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TCM Review 03 Etiology and Pathogenesis of TCM

Chapter 3    Etiology and Pathogenesis of TCM

1.  Etiology: Study of causes of diseases
2.  Pathogenesis: Study of the mechanism of occurrence, development, and change of a disease.

Etiology
1. Concept of pathogenic factors: The factors that break up the state of relative balance in the body and lead to diseases are etiological factors.
2. Various factors that cause disease primarily include:
External factors: six exogenous pathogens, epidemic pathogens
Internal factors: seven emotion, and improper diet, maladjustment of work and rest, and traumatic injury.
3. Six External Pathogens: wind, cold, summer heat, dampness, dryness, and fire.
A.  Under normal circumstance they will not cause disease.
B.  When the climate changes suddenly, violently, or abnormally, disease may occur. Under these conditions, the six environmental factors transform into six external pathogens.
4.  General characteristics of six external pathogens
   A. Attack from outside of the body, through skin, muscles nose, or mouth.
   B. Are related to season, environment.
   C. May attack the human body alone or in combination.
   D. May transform into another pathogen.
5.  Five endogenous pathogens: interior wind, cold, dampness, dryness, heat (fire).

A.  Six exogenous pathogens:
Wind:
1. A Yang pathogen, tends to rise, disperse, and attack at the Yang level.
2. Rapid onset, tends to migrate and change
3. Leads to mobility           
4. Acts as the leading pathogen: other evils invading the body are dependent on wind.
Cold:
1. A Yin pathogen, tends to impair Yang Qi
2. Causes coagulation and obstruction
3. Causes contraction and constriction
Summer Heat:
1. A Yang pathogen, scorching in nature
2. Tends to rise and disperse, can exhaust Qi and body fluid easily
3. It is apt to disturb the mind
4. Usually is accompanied by dampness
A. Summer heat: high ˚F, restlessness, flushed face
B. Dampness: tired limbs, distress, sticky BM
Dampness:
1. It is heavy and turbid in nature
A. Heavy manifestation: heaviness of head and body, and distension and soreness of the trunk and extremities.
B. Turbidity: The secretions and excretions are turbid, e.g., discharge, urine (turbid), BM (mucous), leukorrhea
2. It is viscous and lingering in nature.
A.  The nature of stickiness: e.g., sticky dejecta and secretions, greasy tongue coating, sticky BM and urine
B.  Difficult to cure due to their long course and frequent recurrence, such as conditions as damp blockage (Bi), eczema, damp warm disease. 
3. It tends to go downward
It is a yin pathogenic factor, which often attacks the lower portion of the body.  Clinical manifestations are ulceration and edema of the lower extremities, soreness of muscles, joint pain of the lower limbs, stranguria with turbid urine, diarrhea, dysentery, etc.
4.  A Yin pathogen, tends to impede the flow of Qi and impair Yang Qi and Sp.
Spleen is susceptible to dampness. If spleen yang is checked by pathogenic damp, it will cause a dysfunction of transportation and transformation, and obstruct the functional activity of qi.  The following symptoms will occur: distension and fullness of the epigastric and abdominal regions, anorexia, sweetish taste in the mouth, loose stool, cold extremities, etc.
Dryness:
1.  Tends to impair the body fluid
It leads to dryness of the mouth, lips and nose, dryness of the tongue, dry, rough, and chapped skin, and dry stool.
2.  Tends to impair the lung
The lung is considered a tender organ, which prefers moisture, cleanliness, and descent.  If pathogenic dryness attacks the body from the mouth and nose, the yin fluid of the lung is likely to be consumed.  It may lead to the dysfunction of dispersion and descent, and manifest as dry cough with scanty sputum, sticky mucus causing difficult expectoration, bloody sputum, etc.
Fire
1.  Fire tends to burn and scorch
Clinical manifestations are fever, thirst, profuse sweating, etc.  If pathogenic fire travels inward to attack the mind, it causes irritability, anxiety, insomnia, or even mania, unconsciousness, and delirium in severe cases.
2.  Tends to flare up
Since pathogenic fire is likely to flare upward, the clinical manifestations may be mostly on the head and facial regions, such as swelling and pain of the gums due to extreme stomach fire, ulcers of the tongue and mouth, headache, and redness, pain, and swelling of the eyes.
3.  Tends to impair the body fluid and the Qi
4.  Tends to produce endogenous wind
Symptoms and signs: high fever, convulsion, opisthotonus, tremor, spasm
5.  Tends to accelerate blood circulation and cause bleeding (disseminated intravascular coagulation)
6.  Tends to cause carbuncles and sores
Heat and fire go in blood, stays in local area, burns the tissues, leading to sores, carbuncles, and pus.
7.  Tends to irritate the heart and spirit
Heat and fire correspond to Ht, if heat & fire are in excess, they lead to heat in blood and bleeding due to heat, also causing mania, anxiety, restlessness, delirium.   

