Deep vein thrombosis of the lower limbs, a common and frequent clinical disease, mainly manifests as pain and increased tension in the lower limbs, often accompanied by superficial varicose veins, and the skin temperature of the affected limbs may increase. Many patients with the above symptoms do not know which department to visit, and even many primary care physicians lack knowledge of the disease. Therefore, the author feels that a general introduction to the disease should be made.
Thrombosis can occur in any part of the deep veins of the lower extremities, from the metatarsal plexus of the foot upward to between the iliofemoral vein system. From the actual clinical situation, it can be divided into: calf deep vein thrombosis, iliofemoral vein thrombosis, femoral cyanosis and lower extremity deep vein thrombosis syndrome. Lower extremity deep vein thrombosis, whether early venous obstruction venous return obstruction, or late venous recanalization venous blood flow backflow, can appear lower extremity venous stasis syndrome – lower extremity swelling, pain, swelling, superficial varicose veins, etc. The symptoms are not identical due to the different locations, extent and degree of lower limb deep vein thrombosis, and each has its own clinical characteristics.
(A) Symptoms of calf deep vein thrombosis
Calf deep vein thrombosis (peripheral type) refers to calf muscle plexus thrombosis and N vein thrombosis.
1.Symptoms of calf muscle plexus thrombosis
It is the thrombosis of the calf muscle plexus, which is commonly caused by post-surgery, long-term bed rest and trauma. Because the lesion is small in scope and does not involve the main veins of the lower limbs, the symptoms are often not obvious, and the patient only has slight calf distension and swelling; light pressure pain in the calf muscle group, and when the foot is sharply dorsiflexed, pain can appear because the calf muscle group (gastrocnemius and flounder muscle) is stretched and elongated (Homans sign positive). Therefore, it is often overlooked, and early diagnosis and early treatment are delayed. However, it is rare for a patient to suddenly develop significant distension and swelling of the calf, not being able to walk as usual, and for thrombosis of the venous plexus of the calf muscle to occur. Mostly, when the thrombus continues to extend from the calf to the thigh, the iliofemoral vein thrombosis occurs, and only then is the patient aware of and pays attention to it.
2.Symptoms of N vein thrombosis
It refers to the thrombosis of N vein and its following trunk veins, which is not uncommon in clinical practice. Without any precipitating cause, the patient suddenly appears with severe swelling and pain in the calf, which is unbearable and cannot be walked; the calf is widely swollen, tight, hard and full, diffuse and bright, with obvious pressure pain, refusing to press and inaccessible to the hand. The systemic reaction is not obvious, and there may be low fever. With treatment, the progression can be controlled and limited to N vein thrombosis, but left with slight swelling and pain in the lower leg and slight swelling in the lower leg and ankle.
Deep vein thrombosis in the calf can occur with thrombus dislodgement and complication of pulmonary embolism, which should be taken seriously. In some patients, the calf deep vein thrombosis is only noticed after the occurrence of pulmonary embolism.
(B) Symptoms of iliofemoral vein thrombosis
Iliofemoral vein thrombosis refers to the thrombosis originating from the iliofemoral vein (central type). The onset is rapid, with sudden onset of obvious swelling and pain in the iliac recess, inner thigh (femoral triangle), or widespread swelling and pain in the lower extremity, followed by rapid onset of widespread obvious swelling and coarse swelling in the whole lower extremity, accompanied by angry and varicose superficial veins in the lower extremity; widespread blue microscopic network (network stasis) appears on the skin due to the expansion of skin capillaries (fine veins). Due to iliofemoral vein thrombosis, the femoral vein can often be found in the femoral triangle in the form of stiff cords, with pressure pain. The entire lower extremity is full and tight, especially in the lower leg, with pressure pain and a positive Homans sign. The thrombus extends distally retrograde and involves the whole lower extremity, and total lower extremity deep vein thrombosis occurs. The patient has a mild systemic reaction with fever not exceeding 38.5°C.
Whether it is calf deep vein thrombosis with upward extension of the thrombus or primary iliofemoral vein thrombosis with downward retrograde extension of the thrombus, the whole lower extremity deep vein system can be involved and total lower extremity deep vein thrombosis (mixed type) occurs, which is more common in clinical practice. It should be especially mentioned that calf muscle plexus thrombosis has no obvious clinical manifestations at the onset until it involves the iliofemoral vein and occurs when iliofemoral vein thrombosis is detected. Therefore, the onset period does not correspond to the symptomatic period, which is longer than the symptomatic period. By the time iliofemoral vein thrombosis is detected, the lesion is already in the late stage.
Clinically, deep vein thrombosis of the left lower extremity is the most common. This is because the left iliofemoral vein is located in the narrow zone between the inguinal ligament and the pelvis, and the right common iliac artery often crosses over the left common iliac vein, which can easily compress the iliofemoral vein and obstruct the venous return and stagnate the blood, making it easy for iliofemoral vein thrombosis to occur.
Clinically, we see that unilateral lower extremity deep vein thrombosis occurs first and then contralateral lower extremity deep vein thrombosis occurs, and both lower extremities are widely swollen, distended and painful with superficial varicose veins, accompanied by angry and varicose superficial veins in the lower abdominal wall and perineum, two conditions should be considered.
(1) iliofemoral vein thrombosis on both sides;
(2) Occurrence of inferior vena cava obstruction.
