Xiaoming Cheng

Abstract: The Eight Principle diagnostic features are Exterior-Interior, Cold-Heat, Deficient-Excess, and Yin-Yang. These methods of differential diagnosis are used to determine the nature and location of pathological changes. The conflict between the body, the Vital Essence, and the pathogens are evaluated in terms of these Eight Principles. This determination is based on a comprehensive analysis of the clinical evidence obtained by inspection, auscultation, olfaction, interrogation, quality of pulse and palpation.

This method of differential diagnosis is used to determine the location of the pathogen and the probability for the development of a disease (i.e. the potential for transformation).

The main syndromes are listed below.

Exterior Syndrome

This refers to a syndrome caused by an attack of the superficial or Exterior of the body by the Six Pathogenic Influences through the skin, hair, mouth or nose. It is sudden in onset, superficial (limited to the Exterior), mild in nature, and short in duration without affecting the function of Zang Fu in most cases.

Interior Syndrome

In contrast to the Exterior syndrome, the Interior syndrome is characterized by pathological changes of the internal organs. The Interior syndrome may be caused by pathogenic influences, which either enter from outside of the body or transfer into the interior, or by their direct invasion of the Zang Fu. The Interior syndrome may also be caused by some “internal influences”, such as emotional upset, improper diet or psychological stress, which directly affect the function of the Zang Fu.

Invasion from the Exterior to the Interior

This refers to the invasion of pathogens from superficial aspects of the body to the deep, or the replacement of an Exterior syndrome by an Interior one.A patient with an Exterior syndrome may have such symptoms as fever and aversion to cold, and the tongue may be normal with a white thin coating and a floating pulse. If the sensation of aversion to cold is replaced by aversion to heat, then new symptoms may appear. These symptoms include thirst, scanty dark urine, redness of the tongue with yellowish coating and rapid pulse, indicating that the disease has manifested itself by an Interior Heat syndrome due to an invasion of pathogenic agents from the superficial part of the body to the deep.

Invasion from the Interior to the Exterior of the body

This refers to the conditions in which the pathogenic factors are brought out from the Interior to the body’s Exterior. For example, in the case of an Interior syndrome due to Interior Heat, at first there is the appearance of restlessness, shortness of breath, cough and chest stuffiness.Then there is progression to fever and sweating, the restlessness subsides or a rash develops. These symptoms indicate that the pathogenic agent has been brought out to the surface and the Interior syndrome has subsided. This usually results from proper and prompt treatment and appropriate nursing, which helps to build up the body’s resistance. The transmission of pathogens from the Interior to the Exterior is indicative of the convalescence of a disease in which the pathogens have been expelled, and the condition of the illness has abated.

Mixed Syndrome of Exterior and Interior

This refers to the simultaneous appearance of features from both the Exterior syndrome and the Interior syndrome in a patient. Evidence of both Exterior and Interior syndromes appears in the initial stage of an illness. For example, when in late summer or in early autumn, there may appear symptoms characteristic of Exterior syndrome, such as fever, aversion to cold, headache, and general aching sensation on the body. In addition, symptoms characteristic of Interior syndrome, such as epigastria stuffiness, anorexia, diarrhea, thick whitish coating of the tongue, etc. may also be present. This is due to an invasion by External pathogenic Cold and Internal pathogenic Dampness.

Differential Diagnosis of Cold and Heat Syndromes

This refers to the method of differentiating the nature of a disease. It is identical with the differentiation of Excess and Deficiency of Yin and Yang, because Cold and Heat are the manifestations of Excess and Deficiency of Yin and Yang in the body.

The main syndromes are:

Cold Syndrome

This syndrome can be caused by an invasion of a Cold Pathogenic Influence, also known as Excessive Cold. Another form of Cold syndrome is Interior Deficiency Cold, in which the client always feels cold internally. This is due to insufficiency of Yang and excess of Yin. Clinical manifestations of a Cold syndrome are: aversion to cold, seeking or desire for warmth, no thirst, pale complexion, huddling up when cold, copious clear urine, loose stools, pale tongue with whitish coating, and a tense or slow pulse.

Heat Syndrome

This is a syndrome caused by invasion of pathogenic Heat or hyperactivity of the body due to a Deficiency of Yin and Excess of Yang. Clinical manifestations are fever, aversion to heat and preference for cold, thirst with a preference for cold drinks, flushed face, congested eyes, fidgeting, scanty dark urine, constipation, reddened tongue with dry brownish coating and a rapid pulse.

