Concepts of diseases.................pptx

concepts of diseases

1. Concepts of diseases DR. MADHU S M

2. Definitions A condition in which body function is impaired, departure from a state of health, an alteration of the human body interrupting the performance of the vital functions. The condition of body or some part of organ of body in which its functions are disrupted or deranged. Disease is considered a social phenomenon, occuring in all societies and defined and fought in terms of the particular cultural forces prevalent in the society. A maladjustment of human organism to the environment

3. Illness : It is a subjective state of the person who feels aware of not being well. Sickness : It is a state of social dysfunction. Disease : It is a physiological/ psychological dysfunction. Carrier : A person with subclinical infectious disease who can transmit the disease to others is called a carrier.

4. Concepts of disease causation

5. Theories of disease causation Old theories (the ayurveda and the chinese medicine ) 2) Germ theory of disease 3) Biomedical model 4) Theory of multifactorial causation 5) Epidemiological triad

6. Till the end of 18 th century, various theories were in vogue. Ex : Supernatal theory of disease ( eg - curse of god ; an evil eye ) The ayurveda considers that the disease is due to imbalance of the ‘ tridosha ’ These are vata (air), pitta (bile) and kapha (mucus). The chinese medicine believes that the disease is caused due to imbalance of male principle(yang) and female principle(yin). Imbalances of male principle(yang) are warm, active, dry, sky and bright; female principle(yin) are cool, rest, moist, earth and dark. Old theories

7. Germ theory of disease is based on the concept that many disease are caused by infections with microorganisms, typically only visualized under high magnification. Such microoragnisms can consists of bacterial, viral, fungal or protist species. 2) Germ theory of disease

8. This model explains the disease as a result of malfunctioning organs or cells. Ex : Diabetes is caused by malfunctioning of pancreas. But the drawback with it is focuses on cause and effect relationships, and ends to ignore the psychological component of the disease. 3) The Biomedical model

9. Now it is recognized that a disease is not caused by an organism but also predisposed by many factors contributing to its occurance , specially ‘Modern Disease’ of civilization like lung cancer, diabetes, coronary heart disease, mental illness etc. These predisposing factors are social, economic, cultural, genetic psychological factors etc. ( including poverty, illiteracy, ignorance and poor living conditions). This theory of multifactorial causation was put forward by Pettenkoffer Munich(1819-1901). This theory deemphasizes the “ Germ theory” (or single cause idea) 4) Theory of multifactorial causation

10. 5) Epidemiological triad Epidemiological Triad Environment Agent Host

11. 6) Web of causation

12. Natural history of disease

13. Natural history of disaese PHASE - 1 Pre- pathogenesis phase PHASE - 2 Pathogenesis phase

14. Prepathogenesis Phase This phase refers to the period before the onset of disease. During this phase, interaction is taking place among the three components of epidemiological triad namely agent, host and environment each… Disease agent has not entered man, but factors favouring disease exist in the environment.

15. PRE-PATHOGENESIS PHASE HOST ENVIRONMENT AGENT Age, sex, race, genetic profile, previous diseases, immune status, religion, customs, occupation, marital status, family backgrounds Temperature, humidity, altitude, Crowding, housing, neighborhood , Water, milk , food, radiation Biologic- bacteria, viruses Chemical-poison, alcohol, smoke Physical- trauma, radiation, fire Nutritional- lack, excess

16. Agent factor A disease ‘agent’ is defined as a substance, living or nonliving or a force, the excessive presence or relative lack of which initiates the disease process. The disease agents are broadly classified into the following groups Physical agents : heat, cold, radiation, noise, atmospheric pressure, humidity etc. Chemical agents : Endogenous: Urea, uric acid, bilirubin , ketones , calcium oxalate etc. Exogenous : Dust, gas, fumes, metals, allergens etc. Biological agents: viruses, rickettsia , bacteria, fungi, protozoa, helminthes etc. Mechanical agents: friction, force, injury, sprain, accidents etc. Nutritional agents: proteins, fats

17. 2) Host factors Age : certain disease is peculiar in certain age groups. Gender : certain disease like lung cancer and coronary heart disease are common among men and rheumatoid arthritis, diabetes and obesity are common among women. Ethnicity : sickle cell anaemia is more frequent among the negroes. Occupation : This not only determines the income but also the health hazards arising out of the occupation. Ex- pneumoconiosis Literacy level : The higher the literacy level, the lower is the incidence of the disease.

