Family Medicine & Community Health 2 Preventive Medicine Gloria Peret-Clarion, MD, DFM, FPAFP | 18 August 2018 | Topic 3 Outline I. Health A. Levels of Health II. Disease as a process A. Factors in disease causation III. Natural History of disease and levels of prevention A. Two Phases B. Pathogenesis C. Six requirements D. Incubation period E. Clinical Horizon F. Outcomes of the disease G. Levels of Disease Prevention I. HEALTH - State of complete physical, mental, and social well being Not merely absent of disease (World Health Organization) - A. LEVELS OF HEALTH Excellent Fairly well Feeling under par Definitely sick or ill II. DISEASE AS A PROCESS 1. 2. 3. - disease results from an imbalance between disease agents and man nature and extent of the imbalance depends on the nature and characteristics of the host and agent the characteristic of agent and a host with their interaction in directly related to and depends largely on the nature of the environment A. FACTORS IN DISEASE CAUSATION agent host environment 1. AGENT CAUSATIVE FACTORS - An element, substance or force, animate or inanimate that serves stimulus to initiate or perpetuate in a disease process Different agent Biologic agents Nutrient agents Chemical agents Physical agents Mechanical agents - Carbohydrates Fat Protein Vitamins (fat soluble ADEK, excess may be toxic in the body) Mineral Water Chemical agents Endogenous – This is produced by the human (hypercholesterolemia, Hearth problem, abnormalities in metabolism Exogenous – outside of the host (eg. Inhalation of the pollutants, Lead poisoning) Physical agent Atmospheric pressure Temperature – Miliaria Rubra (Bungang araw), Redness of skin fold, heath stroke Humidity Sound – High decibel machines, may end up with hearing problem) Radiation o Non ionizing radiation § Infrared Radiation • Thermal damage to the cornea, iris, or lens (cataract formation) § Ultraviolet Radiation • Eye injury and skin damage (accelerated aging o Ionizing Radiation § X-rays § Gamma Rays • Acute radiation Syndrome, Radiodermatitis, teratogenic, premature aging, carcinoma Cold – trechfoot, frostbite Mechanical Agent Chronic Friction – eg. Vibrating tools (Jackhammer) Vasospasm of fingers will lead to carpal tunnel syndrome Mechanical Forces – Vehicular accidents, whiplash injury Characteristic if agent of disease 1. Inherent characteristic • Physical • Biologic • Chemical • Viability and resistance Categorized into Anthropoids Helminthes Protozoa Fungi Bacteria Rickettsia Viruses Transcribed by: Nutrient - 2. Marmar, Tabjan, Velasco Characteristic directly related to man a. infectivity ability to gain access and adapt to human host b. pathogenicity a measure of the ability of an agent when lodged on the body to set up a specific reaction c. Virulence Page 1 of 4 FMC201 Preventive Medicine d. 3. a. A measure of the severity of the reactions b. Measured in terms of fatality Antigenicity a. Ability to stimulate the host to produce defense mechanism Characteristic relation to the environment Reservoir - Man, animals, plants, soils or inanimate organic matter in which an infections agents alive and multiplies and depends primarily for survival - A thing, person, object or substance, from which an infectious agent passes immediately to the host May be a vehicle, vector, intermediate host or contaminated article Source - Mode of transmission Mechanism in which an infectious agent is transported from reservoir to a susceptible human host Types: - T3 - Elements: o Physical o Biological o Social and economic Interaction if the Agent, Host and environment 1 Agent – environment interaction a. Condition in which agent is a directly affected by the environment 2 Host- environment interaction a. Conditions under which the host is directly affected by the environment b. Regardless of the agents 3 Human Host – Agent Interaction a. Conditions under which agent lodges in the host, increases in the quantity and possibly stimulates the host 4 Agent – host – environment interaction a. Condition under which agent, host and environment affect each other to initiate or perpetuate a disease process III. NATURAL HISTORY OF DISEASE AND LEVELS OF PREVENTION Importance of knowing the natural history of disease Prevention Diagnosis Prognosis Treatment Contact Vehicle Vector Air-borne Portal of exit Respiratory tract, GIT, GUT, open lesion Mechanical – insert sucking, blood transfusion 2. HOST - The individual exposed to the disease Characteristics: Age, sex and racial characteristics Habits and customs Marital factors Occupational factors Other factors o Nutrition o Education o Constitution and heredity General and specific defense mechanisms First line o Natural