html xmlns=”http://www.w3.org/1999/xhtml” xmlns:bk=”http://www.elsevier.com/xml/bk/dtd” xmlns:ops=”http://www.idpf.org/2007/ops” xml:lang=”en”>
3. Aetiology and pathology of pain
Aetiology of pain
External factors
There are different External pathogenic factors, mainly Wind, Cold, Summer-Heat, Damp, Dryness and Fire (Heat). The pain caused by invasion of External factors is characterised by the following features:
• Acute onset
• Relative short duration
• Often related with seasonal changes
• Pain mostly on the superficial portion of the body
• Not much disturbance in the Internal Zang-Fu organs
• Usually are accompanied by some External symptoms
• Relative easy treatment with quick and good results.
Invasion of External factors usually occurs due to three main reasons: weakness of Zheng Qi (Anti-pathogenic Qi) resulting from various kinds of causes, careless in the daily life and too strong pathogenic factors.
Wind
Wind is one of six External factors, which is predominant in the spring but may also occur in any of other seasons. When attacking the body, Wind is likely to combine with another of the pathogenic factors, such as Cold, Damp or Heat, etc., leading to disorder between the Nutritive and Defensive Qi, blockage of Wei Qi (Defensive Qi), disharmony of Channels and Collaterals, retardation of Qi and Blood circulation will be the result. Due to retardation of Qi and Blood circulation, stagnation of Qi and Blood may occur in the muscles, tendons, joints and channels, and pain follows. Invasion of Wind mostly happens in the superficial layer of the body, seldom involving the Internal Zang-Fu organs.
Wind is classified as a Yang pathogenic factor because it has the characteristics of upward and outward movement. Because of this quality, it may easily invade the upper and superficial areas of the body, for instance the face, head, neck, shoulders, arms, chest, upper back, etc. So pain that is caused by Wind is found mostly in the top half of the body.
In nature Wind blows in gusts and is subject to rapid changes. Similarly, in the body it causes symptoms that are characterised by their migratory appearance. When a pain has no fixed location, but rather tends to wander around, this implies that its primary causative factor is Wind.
Cold
Cold is the predominant factor in winter. Although it can be seen in other seasons, in these its nature is not so severe. Cold invasion normally results from wearing too little clothing, exposure to cold after sweating, being caught in rain, or wading through water in cold weather.
Cold is a Yin pathogenic factor and is likely to damage the Yang Qi of the Heart, Stomach, Spleen or Kidney. Cold includes both External and Internal Cold pathogenic factors; the former refers to Cold due to External invasion, and the latter to Cold due to Deficiency of Yang Qi. External Cold and Internal Cold may mutually influence and transform each other. For instance, External Cold may change into Internal Cold where there is prolonged persistence of the condition, resulting in damage to the Internal Yang Qi; conversely, a state of Internal Cold may easily induce weakness of Yang Qi in the superficial layer of the body with deficiency of Wei Qi, resulting in invasion of External Cold. When there is pain caused by invasion of External Cold, there is usually feeling of aversion to cold with cold hands and feet and preference to the warmth, and aggravation of the pain by exposing to cold, thin and white coating, etc.
Cold is characterised by stagnation and contraction, so Cold can easily slow the circulation of Qi and Blood. Thus, pain accompanied by a sensation of contraction, limitation of joint movement, aversion to cold and anhidrosis will be classified as being caused by Cold.
Cold may invade the body not only through the skin, mouth and nose, and drinking of cold liquids, but also through the uterus (e.g. after walking in the rain, or swimming or sex during menstruation). Moreover it can directly invade the muscles and joints, or even the Internal Zang-Fu organs if the Cold is very extreme, or the body very weak. The other opportunity for External Cold to invade is through the practice of walking barefoot. In Western countries, many people often do this inside the house, even on a cold floor, and in winter. Since the Kidney, Liver and Spleen channels all begin on the foot, External Cold may easily invade the Spleen, Kidney and Liver through these channels, especially the Kidney channel, which begins on the soles, in people who too frequently walk around barefoot on a cold floor.
Nowadays more and more homes and other buildings have air-conditioning to cool the place in the heat of summer. Consequently, many people now suffer from pain that becomes worse when they are sitting in their office equipped with air-conditioning, and they improve spontaneously once they leave the office and go out in sun. Thus they form a clear impression that cold places are bad and warm places are good for them, which is true. This is because our skin pores stay relatively open in the summer in order that we may sweat and keep our body temperature down. However, this also provides a very good opportunity for invasion of Cold, as the artificially cooled air can enter the body through the opened pores. Being characterised by contraction and stagnation, Cold may cause closure of the skin pores; this results in accumulation of Cold in the joints and muscles, so leading to pain due to Qi and Blood stagnation. Moreover, since the skin pores are now closed, Internal Heat cannot easily leave the body in sweat evaporation, so accumulated Cold can soon change into Heat, leading to symptoms of that aggravation, including redness, hotness, pain and swollen joints and muscles.
