Pathogenesis

Lecturer: QU Hongyan

Pathogenesis refers to the mechanism of the occurrence, development, and changes of

disease. The theory of pathogenesis is the theory to

study the occurrence, development and changes of disease, and to discuss the basic pathogenesis and transmission.

Basic pathogenesis

It probes the basic laws of the occurrence, development, and changes of disease integratedly, can be generalized into the following five aspects

Disharmonyof qi and blood

Yin yang disharmony

preponderanceand decline of pathogenic

or healthy qi

Metabolic disordersof body fluids

Five endogenouspathogenic factors

Preponderance and decline of pathogenic or healthy qi

preponderanceand decline of

pathogenic or healthy qi

Onset ofdisease

Deficient andexcessive changes

of disease

Developmentof disease

Diseaseoutcome

Pathogenesis of deficiency and excess

ExcessCharacteristics: preponderance

of pathogenic qi Manifestations: a series of exces

sive symptomsIt usually occurs at the early or mi

ddle stage of exogenous or endogenous diseases with a short course

DeficiencyCharacteristics: insufficiency of healthy qi Manifestations: a series of deficient symptoms It is commonly seen at the advanced stage of exogenous diseases or various chronic diseases with a long course

Deficiency-excess in complexity

It refers to a pathological condition in which the struggle between healthy and pathogenic qi leads to the coexistence of exuberant pathogenic qi and declined healthy qi in the process of a disease.

Deficiency complicated by excess

Excess complicated by deficiency

Deficiency complicated by excess

Excess complicated by deficiency

Predominance of insufficient healthy qi is complicated by excess

of pathogenic qi

Predominance of excesspathogenic qi is complicated by

insufficient healthy qi

Conversion between deficiency and excess

It refers to the pathological conversion between

deficiency and excess, which is the result of impairment of

healthy qi due to retention of pathogens, or accumulation of

excessive pathogens resulting from insufficient healthy qi in

the development of a disease.

Conversion of excess into deficiency

Excess resulted from deficiency

1 ． Conversion of excess into deficiency

Excesssyndrome

Delayed or improper treatment

Healthy qi is injured by exuberant pathogenic qi

Pathogenic qi was removed and healthy qi was weakness

Zang-fu organs were injured

Deficient syndrome

Excess complicated by deficiency

Deficiency complicatedby excess

2 ． Excess resulted from deficiency

Deficientsyndrome

The healthy qi is originallydeficient and can noteliminate pathogenic qi

Deficient healthy qi leads to accumulation of excessive pathogens such as stagnant blood, phlegm-fluid, etc.

True or false excess and deficiency

1 ． True deficiency with false excess

Deficientsyndrome

Deficientsyndrome

Nature of disease

False clinical manifestation

2 ． True excess with false deficiency

Excesssyndrome

excesssyndrome

Nature of disease

False clinical manifestation

True or false excess and deficiency

Sequelae of disease and preponderance a

nd decline of pathogenic or healthy qi

Domination of healthy qi with decline of pathogenic qi

Withdrawal of pathogenic qi with decline of healthy qi

Insufficient healthy qi with pathogenic qi lingering

Domination of pathogenic qi with decline of healthy qi

Healthy qi and pathogenic qi being locked in a stalemate

Yin-yang disharmony

——changes of cold and heat

1

Mutual impairment of yin and yang

Mutual rejection of yin and yang

5 Exhaustion of yin or yang

4

3

2 Decline of yin or yang

Preponderance of yin or yang

Preponderance of yin or yang, a morbid state marked by abs

olute excess of yin or yang aspect, refers to excess syndrom

e that "exuberance of pathogens leading to excess".

Preponderance of yang is usually characterized by heat s

ymptoms while preponderance of yin by cold symptoms.

Preponderance of yin or yang

Yangpathogens

Yinqi

Preponderanceof yang

Excessiveheat

syndrome

Yang in excessleads to

weaknessof yin

Yinpathogens Preponderance

of yin

Excessivecold

syndrome

Yin in excessleads to

weaknessof yang

Yangqi

EquilibriumExcessive yang causes heat

（ 1 ） Preponderance of yang

A pathological state characterized by exuberance of yang with functional hyperactivities, increased metabolic action, and enhanced bodily reactivity .