barriers o Reflex Second line o Filtration by lymphatic system o Humoral and cellular action 3. ENVIRONMENT A. TWO PHASES 1. PRE-PATHOGENESIS PERIOD - Marmar, Tabjan, Velasco Phase before man is involved Preliminary interactions of potential agent, host and environment Wala pa tayong sakit dito 1. PRE-PATHOGENESIS PERIOD - - The aggregate of all external conditions and influences affecting the life and development of a human behavior, organism or society Transcribed by: Fig 1. Factors in influencing the health equilibrium When the agent become established in the host B. PATHOGENESIS When the agent becomes established in the host Host-Agent Interaction under the Pathogenesis Period: a. The process of infection b. The incubation period c. Clinical horizon Page 2 of 4 FMC201 d. Preventive Medicine T3 Outcome of the Disease Notes: “so sa food poisoning, kayo lahat may handaan, kumain kayo ng pansit malabon. Ang pansit malabon ay napakabilis masira. 2 hours siya from the time na niluto dapat ma-consume na. ‘yang two hours ay nagiincrease na ang tendency for the bacteria to multiply. Lahat kayo kumain ng pansit malabon pero 4 or 5 lang ang nadala sa ER, it depends on the amount of the agent na nakain and if yung concentrated bacteria ay nasa plate mo. You would end up acquiring the disease rather than sa mga kasama mo.” C. SIX REQUIREMENTS FOR SUCCESSFUL PARASITISM Ø Presence of a parasitic agent Ø Suitable reservoir Ø Presence of a susceptible host Ø Satisfactory portal of entry Ø Accessible portal of exit Ø Appropriate means of dissemination Manifestation depend on: Characteristic and dosage of the agent; duration of exposure Reaction of the host Portal of entry D. INCUBATION PERIOD - the lapse of time before the disease becomes manifest -“this is the interval between the time of entry of the agent to the host and the onset of signs and symptoms bago magkaroon ng physical manifestation.” May vary depending on: 1. Virulence, dose and portal of entry 2. Previous experience and resistance of the host 3. Inherent character of the organism E. CLINICAL HORIZON appearance of characteristic signs and symptoms Notes: “may sakit ka na nito. May lagnat ka na, probably pwede ka na magkaroon ng rashes.like for example, rubella or german measles. Rubella ay magkakaroon ka muna ng 2-3 days ng fever, after that yung fever mo mawawala but then magstastart na ng appearance ng rashes mo. Aside from rashes, magkakaroon ka ng lymphadenopathy which is very particular in rubella.” Fig 2. Phases/Steps of Parasitism - - F. OUTCOME OF THE DISEASE Ø Host wards off the pathogen Ø Balanced equilibrium (In-apparent infection) “means wala ka nararamdaman, hindi mo rin nalalaman na meron ka nyan. Maraming Hepa B cases na ganyan.” Ø Sub-clinical infection “the signs and symptoms are so mild na hindi mo napapansin.” Ø Ø Full-blown Clinical Case Complete Recovery or Progress to: • Carrier state • Temporary disability • Permanent disability • Death Fig 3. Steps how and Aedes Mosquitoes transmit diseases Transcribed by: Marmar, Tabjan, Velasco Page 3 of 4 FMC201 Preventive Medicine T3 - Control of the environment 1. Reservoir 2. Source of Infection 3. Mode of Transmission Disability Limitation Ø Adequate treatment Ø Provision of facilities 3. TERTIARY LEVEL consist of: 1. Rehabilitation • Facilities for re-training and education • Education of the public and the industry Fig 4. Natural History of any disease process in man Ø Ø Ø G. LEVELS OF DISEASE PREVENTION Primary level Secondary level Tertiary level Ø Ø Ø Ø Full employment as possible Selective placement Work therapy Sheltered colony 1. PRIMARY LEVEL Ø Ø Ø Ø Ø True form of prevention Improving host, agent, and environment factors Focuses on preventing disease before it occurs Applied during the pre-pathogenesis period Consists of: 1. General health promotion 2. Specific protection General Health Promotion Ø Good standard of nutrition Ø Personality development Ø Adequate housing, recreation and agreeable working condition Ø Marriage counseling Ø Genetics Ø Periodic selective examination Specific Protection Ø Specific immunization Ø Personal hygiene Ø Environmental sanitation Ø Protection vs occupational hazards Ø Use of specific nutrients Ø Protection from carcinogen Ø Avoidance of allergens 2. SECONDARY LEVEL -may sakit na ang patient, pumasok na siya sa clinical horizon Consists of: 1. 2. Early diagnosis and prompt treatment Disability limitation Early Diagnosis and Prompt Treatment - Control of the patient 1. Case finding measure 2. Screening Survey 3. Selective examination Transcribed by: Marmar, Tabjan, Velasco REFERENCES 1. 2. 3. Dra. Peret-Clarion’s PPT and Discussion Recordings Old Trans Page 4 of 4