Simultaneous Occurrence of Cold and Heat Syndromes

This means that a Cold syndrome is intertwined with a Heat syndrome in the same patient.This may appear as an Organ disorder, characterized by a Heat syndrome in the upper part with a Cold syndrome in the lower part of the body, or it may appear in the organs themselves.

In the case of simultaneous occurrence of an Exterior and Interior syndrome, it is marked by a Heat syndrome in the Exterior with Cold syndrome in the Interior, or vice versa.

Transformation of a Cold Syndrome and a Heat Syndrome

This refers to a change in the nature of a disease. There is a transfer from a Cold syndrome to a Heat syndrome. For example, when a Cold Pathogenic Influence invades the body, we can see such symptoms as fever, aversion to cold, no sweat, headache, general aching, thin white coating of the tongue, tight floating pulse, etc. Later, owing to further development of the pathological changes, the aversion to cold disappears but the fever does not abate, and an aversion to heat rather than cold occurs. Moreover, other symptoms progressively appear such as irritability, thirst and yellowish coating of the tongue, indicating that the Exterior Cold syndrome has transformed into an Interior Heat syndrome. On the other hand, a disease can initially manifest as a Heat syndrome followed later by a Cold syndrome. This transformation of a Heat syndrome into a Cold syndrome is seen in the case of a patient with high fever due to delayed treatment or misdiagnosis. The patient may be overcome by the pathogenic factor, which damages the Vital Qi and suddenly develops such symptoms as cold limbs, profuse cold sweat, restlessness, and a faint indistinct pulse. This is also called collapse of Yang.

Heat Syndrome with Pseudo-Cold Symptoms

In this syndrome, the disease has a Heat syndrome nature but also presents with some Cold symptoms, such as cold limbs, deep pulse, etc. It is different from a Cold syndrome in that the patient’s body is warm in spite of cold limbs, and has an aversion to heat instead of cold, and his pulse is deep, but also rapid and forceful. The patient may also have the following symptoms: excessive thirst, preference for cold drinks, dry throat, foul breath, delirium, scanty dark urine, dry stool or dysentery of the Heat type with rectal tenesmus, and a dark reddish tongue with a dry yellowish coating. In this case, the cold limbs and deep pulse are considered “false appearances,” because the Interior Heat is the essence of the disease. This condition is attributable to Excessive Heat inside the body, which keeps Yin superficial. This is what is known as “ Yin kept Externally by Excessive Yang in the Interior”.

Cold Syndrome with Pseudo-Heat Symptoms

In this case, the disease is Cold in nature, but exhibits some Heat symptoms, such as fever, flushed face, thirst, and a large pulse. It differs from a Heat syndrome in that the patient runs a fever, but has a desire for being covered up, feels thirsty, but prefers hot drinks, and the pulse is large but weak. There can be symptoms of a Cold nature observed, such as cold limbs, clear urine, loose stool, and pink tongue with a whitish coating. This syndrome’s cause is an Excessive Yin Cold inside the body, which keeps the Yang External. This is what is called “Yang kept Externally by Excessive Yin in the Interior”.

Overall, the differential diagnosis of cold and heat syndromes constitutes one of the fundamental aspects of Traditional Chinese Medicine (TCM) diagnosis and treatment. Continuing, here are further details on related aspects:

Concurrence of Internal and External Diseases: This refers to a situation where a patient exhibits characteristics of both an internal injury (or internal disease) and an externally contracted disease (or external disease).This might manifest as a heat syndrome in the upper body as per external disease and a cold syndrome in the lower body as per internal injury, or simultaneously in different parts of an organ.

Transformation between Cold and Heat Syndromes: This denotes a change like illness, wherein a cold syndrome might transform into a heat syndrome, and vice versa. Such transformation often accompanies the development of pathological changes, with symptoms gradually altering. In TCM diagnosis and treatment, therapeutic approaches are adjusted according to these changes.

False Cold Symptoms Accompanying Heat Syndrome: I In this scenario, the disease exhibits the characteristics of heat syndrome but also presents some cold symptoms. n this state, the coldness in the limbs and a deep, sunken pulse are considered “false manifestations” because the actual nature of the disease lies in excessive internal heat.

False Heat Symptoms Accompanying Cold Syndrome: In this scenario, the nature of the disease is a cold syndrome but simultaneously presents some heat symptoms. In this state, fever and other heat symptoms are considered “false manifestations” because the actual nature of the disease lies in an excessive yin-cold internally.

