The Eight Principles, namely Yin, Yang, Exterior, Interior, Cold, Heat, Deficiency, and Excess, form one of the theoretical foundations for syndrome differentiation and treatment in Traditional Chinese Medicine (TCM). Through the four examinations, after mastering the diagnostic data, an analysis is conducted based on various factors such as the depth of the disease location, the nature of the pathogenic factor, and the strength of the body’s righteous Qi, which is then summarized into eight different categories of symptoms, referred to as the Eight Principles of Syndrome Differentiation.
Although the manifestations of diseases are extremely complex, they can generally be categorized using the Eight Principles. For instance, diseases can be divided into Yin and Yang syndromes; the depth of the disease can be classified as Exterior or Interior syndromes; the nature of the disease can be categorized as Cold or Heat syndromes; and the strength of the pathogenic and righteous Qi can be classified as Excess or Deficiency syndromes. Thus, by applying the Eight Principles of Syndrome Differentiation, the intricate clinical manifestations can be summarized into four pairs of guiding syndromes: Exterior-Interior, Cold-Heat, Deficiency-Excess, and Yin-Yang, thereby identifying the key aspects of the disease, mastering its essentials, determining its type, predicting its trend, and guiding treatment direction. Among these, Yin and Yang can also encompass the other six principles, with Exterior, Heat, and Excess being classified as Yang; and Interior, Cold, and Deficiency being classified as Yin, thus Yin and Yang serve as the overarching principles within the Eight Principles.
The Eight Principles represent a method for analyzing the common characteristics of diseases and serve as the general framework for various syndrome differentiations. In the diagnostic process, they play a role in simplifying complexity and highlighting key points. They are applicable to syndrome differentiation across all clinical specialties, including internal medicine, external medicine, gynecology, pediatrics, ophthalmology, otolaryngology, etc., all of which utilize the Eight Principles for summarization. Based on the Eight Principles, when combined with the characteristics of organ and viscera changes, it branches into organ syndrome differentiation; when combined with the characteristics of Qi, Blood, and Body Fluids changes, it branches into Qi, Blood, and Body Fluids syndrome differentiation; and when combined with the characteristics of warm diseases, it branches into Wei, Qi, Ying, and Blood syndrome differentiation, etc. Any form of syndrome differentiation cannot be separated from the Eight Principles, hence it is said that the Eight Principles of Syndrome Differentiation are the foundation of all types of syndrome differentiation.
The Eight Principles of Syndrome Differentiation do not imply a rigid division of various syndromes into eight distinct areas; they are interconnected and inseparable.
For example, the relationship between Exterior-Interior and Cold-Heat, and between Cold-Heat and Deficiency-Excess, is interrelated. Due to the changes in diseases, they often do not present simply, but frequently exhibit mixed conditions where Exterior and Interior, Cold and Heat, and Deficiency and Excess intertwine, such as simultaneous Exterior and Interior diseases, mixed Deficiency and Excess, and mixed Cold and Heat. Under certain conditions, diseases may also undergo transformations to varying degrees, such as Exterior pathogens entering the Interior, Interior pathogens emerging to the Exterior, Cold syndromes transforming into Heat, Heat syndromes transforming into Cold, Excess syndromes transforming into Deficiency, and Deficiency leading to Excess, etc. At certain stages of disease progression, some phenomena may also appear that are contrary to the nature of the disease, such as true Cold presenting as false Heat, true Heat presenting as false Cold, true Deficiency presenting as false Excess, and true Excess presenting as false Deficiency. The same applies to Yin and Yang syndromes; there can be Yin within Yang and Yang within Yin, and diseases can transition from Yang to Yin and vice versa. Therefore, when conducting Eight Principles of Syndrome Differentiation, it is essential to not only master the characteristics of various syndromes but also to pay attention to their interrelations, transformations, mixtures, and the authenticity of symptoms to achieve a correct and comprehensive understanding and diagnosis of the disease.
Section 1: Exterior and Interior
Exterior and Interior are a pair of principles used to distinguish the location of the disease and the depth of its severity. It is a relative concept. In terms of the body structure and internal organs, the body surface is considered Exterior, while the internal organs are considered Interior; in terms of Zang and Fu organs, Fu organs are Exterior, while Zang organs are Interior; in terms of meridians and organs, meridians are Exterior, while organs are Interior, etc. From the perspective of disease depth, in cases of external pathogenic diseases, the pathogenic factor enters one layer into the Interior, indicating a deeper disease; while exiting the Exterior indicates a lighter disease. This understanding of relative concepts is particularly important in the differentiation of the six meridians and the differentiation of Wei, Qi, Ying, and Blood. The above represents the broad concept of Exterior and Interior. The narrow concept of Exterior and Interior refers to the skin, muscles, and meridians as Exterior, where these areas are affected by pathogens, constituting Exterior syndromes; while the internal organs, Qi, Blood, and bone marrow are considered Interior, where these areas develop diseases, constituting Interior syndromes. The differentiation of Exterior and Interior syndromes is of significant importance in the differentiation of external pathogenic diseases. It allows for the assessment of the severity of the disease, clarifies the depth of the pathological changes, and predicts the trend of pathological changes. Exterior syndromes are shallow and light, while Interior syndromes are deep and severe. When Exterior pathogens enter the Interior, it indicates disease progression, while when Interior pathogens emerge to the Exterior, it indicates disease regression. Understanding the severity and progression of the disease enables mastery of the evolution of the disease and the ability to take appropriate treatment measures.
1. Exterior Syndrome
Exterior syndrome refers to the symptoms produced when the six excesses and epidemic pathogens invade through the skin and mucous membranes. It is commonly seen in the early stages of external pathogenic diseases, generally presenting with an acute onset and a short course of illness.
Exterior syndrome has two distinct characteristics. First, it is caused by the invasion of pathogenic factors from the outside. Second, the pathogenic disease is mild.
The location of Exterior syndrome is in the skin and muscles, and it is easily treatable.
【Clinical Manifestations】Chills, fever, headache, body aches, thin white tongue coating, floating pulse, along with symptoms such as nasal congestion, runny nose, cough, sneezing, and sore throat.
【Pathological Analysis】Due to the six excesses invading the muscle surface, they obstruct the normal dispersal of Wei Qi, leading to heat accumulation. When Wei Qi is obstructed, it loses its function of warming and nourishing the muscle surface, resulting in chills. The pathogenic factor obstructs the meridians, causing Qi and Blood to flow poorly, leading to headache and body aches. The lungs govern the skin and hair, and the nose is the orifice of the lungs; the pathogenic factor enters the lungs through the skin and mucous membranes, affecting the lungs, which lose their ability to disperse Qi, resulting in nasal congestion, runny nose, and cough. Sneezing and sore throat often accompany these symptoms. Since the pathogenic factor is still in the Exterior and has not harmed the Interior, the tongue coating may show no changes, remaining primarily thin and white. The righteous Qi rises to resist the pathogenic factor, and the pulse is floating due to the Qi being driven outward.