Pathogenic Factors Pathogenic Characteristics
     Wind It is of Yang nature; tends to disperse and rise; tends to attack the upper part of the body; tends to migrate and changes; leads mobility; acts as the leading pathogen. 
     Cold It is a Yin pathogen; tends to impair Yang Qi; tends to cause coagulation, obstruction, and constriction.
  Summer-
  heat It is a Yang pathogen and scorching in nature; tends to rise and disperse; is apt to impair body fluid and exhaust Qi; is apt to disturb the mind; is usually accompanied by dampness.
    Dampness It is a Yin pathogen; is heavy and turbid in nature; is viscous and lingering in nature; tends to go downward and attack the Yin part; tends to impede the free flow of Qi and impairs spleen Yang.
    Dryness It is dry and tends to impair body fluid; is apt to attack the lungs.
  Fire and
  Heat They are Yang pathogens; tend to flare up; tend to consume Qi and body fluid; tend to produce endogenous wind, accelerate the blood circulation and cause bleeding; are liable to cause painful swelling of the body; tend to irritate the heart and mind.

B.  Epidemic pathogenic factors
1.  Concept: Epidemic pathogens are pathogens with strong infectivity.  Pestilential evil is a kind of pathogenic factor with intense infectivity.  Attacks of pestilential evils are usually related to unusual climates, such as droughts, floods, extreme heat, as well as pollution and unsanitary conditions. Epidemics occur suddenly with severe symptoms and are highly contagious.
2.  Pathological characteristics
A. Sudden onset
B. Severe condition of illness
C. Similar manifestation (major syndrome is heat)
D. Strong infectivity & strong epidemicity (e.g., typhoid, cholera)
3.  Factors related to outbreak of diseases due to epidemic pathogen
A.  Unusual climate
B.  Water or food contamination
C.  Failure of timely effective prevention and isolation

C.  Seven emotions
1.  Concept of seven emotions refers to seven kinds of emotional reactions, namely: joy, anger, melancholy, sadness, worry, fear, and terror, which are the different responses of human body to environmental stimuli.
2.  Each Zang Fu organ is related to a certain emotion, i.e. Heart—Joy, Liver—Anger, Lung—Sadness/Melancholy, Spleen—Worry, Kidney—Fear/Fright
3.  The pathological characteristics of seven emotions
a.  Directly affecting the internal organs
The following three organs and Qi blood are most likely affected by seven emotions: Heart, Liver, Spleen.
1)  Overthinking & worrying often cause Qi & blood deficiency of Ht and Sp
2)  Suppression & anger often impair Liv: Qi stagnation in Liv  
3)  The factors may transform into fire, lead to deficient Yin, dampness, undigested food, and phlegm.
b.  Causing diseases by disturbing the flow of Qi
1)  Rage causes adverse upward flow of Qi: i.e., red face and eyes, spitting blood, or even coma.
2)  Excessive joy relaxes the heart Qi: i.e., failure of concentrating attention, and in critical cases, mental disarrangement.
3)  Excessive sadness leads to the consumption of Qi: i.e., leads to suppression of the Lung Qi, consumption of Lung Qi.
4)  Fear causes the sinking of Qi: i.e., leads Ki Qi to become unfixed and go downward, which produces urinary and fecal incontinence.
5)  Fright causes derangement of Qi: i.e., leads to mental disarrangement, confusion of thought and reaction to reality.
6)  Worry causes stagnation of Qi: i.e., when one is overly thinking, the Qi will be obstructed, affecting Ht & Sp.
c.  Seven emotions may influence the condition of a disease

Seven
Emotions Impaired
Organs Disorders of Functional
Activity of Qi 
   Pathogenic Mechanism
Joy  Heart     Slowness Heart Qi is relaxed.  Blood circulation is slowed.
Anger  Liver  
   Upward flow The liver does not work well in smoothing and regulating the flow of Qi and blood.  Blood is brought up with the ascending Qi.
Over-
thinking  Spleen     Stagnation Qi is obstructed.  The spleen fails to effectively transform, distribute, and transport nutrients.
Grief  Lung     Consumption Lung Qi is consumed, and one is despondent
  Fear  Kidney      Sinking Kidney Qi is unconsolidated and sinking
 Fright  Kidney     Disturbance The kidney can not store the memory.  The mental activities are attached to nothing.

C. Diet
1.  Abnormal ingestion
A. Excessive hunger
B. Excessive eating
2.  Unsanitary food
3.  Food preference
A.  Preference for cold food—impairs spleen yang.
B.  Preference for hot food—causes heat in the stomach and intestine
C.  Preference for alcohol—causes heat and injures the vessels; leads to the production of damp-heat and phlegm.