Damp
Invasion of External Damp is usually induced by humid weather, walking in the rain, living and working too long in humid places, or not changing out of one’s wet clothing after sweating. There is also a condition of Internal Damp, which is normally caused by disorder of the transportation and transformation functions of the Spleen and Stomach leading to formation of excessive water in the body. External Damp and Internal Damp often mutually influence each other in the causation of pain – that is to say, invasion of External Damp often attacks the Spleen and Stomach, while weakness of the Spleen and Stomach with formation of Damp may easily induce invasion of External Damp.
Damp is similar to water, which is characterised by heaviness. When it attacks the body, it causes pain accompanied by a feeling of heaviness of the head, limbs and body, together with a sense as though the body is bound. Where there is invasion of the skin and muscles by External Damp, this results in a blockage of the Clear Yang and disharmony of the Nutritive and Defensive Qi, which manifests as symptoms such as soreness of the limbs and joints, numbness of the limbs and muscles, and lassitude.
Damp is also characterised by viscosity and stagnation. Following on from this principle, pain that is caused by Damp is, generally speaking, stubborn and tends to be prolonged and intractable, compared with that caused by other pathogenic factors.
Damp is a Yin pathogenic factor and easily blocks Qi circulation and impairs Yang. When Damp accumulates in the Zang-Fu organs, joints, muscles or channels it may affect the ascending and descending of the Qi, leading to symptoms such as numbness of the skin and joints, and limitation of movement.
Dryness
Dryness is predominant in autumn, and tends most often to impair the Lung, impeding the dispersal of Lung-Qi and causing stagnation, leading to symptoms such as throat and chest pain.
Dryness can also damage the Body Fluids, causing dryness of the skin, nose and throat. Furthermore, it may disturb and consume the Blood; then the blood vessels are not properly nourished resulting in narrowed vessels, and then the Qi and Blood stagnate, leading to painful skin.
Heat (Fire, Warmth)
Fire and Heat both indicate excessive Yang Qi, thus in most cases they are interchangeable, but there is still some slight difference between them. In terms of pathology, Heat is usually caused by External invasion, for instance Wind-Heat or Damp-Heat, whereas Fire is often caused by Internal disorders, for example flaming up of Heart-Fire or hyperactivity of Liver-Fire. In terms of the physiology, Fire has a proper function, which is to warm the Zang-Fu organs and promote Qi transformation and energy production; only if it becomes excessive does it become a kind of pathogenic factor causing over consumption of energy in the body. Heat, in contrast, is simply a pathogenic factor.
Warmth is like Fire, with a physiological role but potentially pathogenic, and is also a kind of Heat, but milder. Of the three, Fire is the most severe, and Warmth the least severe, yet they all share similar characteristics. In practice, the terms Fire-Heat and Warmth-Heat are often used interchangeably.
Heat, a Yang pathogenic factor, is characterised by flaming up, burning and hotness. When it attacks the body, it may cause abnormal Qi and Blood circulation as well as injury to the Blood Vessels, causing pain accompanied by a burning feeling, a hot sensation, or redness. When Heat disturbs the Blood, the Blood circulation will be accelerated and the Blood Vessels can be damaged, causing swelling of the joints, muscles, or even bleeding, such as epistaxis, etc. Heat may also often disturb the Heart, which houses the Mind, causing restlessness and insomnia.
Like pathogenic Wind, Heat often attacks the top half of the body because of its characteristics of flaming up and moving in an upward direction, thus a combination of Wind and Heat causation is often seen. In most case of acute inflammatory joints and muscles in the upper parts of the body, Wind-Heat is the chief causative factor, thus the main treatment principle will be to dispel Wind and clear Heat. However, when combining with Damp, due to the characteristics of downward flowing, Heat then could often attack the lower half of the body, especially the hip, knee, ankle and foot, resulting in pain with redness, swelling, hotness and restlessness, etc.
Emotional factors
It is often a clear fact that sometimes the pain, such as headache, neck pain, chest pain, abdominal pain, etc., gets much better when the patients have a very positive attitude, and it may become much worse when there is negative emotion. Since human beings consist of spirit and physical body, pain, in fact, is an indication of human suffering, being frequently rooted in emotional distress as well as in physical trauma. In practice, treatment of pain while neglecting the emotional state is incorrect, and is against the principle of TCM.
