extremities. In daily life, we can pay attention to the following matters:

1. Avoid sitting or lying down for long periods of time.

2. Drink more water to replenish water and enhance metabolism, which can dilute blood viscosity.

3. Exercise more to strengthen your body, speed up blood circulation and prevent blood clotting.

4. Avoid drinking excessive amounts of high-sugar beverages and avoid taking contraceptives for a long time to avoid causing or increasing blood viscosity.

5. For those who need to stay in bed for a long time due to trauma, illness, childbirth, etc., they should turn over frequently, strengthen rehabilitation, or perform ankle pump exercises on the lower limbs to artificially help blood return. If conditions permit, get out of bed and move around as soon as possible.

7. Lose weight, control blood sugar, and reduce bad living habits.

8. For hypercoagulable state of blood caused by congenital diseases, anticoagulant drugs can be used as prescribed by the doctor to prevent thrombosis.

Author: Guo Xianli, Director of the Vascular/Tumor Minimally Invasive Intervention Department of Bazhou Third Hospital

Reviewer: Ao Guokun Xuanwu Hospital Affiliated to Capital Medical University