It is usually due to invasion of exogenous warm pathogen of yang nature, interior transformation of heat from exogenous cold pathogen of yin nature, or transformation of five emotions into fire, or transformation of heat from qi stagnation, stagnant blood, or dyspepsia.

In pathogenesis, it is of excess heat syndrome marked by excess of yang without apparent yin deficiency

Yang

Yin

Yang w

axes

Yin w

anes

EquilibriumExuberant yin causes cold

(2) Preponderance of yin

It refers to a morbid state characterized by exuberance of yin, suppressed or declined bodily function, insufficient production of heat, and accumulation of pathological products.

Reasons : invasion of pathogenic cold or dampness of yin nature, excessive intake of uncooked and cold food that lead to cold stagnation in middle energizer and interior exuberance of yin cold

In pathogenesis, it is of excess cold syndrome marked by excess of yin without apparent yang deficiency. yang

Yin

Yin w

axesYan

g

wan

es

（ 1 ） Decline of yang

It refers to a morbid state characterized by insufficient yang qi, decreased bodily function and reaction as well as inadequate production of heat energy.

It usually results from congenital deficiency, postnatal malnutrition,overstrain, or impairment of yang qi due to prolonged disease.

The pathogenesis of decline of yang is usually characteristic ofdeficiency-cold syndrome in which the impaired yang qi fails to restrict yin, leading to the relative excess of yin.

EquilibriumYang deficiency leads to cold

Yan

g

wan

es

yang

Yin

Yin w

axes

Insufficient yang qi mainly involves the spleen and kidney

（ 2 ） Decline of yin

It refers to a pathological state in which yin qi is insufficient and fails to restrict yang, resulting in relative excess of yang and asthenic bodily hyperfunction.

It usually results from exuberant heat scorching body fluids in febrile disease, ortransformation of five emotions into fire impairing yin, or prolonged disease consuming yin fluid.

decline of yin is characteristic of deficient heat syndrome in which insufficient body fluids and decreased function of nourishing and quietening result in relative excess of yang

EquilibriumYin deficiency leads to heat

Yin deficiency may occurin all five viscera, but mainly involves the lung, liver and the kidney

yang

Yin

Yang w

axes Yin

wanes

Mutual impairment of yin and yang

Yin impairment involving yang a morbid condition in which consumption of yin essence affects yang qi and causes inadequate production or exhaustion of yang qi

Yang impairment involving yin refers to a morbid condition in which consumption of yang qi involves yin essence and causes inadequate production of yin essence, consequently bringing on deficiency syndrome of both yin and yang with a predominance of yang deficiency

Solitary yang cannot exist and solitary yin canno

t grow

Repelling of yin and yang

It refers to such a pathological change that either yin or yang is of extreme excess inside and rejects its opposite aspect outside.

It results from the breakdown of the interdependence of yin and yang due to various factors, bringing on complicated pathological phenomena such as true cold with false heat and true heat with false cold.

preponderant yin repelling yang preponderant yang repelling yin

Repelling of yin and yang

Flushed cheeks, dysphoria and fever, large pulse without root

1. Preponderant yin repelling yang

pale complexion, coldextremities, listlessness, intolerance of cold and lying with the knees crouched

true cold

Yang is extremely weaknessYin cold is excessivenature

False phenomena

False heat

Yin is extremely

excessive inside

Force yang to

float outside

Repelling of yin and yang

Cold extremities but not relieved by clothes and quilts

2. Preponderant yang repelling yin

high fever, red complexion, hoarse breath, dysphoria, red tongue, rapid, large and forceful pulse

true heat

Extreme yang heatstagnates insidenature

False phenomena

False cold

Extremely heat

inside

Stagnates yang qi and prevents It from reachingthe limbs

Exhaustion of yin or yang

It is a critical state of collapse due to massive loss of

yang qi in a short time or sudden and severe visceral failure.

Reasons massive loss of yang qi due to the failure of healthy

qi to fight against exuberant pathogenic qi, or induced by

frequent deficiency of yang qi, insufficient healthy qi as well as

overstrain; or by profuse sweating, excessive vomiting and

diarrhea, or by chronic consumptive disease,

Clinical manifestations dripping with sweat, thin and cold

sweat, cold extremities, listlessness, indifferent complexion, or

even coma and faint pulse, etc..