18. Income : This is the key factors determining the standard of living and influences the development of the disease. Lower socioeconomic status predisposed for infectious disease and higher status for non communicable disease. Marital status : cancer cervix is common among the married women than the unmarried women. Nutritional status : Poor nutritional status makes a person more vulnerable to infectious disease. Lifestyle factors : Like smoking, alcoholism, drug abuse, lack of exercise, multiple sexual partnership etc favour the development of disease

19. 3 ) Environmental factors These are classified into physical, biological and sociological environment. Physical environment: air, water, soil, food, etc. Biological environment: plants, animals, insects, rodents, microbes, etc. Sociological environment : death, divorce of parents, desertion, loss of employment =, birth of a handicapped child, etc.

20. 2. Pathogenesis phase The pathogenesis phase begins with the entry of the disease ‘agent’ in the susceptible host. The further events in the pathogenesis phase are clear cut in infectious disease, the disease agent multiply and induces tissue and physiological changes, the disease progresses through a period of incubation and later through early and late pathogenesis. The final outcome of disease may be recovery, disability or death. The pathogenesis phase may be modified by intervention measures such as immunization and chemotherapy.

21. Exposure Host Disease recovery Disability Death

22. cont.. The infection may be clinical or sub clinical and when it is subclinical, the person will not have recognizable signs and symptoms nut may spread the disease agent to others, acting as a ‘carrier’ as in typhoid and diphtheria. When the person develops clinical signs and symptoms, he is called a ‘clinical case’.

23. 3) Iceberg phenomenon of disease According to this concept, the disease in the community is compared to an iceberg. When a piece of ice is allowed to float on water, a small portion is visible and a major portion is submerged in the water. The visible tip of ice is compared to clinical cases, which the physician sees in the community.

24. Cont… The major submerged portion of ice corresponds to the hidden mass of unrecognized disease such as latent cases, in apparent, carriers, asymptomatic, and undiagnosed cases in the community, which are all responsible for the constant prevalence of the disease in the community.

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26. Concepts of control

27. Concept of control The term disease control refers ongoing operation aimed at reducing- The incidence of disease The duration of disease and the consequently the risk of transmission The effects of infection including physical and psychological complication. The financial burden to the community.

28. Cont… Disease control includes….. Control : public policy intervention that restricts the circulation of an infectious agent beyond the level that would result from spontaneous, individual behaviours to protect against infection. Elimination: Reduction to zero of the incidence of a specified disease in a defined geographical area as a result of deliberate efforts. Eradication : termination of all transmission of infections by extermination of infectious agents. Extinction : The specific infectious agent no longer exists in nature or in the laboratory

29. Disease monitoring: Defined as “the performance and analysis of routine measurement aimed at detecting changes in the environment or health status of population.” Ex: growth monitoring of child, monitoring of air pollution, monitoring of water quality etc. Disease surveillance: Defined as “ the continuous scrutiny of the factors that determine the occurrence and distribution of disease and other conditions of ill health”. Ex: poliomyelitis surveillance programme of WHO.

30. What’s the difference??? Monitoring - Requires careful planning, use of standardized procedures and methods of data collection and can then be carried over extended period of time by technicians and automated instrumentation. Surveillance -Requires professional analysis, sophisticated judgement of data leading to recommendation for control activities.

31. Concepts of prevention

32. Concepts of prevention The goal of medicine are to Promote health To preserve health To restore health when it is impaired And to minimize suffering and distress. These goals are embodied in the word “ prevention ”

33. Cont.. Actions aimed at eradicating, eliminating or minimizing the impact of disease and disability, or if none of these are feasible, retarding the progress of the disease and disability. The concept of prevention is best defined in the context of levels, traditionally called primordial, primary, secondary and tertiary prevention. A fourth level, called primordial prevention, was later added.

