Pathological Physiology: Health and Disease

• Pathological physiology explains how disease occurs and how physiological and biochemical functions change when an organism transitions from health to disease

Dynamic Processes of Health and Disease

• Higher animals and humans exist in external (milieu exterieur) and internal (milieu interieur) environments
• Homeostasis maintains the stability of the internal environment
• A healthy human organism maintains the constancy of its structure, chemical composition, biochemical reactions, and physiological functions
• Health exists as long as the organism can resist harmful influences or repair changes
• Disease begins if defense or regulatory mechanisms fail, causing internal environment changes to manifest as disease
• Homeostasis is a state of dynamic balance thrown off by environmental challenges

Health and Disease Definitions

• Health is a state of complete physical, mental, and social well-being, beyond just the absence of disease
• Health represents a harmonious balance of structure and function for full working capacity and enjoyment of life
• Illness arises from a disturbance of harmonious balance, reducing work capacity, enjoyment, and increasing mental stress
• Health describes what is normal, while illness represents a deviation
• Health equals life with maintained homeostasis; disease equals a state with disturbed homeostasis

Symptoms and Disease Signs

• Changes occurring in disease manifest as symptoms and signs
• A series of signs and symptoms reflect morphological and functional changes
• Pathological processes rarely occur without symptoms or signs; diseases without symptoms are asymptomatic
• Symptoms are reported by the patient and discussed in the medical history
  • Examples include dyspnea, cough, hemoptysis, and pleuritic chest pain
• Signs are noted by the examiner and discussed in a physical exam
  • Examples include normal vesicular breath sounds, crackles, wheezes, stridor, pleural friction rub, altered transmission of sounds, abnormal tactile fremitus, cyanosis and clubbing
• Signs are objective manifestations of disease
• Symptoms are subjective feelings noticed by the patient alone
  • Examples include pain, nausea, weakness, and tinnitus
• Objective disease signs can be proven during physical examination or functional tests
• Symptoms can be nonspecific and can also be specific (pathognomonic)
• A syndrome is a group of symptoms appearing together in a disease

Disease Stages

• Incubation (latent) includes no S/S of disase
• Prodromal is characterized by an organism showing weakly expressed pathological disorders
• Manifest features periods of illness and decline
• Recovery occurs when the condition returns to normal

Incubation

• Etiological factor acts on organism without causing visible disorders
• Best expressed in infectious diseases

Prodromal

• Characterized by weakly expressed pathological disorders in the organism
• Does not indicate the disease has actually started
• Studying incubation and prodromal stages is important to detecting disease in the earliest stages

Manifest

• Is when the complete picture of disease appears
• Etiological factor has developed its effect and lead to damages

Disease Outcomes

• Complete recovery (restitutio ad integrum)
• Incomplete healing
• Transition to a pathological state
• Lethal outcome or death (exitus lethalis)
• Remission describes temporary stopping of disease development
• Exacerbation describes the continuation of disease worsening

Etiology

• “aitia” means cause, and “logos” means science
• It's the causative agent that disrupts physical defense forces, or its environment, to disrupt homeostasis

Etiological Factors by Origin

• Can be both external and internal
• External etiological factors include
  • Biological: living agents like bacteria, viruses, fungi, and parasites
  • Physical: physical forces like temperature, pressure, electric current, and radiation
  • Chemical: substances acting chemically
  • Nutritional: lacking nutrients consumed
  • Social: social environment
• Internal etiological factors include
  • inherited factors
  • etiologic factors of life age
  • etiologic factor of sex

Infection Etiology

• It's a disorder caused by the penetration of pathogenic microorganisms foreign to the body (heteroinfection), or germs already in the body (autoinfection)
• Entrance includes the respiratory, digestive, skin and mucous membranes
• The source is transmitted from sick people or carriers, or air, pollutants, water, diseased animals (zoonosis) and insects

Types of Etiology

• Primary:
  • Primary etiological factors are a main cause that determines the type of disease
• Secondary:
  • Secondary etiological factors enable primary factors

Pathogenesis

• “pathos” means suffering and “genesis” means origin
• Pathogenesis studies the mechanisms of structural and functional disorders
• The way in which the etiological factor leads to pathological changes in the organism
• Pathogenesis is the cause and effect relationship (inflammation of the gallbladder - bleeding)
• Determining the mutual dependence of pathological processes in the organism is important because pathological processes in diseases do not occur independently influencing each other enabling the development of another
• Pathogenesis related to pollen sneeze and stomach ulcers
• An example of pathogenesis is acute pancreatitis

Explore pathological physiology, detailing disease origins and physiological/biochemical changes during health-to-disease transitions. Learn about homeostasis, maintaining internal stability, and how disruptions lead to disease. Understand health as a balance between resisting harm and repairing changes.