CONCEPT OF DISEASECONCEPT OF DISEASE

DiseaseDisease is a physiological/psychological is a physiological/psychological dysfunction. It is departure from the dysfunction. It is departure from the

state of health.state of health.

IllnessIllness is a subjective state of the person is a subjective state of the person who feels aware of not being wellwho feels aware of not being well

SicknessSickness is a state of social dysfunction, is a state of social dysfunction, i.e., a role that the individual assumes i.e., a role that the individual assumes when ill when ill (“sickness role”).(“sickness role”).

CONCEPT OF CAUSATIONCONCEPT OF CAUSATION

Disease results from a complex interaction between Disease results from a complex interaction between man, an agent (or cause of disease) and the man, an agent (or cause of disease) and the environment, (Epidemiological triad)environment, (Epidemiological triad)

Germ theory of diseaseGerm theory of disease

Disease agent → Man → DiseaseDisease agent → Man → Disease

Multifactorial causationMultifactorial causation

The multifactorial concept offers multiple approaches The multifactorial concept offers multiple approaches for the prevention/control of disease.for the prevention/control of disease.

Web of causationWeb of causation

The “web of causation” considers all the predisposing The “web of causation” considers all the predisposing factors of any type and their complex interrelationship factors of any type and their complex interrelationship with each other. with each other.

NATURAL HISTROY OF DISEASENATURAL HISTROY OF DISEASE

The natural history of The natural history of disease disease is consisting is consisting of two of two phases: phases:

Prepathogenesis (i.e., the Prepathogenesis (i.e., the process in the process in the environment) environment)

Pathogenesis (i.e., the Pathogenesis (i.e., the process in man).process in man).

Agent factorsAgent factors The disease “agent” is defined as a The disease “agent” is defined as a

substance, living or non-living, or a force substance, living or non-living, or a force tangible or intangible, the excessive tangible or intangible, the excessive presence or relative lack of which may presence or relative lack of which may initiate or perpetuate a disease process.initiate or perpetuate a disease process.

A disease may have a single agent, a number A disease may have a single agent, a number of independent alternative agents or a of independent alternative agents or a complex of two or more factors whose complex of two or more factors whose combined presence is essential for the combined presence is essential for the development of the disease.development of the disease.

Types of Causative AgentsTypes of Causative Agents

Biological agentsBiological agentsNutrient agentsNutrient agentsPhysical agentsPhysical agentsChemical agentsChemical agentsMechanical agentsMechanical agentsAbsence or insufficiency of excess of a Absence or insufficiency of excess of a

factor necessary to healthfactor necessary to healthSocial agentsSocial agents

Host factorsHost factorsThe host factors may be classified as The host factors may be classified as Demographic characteristics such as age, sexDemographic characteristics such as age, sexethnicity;ethnicity;

(ii) Biological characteristics such as genetic factors; (ii) Biological characteristics such as genetic factors; (iii) Social and economic characteristics such as socio-(iii) Social and economic characteristics such as socio-

economic status, education, occupation, stress, economic status, education, occupation, stress, marital status, housing, etc. andmarital status, housing, etc. and

(iv) Lifestyle factors such as personality traits, living (iv) Lifestyle factors such as personality traits, living habits, nutrition, physical exercise, use of alcohol, habits, nutrition, physical exercise, use of alcohol, drugs and smoking.drugs and smoking.

Behavioural patterns, etc. The association of a Behavioural patterns, etc. The association of a particular disease with a specific set of host factors particular disease with a specific set of host factors frequently provides an insight into the cause of frequently provides an insight into the cause of disease.disease.

Environmental factorsEnvironmental factors

The study of disease is really the The study of disease is really the study of man and his environment. study of man and his environment. the environment of man has been the environment of man has been divided into three components-divided into three components-

Physical,Physical, Biological Biological

Psychosocial.Psychosocial. It should be emphasized that this It should be emphasized that this

separation is artificial. They are separation is artificial. They are closely related to each other and closely related to each other and

with host factors.with host factors.

Risk factorsRisk factorsThe term "risk factor" is used by different authors with at The term "risk factor" is used by different authors with at least 2 meanings.least 2 meanings.

An attribute or exposure that is significantly associated An attribute or exposure that is significantly associated with the development of a diseasewith the development of a disease

A determinant that can be modified by intervention, A determinant that can be modified by intervention, thereby reducing the possibility of occurrence of thereby reducing the possibility of occurrence of disease or other specified outcomes.disease or other specified outcomes.

Some risk factors can be modified; others cannot be Some risk factors can be modified; others cannot be modified. The modifiable factors include smoking, modified. The modifiable factors include smoking, hypertension, elevated serum cholesterol, physical hypertension, elevated serum cholesterol, physical activity, obesity, etc. They are amenable to intervention activity, obesity, etc. They are amenable to intervention and are useful in the care of the individual. The and are useful in the care of the individual. The unmodifiable or immutable.unmodifiable or immutable.

Risk factors such as age, sex, race, family history and Risk factors such as age, sex, race, family history and genetic factors are not subject to change.genetic factors are not subject to change.

