Health, Sickness, and Natural History of Disease

Health, Sickness & Natural History of Disease

Health and Disease

• Health: A state of complete physical, mental, and social well-being, not merely the absence of disease.
• Disease: An imbalance with a failure of the organism's adaptive mechanisms, affecting its well-being.
• Health and disease are not opposite concepts but different degrees of adaptation of the organism to the environment in which it lives.

Health Dimensions

• Physical: Bodily functions. Need for physical activity, healthy eating, and adequate sleep.
• Intellectual: Ability to think and learn from life experiences. Ability to question and evaluate information through critical thinking.
• Emotional: Ability to cope effectively with life and express emotions appropriately.
• Social: Ability to interact with other people and create support systems.
• Spiritual: Having a sense of purpose and meaning in life.
• Occupational and Financial: Career that aligns with your values and managing money properly.
• Environmental: Impact of our environment on our well-being.
• Community Health: Health programs that bring individuals closer to health.

Wellbeing

• Wellness is defined as a purposeful and enjoyable way of living.
• Characterized by personal responsibility and optimal improvement of physical, mental, and spiritual health.

The Epidemiologic Triad/Triangle: A Model of Infectious Disease Causation

• Helps us understand the spread of diseases through 3 components: agent, environment, and host.
• Agent: What causes the disease.
  • Types of agents:
    • Biological: bacteria, virus, fungi, parasites.
    • Physical: changes in temperature, mechanical action of objects, electricity, radiation.
    • Chemical: toxic substances.
• Host: Organism that gets the disease.
• Environment: Factors that affect the agent and the opportunity for exposure.
• Minimizing the interactions between these components can help prevent disease (Ex: Covid 19).

Natural History of Disease: How a Disease Progresses Without Treatment

• Stages:
  • Stage of susceptibility:
    • Also known as pre-pathogenic period.
    • Epidemiological triad occurs.
    • The person is not yet infected/sick.
  • Exposure
  • Stage of subclinical disease:
    • Pathogenic period.
    • The person is already infected/sick but is NOT showing symptoms.
  • Stage of clinical disease:
    • Symptoms appear.
    • Pathologic changes.
    • Diagnosis is made.
  • Stage of recovery, disability, or death:
    • Resolution: The disease ends with recovery, disability, or death.

Signs vs. Symptoms

• Sign: Health issues that can be observed and/or measured.
• Symptom: Manifestations of disease that are only apparent to the patient. Subjective experience of a potential health issue.

Levels of Prevention: Health Activities Aimed to Promote Health

• Primary Prevention:
  • True prevention, precedes disease.
  • Aimed at health promotion, focus on maintaining or improving health.
  • Includes health education, vaccines, physical and nutritional activities, water sanitation, garbage collection, etc.
• Secondary Prevention:
  • Aimed at diagnosing diseases early and treating them early.
  • The earlier the treatment, the better the outcome.
• Tertiary Prevention:
  • Occurs when a defect is permanent.
  • Aimed at preventing complications and deterioration.
  • Rehabilitation and quality of life.

Prevention in Relation to the Natural History of Disease

• Primary Prevention: Occurs during the stage of susceptibility (pre-pathogenic period) and exposure.
• Secondary Prevention: Occurs during the stage of subclinical disease and the stage of clinical disease.
• Tertiary Prevention: Occurs during the stage of recovery, disability, or death (resolution).

Hygiene

• Conditions and practices that help to maintain health and prevent the spread of diseases.
  • Individual hygiene:
    • Washing hands
    • Dental hygiene
    • Sleep habits
  • Collective hygiene:
    • Housing
    • Workplace
    • Transportation
    • Infrastructure and services
    • Governance and authorities