2. Interior Syndrome
Interior syndrome refers to a type of syndrome where the disease is deeply located in the Interior (organs, Qi, Blood, and bone marrow). It is the opposite of Exterior syndrome. It is commonly seen in the middle and later stages of external pathogenic diseases or in internal injuries. The causes of Interior syndrome can generally be classified into three situations: first, the transmission of Exterior pathogens into the Interior, invading the organs; second, direct invasion of the organs by external pathogens; and third, emotional disturbances, irregular diet, and excessive exertion, which damage the organs, leading to dysfunction and causing disease due to Qi and Blood stagnation.
The scope of Interior syndrome is vast; apart from Exterior syndrome, all other diseases can be considered Interior syndromes. The characteristics of Interior syndrome can be summarized in two points: first, the disease is located deeply; second, the condition of Interior syndrome is generally more severe.
【Clinical Manifestations】The causes of Interior syndrome are complex, the locations are broad, and the symptoms are diverse, often appearing in forms of either Cold or Heat, or Deficiency or Excess, thus detailed content can be found in various chapters on syndrome differentiation. Here are a few common symptom-pulse analyses:
High fever with aversion to heat or mild fever with tidal fever, irritability, mental confusion, thirst with a desire to drink, or aversion to cold with cold limbs, fatigue, and excessive salivation. Constipation, short and red urine, or loose stools, clear and long urine, abdominal pain, nausea, thick tongue coating, and deep pulse.
【Syndrome Analysis】The above-listed symptoms are common in various Interior syndromes of Cold, Heat, Deficiency, and Excess. In terms of Heat and Cold, Interior syndromes can be either purely Heat or purely Cold; Heat can manifest as high fever or mild tidal fever. High fever is caused by the invasion of Heat pathogens into the Interior, leading to excessive Heat. Mild tidal fever is often seen in cases of internal injury with Yin deficiency, where the deficiency fire rises. Cold manifestations include aversion to cold, and the desire for warmth can alleviate this, which is due to insufficient Yang Qi or internal invasion of Cold pathogens, damaging Yang Qi, resulting in Cold. Irritability and mental confusion are manifestations of Excess Heat disturbing the mind; thirst with a desire to drink and short red urine are due to Excess Heat consuming body fluids. Constipation occurs due to Heat obstructing the intestines, leading to depletion of body fluids and loss of normal function. Those with insufficient Yang Qi often exhibit fatigue and cold limbs, while those with Deficiency may show excessive salivation and loose stools due to Spleen Qi deficiency.
The abdomen is associated with Yin, where the symptoms include abdominal pain, vomiting, constipation, loose stools, short red urine, or clear long urine, all of which are signs of Interior disease. Thick tongue coating and deep pulse are signs of disease being located within.
[Appendix] Half Exterior Half Interior Syndrome
When an external pathogenic factor transmits into the Interior but has not yet fully entered, or when an Interior pathogenic factor emerges to the Exterior but has not yet reached the Exterior, and the pathogenic and righteous Qi are in conflict between the Exterior and Interior, it is referred to as Half Exterior Half Interior Syndrome. Its manifestations include alternating Cold and Heat, fullness in the chest and hypochondria, irritability with a desire to vomit, reluctance to eat or drink, bitter mouth, dry throat, dizziness, and wiry pulse. This understanding of Half Exterior Half Interior is essentially similar to the Shaoyang disease in the differentiation of the six meridians.
3. Differentiating Between Exterior and Interior Syndromes
The skin and internal organs of the human body are interconnected through the meridians. During the progression of a disease, under certain conditions, mixed Exterior and Interior syndromes can occur, as well as mutual transformations, such as simultaneous Exterior and Interior diseases, Exterior pathogens entering the Interior, and Interior pathogens emerging to the Exterior.
(1) Simultaneous Exterior and Interior Diseases
When Exterior and Interior syndromes appear at the same time, it is referred to as simultaneous Exterior and Interior diseases. This situation arises when, in the initial stages of the disease, both Exterior and Interior syndromes are present, or when the Exterior syndrome has not resolved and has affected the Interior, or when there is a pre-existing internal injury that is compounded by an external pathogenic factor, or when there is an initial external pathogenic factor that has caused dietary injury.
The appearance of simultaneous Exterior and Interior diseases is often associated with the intermingling of Cold and Heat, and Deficiency and Excess. Common examples include Exterior Cold with Interior Heat, Exterior Heat with Interior Cold, Exterior Deficiency with Interior Excess, and Exterior Excess with Interior Deficiency, etc., which can be found in detail in the differentiation of Cold, Heat, Deficiency, and Excess.
(2) Exterior Pathogens Entering the Interior
When there is an Exterior syndrome, if the Exterior pathogenic factor does not resolve and enters the Interior, it is referred to as Exterior pathogens entering the Interior. This often occurs due to a decrease in the body’s ability to resist pathogens, or due to excessive pathogenic factors, improper care, or misdiagnosis and mistreatment. For example, in the case of an Exterior syndrome with chills and fever, if the chills resolve but the patient experiences fever instead, along with thirst, red tongue with yellow coating, and red urine, this indicates that the Exterior pathogenic factor has entered the Interior.
(3) Interior Pathogens Emerging to the Exterior
In certain Interior syndromes, when the pathogenic factor emerges from the Interior to the Exterior, it is referred to as Interior pathogens emerging to the Exterior. This is often the result of appropriate treatment and care, leading to an enhancement of the body’s resistance. For example, in cases of internal Heat with irritability, cough, and chest tightness, followed by fever and sweating, or rashes emerging from the Interior to the Exterior, this indicates that the pathogenic factor has emerged from the Interior to the Exterior.
The entry of Exterior pathogens into the Interior indicates a worsening of the disease, while the emergence of Interior pathogens to the Exterior reflects a pathway for the pathogenic factor to exit, indicating an improvement in the disease. Understanding the changes in the relationship between Exterior and Interior is crucial for predicting the development and outcome of the disease.
4. The Relationship Between Exterior and Interior Syndromes
The skin and internal organs of the human body are interconnected through the meridians. During the progression of a disease, under certain conditions, mixed Exterior and Interior syndromes can occur, as well as mutual transformations, such as simultaneous Exterior and Interior diseases, Exterior pathogens entering the Interior, and Interior pathogens emerging to the Exterior.
(1) Simultaneous Exterior and Interior Diseases
When Exterior and Interior syndromes appear at the same time, it is referred to as simultaneous Exterior and Interior diseases. This situation arises when, in the initial stages of the disease, both Exterior and Interior syndromes are present, or when the Exterior syndrome has not resolved and has affected the Interior, or when there is a pre-existing internal injury that is compounded by an external pathogenic factor, or when there is an initial external pathogenic factor that has caused dietary injury.
The appearance of simultaneous Exterior and Interior diseases is often associated with the intermingling of Cold and Heat, and Deficiency and Excess. Common examples include Exterior Cold with Interior Heat, Exterior Heat with Interior Cold, Exterior Deficiency with Interior Excess, and Exterior Excess with Interior Deficiency, etc., which can be found in detail in the differentiation of Cold, Heat, Deficiency, and Excess.