D. Improper work and rest
Yellow Emperor’s Internal Classics contains the following summary:
 Excessive use of the eyes injures the blood
 Excessive lying down injures the Qi
 Excessive sitting injures the muscles
 Excessive standing injures the bones
 Excessive walking injures the tendons
1.  Mental overwork will most likely impair heart and spleen.
2.  Physical overwork consumes Qi.
3.  Excessive sexual activity may impair the kidney essence.
4.  Excessive rest:
A.  Impedes the flow of Qi and blood, leading to flaccidity and fragility of the tendons, muscles, and bones
B.  Weakens spleen and stomach function

Pathological Products
1.  Retention of phlegm and fluid
A.  Causes: Six external pathogens, abnormal seven emotions, improper diet, work, or rest →Dysfunction of lung, spleen and kidney→Disordered water metabolism→Retention of body fluid.
B.  The concept of phlegm in TCM:
a. Concrete phlegm/substantial phlegm: Refers to phlegm that has form and is visible, palpable, and audible.
b. Formless phlegm/non-substantial phlegm: Refers to phlegm without form.  It manifests only as the disorder it causes, and the disorder can be relieved or cured by the method of eliminating phlegm.
C.  The pathological characteristics
a.  Tends to obstruct Qi
b.  May cause various disorders
c.  Some diseases caused by phlegm are lingering in course, complicated and difficult to treat.  “Strange disorders are most likely attributed to phlegm.”
   d.  Tongue: Slippery and/or greasy coating.
   e.  Pulse: Slippery or wiry
D.  Classification of phlegm: Heat phlegm, Cold phlegm, Damp phlegm, Dry phlegm, Wind phlegm
2.  Blood stasis
A.  Concept: Blood stasis refers to the pathological state in which blood circulation is slow or blocked, as well as blood outside of the vessels that remains in the body and fails to disperse.
B.  Causes:
a.  Qi deficiency
b.  Qi stagnation
c.  Blood heat
d.  Blood cold
e.  Traumatic injury
C.  Pathological characteristics of blood stasis:
a.  Tends to impede the flow of Qi, blood and body fluid. “The ‘newly’ is hard to generate if the blood stasis is not removed”.
b.  May cause various disorders.
D.  General manifestation related to blood stasis:
a.  Pain
b.  Swelling or mass
c.  Bleeding
d.  Cyanosis
e.  Tongue: Purple tongue or a tongue with purple spots
f.  Pulse: Choppy
3.  Stone
A.  Causes
Improper diet, abnormal emotion→Damp-heat→Stone
B.  Pathological Characteristics
a.  Tends to obstruct Qi
b.  May damage vessels

E. Miscellaneous Pathogens
1.  Trauma: Physical traumas include gunshots, incisions, contusions, sprains, etc. The basic pathogenesis of traumas is stagnation of Qi and blood, which give rise to pain, bruising, and swelling.
2.  Parasites
3.  Poisons
4.  Wrong treatment
Acupuncture
A.  Injure internal organs (Lu 1, St 12, UB 15, Ren 3, UB 22)
B.  Injure central nervous system (Du 15)
C.  Injure big arteries, nerves (Lu 9)
D.  Harm the fetus


Pathogenesis
Concept:
Pathogenesis describes the mechanism of the occurrence, development, and change of a disease.

1.  The Condition of Vital Qi and Pathogenic Factors
A. The condition of vital Qi and evil Qi determines the occurrence of disease.
B.  The condition of vital Qi and evil Qi determines deficiency and excess.
a.  Real excess with false deficient manifestation
E.g.,  Heat accumulated in the stomach and intestines (interior heat)® constipation, abdominal fullness, pain and hard mass in abdomen, doesn’t like to be pressed,  tidal fever,  manic ®Yang Qi is trapped inside the body ®p’t presents pale manifestation, aversion to cold, cold limbs, fatigue , looks like deficient cold symptoms.
b.  Real deficiency with false excess manifestations
E.g., Vital Qi is deficient, insufficient Qi and blood of Zang Fu organ, clinical manifestation is fatigue, poor appetite, since vital Qi is deficient, it causes stagnation-like abdominal distention (not all the time) and pain (likes to be pressed), looks like excess symptoms.
C.  The condition of vital Qi and evil Qi determines the outcome of disease.

2.  Imbalance between Yin and Yang
A.  Excess of Yang leads to heat syndrome
B.  Excess of Yin leads to cold syndrome
C.  Mutual damage (injury) of Yin and Yang: Yin damage involves Yang; Yang damage involves Yin.
D.  Repellence between Yin and Yang
a.  Repellence of Yin is the pathogenesis of real heat syndrome with false cold manifestations (陽盛格陰)
b.  Repellence of Yang is the pathogenesis of real cold syndrome with false heat manifestations (陰盛格陽)
E.  Exhaustion of Yin and Yang

3.  Pathogenesis of Qi, blood, and body fluid
A.  Pathogenesis of abnormality in Qi: Deficiency Qi; Sinking of Qi;
B.  Abnormality in the movement of Qi: Stagnation of Qi; Reversed flow of Qi; Closed Qi; Exhaustion of Qi;
C.  Pathogenesis of blood abnormality: Deficiency of blood; Impairment of blood; Blood heat; Overflow of blood;
D.  Pathogenesis of body fluid abnormality: Body fluid deficiency; Accumulation of fluid.

4.  Five endogenous pathogens refer to endogenous wind, cold, dampness, dryness, and heat.
A.  Internal Movement of wind:
a.  Liver Yang transforming into wind
b.  Extreme heat producing wind
c.  Deficiency Yin stirring up wind
d.  Deficient blood producing wind
e.  Dryness of the blood producing wind

B.  Internal production of cold
C.  Internal production of dampness
D.  Insufficient body fluid transforming into dryness
E.  Internal production of fire and heat