Differentiating these cold and heat syndromes aids TCM practitioners in accurately understanding the nature and location of the pathology, thus allowing for the creation of personalized treatment plans. It is important to emphasize that TCM diagnosis and treatment is a comprehensive medical science that not only considers the etiology and pathogenesis of the disease but also considers individual differences, environmental factors, and a principle that integrates prevention and treatment.

Differential Diagnosis of Deficiency and Excess Syndrome

This is a method used to determine the strength of the Vital Qi of the body and the virulence of pathogenic factors.

Deficiency Syndrome

This syndrome manifests by a Deficiency of Vital Qi.

An individual may be born with a Deficiency of Vital Qi. More commonly a Deficiency of Vital Qi is due to a lack of proper living, excess, or imbalance in one’s life. For example, improper diet may lead to weakness of the body’s constitution; emotional upset may impair the Qi and Blood of the Zang Fu; sexual indulgence may consume the Kidney Qi; and prolonged illness may impair the Vital Qi.All these factors may result in various Deficiency syndromes, which include insufficiency and impairment of Yin, Yang, Qi, Blood, Essence of life, body fluid, and the Zang Fu.Clinical manifestations are: pale or yellowish complexion, restlessness, emaciation, fatigue and weakness, disinclination to talk, palpitation, shortness of breath, lassitude in loins and knees, spontaneous perspiration, night sweat, incontinence of stool and urine, pain relieved by pressing, pink tongue with little or not coating, and feeble or weak pulse.

Excess Syndrome

This syndrome is manifested by exuberant pathogens. It may result from an excess of pathogens with the Vital Qi not in decline; this condition leads to an intense struggle within the body between these two forces. The main manifestations of Excess syndrome are: strong physical constitution, high fever, agitation, loud voice, abdominal distension, pain and tenderness, constipation, hot burning sensation in urine, rough pale tongue with thick and greasy coating, replete and forceful pulse.

Deficiency Syndrome complicated with Excess Syndrome

This refers to the simultaneous occurrence of a Deficiency syndrome and an Excess syndrome in the same patient at the same time. For example, if a Deficiency syndrome is dominant, and is complicated with Excess symptoms, a patient may exhibit Blood-Deficient insomnia, with a headache in the back of the head, which is caused by a stiff neck.

In the case where an Excess syndrome is predominant, but accompanied by Deficiency symptoms, a patient may suffer from a Cold Pathogenic Influence, with headache, body aches and cough, meanwhile also displaying symptoms of Spleen Deficiency, such as feeling tired, loose stools and bloated abdomen.

Transformation of Excess Syndrome to Deficiency Sndrome

An Excess syndrome characterizes the disease in its initial stage. However, due to delayed treatment or misdiagnosis, it evolves into a Deficiency syndrome as a result of a decline of the pathogen and the impairment of Vital Qi due to the protracted course of disease. For example, a patient develops acute diarrhea and is not properly treated or is misdiagnosed. After a few months, it transfers to a Deficiency syndrome, i.e. chronic diarrhea. This is what is known as the transformation of Excess syndrome to Deficiency syndrome.

Transformation of Deficiency Syndrome to Excess Syndrome

In this syndrome a Deficiency syndrome characterizes the disease in its early stage. Due to insufficiency of Vital Qi, substantial pathogens gradually accumulate inside the body and give rise to some Excess symptoms. For example, Qi Deficiency in the elderly may cause exhaustion of body fluid and dryness of the intestine. This may then lead to an Excess syndrome manifested by constipation. This is known as Excess syndrome due to Deficiency syndrome.

Excess Syndrome with Pseudo-deficiency Symptoms

This is a syndrome of Excess type characterized by the accumulation of pathogens, but accompanied by symptoms similar to a Deficiency syndrome. It is also known as “appearance of Deficiency in extreme Excess”. For example, the accumulation of Heat or retention of Phlegm and food in the Stomach and Intestines may lead to blockage of movement of Stomach and Intestinal Qi. This is accompanied with symptoms such as lassitude, chilliness and cold limbs, and slow deep hidden pulse. Upon careful examination, other symptoms may be found such as loud voice, rough breathing, deep and slow or hidden but strong pulse, indicating that accumulation of pathogens in the interior as the real essence of disease, while symptoms resembling a Deficiency syndrome are merely false phenomena.