(2) Exterior Pathogens Entering the Interior
When there is an Exterior syndrome, if the Exterior pathogenic factor does not resolve and enters the Interior, it is referred to as Exterior pathogens entering the Interior. This often occurs due to a decrease in the body’s ability to resist pathogens, or due to excessive pathogenic factors, improper care, or misdiagnosis and mistreatment. For example, in the case of an Exterior syndrome with chills and fever, if the chills resolve but the patient experiences fever instead, along with thirst, red tongue with yellow coating, and red urine, this indicates that the Exterior pathogenic factor has entered the Interior.
(3) Interior Pathogens Emerging to the Exterior
In certain Interior syndromes, when the pathogenic factor emerges from the Interior to the Exterior, it is referred to as Interior pathogens emerging to the Exterior. This is often the result of appropriate treatment and care, leading to an enhancement of the body’s resistance. For example, in cases of internal Heat with irritability, cough, and chest tightness, followed by fever and sweating, or rashes emerging from the Interior to the Exterior, this indicates that the pathogenic factor has emerged from the Interior to the Exterior.
The entry of Exterior pathogens into the Interior indicates a worsening of the disease, while the emergence of Interior pathogens to the Exterior reflects a pathway for the pathogenic factor to exit, indicating an improvement in the disease. Understanding the changes in the relationship between Exterior and Interior is crucial for predicting the development and outcome of the disease.
Section 2: Cold and Heat
Cold and Heat are two principles used to differentiate the nature of diseases. Cold syndromes and Heat syndromes reflect the relative predominance and deficiency of Yin and Yang in the body. Excessive Yin or deficient Yang manifests as Cold syndromes; excessive Yang or deficient Yin manifests as Heat syndromes. The differentiation of Cold and Heat syndromes is of great significance in treatment. As stated in the “Suo Wen: The Great Discussion on the True Essentials”: “Cold leads to Heat,” and “Heat leads to Cold,” the treatment methods for the two are exactly opposite. Therefore, the differentiation of Cold and Heat must be accurate.
1. Cold Syndrome
Cold syndrome refers to a type of syndrome where the essence of the disease is Cold in nature. It can be caused by the invasion of Cold pathogens or by the body’s own Yang deficiency and excessive Yin.
Due to the different causes and locations of Cold syndromes, several different types can be distinguished. For instance, the invasion of Cold pathogens can affect the muscle surface or directly invade the internal organs, leading to distinctions between Exterior Cold and Interior Cold. The causes of Interior Cold can be due to the invasion of Cold pathogens or due to internal Yang deficiency, thus distinguishing between Excess Cold and Deficiency Cold. Here, we will first analyze the common characteristics of Cold syndromes.
【Clinical Manifestations】The clinical manifestations of various Cold syndromes are not entirely consistent, but common symptoms include: aversion to cold, preference for warmth, pale complexion, cold limbs, desire to curl up, lack of thirst, clear and thin phlegm, clear and thin nasal discharge, clear and long urine, loose stools, pale tongue with white and slippery coating, and slow or tight pulse.
【Syndrome Analysis】Insufficient Yang Qi or injury from external Cold prevents the body from warming and nourishing itself, leading to coldness and cold limbs, curling up, and a pale complexion. Excessive internal Cold leads to a lack of thirst. Insufficient Yang fails to transform body fluids, resulting in clear and thin phlegm, nasal discharge, and urine. Cold pathogens harm the Spleen, or prolonged Spleen Yang deficiency leads to poor transformation and transportation, resulting in loose stools. Insufficient Yang fails to transform, leading to internal Cold and thus a pale tongue with white and slippery coating. Weak Yang Qi fails to drive the blood and Qi circulation, resulting in a slow pulse; Cold constricts the vessels, leading to a tight pulse.
2. Heat Syndrome
Heat syndrome refers to a type of syndrome where the essence of the disease is Heat in nature. It can be caused by the invasion of Heat pathogens or by the body’s own Yin deficiency and excessive Yang.
Based on the different causes and locations of Heat syndromes, several different types can also be distinguished. For instance, external invasion of Heat pathogens or Heat pathogens entering the Interior can lead to distinctions between Exterior Heat and Interior Heat. Among Interior Heat, there can be Excess Heat due to invasion or Deficiency Heat due to internal weakness. Here, we will analyze the common characteristics of Heat syndromes.
【Clinical Manifestations】The manifestations of various Heat syndromes are also not entirely consistent, but common symptoms include: aversion to Heat, preference for coolness, thirst with a desire for cold drinks, red face and eyes, irritability, thick and yellow phlegm, hemoptysis, short and red urine, dry and constipated stools, red tongue with yellow and dry coating, and rapid pulse.
【Syndrome Analysis】Excessive Yang leads to aversion to Heat and preference for coolness. Fire Heat injures Yin, leading to thirst and a desire for cold drinks. Fire rises and disturbs the mind, leading to irritability. Excessive Yang consumes body fluids, resulting in thick and yellow phlegm. Fire Heat injures blood vessels, leading to hemoptysis. Heat in the intestines leads to constipation. A red tongue with yellow coating indicates Heat syndrome, while a dry tongue with little moisture indicates Yin injury, and rapid pulse indicates accelerated blood flow due to excessive Yang.
3. Differentiating Between Cold and Heat Syndromes
To differentiate between Cold and Heat syndromes, one cannot rely solely on a single symptom; rather, a comprehensive observation and analysis of the entire disease presentation is necessary, especially regarding preferences and aversions to Cold and Heat, thirst or lack thereof, complexion, temperature of the limbs, as well as the characteristics of the two excretions, tongue, and pulse.
4. The Relationship Between Cold and Heat Syndromes
Although Cold and Heat syndromes are fundamentally different, they are also interconnected. They can simultaneously appear in the same patient, presenting as mixed Cold and Heat symptoms, and can also transform into one another under certain conditions, leading to Cold transforming into Heat and Heat transforming into Cold. During the progression of a disease, especially in critical stages, false Cold or false Heat phenomena may also occur.
(1) Mixed Cold and Heat
When Cold and Heat syndromes appear simultaneously in the same patient, it is referred to as mixed Cold and Heat. There are different types of mixed Cold and Heat, including upper Cold and lower Heat, and upper Heat and lower Cold. The upper and lower are relative concepts; for instance, the chest is considered upper, while the abdomen is considered lower. The upper abdomen (stomach) is also considered upper, while the lower abdomen (bladder, large intestine) is considered lower.
(1) Upper Cold and Lower Heat: The patient presents with Cold symptoms in the upper body and Heat symptoms in the lower body at the same time. For example, if the patient experiences cold pain in the stomach, vomiting clear phlegm, while also having frequent urination, painful urination, and short red urine, this indicates Cold in the stomach and Heat in the bladder. This represents Cold in the middle and Heat in the lower, with the middle being above the lower.
