Pathophysiology Overview and Disease Mechanisms

Pathophysiology Overview

• Pathophysiology studies how diseases alter body functions, combining pathology (disease study) and physiology (normal function).
• Key components include etiology (cause), pathogenesis (disease development), manifestations (signs/symptoms), prognosis (outcome), morbidity (disease presence), mortality (death rate), complications, diagnostic tests, and therapeutics.

Disease Mechanisms

• Genetics: Inherited mutations or predispositions cause disease.
• Infectious Agents: Bacteria, viruses, fungi, and parasites cause illness.
• Autoimmunity: Immune system attacks body tissues.
• Degeneration: Cell/tissue deterioration.
• Tumors: Abnormal growths (benign or malignant).
• Malnutrition: Nutrient deficiencies impact health.
• Pathogenesis: Sequence of events in disease development.
• Inflammation: Body's response to injury or infection.
• Necrosis: Cell/tissue death from injury or disease.

Factors Influencing Disease

• Age: Older age often increases disease risk.
• Gender: Certain diseases affect one gender more.
• Lifestyle: Diet, exercise, habits (smoking) impact health.
• Stress: Chronic stress worsens or contributes to illness.
• Environment: Exposure to pollutants, toxins, infectious agents affects health.

Case Study: COVID-19

• Etiology: SARS-CoV-2 virus.
• Pathogenesis: Virus replication leads to respiratory and systemic symptoms.
• Manifestations: Cough, fever, shortness of breath, loss of taste/smell.
• Prognosis: Variable; some fully recover, others experience long-term effects (long COVID).
• Morbidity: Significant impact on healthcare systems due to severe cases.
• Mortality: Higher risk in older adults and those with comorbidities.
• Complications: Pneumonia, ARDS, thromboembolic events.

Infectious Processes

• Chain of Infection: Pathogen, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host.
• Local Infections: Limited to a specific area (e.g., abscess).
• Systemic Infections: Affect the entire body (e.g., sepsis).
• Stages of Infection: Incubation, prodromal, illness, decline, convalescence.

Compensatory Mechanisms

• Fever: Increased body temperature combats infection.
• Inflammation: Localized response to injury/infection.

Manifestations; Key Symptoms

• Fever, pain, swelling, redness indicate immune response and tissue damage.

Complications

• Potential complications include organ failure, SIRS, and septic shock.

Diagnostic and Therapeutic Plans

• Diagnostic: Cultures, imaging, blood tests to identify pathogens.
• Therapeutics: Antibiotics, antivirals, supportive care (e.g. for Pneumonia).

Fever

• Definition: Elevated body temperature (typically above 38°C).
• Regulation: Hypothalamus controls temperature through thermoregulation.
• Triggers: Infection, inflammatory conditions, malignancies.
• Pathophysiology: Pyrogens (fever-inducing substances) reset hypothalamic temperature set point.
• Stages: Onset, plateau, defervescence.
• Manifestations: Chills, sweating, headache, malaise.
• Treatments: Antipyretics (like acetaminophen), hydration, monitoring underlying causes.

Other Important Terms

• Colonization: Microorganism growth without disease.
• Commensalism: Symbiotic relationship where one benefits; other unaffected.
• Epidemiology: Population-level disease study.
• Etiology: Disease cause (genetics, infections, environment).
• Eukaryote: Organisms with nuclei and organelles.
• Incidence: New disease cases in a population.
• Leukocytosis: Increased white blood cells.
• Leukopenia: Decreased white blood cells.
• Manifestation: Observable signs and symptoms.
• Morbidity: Disease prevalence in a population.
• Mortality: Death rate due to a disease.
• Mutualism: Symbiotic relationship where both benefit.
• Pathogen: Disease-causing organism.
• Prevalence: Total disease cases in a population.
• Prognosis: Predicted disease outcome.
• Prokaryote: Single-celled organisms without nuclei.
• Sepsis: Life-threatening response to infection.
• Vector: Organism transmitting pathogens.
• Virulence: Pathogen's disease-causing ability.

This quiz explores the fundamental concepts of pathophysiology, including how diseases affect body functions. It covers key components such as etiology, pathogenesis, and the various disease mechanisms like genetics, infections, and autoimmunity. Test your knowledge on how these factors contribute to health and disease.