Risk groupsRisk groups

Something for all, but more for Something for all, but more for those in need - in proportion to the those in need - in proportion to the

need" Therefore it is stated that need" Therefore it is stated that risk factor is a proxy for need'- risk factor is a proxy for need'-

indicating the need for promotive indicating the need for promotive and preventive health services.and preventive health services.

Spectrum of diseaseSpectrum of diseaseAt one end of the disease spectrum are At one end of the disease spectrum are

subclinical infections which are not subclinical infections which are not ordinarily identified and at the other end ordinarily identified and at the other end are fatal illnesses.are fatal illnesses.

The sequence of events in the spectrum of The sequence of events in the spectrum of disease can be interrupted by early disease can be interrupted by early diagnosis and treatment or by preventive diagnosis and treatment or by preventive measures.measures.

Iceberg of diseaseIceberg of disease

According to this concept, disease in a According to this concept, disease in a community may be compared with an community may be compared with an iceberg. The floating tip of the iceberg iceberg. The floating tip of the iceberg

represents what the physician sees in the represents what the physician sees in the community, i.e., clinical cases. The vast community, i.e., clinical cases. The vast

submerged portion of the iceberg represents submerged portion of the iceberg represents the hidden mass of disease, i.e., latent, the hidden mass of disease, i.e., latent,

inapparent, presymptomatic and inapparent, presymptomatic and undiagnosed cases and carriers in the undiagnosed cases and carriers in the

community. The "waterline" represents the community. The "waterline" represents the demarcation between apparent and demarcation between apparent and

inapparent disease. inapparent disease.

Prevalence of risk factors in patients admitted in Cardiology wardPrevalence of risk factors in patients admitted in Cardiology wardPersonal profilePersonal profile

Reg. No.______________Date of Admission _______ Diagnosis__________________Reg. No.______________Date of Admission _______ Diagnosis__________________Name:_____________________Age:_____ Sex ______Education_________________Name:_____________________Age:_____ Sex ______Education_________________Occupation:___________Income per month_________No. of Children: ____M___F___Occupation:___________Income per month_________No. of Children: ____M___F___Address:_______________________________________________________________Address:_______________________________________________________________Number of Rooms:______ Residence: Urban / Rural ____ Type of Family___________Number of Rooms:______ Residence: Urban / Rural ____ Type of Family___________B.P _______Pulse_____Temp_________Weight____________Height_____________B.P _______Pulse_____Temp_________Weight____________Height_____________ Smoker _Yes / No Form of smoking(cigarettes,huqqa, naswar)any other_____Smoker _Yes / No Form of smoking(cigarettes,huqqa, naswar)any other_____ Regular / Occasional smoker _______Number of cigarettes _________________Regular / Occasional smoker _______Number of cigarettes _________________ Duration of smoking _____________Why start smoking ___________________Duration of smoking _____________Why start smoking ___________________ Did you try to quit smoking Yes / No. Did you try to quit smoking Yes / No. Why ________________________ Why ________________________ Any other addiction ______________Duration ___________________________Any other addiction ______________Duration ___________________________ Any physical activity ______(inactive, walking 30 minutes in a day Heavy work)Any physical activity ______(inactive, walking 30 minutes in a day Heavy work) Type of diet mostly used (vegetable,meat,fish,rice, broast, etc) weekly/daily_____Type of diet mostly used (vegetable,meat,fish,rice, broast, etc) weekly/daily_____ Use of Milk Use of Milk frequency ______ Use of Butter, ghee, Oil___________________frequency ______ Use of Butter, ghee, Oil___________________

Use of Tea Use of Tea frequency___________ Soft drink _________________________frequency___________ Soft drink _________________________ Frequency of meal :Frequency of meal : Twice / Thrice a day ______________________________Twice / Thrice a day ______________________________

Past History of Illness:Past History of Illness: Type of disease, Heart, Hypertension, Diabetes, Obesity, Type of disease, Heart, Hypertension, Diabetes, Obesity, Addiction, Addiction, any other: ___________________________________________________________any other: ___________________________________________________________

Family History:Family History: Type of disease ___________________ To whom _____________ Type of disease ___________________ To whom _____________Uncertain death ________________________________ any other detail _________Uncertain death ________________________________ any other detail _________Treatment History:Treatment History: No. of times admitted in hospital __________ for disease_____ No. of times admitted in hospital __________ for disease_____Which associated symptoms developed and at what age______________________Which associated symptoms developed and at what age______________________Knowledge about the Disease:Knowledge about the Disease: Do you know about what causes heart attack_____ Do you know about what causes heart attack_____What are the risk factors ____________How can be prevented from heart attack ___What are the risk factors ____________How can be prevented from heart attack ___Do you get better after treatment taken before ______________________________Do you get better after treatment taken before ______________________________What preventive care you have adopted after treatment _______________________What preventive care you have adopted after treatment _______________________What prevention you will adopt after discharge ______________________________What prevention you will adopt after discharge ______________________________Follow up :Follow up : Following the instructions of physician Yes / No. Reduce salt intake Following the instructions of physician Yes / No. Reduce salt intake Yes/NoYes/No

Reduce fat intake Reduce fat intake Yes / No. Yes / No. Reduce sugar intake Reduce sugar intake Yes Yes NoNo

Regular physical activity Yes /No . Regular physical activity Yes /No . Regular treatment intake Regular treatment intake Yes/NoYes/No