Exhaustion of yin or yang

Yindeficiency Yang

deficiency

Yin

exhaustion

Yin

exhaustion

Results ： exhaustion of yin or yang one’s life in dangerous

Pathogenesis of yin-yang disharmony

Early stage Development Prognosis

Yang in excess leads to weakness of yin

Yin in excess leads to weakness of yang

Preponderance yin repelling yang

Preponderance yang repelling yin

Preponderant yangtransform yin

Preponderant yintransform yang

Yin impairmentInvolving yang

Yang impairmentInvolving yin

Yang exhaustion

Yin exhaustion

Yin-yang in balance

Preponderanceof yin or

yang

Decline of yin

or yang

Disharmony of qi and blood

Disorders of qi

Qi deficiency

Disorders of qi movement

Fails to ascend

and descend

Reversed flow of qi

Qi sinking

Fails to exit and enter the body

Qi blockage

Qi prostration

Unsmooth flow Qi stagnation

Qi deficiency

Qi deficiency refers to a morbid state in which qi of the whole body is inadequate in quantity and declined in function.

It is caused by inadequate production of qi due to congenital deficiency, postnatal malnutrition, hypo-function of the lung, spleen and kidney, or by excessive consumption of qi due to overstrain, severe or prolonged illness.

Its common clinical manifestations are fatigue, dispiritedness, spontaneous sweating, susceptibility to cold, dizziness and tinnitus, weak or faint and thin pulse, etc..

It refers to a morbid state characterized by unsmooth flow and obstruction of qi inside the body.

It results from emotional depression, or the blockage of phlegm, dampness, indigestion and stagnant blood. Since the liver qi and spleen qi tend to ascend and the lung qi and stomach qi function to descend, they are of great importance in regulating qi movement. Therefore qi stagnation usually involves the lung, liver, spleen and stomach.

Distension, fullness and pain in local regions are their common symptoms.

Qi stagnation

Disorders of qi movement

It is a morbid state in which the excessive upward flow of qi or failure of qi to descend leads to the upward adverse flow of visceral qi

It usually results from emotional disorders, improper cold or warm diet, or stagnation of phlegm-turbidity.

Such condition commonly occurs in the disorders of the lung, stomach, and liver.

For example, the adverse rising of lung qi leads to cough with dyspnea; the adverse rising of stomach qi causes symptoms of nausea, vomiting or hiccup and belching; the adverse rising of liver qi brings about distending pain of head, red eyes and complexion, susceptibility to anger, etc..

Reversed flow of qi

Disorders of qi movement

It refers to a morbid state in which the failure of qi to ascend or excessive descent of qi leads to the decline of qi in its lifting or holding function.

Generally, qi sinking develops gradually from qi deficiency and especially has the closest relationship to spleen qi.

If spleen qi fails in sending up the clear to nourish the head and eyes, it will lead to dizziness, tinnitus, lassitude, pale and lusterless complexion. If it fails to rise up, it may cause prolapse of internal viscera, such as gastroptosis, nephroptosis, hysteroptosis and proctoptosis, etc..

Qi sinking

Disorders of qi movement

It refers to a morbid state marked by interference of qi in exiting due to sudden blockage of qi movement, usually manifested as syncope.

It usually results from emotional depressions, obstruction of exogenous pathogens and phlegm-turbidity

The commonly seen manifestations are sudden syncope, unconsciousness, or accompanied by coldness or convulsion of the four limbs.

Qi blockage

Disorders of qi movement

It refers to a critical state characterized by extravasation of qi due to the failure of qi to stay internally.

It is usually caused by the failure of healthy qi to ward off pathogenic qi, or by prolonged consumption of healthy qi due to chronic disease, or by exhaustion of qi resulting from massive bleeding, profuse sweating, frequent vomiting and diarrhea

The commonly seen manifestation are pale complexion, endless sweating, closed eyes with mouth open, general flaccidity, urinary and fecal incontinence, faint pulse, etc.

Qi prostration

Disorders of qi movement

Disorders of blood

Disorder of blood

Blood deficiency

Hemorrhage

Blood cold

Blood stasis

Blood heat

Blood deficiency

It refers to a morbid state characterized by insufficiency of blood

and its declined nourishing function.