(2) Upper Heat and Lower Cold: The patient presents with Heat symptoms in the upper body and Cold symptoms in the lower body at the same time. For example, if the patient has Heat in the chest and Cold in the intestines, presenting with both Heat symptoms in the chest and throat, and abdominal pain with a preference for warmth and loose stools, this indicates Heat in the upper and Cold in the lower.
(2) Transformation of Cold and Heat
1. Cold Transforming into Heat: When a patient initially has Cold syndrome, and later develops Heat syndrome, with the Heat symptoms appearing while the Cold symptoms gradually disappear, this indicates Cold transforming into Heat. This often occurs due to excessive Yang Qi, where Cold pathogens transform into Heat. It can also be seen in patients who have been improperly treated with excessive warming and drying herbs. For example, if a patient initially presents with Cold syndrome, experiencing chills and fever, with no sweating, a white tongue coating, and a floating pulse, as the condition progresses, the Cold pathogens enter the Interior and transform into Heat, leading to the disappearance of chills and the emergence of high fever, irritability, thirst, yellow tongue coating, and rapid pulse, indicating a transformation from Cold to Heat.
2. Heat Transforming into Cold: When a patient initially has Heat syndrome, and later develops Cold syndrome, with the Cold symptoms appearing while the Heat symptoms gradually disappear, this indicates Heat transforming into Cold. This often occurs due to excessive pathogenic factors or deficiency of the righteous Qi, leading to a decline in function. This transformation can be gradual or rapid. For instance, in cases of prolonged high fever, the Yang Qi may be consumed, leading to a transformation into Deficiency Cold. In cases of high fever, if the patient experiences excessive sweating, or excessive vomiting or diarrhea, leading to a sudden drop in body temperature, cold limbs, pale complexion, and a weak pulse, this indicates a rapid transformation into Deficiency Cold (loss of Yang).
The transformation of Cold and Heat reflects the changes in the strength of the pathogenic and righteous Qi. The transformation from Cold to Heat indicates that the body’s righteous Qi is still strong, and the Cold pathogens are transforming into Heat; while the transformation from Heat to Cold often indicates that the pathogenic factor is strong and the righteous Qi is weak.
(3) True and False Cold and Heat
When Cold or Heat syndromes develop to an extreme, sometimes phenomena contrary to the essence of the disease may appear, such as “true Cold appearing as false Heat” and “true Heat appearing as false Cold.” These phenomena are often seen in critical stages of the disease, and if not carefully observed, can lead to misdiagnosis and potentially fatal consequences.
1. True Cold Appearing as False Heat: This refers to a condition where true Cold exists internally, but appears as false Heat externally. The mechanism behind this is that excessive internal Cold obstructs the external Yang, leading to a phenomenon where Yin is excessive internally and obstructs Yang externally, resulting in false Heat symptoms. The manifestations include: body heat, flushed face, thirst, and a rapid pulse that appears to be Heat syndrome, but the patient feels hot yet desires to cover themselves with clothing, has a desire for hot drinks but cannot drink much, and the flushed face appears intermittently, not resembling the full redness of true Heat. The pulse may be rapid but weak upon palpation. Additionally, cold limbs, clear diarrhea, and clear long urine may be present. Therefore, the Heat symptoms are false, and the essence of the disease is excessive internal Cold.
2. True Heat Appearing as False Cold: This refers to a condition where true Heat exists internally, but appears as false Cold externally. The mechanism behind this is that excessive internal Heat obstructs the Yang Qi, preventing it from reaching the extremities, leading to a phenomenon where internal Heat is excessive while external Yin is obstructed, also known as “Yang obstruction” or “Heat obstruction.” The more severe the internal Heat, the more severe the coldness of the limbs, hence the term “the deeper the Heat, the deeper the cold.” The manifestations include: cold hands and feet, a deep pulse, which appears to be Cold syndrome, but the patient has warm body temperature and does not feel cold, rather they feel hot, with a rapid pulse that is strong, along with symptoms of thirst, preference for cold drinks, dry throat, foul breath, short red urine, dry and constipated stools, or Heat diarrhea. This situation indicates that the coldness of the limbs is false, while the internal Heat is the essence of the disease.
To differentiate between true and false Cold and Heat, it is essential to understand the entire course of the disease and pay attention to the following two aspects:
(1) The appearance of false symptoms often occurs in the extremities, skin, and complexion, while the internal manifestations of the organs, Qi, Blood, and body fluids often reflect the true essence of the disease. Therefore, when differentiating, the internal symptoms, tongue appearance, and pulse characteristics should be the primary basis.
(2) False symptoms differ from true symptoms; for instance, false Heat may present as a flushed face, while true Heat presents as a fully flushed face. False Cold often presents as cold limbs, while the chest and abdomen may be hot to the touch, or the entire body may feel cold yet the patient does not want to be covered. True Cold presents as a curled-up body desiring warmth.
The Relationship Between Cold, Heat, and Exterior-Interior
Cold syndromes, Heat syndromes, and Exterior-Interior syndromes are interconnected. They can form various syndromes, including the aforementioned Exterior Cold, Exterior Heat, Interior Cold, and Interior Heat syndromes. The details are as follows:
(1) Exterior Cold Syndrome
This syndrome is caused by the invasion of Cold pathogens into the muscle surface.
【Clinical Manifestations】Severe aversion to cold, mild fever, headache, body aches, no sweating, thin white tongue coating, and floating tight pulse.
【Syndrome Analysis】Cold pathogens invade the surface, injuring the Yang Qi, which cannot warm the muscle surface, leading to severe aversion to cold. The righteous Qi is obstructed, leading to mild fever. Cold is Yin, hence the severe aversion to cold and mild fever. Cold pathogens obstruct the meridians, leading to poor circulation of Qi and Blood, resulting in headache and body aches. Cold constricts, preventing the normal flow of Qi, leading to no sweating. The floating tight pulse indicates the presence of Cold pathogens obstructing the surface; Exterior Cold syndrome is a type of Exterior syndrome characterized by severe aversion to cold, mild fever, no sweating, and a floating tight pulse.
(2) Exterior Heat Syndrome
This syndrome is caused by the invasion of Heat pathogens into the muscle surface.
【Clinical Manifestations】Fever, mild aversion to wind and cold, headache, dry mouth, mild thirst, or sweating, red tongue edges, and floating rapid pulse.
【Syndrome Analysis】Heat pathogens invade the surface, obstructing the Wei Qi, leading to fever and mild aversion to cold. Heat is Yang, hence the heavy fever and mild aversion to cold, often accompanied by dry mouth and mild thirst. Heat rises and disturbs the mind, leading to headache. The red tongue edges and floating rapid pulse indicate the presence of Heat in the surface.
Exterior Heat syndrome is also a type of Exterior syndrome characterized by heavy fever, mild aversion to cold, often with sweating, and a floating rapid pulse.
(3) Interior Cold Syndrome
This syndrome is caused by the invasion of Cold pathogens into the internal organs or due to Yang Qi deficiency.