Deficiency Syndrome with Pseudo-excess Symptoms

This is a syndrome of Deficiency, but accompanied by symptoms similar to an Excess syndrome. It is also called “False Excess symptoms in extreme Deficiency”. For example, dysfunction of Zang Fu in digesting and transporting nutrients due to insufficiency of Qi and Blood may produce symptoms similar to an Excess syndrome, such as abdominal fullness, distension and pain, wiry pulse, etc. However, upon careful examination it may be found that the abdominal distension is slight, not severe. Moreover it is not persistent and can be relieved by pressure, and that the patient’s pulse is wiry and weak indicating that an insufficiency of Qi and Blood of Zang Fu is the real essence of disease. Once again the symptoms similar to an Excess syndrome are but false phenomena.

Complicated Syndromes

Exterior Syndrome of Excess type: This syndrome results in a tight sensation of the skin and muscles due to invasion of the superficies by a Pathogenic Influence. This manifests as dry skin, no sweat, fever, aversion to cold, headache, body aching, stuffy nose, and a tense floating pulse.

Exterior Syndrome of Deficiency type: This syndrome is also called “Disharmony of Ying and Wei Qi.” Its clinical manifestations are spontaneous sweating, fever, aversion to wind, sweating, and a slow floating pulse.

Cold Syndrome of Deficiency type: This syndrome is caused by a Yang Qi deficiency. It is manifested by lassitude, pale complexion, aversion to cold and cold limbs, abdominal pain, which is relieved by warmth and pressure, loose stool, frequent clear urine, shortness of breath and weakness, pale tongue, feeble or deep, slow and weak pulse, etc.

Cold Syndrome of Excess type: This syndrome is due to Excessive Yin-Cold inside the body, and stagnation of Yang Qi. This syndrome results from excessive intake of cold or raw food, or direct invasion of the Interior by a Cold Pathogenic Influence. It manifests as aversion to cold and cold limbs, epigastric chilliness and pain, abdominal pain and tenderness, vomiting of watery fluid, borborygmus, chronic diarrhea, cough with profuse thin and whitish sputum, asthma, whitish slippery coating of the tongue, and slow or tense pulse.

Yin Yang Dialectics

Differential Diagnosis of Yin and Yang is a general guiding principle underlying all Differential Diagnoses by the Eight Principles. The principles of Yin and Yang govern the other six principles. In times when there is no clear pattern for diagnosis, one can simplify their approach to the patient by applying the differential diagnosis of Yin and Yang.

Basic Concepts of Yin and Yang:

Mutual Relationship of Yin and Yang: Yin and Yang are concepts of mutual dependence and restraint. They exist in a relationship where one is relative to the other. The balance of the body relies on the equilibrium of Yin and Yang.

Dynamic Changes of Yin and Yang: Yin and Yang are dynamically changing, not static. The balance between Yin and Yang can vary with factors such as time, season, environment, etc.

Relativity of Yin and Yang: Yin and Yang are relative, meaning one exists in relation to the other. In a specific context, something may manifest as Yin in one aspect and Yang in another.

Mutual Transformation of Yin and Yang: Yin and Yang can transform into each other under certain conditions. This dynamic balance helps maintain stability in both physiological and pathological states.

Application of Differential Diagnosis of Yin and Yang:

No Clear Diagnostic Pattern: When a patient’s symptoms do not clearly align with any specific pattern of the Eight Principles, the differential diagnosis of Yin and Yang can be applied to preliminarily assess the patient’s constitution and pathological characteristics.

Guidance for Holistic Diagnosis: Differential Diagnosis of Yin and Yang aids in guiding the overall diagnostic process. Understanding the balance of Yin and Yang within the patient’s body contributes to a more comprehensive understanding of the disease process.

Individualized Treatment Plans: Differential Diagnosis of Yin and Yang assists in formulating more individualized treatment plans. Adjusting treatment strategies based on the specific imbalance of Yin and Yang in the patient’s body promotes overall balance.

In summary, the Differential Diagnosis of Yin and Yang is fundamental to traditional Chinese medicine diagnostics and treatment. It provides a holistic and dynamic analytical framework, helping physicians more accurately comprehend the patient’s physiological condition and devise corresponding treatment plans.

Author Introduction:

Professor Xiaoming Cheng, a Chinese medicine physician at the Institute of Integrative Medicine, Harvard Medical School, Executive Associate Editor of New England Journal of Traditional Chinese Medicine, Visiting Professor of Zhejiang Chinese Medicine University, special expert of Shanghai Fudan Medical College and Huashan Hospital, holographic life system integration expert, has been engaged in Chinese medicine teaching, research and clinical work for 45 years at home and abroad.

He is the author of the English version of Acupuncture and Moxibustion Clinical Desk Reference and the Chinese version of Ten Lectures on TCM Methodology.