Reasons inadequate production of blood because spleen and

stomach are too weak to receive, transport and take enough food,

or from heavy bleeding, or from consumption of blood due to

prolonged illness or excessive anxiety

Clinical manifestations pale or sallow complexion, light-

colored tongue, lip and nails, listlessness and lack of strength,

vertigo, tinnitus, dry eyes, blurred vision, numbness of hands and

feet, thin pulse, etc.

Disorders blood

difference

Yang deficiencyQi deficiency

The former is a deficient syndrome but without apparent cold symptoms

Blood deficiency Yin deficiency

difference The former is a deficient syndrome but without apparent heat symptoms

Blood stasis

It refers to a morbid state marked by slow and unsmooth

blood circulation.

Reasons qi stagnation, blood cold, blood heat, obstructi

on of phlegm-turbidity, traumatic injuries, etc.

Clinical manifestations pain of fixed location or with the formation of swelling, accompanied by dark complexion, scaly skin, cyanotic lips and nails, purplish tongue or with petechiae, ecchymosis, etc.

Disorders blood

Hemorrhage

It denotes the excessive discharge of blood from blood ve

ssels.

Reasons failure of deficient qi to control blood, failure of

liver to store blood, exuberance of pathogenic heat, traumatic

injuries.

Clinical manifestations a various symptoms of bleeding such as hemoptysis, hematemesis, epistaxis, hematuria and hematochezia, etc.

Disorders blood

Blood heat

It refers to a pathological change characterized by acceler

ated or abnormal blood flow resulting from heat in the blood phase.

Reasons invasion of exuberant heat pathogen into the blood phase, five emotions in excess may change into fire

Clinical manifestations red complexion and eyes, fever aggravated at night, dry mouth with no desire for drink, dysphoria, mania, delirium, or even coma, bleeding, hematemesis, hematuria, shortened menstrual cycle and excessive menstruation, deep red tongue and rapid pulse, etc.

Disorders blood

Blood cold

It refers to a pathological change marked by unsmooth

blood circulation due to cold affecting the blood vessels

Reasons the invasion of pathogenic cold into the blood

phase, failure of yang qi to warm

Clinical manifestations symptoms of yin cold, pain,

cyanosis of hand, feet, nails and skin, purplish tongue.

Disorders blood

deficiency ofboth qi and

blood

Qi deficiencyand blood

stasis

failure of qito control

blood

collapse of qi due to

hemorrhage

Qi stagnationand blood

stasis

Dish

armo

ny b

etween

qi an

d b

loo

d

Disharmony between qi and blood

Qi stagnation and blood stasis

It refers to a pathological state in which unsmooth and depressed flow of qi makes the blood flow sluggish.

Emotionaldepression

Qi stagnationQi can not

promote theblood flow

Fullness and pain in thechest and hypochondrium,

petechia, ecchymosis,abnormal mass

Disharmony between qi and blood

Qi deficiency and blood stasis

It refers to a pathological state in which insufficient qi fails to promote blood flow and results in the disturbance of blood flow.

Longstanding illness, visceral weakness

in the aged

Qi is insufficientand fails to

circulate blood

Asthenic breathing, lack of Strength palpitations, chest

pain, purplish tongue

Disharmony between qi and blood

The failure of qi to control blood

It refers to a pathological state in which insufficient qi fails to keep blood flow inside the vessels, consequently resulting in various symptoms.

Prolonged illness

Impair thespleen qi

Spleen fails tocontrol blood

Hematochezia, hematuria, metrorrhagia, ecchymosis,and subcutaneous bleeding

Collapse of qi due to hemorrhage

It refers to a critical pathological condition of sudden and

massive exhaustion of yang qi caused by heavy bleeding.

Reasons severe traumatic bleeding, metrorrhagia and postpartum hemmorrhage.

Clinical manifestations cold and endless sweating, cold extremities, syncope and hollow pulse, etc..

Disharmony between qi and blood

Disharmony between qi and blood

Deficiency of blood and qi

It refers to a pathological condition characteristic of deficiency of both qi and blood

Prolonged illness

Insufficient qi

Over-consumeqi and blood

Depletion of qiLoss of blood

Inadequate production of

blood

Pale or sallow complexionasthenic breathing, reluctance

to speak, lassitude,lack of strength,etc