(C) Symptoms of femoral cyanosis
Femoral cyanosis is a serious type of total lower limb deep vein thrombosis (mixed type), in which the whole lower limb deep vein system is completely obstructed by extensive thrombosis, and the venous blood return to the lower limb is severely impaired, which also causes arterial spasm in the limb and the lower limb blood circulation is impaired (stasis and ischemia of the limb co-exist). However, it is very rare in clinical practice.
The onset of femoral cyanosis is rapid, with severe swelling and pain of the affected limb, extensive and severe swelling of the entire lower limb with cyanosis, accompanied by petechiae, blisters, cold limb, weakened femoral artery pulsation, and disappearance of dorsalis pedis and posterior tibial artery. Moreover, the systemic reaction was severe, with fever of 39°C or more. Due to the large amount of plasma and tissue fluid storage in the affected limb, it causes hypovolemic shock. At the same time, venous limb gangrene can occur, which is complicated by systemic multi-organ failure and critical condition, leading to death.
(D) Symptoms of lower limb deep vein thrombosis syndrome
Clinically, we see that there are far more patients with lower limb deep vein thrombosis syndrome than acute lower limb deep vein thrombosis because they fail to get a clear diagnosis and effective treatment for acute lower limb deep vein thrombosis in the early stage of its onset, and come to the clinic only after months or years of its onset.
In the early stage of lower extremity deep vein thrombosis, the venous blood return is impaired due to obstruction of veins by thrombus formation. At the later stage, the thrombus in the vein is mechanized and recanalized, but the vein is narrowed, dilated and tortuous, the venous valve is destroyed, as well as the venous valve of the traffic branch is destroyed, the blood of the deep vein flows backward to the superficial vein, which causes stasis in the veins of the lower extremity, the venous pressure is increased, the tissue is hypoxic, and finally the syndrome of deep vein thrombosis of the lower extremity – venous stasis syndrome appears. The main clinical manifestations are.
1, varicose veins of lower limbs From venous anger to varicose, as well as skin microscopic anger, presenting extensive varicose veins of lower limbs.
2.Swelling of lower limbs
3.Eczema dermatitis
4.Pigmentation of skin
5.Secondary infection of lower limbs The lower limbs are in stasis for a long time, the local resistance is reduced, and minor skin damage is easily secondary to cellulitis, dermatitis and other diseases. The most common is chronic inflammation of the lower leg, with redness and burning painful hard lumps (chronic stasis inflammation), without fever. Clinically, it is common to see that the syndrome of deep vein thrombosis of the lower extremities, often secondary to recurrent episodes of dermatitis, with high fever of 39-41°C, thick, hard and tough affected areas, and the formation of elephantiasis. Treatment of deep vein thrombosis of the lower extremities complicated by elephantiasis (chronic stasis of severe disease) is quite difficult.
Causes of deep vein thrombosis of the lower extremities
In the mid-nineteenth century, Virchow proposed three major factors for the formation of deep vein thrombosis: stagnant venous blood flow, damage to the venous wall and hypercoagulable blood, which are still recognized by scholars in various countries. They are described below.
Venous flow retardation
Venous flow stagnation is caused by spinal anesthesia or general anesthesia during surgery, resulting in dilatation of peripheral veins and slowing down of venous flow; complete paralysis of lower limb muscles due to anesthesia during surgery, resulting in loss of contractile function, and bed rest after surgery due to incision pain and other reasons, resulting in relaxation of lower limb muscles, resulting in blood flow stagnation and triggering deep vein thrombosis of lower limbs.
Damage to the venous wall
1, chemical injury intravenous injection of various irritant solutions and hypertonic solutions, such as various antibiotics, organic iodine solution, hypertonic glucose solution, etc. can stimulate the intima in varying degrees, leading to phlebitis and venous thrombosis.
2, mechanical injury venous local contusion, lacerations or fracture fragment trauma can produce venous thrombosis. Fracture of the femoral neck can damage the common femoral vein, and fracture of the pelvis can often damage the common iliac vein or its branches, which can be complicated by iliofemoral vein thrombosis.
3, infectious injury septic thrombophlebitis caused by the foci of infection around the veins, less common, such as infectious endometritis, can cause septic thrombophlebitis of the uterine veins.
Hypercoagulable state of blood
The hypercoagulable state of blood is one of the basic factors causing venous thrombosis. Various major surgeries are causing hypercoagulable platelet aggregation; postoperative serum levels of inhibitors of both pre-fibrinolytic activators and fibrinolytic enzymes are elevated, resulting in reduced fibrinolysis. Blood coagulability can be increased after splenectomy due to the sudden increase in platelets, and blood concentration due to burns or severe dehydration. Advanced cancer such as lung cancer, pancreatic cancer, others such as ovarian, prostate, gastric or colon cancer, when cancer cells destroy tissues at the same time, they often release many substances, such as mucin coagulant, etc. The increased activity of certain enzymes can also make blood coagulation pregnant drugs, which can reduce the level of antithrombin III, thus increasing blood coagulation. High dose application of hemostatic drugs can also make the blood in a hypercoagulable state.
Diagnosis and treatment of lower limb deep vein thrombosis
Patients with the above symptoms should go to the hospital in time and firstly perform arteriovenous ultrasound examination of the lower extremities to clarify whether it is thrombosis or not, and if it is diagnosed as thrombosis, they should be hospitalized. Recommended departments: interventional department, vascular surgery department.
The main treatment options are: anticoagulation, inferior vena cava filter to prevent pulmonary embolism, thrombolysis, angioplasty, surgery, mechanical ablation, ultrasound ablation and postoperative care. After consultation, a plan will be made by a professional physician according to the condition.