【Clinical Manifestations】Cold limbs, pale complexion, lack of thirst, or preference for warm drinks, quietness, and little speech, clear long urine, loose stools, pale tongue, white slippery coating, and slow or tight pulse.
【Syndrome Analysis】Cold pathogens invade the internal organs, damaging Yang Qi, or the functions of the organs decline, leading to Yang Qi deficiency, which cannot warm the body, resulting in cold limbs and pale complexion. Excessive internal Cold leads to a lack of thirst. Cold is Yin, hence the quietness and little speech. Clear urine and loose stools, pale tongue, white slippery coating, and slow or tight pulse are all signs of Interior Cold.
(4) Interior Heat Syndrome
This syndrome is caused by the invasion of Heat pathogens into the internal organs or due to Yin fluid deficiency leading to internal Heat.
【Clinical Manifestations】Red face, body heat, thirst, preference for cold drinks, irritability, excessive speech, short red urine, dry and constipated stools, red tongue, yellow coating, and rapid pulse.
【Syndrome Analysis】Internal Heat rises, leading to red face and body heat. Heat injures body fluids, leading to thirst and a preference for cold drinks. Heat disturbs the mind, leading to irritability and excessive speech. Heat obstructs the intestines, leading to constipation. A red tongue with yellow coating indicates Heat syndrome.
Section 3: Deficiency and Excess
Deficiency and Excess are two principles used to differentiate the strength of the pathogenic and righteous Qi. Deficiency refers to insufficient righteous Qi; Excess refers to excessive pathogenic Qi. Deficiency syndromes reflect weakness of the body’s righteous Qi, while Excess syndromes reflect excessive pathogenic Qi. The differentiation of Deficiency and Excess can help understand the state of the patient’s pathogenic and righteous Qi, providing a basis for treatment; Excess syndromes should be attacked, while Deficiency syndromes should be tonified. Only with accurate differentiation can appropriate treatment be applied, avoiding the errors of confusing Deficiency with Excess.
1. Deficiency Syndrome
Deficiency syndrome is a pathological summary of various clinical manifestations of weak righteous Qi in the body. The formation of Deficiency syndrome can be attributed to various reasons, including congenital insufficiency, lack of nourishment, and consumption due to illness.
Due to the complexity of clinical manifestations of Deficiency syndrome, only some common and regular manifestations will be introduced here.
【Clinical Manifestations】The manifestations of various Deficiency syndromes are extremely inconsistent and difficult to summarize comprehensively. Common symptoms include: pale or sallow complexion, mental fatigue, weakness, palpitations, shortness of breath, cold limbs, spontaneous sweating, loose stools, urinary incontinence, pale and swollen tongue, weak and slow pulse, or five hearts heat, weight loss, red cheeks, dry mouth and throat, night sweats, tidal fever, red tongue with little coating, and rapid pulse.
【Syndrome Analysis】The pathogenesis of Deficiency syndrome primarily manifests as Yin or Yang deficiency. If Yang is deficient, the symptoms will primarily reflect Yang deficiency. Due to the loss of Yang’s warming and consolidating functions, symptoms such as pale complexion, cold limbs, fatigue, palpitations, shortness of breath, loose stools, and urinary incontinence may occur. If Yin is deficient, the symptoms will primarily reflect Yin deficiency. Due to the inability of Yin to restrain Yang, the loss of nourishing and moistening functions leads to symptoms such as heat in the palms and soles, irritability, sallow complexion, or red cheeks, and tidal fever. Yang deficiency leads to excessive Yin, resulting in a pale and swollen tongue, while Yin deficiency leads to excessive Yang, resulting in a red and dry tongue with little coating.
2. Excess Syndrome
Excess syndrome is a pathological summary of various clinical manifestations caused by the invasion of external pathogens or the accumulation of pathological products within the body. The causes of Excess syndrome can be attributed to two aspects: one is the invasion of external pathogens, and the other is the dysfunction of the organs leading to the accumulation of pathological products such as phlegm, dampness, and blood stasis. Due to the differences in the nature of the external pathogens and the pathological products, various symptoms can be observed.
Due to the diverse manifestations of Excess syndrome, only some common and general issues will be introduced here.
【Clinical Manifestations】Due to different causes, the manifestations of Excess syndrome are also extremely inconsistent, but common symptoms include: fever, abdominal distension and pain, chest tightness, irritability, and even mental confusion, coarse breathing, excessive phlegm, constipation, or diarrhea, urgency and heaviness in the abdomen, difficulty urinating, and a strong pulse with a pale tongue and thick greasy coating.
【Syndrome Analysis】Excessive pathogenic Qi leads to a struggle against the righteous Qi, resulting in excessive Yang and thus fever. Excessive pathogenic Qi disturbs the mind or obscures consciousness, leading to irritability and even mental confusion. If the pathogenic Qi obstructs the lungs, it leads to difficulty in normal respiration and chest tightness. If phlegm is excessive, it may lead to a rattling sound in the throat.
Excessive pathogenic Qi obstructs the intestines, leading to constipation and abdominal distension. If damp-heat attacks downward, it may lead to diarrhea with urgency and heaviness in the abdomen, while water and dampness stagnate, leading to difficulty urinating. The struggle between pathogenic and righteous Qi manifests as a strong pulse. Excessive damp-heat leads to a thick and greasy tongue coating.
3. Differentiating Between Deficiency and Excess Syndromes
The manifestations of Deficiency and Excess syndromes have been introduced above, but clinically, some symptoms can appear in both Excess and Deficiency syndromes. For example, abdominal pain can occur in both. Therefore, to differentiate between Deficiency and Excess, it is necessary to consider all four examinations, including observing the body shape, tongue appearance, listening to the voice, inquiring about the onset of the disease, palpating the abdomen, and examining the pulse. Generally speaking, Deficiency syndromes are characterized by weakness, while Excess syndromes are often associated with a robust body. Deficiency syndromes present with low voice and weak breathing, while Excess syndromes present with loud voice and coarse breathing. Chronic diseases tend to be Deficiency, while acute diseases tend to be Excess. A pale and tender tongue with a weak pulse indicates Deficiency, while a pale and old tongue with a strong pulse indicates Excess.
4. The Relationship Between Deficiency and Excess Syndromes
Disease is a complex process of development, and due to various factors such as constitution, treatment, and care, Deficiency and Excess syndromes often exhibit mixed, transformed, and false symptoms. If not carefully observed, misdiagnosis can easily occur. The following will be discussed:
(1) Mixed Deficiency and Excess
When Deficiency syndromes are mixed with Excess syndromes, or Excess syndromes are mixed with Deficiency syndromes, as well as the simultaneous presence of both, it is referred to as mixed Deficiency and Excess. For example, Exterior Deficiency with Interior Excess, Exterior Excess with Interior Deficiency, Upper Deficiency with Lower Excess, and Upper Excess with Lower Deficiency, etc. The presence of mixed Deficiency and Excess syndromes indicates that both Deficiency and Excess are present, thus treatment should involve both attacking and tonifying. However, in the process of attacking and tonifying, it is essential to distinguish which is more predominant, as this will influence the choice of treatment. In mixed Deficiency and Excess syndromes, there are three situations based on the predominance of Deficiency or Excess.
