Chinese theory of etiology in TCM
The theory of etiology in TCM elaborates all the pathogenic causes for breakdown of the healthy state of the body leading to the occurrence of disease. The various natures, pathogenic characteristics, and clinical manifestations of diseases caused by them are also included.
In the natural world, the six kinds of climates, i.e. , wind, cold, summer heat, dampness, dryness and fire, are called six climatic factors. They are considered to be necessary for the growth of all living things under regular conditions. When the climate varies abnormally by either a sudden or violent change, or an extremely irregular variation it can attack people, especially those who have an asthenic [deficient] body that might even be attacked by a normal climatic change
¡°The six exopathogens¡± refer to six kinds of exogenous pathogenic evils of wind, cold, summer-heat, dampness, dryness and fire.
Being closely related with the seasons, climates and living environment, the six exogenous pathogens have some common pathogenic characteristics. They are able to invade the human body either alone or in combination, attack the body surface first. Exogenous pathogens are also able to transform into each other in course of disease.
Wind-pathogen, which belongs to the Yang pathogen, tends to open outward and usually intrudes the Yang positions of the body. It is apt to migrate and vary quickly, is responsible for abnormal body motion, and is often the leading pathogen in all the exogenous diseases.
Pathogenic cold belongs to the Yin pathogen. It tends to impair Yang-Qi, and is characterized by coagulation/stagnation and closure/contraction
Summer heat-pathogen prevails in summer and pertains certainly to Yang. It has a scorching nature, tends to move upward and outward, and is apt to impair Qi and body fluid. It also disturbs the mind, causes endogenous wind-syndrome, and is often accompanied by damp-pathogen
Damp-pathogen is quite common in all seasons, especially in late summer. As a Yin pathogen, it easily obstruct the flow of Qi and damage Yang Qi. It is marked by heaviness/turbidity and viscousness/lingering, and is apt to go downward and attack the Yin localities.
Pathogenic dryness prevails in autumn. This pathogen is dry in nature, tends to impair body fluid and the lung.
Pathogenic fire and heat belong to Yang pathogen. It is scorching and burning upward in nature. Pathogenic fire is liable to consume body fluid and Qi, stir up the liver-wind and disturb blood circulation. It is also irritating the heart-mind and causing carbuncles and sores.
Pestilential pathogens are those which are highly contagious. They are different from the six exogenous pathogens to a certain extent. They usually invade the human body through the mouth and nose. Sudden onset, severe conditions of illness, similar manifestations, strong infectivity and epidemicity are the basic pathological characteristics of pestilential pathogens
Pestilence may occur sporadically and can also prevail in a large area. To prevent the occurrence of pestilence, immunization are widely used.
The emotional activities of human beings, referring habitually to seven basic emotions, I.e., joy, anger, melancholy, anxiety, grief, fear and fright, are man¡¯s natural responses to his environmental stimuli. The emotions within the normal range of mental activities do not cause disease. Positive emotions and a relaxed mood can even contribute to good health and a speedy recovery. Only when sudden ,violent, or long-term emotional stimuli exceed the body¡¯s adaptability and endurance limit, will disease occur.
TCM thinks that emotional activities are governed by the respective Zang-viscera, i. e., anger is governed by the liver, joy by the heart, anxiety by the spleen, melancholy by the lung, and fear by the kidney. Consequently, the excessive emotions may also influence the corresponding Zang-viscus to cause disease. In this case, the heart, liver and spleen are easier damaged. Excessive emotions can disturb the Qi-movement in various ways. For example, rage gives rise to adverse ascent of Qi, excessive joy to retardation of Qi, excessive fear to sinking of Qi, and excessive fright to disarrangement of Qi.
Undue hunger, overrating, intake of unsanitary food and drink, preference for superheated or over-cooled food, addiction to one of the five flavors can call cause diseases
physical overstrain easily impairs Qi of the spleen and lung, excessive mental strain is apt to impair both the heart-blood and the spleen-Qi, and sexual overstrain leads always to the kidney deficiency . While too much leisure may cause hypofunction of the spleen and stomach and retarded flow of Qi-blood, and long-term leisure also can weaken vital Qi and the constitution, presenting poor muscle tone, lassitude, sleepiness, depression, loneliness, and the other psychosomatic diseases.
Surgical trauma refers to various injuries due to external force. These can result from a fall, contusion, sprain, incision, or other wound. There are also trauma caused by burns, scalds, frostbite, bites by insects or beasts, or poisonous snakes. Most of these usually have an acute onset, but some times have a chronic morbid process
Phlegm and water-pathogen are both pathological products resulting from disturbance of the metabolism of body fluid. Tangible one is thought of as palpable, visible, or audible, e.g., sputum expectorated or slobber vomited. Inferred type refers to the pathogens unable to be sensed directly but recognized by analyzing the symptoms and signs, such as vertigo, nausea, wheezing sound, chest oppression, depressive psychosis, subcutaneous nodules and scrofula, greasy or slippery tongue coating and rolling pulse.
Clinical presentations due to retention of phlegm within the body are rather varied and complicated. Therefore there is a saying in TCM that ¡°A lot of disorders result from mischief of phlegm¡±.
Commonly seen syndromes caused by water-pathogen are traditionally divided into four types: gastrointestinal water syndrome, pleural water syndrome, suffocative water syndrome, suffocative water syndrome
Blood stasis refers to the retarded, stagnated blood inside the vessels or the blood extravasated outside the vessels and within the body.
Once blood stasis forms, the blood not only fails to perform its nutritive function, but the stasis further hiders the systemic or local blood circulation. Blood stasis is a pathological product in the course of disease, but it can also lead to new pathological changes and is considered one of the main pathogens.