Deep vein thrombosis (DVT) is more common clinically, and although any venous system may be involved, most occur in the lower extremities (especially the left lower extremity), and in the upper extremities the axillary-subclavian veins may be involved. Inferior vena cava thrombosis is often the result of upstream reproduction of iliac-femoral vein thrombosis on one side; superior vena cava thrombosis, mostly secondary to mediastinal lesions, is rarely seen clinically. We focus on deep vein thrombosis of the lower extremities.
Etiology
According to Weil’s tsunami doctrine, the three major factors of venous thrombosis are stagnant blood flow, venous wall damage and hypercoagulable state. Deep vein thrombosis is the result of a combination of local and systemic factors contained in these three basic elements, especially slow blood flow and hypercoagulability. There are many specific risk factors for thrombosis, including heart disease, malignancy, trauma, surgery, pregnancy, childbirth, hyperviscosity, erythrocytosis, leukocytosis and other allergic diseases, thrombocytosis, obesity, old age, and oral contraceptives, but the most closely related are trauma and post-surgical bed rest.
Deep vein thrombosis of the lower extremities can be divided into three types.
I. Peripheral type (also called calf muscle plexus thrombosis): thrombosis begins in the calf muscle plexus not exceeding the N vein. It is characterized by swelling of the calf and swollen and full muscles, squeezing pain, and excessive dorsiflexion of the ankle may excite pain in the gastrocnemius muscle (Homans’ sign) and have gastrocnemius pressure pain (Neuhof’s sign), with a high chance of recanalization.
Central type (also called iliofemoral vein thrombosis): The thrombosis starts from the iliac and femoral veins (root of thigh), and the distal side of the limb is swollen due to obstructed reflux, with superficial varicose veins, and rarely recanalization.
Third, mixed type: the type that can be developed from the above two or both, which is clinically common.
In addition, there is a special type of lower limb DVT, namely femoral cyanosis, which is rare clinically, as the lower limb DVT is widely occluded, lymphatic return is obstructed, and causes strong spasm of limb artery, insufficient blood supply to the limb, strong systemic reaction, and often venous gangrene.
DVT of the upper extremity refers to thrombosis of the axillary and subclavian veins, also known as Paget-Schroetter’s disease. It accounts for about 2-3% of all DVT. Mostly due to anatomical abnormalities of the upper extremity, the axillary vein or subclavian vein is compressed, plus the upper extremity strain or contusion is the main cause of this disease, a few can be secondary to congestive heart failure, metastatic cancer in the axilla or subclavian vein cannulation, etc., mostly primary.
In terms of pathophysiological process, deep vein thrombosis can be attributed to the formation of thrombus, the multiplication and growth of thrombus, the dissolution of thrombus, the mechanization and retubulation of thrombus, and the endothelialization; accordingly, there are different clinical manifestations as well as regression and outcome.
Clinical features
The clinical manifestations of deep vein thrombosis vary depending on the site and period of occurrence. In the acute phase, reflux obstruction predominates and may be accompanied by an acute inflammatory response in the limb; in the chronic phase, its course evolves from occlusion to recanalization, from reflux obstruction to reflux and reflux deep venous insufficiency. And high venous pressure and stasis are the most important features after venous thrombosis.
1. Swelling is one of the main manifestations of DVT in the limb.
Acute phase: The affected limb can be swollen rapidly due to acute venous reflux obstruction, with varying severity, mostly more severe. In the case of calf muscle plexus thrombosis, it shows fullness and tension in the calf, especially in the gastrocnemius muscle, and the swelling is non-finger sunken, accompanied by local pressure pain and pulling pain, sometimes the symptoms are not very obvious, so that the diagnosis is missed; in the case of iliac-femoral vein thrombosis, the acute swelling of the whole limb or the distal 2/3 of it can appear, and the swelling is mostly sunken, and the limb is swollen even more than the foot, accompanied by pain and pressure pain in the direction of deep vein travel. The swelling is mostly depressed, and the swelling of the limb is more than the foot, accompanied by pain and pressure in the direction of the deep vein. The skin may be mildly cyanotic, and the skin temperature may be slightly elevated. However, sometimes lymphatic drainage may be impaired, and the swelling may be non-finger sunken or mixed, with significant swelling of the foot (e.g., arch and toes). If femoral cyanosis occurs, there will be widespread and marked swelling of the lower extremities with tense, shiny skin and extremely high tension, which may be accompanied by skin cyanosis, blisters and severe pain. In severe patients, the affected limb can be thickened by more than 10 cm on the opposite side in one day.
Deep vein thrombosis in the lower extremities can extend proximally and involve the inferior vena cava, causing bilateral lower extremity edema, often symmetrical, and swelling in the suprapubic area and vulva.
In the acute stage, if the treatment is active and regular, such as the application of thrombolysis, anticoagulation, Chinese herbal medicine and measures to elevate the limbs and promote reflux, the swelling can gradually or even rapidly reduce or subside.