34. Leavell’s levels of prevention Stage of disease Level of prevention Type of response Pre - disease Primary prevention Health promotion and specific protection Latent disease Secondary prevention Pre-symptomatic diagnosis and treatment Symptomatic disease Tertiary prevention Disability limitation for early symptomatic disease Rehabilitation for late symptomatic disease

35. Primordial prevention Definition: “ it is the prevention of the emergence or development of risk factors in countries or population groups in which they have not yet appeared. Intervention: The main intervention is primordial prevention is through individual and mass health education. 2 approaches (WHO) – 1) Mass strategy – Directed towards socioeconomic, behavioural and lifestyle changes. 2) High risk strategy- Aims to bring preventive care to individual at special risk.

36. Primary prevention Primary prevention can be defined as the action taken prior to the onset of disease, which removes the possibility that the disease will ever occur. Signifies intervention in the pre-pathogenesis phase of disease or health problem. Relies on measures designed to promote health or to protect against specific disease agents or hazards. Applied to prevention of chronic diseases like CHD, HT, cancer based on elimination or modification of risk factors of disease.

37. Secondary prevention Action which halts the progress pf the at its incipient stage and prevents complications. Early diagnosis and treatment- arrest the disease process and protect others in the community from acquiring the disease. Health programs initiated by government are usually at this level.

38. Tertiary prevention Signifies intervention at late pathogenesis stage. All measures available to reduce or limit impairment and disabilities, minimise suffering caused by existing departure from good health and to promote patient adjustment to irremediable conditions. Through disability limitation and rehabilitation.

39. Modes of Intervention

40. Modes of Intervention Intervention is any attempt to intervene or interrupt the usual sequence in the development of disease. Five modes of intervention corresponding to the natural history of any disease are : Health promotion Specific protection Early diagnosis and adequate treatment Disability limitation Rehabilitation

41. Health promotion It is the process of enabling people to increase control over disease, and to improve their health. It is not directed against any particular disease but is intended to strengthen the host through a variety of approaches(interventions): Health education Environmental modification Nutritional Intervention Lifestyle and behavioural changes

42. Specific protection Currently available interventions Immunization Use of specific nutrients Chemoprophylaxis Protection against occupational hazards Protection against accidents Protection from carcinogens Avoidance of allergens

43. Early diagnosis and treatment WHO defined early detection of health impairment as “the detection of disturbances of homeostatic and compensatory mechanism while biochemical, morphological and functional changes are still reversible.” Ex : essential hypertension, cancer cervix and breast cancer

44. Disability limitation Objective – Is to prevent or halt the transition of the disease process from impairment to handicap. Sequence of events leading to disability amd handicap:

45. WHO defined these terms – Impairment: Loss or abnormality of psychological, physiological/anatomical structure or function. Disability: Any restriction or lack of ability to perform an activity in a manner considered normal for one’s age ,sex, etc. Handicap: Any disadvantage that prevents one from fulfilling his role considered normal.

46. Rehabilitation “Combined and coordinated use of medical, social, educational and vocational measures for training and retraining the individual to the highest possible level of functional ability”. Areas of concern in rehabilitation : medical, vocational, social, psychological.

47. Changing patterns of disease Although diseases have not changed significantly through human history, their patterns have. Every decade produces its own patterns of disease. Developing countries : Increased chronic disease Increased infections

48. Disease classification A system of classification was needed whereby diseases could be grouped according to certain common characteristics, that would facilitate the statistical study of disease phenomena. International classification of disease (ICD) by WHO- accepted for national and international use. Revised once in 10 years.

49. ICD-10 arranged in 21 different chapters Major categories of the international classification of diseases and related health problems(10 th Revision) Certain infectious and parasitic diseases Neoplasms Diseases of the blood Endocrine, nutritional and metabolic disorders Mental and behavioural disorders Diseases of the nervous system Diseases of the eye and adnexa Diseases of the ear and mastoid process Diseases of the circulatory system Diseases of the respiratory system Diseases of the digestive system Diseases of the skin and subcutaneous tissue

50. Conclusion Understanding disease pathology is the first step towards formulating preventive measures. As a physiotherapist or public health worker it is our primary responsibility for the prevention of diseases in community as well as individual.

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