One of the medical terms in Korean Medicine that is unfamiliar for learners is "patho-mechanism." It is an abbreviation of "the mechanism of pathology," which includes the origin, development and the changes of a disease. It also means any changes that occur in the body.

        The basic mechanism of pathology in KM is represented as the loss of balance either in symbolic or material sense. As all matters in the universe is divided into Eum and Yang, so are the phenomena of the human body. When the balance between Eum and Yang of the body is broken, it makes us susceptible to disease. In the NeiJing says, "When Eum is vigorous Yang is sick, when Yang is vigorous Eum is sick." As Eum Yang represents everything, it is also in the division of the degree of temperature, being hot when Yang is vigorous and cold when Eum is vigorous.

        Partial vigor of Eum or Yang causes excessiveness of pathogenic Ki. Pathogenic Ki, as indicated in the name, is any Ki that does harm to the body.  In the original Chinese characters it is written as 'evil Ki.' (邪氣) The character that means excessive (實) also means healthy or robust, or in yet another meaning full. Here the character carries a negative meaning. As opposed to excessiveness, there is also a deficiency of vital Ki ('righteous Ki') in the diseased body when Eum or Yang is partially weak.

        Disease can originate from the loss of balance between the material that function vitally in the human body. Ki performs various functions that are essential to life, such as activation of movement, warming the body, defending it, making solid or vaporizing. Blood is another substance that performs functions of nourishing and moisturizing organs and members of the body.

        The patho-mechanism of Ki has two sides. The quantitative deficiency of Ki and the decline in its effect is classified as the Deficiency of Ki. The loss of balance in the movement of Ki, caused by the uncontrolled functioning of Ki is expressed as the being stagnant, abnormal uprising, collapsing, draining or closing up of Ki.

l● Deficiency of Ki is caused by the lack of original Ki. What makes original Ki lacking includes inherent insufficiency of life force and loss of acquired nutrition. Excessive labor, chronic illness and decreased functioning of the Lung, Spleen and Kidney also bring about the cause of Ki Deficiency.  They symptoms are natural perspiration and susceptibility to colds (dysfunction of defensive Ki); lethargy (loss of nutrition of limbs and flesh); withering of mentality and tinnitus (clear Yang not rising); weak and small pulse (no force in the circulation of Blood); phlegm and dropsy (difficulty in distribution of fluids); and infirmity that worsens at movement (decreased functioning of the organs and tissues).

l● Hinderance of the movement of Ki by emotional injury and obstacles such as the dampness of phlegm, indigested substance and coagulated Blood brings on the stagnation of Ki throughout the whole body or in specific areas. Dropsy and pain are caused when Ki is blocked in meridians and Blood is not distributed, thus coagulating and making the movement of the clogged Blood even rougher. The pulse is slow and harsh. Some of the dropsy is caused by phlegm that is formed when the flow of body fluid is not smooth. The Ki in Lung, Liver and Spleen is especially well stagnated.

l● The abnormal uprising of Ki is mainly an excess manifestation. Internal injury by the seven emotions, the inappropriateness of the temperature of food, external pathogens, and the deficiency of Ki cause chaos in the movement of Ki. When the balance between elevation and descent is broken Ki rushes up. When the Lung loses its suppressing mechanism the Ki of Lung goes up causing coughs and shortness of breath. When the Stomach does not digest the reversed Ki causes nausea, vomiting and eructation. Problems of the head occurs when the Liver loses control, such as headache, cephalic dropsy, redness of the eye as well as easily being angered. Since the Liver controls blood, when it expands explosively hemoptysis can happen. One can get perplexed and go crazy if Blood follows Ki upward. 奔豚(Bun Don), translated as 'running piggy,' is the state of body when one's heart rate goes up and chest keeps heaving. It happens when the Ki of Liver and Kidney ascends along the Opposition Vessel(衝脈).

l● Collapsed Ki means having difficulty in rising. When a body is constitutionally weak or weakened by a long illness the Spleen can lack Ki and the central Ki can collapse. When that happens clear Ki is unable to go up and the head and eyes are left malnourished, leading to symptoms like dizziness, scotoma and tinnitus. When the Spleen and Stomach are enervated they cannot "lift" Ki, thus the lumbar and abdominal dropsy and often having bowel movements. Collapsed Ki can cause the relocation of organs followed by ptosis of the stomach, kidneys and uterus as well as proctocele. One suffers from shortness of breath and has a small, low voice and a weak pulse when Ki collapses and is deficient.

l● Closed up Ki is usually a cold disease(厥證). 厥證 is a disease with dizziness and cold feet. It is caused by a grand stimulus of the mind or a strong pain. When body externally receives a febrile disease, Yang overflows and closes off Eum. Hence when there is difficulty in the coming and going of Ki, closed up Ki occurs, bringing with it coldness of the limbs, unconsciousness, and incapability to recognize faces.

l● When Ki is drained, it is a serious state that could lead to death. Pathogenic Ki is so bountiful that vital Ki is drained. In the case of a severe hemorrhage, Ki follows Blood out. When perspiration, vomiting, and diarrhea are serious, Ki follows the Bodily Fluid down, and chronic illness harms the more viscous fluids. The body cannot contain Ki, so it disperses, causing the deficiency of Yang and drainage of Ki. Unconsciousness, incapability to recognize faces, automatically keeping eyes closed and mouth open, snoring and taking small breaths, powerless and cold hands, severe perspiration, incontinence of urine and feces, and a small pulse that is about to be cut are all symptoms. Eum and Yang leaves each other and a person dies.

        The patho-mechanism of Blood is always related with any of the following three organs; the Heart, Liver, or Spleen. The Heart oversees the movement of Blood while the Liver stores and controls it. The Spleen is in charge of the forming and regulation of Blood.

l● Deficiency of Blood is caused by losing a great amount of Blood. It results in the insufficient nutrition of flesh and nails, therefore the paleness of the face and light color of lips, tongue and nails are seen. The head and eyes also lose nutrition and it is manifested in dizziness, scotoma and tinnitus.

l● The causes for coagulated Blood are stagnant Ki, deficient Ki, coldness of Blood, heat of Blood, external injury and lochia after childbirth, to name a few.

l● The symptoms of hot Blood include red face and eyes, scarlet tongue (when worn out Blood harms Eum), constricted mind, mania and insanity, and delirium. The pathogenic heat oppresses Blood to wander about.

        The metabolism of the Bodily Fluids is mainly related with the rise and fall; going in and out of Ki, and at the same time closely associated with the effects of organs like the Spleen, Lung, Kidney and the Triple Burners. Therefore the loss of harmony here can lead to the previously mentioned patho-mechanisms.

        Also, there are results of unmanaged interaction of Ki and Blood. These clinically often seen patho-mechanisms include the clogging of Ki and Blood, Ki being unable to lead Blood, Ki following Blood and draining out, reversed flow of Blood that follows Ki, and the deficiency of both Ki and Blood.