Chronic phase: The affected limb can be recanalized due to the dissolution of the thrombus in the embolized vein, the retubulation of the vein, or the gradual establishment of the collateral circulation, and the improvement of the blood return state, but the venous valve is damaged and loses its original function. As a result, there is a series of clinical manifestations of obstruction caused by the obstruction of the return flow and the backflow of blood after recanalization, resulting in venous hypertension and depressed blood. The swelling can be long-term, and the swelling can be finger-sunken or non-finger-sunken, which is aggravated after standing or walking, and there can be intermittent venous claudication, which is sometimes difficult to be completely eliminated by elevating the limb at rest; accompanied by swelling and pain, superficial varicose veins, and some patients can gradually develop nutritional disorders in the foot and boot area. The skin of the lower leg becomes black and itchy, and the scope becomes larger and larger, and eventually a long-lasting ulcer will be formed (commonly known as polycarbonate leg).
2.Pain
Pain and swelling often coexist in the acute stage, with rapid onset, pain and pressure pain at the same time.
The pain of gastrocnemius plexus thrombosis is characterized by painful pulling of the gastrocnemius muscle (Homans sign) and painful squeezing of the gastrocnemius muscle (Neuhof sign), in addition to the painful swelling of the lower leg. The pain of iliofemoral vein thrombosis is caused by two factors: first, the thrombus stimulates inflammatory reaction in the iliofemoral vein, which produces local persistent pain; second, the distal venous blood return obstruction, which causes distension and pain due to depressed blood, with varying degrees of pain, mostly not serious, heavy or dull pain, which is aggravated when standing and can be significantly relieved by lying down or elevating the affected limb. The pressure pain is located on the surface of the iliac-femoral vein, most obvious in the femoral triangle, and in thin bodies, the thrombus-filled strips of the femoral vein can often be found.
If the limb forms femoral cyanosis, the pain is abnormally severe, the swelling is serious, the skin is dark purple and cold, blistering, and the arterial pulsation of the limb disappears, accompanied by high fever, and often shock or even gangrene of the limb.
In the chronic phase (posterior phase), the pain is similar to the swelling and rupture pain of deep venous valve insufficiency, mostly aggravated after standing or walking or after dropping the limb, and can be relieved by elevating the limb. It may be accompanied by superficial venous dilatation, skin pigmentation and nutritional disorders in the foot and shoe area.
3.Superficial varicose vein
After iliofemoral vein thrombosis, superficial venous dilatation is compensatory to increase venous blood return to the distal side of the iliofemoral vein obstruction plane, mostly becoming more obvious as the swelling decreases, while superficial varicose veins can be seen in the lower abdomen and hip of the affected side. When the inferior vena cava is obstructed or the thrombus multiplies to the contralateral iliofemoral vein, the collateral circulation is dilated in order to divert the venous blood from the distal part of the inferior vena cava obstruction. Superficial varicose veins can extend all the way to the abdominal and chest walls, in addition to the bilateral lower extremities and vulva.
The superficial veins of gastrocnemius plexus thrombosis rarely appear dilated and visible in the acute stage, and most of them can be recanalized in the late stage of gastrocnemius plexus thrombosis, but the ankle traffic branch can be damaged and dysfunctional in the early stage, and the superficial veins of distal calf can appear dilated, accompanied by pigmentation, hard nodes, itching and other nutritional changes in the foot and boot area.
4.Other
After deep vein thrombosis, there is a part of loose thrombus in floating state, which is not closely adhered to the vessel wall and easy to dislodge, and there is a risk of forming pulmonary artery embolism, with acute cough, chest pain, hemoptysis, severe respiratory distress and even sudden death.
The onset of DVT in the upper extremity is often preceded by a history of upper extremity strain, excessive exertion, hyperextension or hyperextension, or subclavian vein puncture. The four main symptoms are upper limb swelling, pain, superficial venous anger and skin cyanosis. The superficial veins of the affected limb and the superficial veins of the affected chest wall are compensated and dilated. Initially, the disease may be accompanied by arterial spasm, decreased skin temperature of the extremity, and weakened or absent arterial pulsation. Most of the time, the disease resolves on its own. Initially, the thrombus can also be dislodged and become a pulmonary embolism.
Treatment of deep vein thrombosis
At present, the main treatments for DVT are: conservative treatment based on drugs, interventional treatment by placing inferior vena cava filters combined with thrombolysis and surgical treatment by thrombus removal.
In the acute stage, we treat DVT with comprehensive interventional therapy, and in the chronic stage, we treat it with drug-based therapy, and if necessary (in severe cases such as femoral cyanosis), we remove the thrombus with surgery. Most of the results are satisfactory and normal work and life can be resumed by using thrombolytic, anticoagulant and supportive treatment, together with Chinese herbal medicine and comprehensive treatment.
The effectiveness of treatment depends on the best treatment plan on the one hand, and the timing of treatment on the other: treatment within 72 hours of onset has good effect, while most of them will leave different degrees of sequelae after 72 hours. Therefore, early and correct diagnosis and treatment is a key part of good results.
Special emphasis should be placed on: in the acute stage of deep vein thrombosis, care should be strengthened, patients should be absolutely bedridden, and pushing and massaging of the affected limb is strictly prohibited to avoid sudden death due to pulmonary embolism caused by dislodged thrombus.
If a limb is highly swollen, with purple skin or even blisters, or even high tension causing ischemia of the lower limb, the thrombus must be removed by emergency surgery. In this case, the most ideal treatment is to place a filter in the inferior vena cava to prevent the thrombus from dislodging and forming a pulmonary embolism, and then surgically remove the thrombus, which can quickly relieve the symptoms. Of course, postoperative treatment with Chinese and Western medicine is still needed to prevent the formation of further thrombosis.