Mental activities relating to emotion in TCM are classified into joy, anger, melancholy, meditation, grief, fear and fright, and are known as the seven emotional factors. The seven emotional factors differ from the six External factors in that they affect the Zang-Fu organs, and the Qi and Blood, directly. For this reason, they are considered to be the chief causative factors for various kinds of pain, especially chronic pain. It is believed traditionally that different emotional factors tend to affect the circulation of Qi and Blood of various individual internal organs, resulting in retardation of Qi and Blood circulation, causing blockage to follow, and pain as the main clinical manifestation. The saying ‘anger injures the Liver, joy injures the Heart, grief and melancholy injure the Lung, worry injures the Spleen, and fear and fright injure the Kidney’ (Yellow Emperor’s Classic of Internal Medicine: Simple Questions 1956, p. 17) is an expression of relationship between the different emotional factors and each of the internal Zang-Fu organs. Another saying from ancient medical texts is: ‘anger causes the Qi to rise, joy causes it to move slowly, grief drastically consumes it, fear causes it to decline, fright causes it to be deranged, and worry causes it to stagnate’ (Yellow Emperor’s Classic of Internal Medicine: Simple Questions 1956, pp. 80-81). From this it can be seen clearly that abnormal Qi and Blood circulation is one explanation for the occurrence of pain.
In clinical practice, it is very easy to find a case with pain, which becomes aggravated or alleviated by the emotional state. Take shoulder pain, for instance: if the biceps muscle (which is in the area of the Lung channel) is involved, it is sometimes found that such patients either have suffered much grief in the past or do so at present and usually admit that when their feelings of grief recur, their shoulder pain worsens. Since the Lung and Large Intestine share a pair of channels and collaterals, if the Lung channel is blocked the Large Intestine channel can also become impaired, leading to shoulder or arm pain. In this case, the points nearby (such as LU-2 Yunmen, LU-3 Tianfu, LU-5 Chize or LU-6 Kongzui) are usually found to be tender. There may also be tenderness found around LI-4 Hegu, LI-9 Shanglian and LI-10 Shousanli, as well as LI-11 Quchi. Another example is patients suffering from lower back pain, some of whom may have aggravation of pain with particular emotional states, especially anger and stress. This kind of pain can also radiate to the inguinal region, and even to the interior aspect of the leg along the Liver channel, and consequently along the Gallbladder channel also. Conversely, if the Gallbladder channel is primarily affected, there could be impairment of the Liver channel as well. For instance, disc herniation between L4 and L5 often manifests as pain along the Gallbladder channel, which sometimes refers to the inguinal region. In this case, anger or stress may play a very important rule in the aggravation of the low back pain.
The causation of pain by excessive emotional activities is basically described in following sections.
Excessive joy, fear or anxiety
These often disturb the physiological functions of the Heart, leading to retardation of Qi and Blood circulation in the Heart, causing chest pain, heart pain, and pain in the shoulder along the Heart channel; palpitation and insomnia also occur. A point of distinct tenderness is typically found along the Heart channel, especially at HT-3 Shaohai. Needling or even simple massage at this point can greatly relieve the chest, heart or shoulder pain.
Since the Heart is in charge of promoting the circulation of Blood in the body and housing the Mind, disturbance of the Heart by these pathogenic factors could cause stagnation of Blood in general, which lead to pain not only in the Heart region or in the chest, but also in the general body. Failure of the Heart in housing the Mind could result in oversensitivity to pain. In this case, there is often pain somewhere in the body, but no clear physical impairment could be identified. When the method to promote the Blood circulation, regulate the emotions and calm the Mind is applied to treat such kind of pain in practice, it improves quickly.
Moreover, fear and anxiety in TCM are particularly considered to be chief causes, which could weaken the Kidney, leading to deficiency of Kidney- Essence, headache, lower back pain, pain at knee, etc.
Excessive anger
Anger may cause dysfunction of the Liver, impeding its free flow of Qi, and leading to a condition of stagnation of Liver-Qi. In TCM anger in fact includes other emotions such as frustration and irritation, which also may cause disharmony of the Liver leading to stagnation of Liver-Qi. Liver-Qi stagnation gives rise to symptoms such as headache, hypochondriac pain and distension, depression, abdominal pain and distension, and low back pain, as well as various kinds of gynaecological pain and pain at the genital. Such pain is characterised by being wandering and distending in nature, or intermittent, or fluctuating in intensity and location. Another characteristic is that the pain often occurs or gets aggravated at times of strong emotion, especially anger, stress, nervousness or irritability.
Stagnation of Liver-Qi can also be traced to emotions arising from being mistreated during childhood (e.g. from being beaten, lack of love, limitation of freedom, sexual abuse, or difficulties with friends, parents, brothers or sisters). Stagnation of Liver-Qi originating in childhood may cause either conscious or subconscious blockage in the Liver, bringing on pain at a later date due to severe psychological and physiological problems.
The Liver is in charge of promoting Qi circulation both in the Liver itself and generally in the body. If there is Liver Qi stagnation due to emotional disturbance, the Liver fails to maintain the free flow of Qi in the channels, muscles, and Zang-Fu organs as well. Stagnation of Liver-Qi is one of the main causative factors for various kinds of pain, especially chronic pain resulting from disorder of Internal Zang-Fu organs.
The consequences of stagnation of Liver-Qi can be summarised as follows.
Blood stagnation
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