1. Excess with Deficiency: This often occurs in patients with Excess syndromes where the righteous Qi has been damaged, or in patients who were originally weak but newly contracted an external pathogenic factor. Its characteristic is that Excess is predominant, while Deficiency is secondary. For example, in the case of Bai Hu Jia Ren Shen Tang syndrome from the “Shang Han Lun,” which originally presents with excessive Yangming heat, symptoms include high fever, thirst, and sweating, but due to the heat damaging Qi and Yin, symptoms of dryness and irritability may also appear, indicating a combination of Excess and Deficiency. The treatment should primarily focus on attacking the Excess while also tonifying the righteous Qi.
2. Deficiency with Excess: This syndrome often occurs in patients with severe Excess syndromes that have persisted for a long time, leading to significant damage to the righteous Qi, while the pathogenic factor remains. It can also occur in patients with a pre-existing weakness who are newly affected by a pathogenic factor. Its characteristic is that Deficiency is predominant, while Excess is secondary. For example, in cases of Kidney Yin deficiency appearing in the late stages of warm diseases, the symptoms may include persistent low fever, dry mouth, and a dry tongue, indicating a predominance of Deficiency. The treatment should focus on nourishing Yin and supporting the righteous Qi while also clearing residual Heat.
3. Equal Deficiency and Excess: This syndrome occurs in two situations: one is when there is a severe Excess syndrome that has persisted for a long time, leading to significant damage to the righteous Qi, while the pathogenic factor remains; the other is when there is a pre-existing weakness that is newly affected by a strong pathogenic factor. Their characteristics are that both Deficiency and Excess are very evident, and the condition is relatively severe. For example, in cases of pediatric malnutrition, symptoms may include diarrhea, excessive appetite, thick and turbid tongue coating, and a thin pulse. The disease arises from dietary stagnation, damaging the Spleen and Stomach, thus both Deficiency and Excess are present, and treatment should involve both resolving food stagnation and tonifying the Spleen.
(2) Transformation Between Deficiency and Excess
The progression of disease often reflects the struggle between pathogenic and righteous Qi. The reflection of this struggle in symptoms primarily manifests as changes between Deficiency and Excess. During the course of the disease, some conditions that were originally Excess may transform into Deficiency due to prolonged pathogenic factors damaging the righteous Qi; conversely, some conditions that were originally Deficiency may lead to Excess due to dysfunction of the organs causing stagnation of phlegm, food, blood, or water. For example, in cases of high fever, thirst, and excessive sweating with a strong pulse, if treatment is inappropriate and the condition persists, it may lead to depletion of body fluids, resulting in weight loss, pale complexion, lack of appetite, and a thin pulse, indicating a transformation from Excess to Deficiency. Conversely, if a patient with a weak heart and Spleen Qi experiences sudden and severe chest pain, this indicates that the Deficiency has transformed into an Excess condition due to blood stasis.
(3) True and False Deficiency and Excess
Deficiency and Excess can have true and false manifestations. When differentiating, it is essential to distinguish between true and false symptoms to avoid the error of confusing Deficiency with Excess. The differentiation of true and false Deficiency and Excess is not the same as mixed Deficiency and Excess syndromes, and careful observation is required.
1. True Excess Appearing as False Deficiency: This refers to a condition where the essence of the disease is Excess, but some symptoms appear to be Deficiency. For example, in cases of Heat obstructing the intestines, phlegm and food stagnation, leading to symptoms such as a calm demeanor, cold limbs, and a slow pulse. Upon careful differentiation, it can be found that although the demeanor appears calm, the voice is loud and strong; the pulse may be slow but strong upon palpation; and although the limbs are cold, the abdomen is hot to the touch. This indicates that the symptoms resembling Deficiency are not due to weakness of the body, but rather due to obstruction of the meridians by Excessive pathogenic factors, thus treatment should focus on attacking the Excess.
2. True Deficiency Appearing as False Excess: This refers to a condition where the essence of the disease is Deficiency, but some symptoms appear to be Excess. For example, in cases of Spleen Qi deficiency leading to abdominal distension and pain, the pulse may be wiry. Upon careful differentiation, it can be found that the abdominal distension may lessen at times, unlike the constant distension seen in true Excess; although there is abdominal pain, it is relieved by pressure; the pulse may be wiry, but it is weak upon deeper palpation. This indicates that the symptoms resembling Excess are not due to Excessive pathogenic factors, but rather due to weakness of the body, thus treatment should focus on tonifying.
The key points for differentiating true and false Deficiency and Excess can be summarized as follows:
(1) The strength or weakness of the pulse, the presence or absence of spirit, and the characteristics of the floating or sinking pulse.
(2) The appearance of the tongue, whether it is swollen and tender or pale and old.
(3) The loudness or weakness of the voice.
(4) The strength or weakness of the patient’s constitution, the cause of the disease, the duration of the disease, and the treatment history.
5. The Relationship Between Deficiency and Excess with Exterior-Interior and Cold-Heat
Deficiency and Excess are often reflected through the principles of Exterior-Interior and Cold-Heat, forming various syndromes. Commonly seen in clinical practice are Exterior Deficiency, Exterior Excess, Interior Deficiency, Interior Excess, Deficiency Heat, Excess Heat, Deficiency Cold, and Excess Cold syndromes.
(1) Exterior Deficiency Syndrome
Exterior Deficiency syndrome can be divided into two types: one is caused by the invasion of Wind pathogens, characterized by aversion to wind and spontaneous sweating, representing external Exterior Deficiency. The other is due to Lung and Spleen Qi deficiency, where the Wei Qi cannot secure the surface, leading to spontaneous sweating and susceptibility to external pathogens, representing internal injury Exterior Deficiency.
【Clinical Manifestations】External Exterior Deficiency: headache, stiff neck, fever, sweating, aversion to wind, and floating pulse.
Internal Exterior Deficiency: frequent spontaneous sweating, susceptibility to colds, pale complexion, shortness of breath, fatigue, reduced appetite, loose stools, pale tongue with white coating, and weak pulse.
【Syndrome Analysis】Exterior Deficiency syndrome caused by the invasion of Wind pathogens occurs when the Wind pathogen binds to the Taiyang meridian, leading to headache and stiff neck; the righteous Qi is obstructed, leading to fever; the muscle surface is loose, leading to spontaneous sweating and aversion to wind; the pulse is floating and weak due to the presence of Wind pathogens.
Interior Exterior Deficiency syndrome is primarily due to Lung and Spleen Qi deficiency. The lungs govern the skin, and the spleen governs the muscles; when Qi is deficient, the muscle surface becomes loose, and the Wei Qi cannot secure the surface, leading to spontaneous sweating. When the Wei Qi is weak, symptoms such as pale complexion, shortness of breath, fatigue, reduced appetite, and loose stools may also appear.
