Blood stasis is a kind of pathological substance caused by disturbance of blood circulation. Normally the blood is propelled by heart-qi to flow in the vessels. If blood circulation is stagnated or slowed down by certain factors, it will lead to retention of blood in the vessels or viscera or overflow of blood out of the vessels, causing blood stasis.

Blood stasis is substantial pathological substance, such as clot in the blood, subcutaneous purpura or lump in the body. Sometimes blood stasis is insubstantial, referring to certain symptoms related to blood stasis, such as various kinds of pain, palpitation and mania, etc. Blood stasis and blood stagnation are two different concepts. The former is a kind of pathological substance while the latter is a pathological process. The former is the result of the latter while the latter inevitably leads to the former.

There are various factors responsible for blood stasis. It may be caused by six exogenous climatic factors. For example, cold stagnates and tends to block blood vessels. It may be caused by seven emotions. For example, anxiety binds qi and tends to slow down blood circulation. It may be caused by consumptive disease and overstrain. The following is a brief description of the causes of blood stasis:

Blood circulates with qi. If qi stagnates, it will inevitably lead to blood stasis. Blood stasis results from inhibited blood circulation caused by hindrance of qi activity due to exogenous cold and dampness or agglomeration of qi due to excessive anxiety or failure of liver-qi to disperse or unsmooth flow of qi due to internal blockage of phlegm. For example, protracted stagnation of liver-qi and blood vessels will bring on mass with the manifestations of hypochondriac pain and palpable lumps.

Qi is the commander of blood. Deficiency of qi makes it difficult for qi to propel the blood, eventually causing blood stasis. Various factors are responsible for qi deficiency and blood stasis, such as hypofunction of the viscera, consumptive disease, overstrain, improper diet, protracted disease or puerperium. Patients with protracted disease usually suffer from deficiency of qi and unsmooth blood circulation. General treatment is often ineffective. The proper treatment should focus on supplementing qi to promote blood circulation.

Blood flows with warmth and coagulates with cold. Blood-cold usually slows down blood circulation and causes blood stasis. Various factors are responsible for blood-cold and blood stasis, such as invasion of exogenous cold in the vessels, damage of yang-qi due to predominant dampness, decline of fire in the life gate, insufficiency of primordial yang and stagnation of cold in the vessels due to excessive intake of cold food. Invasion of cold in the uterus will stagnate uterine vessels, leading to lower abdominal pain during menstruation, purplish menses or menses with blood clot, or delayed menstruation or amenorrhea, etc.

Blood flows with warmth. But there is excessive heat, it will drive the blood to overflow and cause blood stasis. If heat is mingled with the blood, it will consume body fluid and condense the blood into stasis. Take taiyang syndrome of blood accumulation in Shanghan Lun for example. It is caused by blood and heat mingled in the lower abdomen with the symptoms of acute abdominal agglomeration and mania. So this syndrome should be treated by Taohe Chengji Decoction for activating blood to resolve stasis and promoting defecation to eliminate stasis and heat.

Apart from damaging the tendons, bones and muscles, traumatic injury also impairs the vessels and causes blood stasis. That is why traumatic injury is often accompanied by local hematoma which is a sign of blood stasis. If traumatic injury drives blood to flow out of the vessels and accumulate in the body, it will also cause blood stasis.

Blood cannot flow with qi if it flows out of the vessels. If the blood that flows out of the vessels is not eliminated and accumulates in local areas, it becomes blood stasis. There are various factors responsible for hemorrhage, such as qi deficiency, failure of the spleen to command blood, failure of the liver to store blood, abnormal flow of blood due to heat, disturbance of blood due to fire transforming from the five emotions and traumatic injury, etc.

The manifestations of diseases caused by blood stasis are various. The following are the common ones.

It is marked by stabbing, fixed and unpapable pain that turns worse at night. If it is caused by blood stasis due to protracted disease and deficiency of qi and blood, the pain is vague and lingering.

Protracted blood stasis gradually develops into lumps which appear hard and fixed. If the lumps are subcutaneous, the skin usually turns cyanotic. If the lumps are in the viscera, hard mass will be caused.

 

Hemorrhage can lead to blood stasis. If blood stasis is retained in the vessels, the impairment caused is very hard to heal and tends to bring on repeated hemorrhage. In this case blood stasis becomes the cause of hemorrhage which can only be stopped by activating blood to resolve stasis to repair the injured vessels. Hemorrhage caused by blood stasis often appears cyanotic and accompanied by blood clot.

The patient with blood stasis is characterized by cyanotic complexion, lips and nails.

The tongue is cyanotic or has ecchymosis and petechia.

The pulse is thin, unsmooth, deep and taut, or knotted or slow regular intermittent.

Besides, there are still some other commonly encountered symptoms, such as blackish complexion, squamous and dry skin, purpura on the skin, amnesia and mania, etc.

Apart from the points mentioned above, clinically blood stasis is diagnosed with the consideration of the following points.

(1) If there are traumatic injury, hemorrhage and history of menstruation, pregnancy and labor, the patient tends to have internal retention of blood stasis.

(2) If the treatment is ineffective before the application of the therapy for activating blood to resolve stasis, the patient must have insubstantial blood stasis though there are no signs of blood stasis.

(3) Protracted disease involving the collaterals often causes blood stasis. If it is lingering, blood stasis has to be taken into consideration.

The above three points are the supplementary methods for diagnosing blood stasis.