(2) Exterior Excess Syndrome
Exterior Excess syndrome is caused by the invasion of Cold pathogens into the muscle surface.
【Clinical Manifestations】Fever, aversion to cold, headache, body aches, no sweating, floating tight pulse.
【Syndrome Analysis】The invasion of external pathogens leads to the Yang Qi rising to resist the pathogens, resulting in fever. The pathogens obstruct the normal dispersal of Wei Qi, leading to a lack of warmth and aversion to cold. The pathogens obstruct the meridians, leading to poor circulation of Qi and Blood, resulting in headache and body aches. Cold constricts, preventing the normal flow of Qi, leading to no sweating. The floating tight pulse indicates the presence of Cold pathogens obstructing the surface; Exterior Cold syndrome is a type of Exterior syndrome characterized by severe aversion to cold, mild fever, no sweating, and a floating tight pulse.
(3) Interior Deficiency Syndrome
Interior Deficiency syndrome encompasses a wide range of conditions, including deficiencies in various organs, meridians, Yin, Yang, and Qi and Blood. These will be elaborated in subsequent chapters. If classified by Cold and Heat, Interior Deficiency syndrome can be divided into Deficiency Cold and Deficiency Heat syndromes, which will be detailed later.
(4) Interior Excess Syndrome
Interior Excess syndrome also encompasses a wide range of conditions, including various organs, meridians, and different types of pathogenic factors. Many specific syndromes will be introduced in subsequent chapters. If classified by Cold and Heat, Interior Excess syndrome can be divided into Excess Cold and Excess Heat syndromes, which will be detailed later.
(5) Deficiency Cold Syndrome
Deficiency Cold syndrome is caused by the deficiency of Yang Qi in the body.
【Clinical Manifestations】Mental fatigue, pale complexion, aversion to cold, cold limbs, abdominal pain with a preference for warmth, loose stools, clear long urine, fatigue, pale and swollen tongue, and weak pulse.
【Syndrome Analysis】The pathogenesis of this syndrome is Yang deficiency. Insufficient Yang fails to promote and transform, leading to symptoms such as mental fatigue, pale complexion, cold limbs, and abdominal pain with a preference for warmth. Insufficient Yang also leads to loose stools and clear long urine.
(6) Deficiency Heat Syndrome
Deficiency Heat syndrome is caused by the deficiency of Yin fluids in the body.
【Clinical Manifestations】Red cheeks, weight loss, tidal fever, night sweats, five hearts heat, dry mouth and throat, red tongue with little coating, and rapid pulse.
【Syndrome Analysis】The depletion of Yin fluids leads to symptoms such as weight loss, inability to restrain Yang, and internal disturbance of Heat, leading to symptoms such as red cheeks, dry mouth, and throat. The rapid pulse indicates the presence of internal Heat.
(7) Excess Cold Syndrome
Excess Cold syndrome is caused by the invasion of Cold pathogens (Yin pathogens) into the body.
【Clinical Manifestations】Aversion to cold, preference for warmth, pale complexion, cold limbs, abdominal pain with a preference for pressure, rumbling in the abdomen, diarrhea, or phlegm and wheezing, clear long urine, pale tongue with white coating, and slow or tight pulse.
【Syndrome Analysis】Cold pathogens invade the body, obstructing Yang Qi, leading to aversion to cold and preference for warmth, cold limbs, and pale complexion. Cold obstructs the meridians, leading to abdominal pain with a preference for pressure. If Cold invades the lungs, it may lead to phlegm and wheezing. Clear long urine and pale tongue with white coating are signs of internal Cold.
Slow or tight pulse indicates the stagnation of blood flow due to Cold obstruction.
(8) Excess Heat Syndrome
Excess Heat syndrome is caused by the invasion of Yang Heat pathogens into the body.
【Clinical Manifestations】High fever, preference for coolness, thirst with a desire for cold drinks, red face and eyes, irritability, abdominal distension and pain, constipation, short red urine, red tongue with yellow coating, and rapid pulse.
【Syndrome Analysis】Excessive internal Heat leads to symptoms such as high fever and preference for coolness. Heat injures body fluids, leading to thirst and a desire for cold drinks. Heat disturbs the mind, leading to irritability. Heat obstructs the intestines, leading to constipation. A red tongue with yellow coating indicates the presence of Heat.
Section 4: Yin and Yang
Yin and Yang serve as the overarching principles of the Eight Principles of Syndrome Differentiation. In diagnosis, diseases can be classified into two main aspects based on the pathological nature of the clinical manifestations. Yin and Yang essentially encompass the Eight Principles, summarizing the other six aspects, namely Exterior, Heat, and Excess as Yang; and Interior, Cold, and Deficiency as Yin. Thus, some refer to the Eight Principles as “Two Principles and Six Essentials.”
In clinical practice, since the relationships between Exterior, Interior, Cold, Heat, Deficiency, and Excess are sometimes intertwined, they cannot be distinctly separated. Therefore, Yin and Yang syndromes are also not always clearly defined, often presenting complex symptoms where Yin exists within Yang and vice versa. For instance, the previously mentioned simultaneous Exterior and Interior diseases, mixed Cold and Heat, and mixed Deficiency and Excess syndromes belong to this category.
In addition to Yin and Yang syndromes, there are also conditions such as true Yin deficiency, true Yang deficiency, and the loss of Yin and Yang, which will be discussed below.
1. Yin and Yang Syndromes
(1) Yin Syndrome
Any syndrome that conforms to the general attributes of “Yin” is referred to as Yin syndrome. For example, Interior syndromes, Cold syndromes, and Deficiency syndromes fall under the category of Yin syndromes.
【Clinical Manifestations】Different diseases exhibit different Yin symptoms, but common manifestations include: dark complexion, mental fatigue, heavy body, cold limbs, lack of energy, low voice, poor appetite, lack of thirst, loose stools, clear long urine, pale and swollen tongue, and slow or weak pulse.
【Syndrome Analysis】Mental fatigue, weakness, and low voice are manifestations of Deficiency syndrome. Cold limbs, lack of thirst, loose stools, and clear long urine are manifestations of Interior Cold syndrome. A pale and swollen tongue, slow pulse, and weak or thin pulse are all signs of Yin deficiency.
(2) Yang Syndrome
Any syndrome that conforms to the general attributes of “Yang” is referred to as Yang syndrome. For example, Exterior syndromes, Heat syndromes, and Excess syndromes fall under the category of Yang syndromes.
【Clinical Manifestations】Different diseases exhibit different Yang symptoms, but common manifestations include: red complexion, aversion to cold and fever, hot skin, irritability, restlessness, loud voice, coarse breathing, dry mouth, thirst, constipation, foul-smelling stools, painful urination, short red urine, red tongue, yellow or black coating, and rapid pulse.
【Syndrome Analysis】Yang syndromes are summarized as Exterior syndromes, Heat syndromes, and Excess syndromes. Aversion to cold and fever are characteristics of Exterior syndromes. Red complexion, irritability, and thirst are manifestations of Heat syndromes. Loud voice, coarse breathing, and constipation are manifestations of Excess syndromes. A red tongue with yellow or black coating and a rapid pulse indicate the presence of Excess Heat.
(3) Differentiating Between Yin and Yang Syndromes
The differentiation between Yin and Yang syndromes can be observed through the four examinations as follows:
1. Yin Syndrome
① Observation: Pale or dark complexion, heavy body, fatigue, lack of energy, pale and swollen tongue, and moist tongue coating.
② Listening: Low voice, quiet demeanor, weak and short breaths.
③ Inquiry: Foul-smelling stools, reduced appetite, lack of thirst, or preference for warm drinks, clear long urine.
④ Palpation: Abdominal pain with a preference for pressure, cold limbs, and a slow or weak pulse.
2. Yang Syndrome
① Observation: Red or flushed complexion, preference for coolness, restlessness, dry lips, red tongue, yellow or old yellow coating, and possibly black coating.
② Listening: Loud voice, irritability, coarse breathing, and restlessness.
③ Inquiry: Hard or constipated stools, foul-smelling, poor appetite, dry mouth, and thirst.
④ Palpation: Abdominal pain with a preference for pressure, warm limbs, and a strong pulse.
The balance of Yin and Yang is relative; when Yang is excessive, Yin is deficient, and vice versa. For instance, if the pulse is strong, the tongue is red and dry, and there are accompanying symptoms of thirst and high fever, it indicates Yang excess and Yin deficiency. Conversely, if the pulse is weak, the tongue is pale and moist, and there are symptoms of abdominal pain and diarrhea, it indicates Yin excess and Yang deficiency. Additionally, the complex changes in Yin and Yang are specifically reflected in the relationships between Exterior, Interior, Cold, Heat, Deficiency, and Excess, as previously discussed and will not be repeated.
2. True Yin Deficiency and True Yang Deficiency
Yin deficiency syndrome is also known as Deficiency Heat syndrome, while Yang deficiency syndrome is also known as Deficiency Cold syndrome, as previously detailed. The kidneys are the root of Yin and Yang in the body. When Yin and Yang are deficient for a long time, or due to prolonged illness, it can lead to the deficiency of kidney Yin or kidney Yang, resulting in true Yin deficiency or true Yang deficiency.
(1) True Yin Deficiency
【Clinical Manifestations】Internal Heat, pale complexion, red cheeks, dry mouth, dry throat, irritability, heat in the palms and soles, dizziness, tinnitus, weakness in the lower back and legs, night sweats, nocturnal emissions, constipation, short and scanty urine, and a thin rapid pulse with a red tongue and little coating.
【Syndrome Analysis】Prolonged illness damages Yin essence, affecting true Yin, leading to the inability of Yin to restrain Yang, resulting in internal Heat symptoms such as pale complexion, red cheeks, dry mouth, and irritability. The thin rapid pulse indicates the presence of internal Heat. Additionally, the damage to kidney function may lead to symptoms such as dizziness, tinnitus, weakness in the lower back and legs, and nocturnal emissions.
(2) True Yang Deficiency (Kidney Yang Deficiency)
【Clinical Manifestations】Pale complexion, cold limbs, pale lips and tongue, preference for warm drinks, spontaneous sweating, fatigue, lack of appetite, abdominal distension, edema in the lower limbs, loose stools, nocturnal diarrhea, impotence, infertility, or cold uterus leading to infertility, pale and swollen tongue, white slippery coating, and a slow or weak pulse.
【Syndrome Analysis】Prolonged illness damages Yang Qi, affecting true Yang, leading to the inability of Yang to restrain Yin, resulting in excessive internal Cold symptoms such as pale complexion, cold limbs, and preference for warm drinks. The slow or weak pulse indicates Yang deficiency. Additionally, the damage to kidney function may lead to symptoms such as shortness of breath, abdominal distension, and edema in the lower limbs.
3. Loss of Yin and Loss of Yang
Loss of Yin and Loss of Yang are critical syndromes of disease. A slight misdiagnosis or delay in treatment can lead to immediate death. Loss of Yin and Loss of Yang are two different types of syndromes. The fundamental cause of Loss of Yin is the significant loss of body fluids, leading to Loss of Yin. The primary cause of Loss of Yang is the loss of Yang Qi. Since Qi can be lost with fluids and blood, Loss of Yang is often seen after excessive sweating, vomiting, diarrhea, or significant bleeding. Additionally, many critical stages of diseases may also present with Loss of Yang. Since Yin and Yang are interdependent, Loss of Yin can lead to Loss of Yang, and Loss of Yang can also lead to the depletion of Yin fluids. In clinical practice, it is essential to differentiate between Loss of Yin and Loss of Yang to provide timely treatment.
(1) Loss of Yin
【Clinical Manifestations】Body heat, warm limbs, irritability, thirst, dry mouth, dry throat, wrinkled skin, very little urine, red tongue, and thin rapid pulse. Typically, excessive sweating is a characteristic of Loss of Yin, with the sweat being warm, salty, and thin (in cases of Loss of Yin due to vomiting or diarrhea, there may not be excessive sweating).
【Syndrome Analysis】The depletion of Yin fluids leads to the loss of moistening functions, resulting in symptoms such as thirst, dry mouth, and dry throat. The depletion of body fluids leads to very little urine. Internal Heat leads to body heat and warm limbs. Irritability is due to internal Heat. A red tongue and thin rapid pulse indicate the presence of internal Heat. Excessive sweating often occurs in patients with pre-existing Heat diseases, where the Heat pathogen forces the sweat to leak out. In this case, excessive sweating is both a cause and a symptom of Loss of Yin.
(2) Loss of Yang
【Clinical Manifestations】Excessive sweating, cold sweat, thin and slightly sticky sweat, cold body, aversion to cold, cold limbs, curled up and fatigued, lack of thirst, or preference for warm drinks, pale tongue, moist tongue, and a weak pulse.
【Syndrome Analysis】Loss of Yang occurs in various conditions leading to Yang Qi deficiency. Yang deficiency fails to secure the body, leading to excessive sweating, which is cold and thin, indicating Loss of Yang. Yang deficiency leads to coldness, resulting in cold body temperature and cold limbs. The body’s functions are diminished, leading to fatigue and a curled-up posture. Lack of thirst and preference for warm drinks indicate Yang deficiency.
Differentiating Between Loss of Yin and Loss of Yang:
1. Loss of Yin Syndrome
Sweat: Warm, salty, not sticky.
Limbs: Warm.
Tongue: Red and dry.
Pulse: Thin, rapid, and weak.
Other: Body heat, irritability, thirst, preference for cold drinks.
2. Loss of Yang Syndrome
Sweat: Cold, thin, slightly sticky.
Limbs: Cold.
Tongue: Pale and moist.
Pulse: Weak and thin.
Other: Cold body, curled up, fatigued, lack of thirst, preference for warm drinks.