L1 Introduction to System Pathology.pptx

Pathophy.

1. SYSTEMIC PATHOLOGY NGOMA FEBIAN

2. Pathology General Pathology Special Pathology or Systemic Pathology Systemic Pathology Clinical pathology Pathophysiology

3. SYSTEMIC Pathology Blood Vessels Heart RBC WBC Lung ENT GI Liver Pancreas Kidney Lower UT/Male Female Breast Endocrine Skin Orthopedic Nerve/Muscle CNS Eye

4. SYTEMIC PATHOLOGY: This course is the basis provided to the students for understanding various disease processes . Pathology lectures will guide you to enhance your understanding of disease. Requires the knowledge of General Pathology Requires correlation between normal Anatomy and Physiology and the process resulting in the manifestations of disease.

5. N ever forget . . . There are 4 aspects of a disease process that form the core of pathology A. Etiology (the cause), B. Pathogenesis (the mechanism), C. Morphology (the alterations), D. Clinical significance (the consequences).

6. 1. Etiology ( the cause ): Finding the primary cause (s)  diagnosis  treatment 2. Pathogenesis ( the mechanism ) refers to the sequence of events in the response of the cells or tissues to the cause from the beginning ( initial stimulus ) to the end ( the manifestations of disease )

7. 3. Morphology ( the alterations ): The morphologic changes refer to the structural and functional alterations in cells and tissues: either characteristic of the disease or diagnostic of the etiologic process

8. 4. Clinical significance ( T he C onsequences ): The nature of the morphologic changes and their distribution in different organs determine Signs and Symptoms Course & Prognosis of the disease.

9. The Pathology of Infectious Diseases Introduction Tissue Responses to Infections

10. Infectious agents Focus on PATHOGENESIS Know basic steps in the pathogenesis of: Viruses Rickettsiae Chlamydiae Mycoplasma Bacteria (incl.spirochetes&mycobacteria) Fungi Protozoa Helminths

11. Definitions Infection: The ability of an organism to invade and establish itself in a host. Note: All infections DO NOT represent DISEASES !!!

12. Infectious Disease Agent: Organisms found in the environment that are capable of replication ( either independently or with the host ) capable of provoking an adverse response in the host

13. Infectivity and Virulence Virulence : R efers to the complex of properties that allows an organism to achieve infection and cause disease of different degrees of severity. The organism must : ( 1) G ain access to the body, ( 2) A void multiple host defenses, ( 3) A ccommodate to growth in the human milieu, ( 4) P arasitize human resources. Virulence : R eflects both the structures inherent to the offending microbe and the interplay of those factors with host defense mechanisms.

14. Epidemiology of Infectious Disease Example: Leismaniasis cutis (oriental sore) Reservoirs ( cave ) Vector ( sandfly ) Susceptibility of the host ( common ) Method(s) of Control ( sanitation ) Microbial Virulence Factors ( antigens ) Host Defense Mechanisms ( cellular ) Chemotherapy ( amphotericin B paromomycin , miltefosine )

15. HOST BARRIERS TO INFECTION I. Local Barriers II. Humoral Immunity A. Antibody B. Complement III. Cell-mediated Immunity A. T-helper B. T-suppressor C. Cytotoxic lymphocyte IV. Phagocyte A. Neutrophil B. Monocyte , macrophage

16. The destruction of Local Barriers Skin Normal flora Staphylococcus epidermidis Candida albicans Dry keratinized epidermis Acidic pH RISK OCCURS WHEN Cuts Lacerations Bites Indwelling l ines Invasive p rocedures

17. Urogenital Tract Urine is normally sterile primarily due to constant flow Peristaltic motion and valves are designed to maintain unidirectional flow UT I nfection rate  Female : Male = 10 : 1 Acidic Ph of vagina RISK OCCURS WHEN Loss of the Acidic pH of Vagina Candida abicans Polygamy HPV Sex Transmtd Dis Urinary Tract Obstructions Exposure to pathogens which adhere to urothelium Some strains of E. coli Proteus Pseudomonas Gonococcus Staphyloccous saprophyticus

18. Respiratory tract Constant exposure to thousands of potential pathogens Unique defense structure: Mucociliary escalator Particles >5 micron : cleared by mucociliary escalator Particles <5 micron: cleared by macrophages & PMNs RISK OCCURS WHEN Mucociliary system is damaged (smoking, COPD, pathogens) There is an attack of infectious agents (capable to adhere to the respiratory epithelium ) Immunocompromised Patient

19. G astrointestinal tract Con s tant contact with organisms via food & water Defense systems: Mucus Gastric acid Pancreatic Fluids Bile salts IgA RISK OCCURS WHEN: Exposure to virulent organism Decrease in gast r ic acid production Antibiotic therapy Abnormal GI motility

20. Barriers.... Skin Tears Normal bacterial flora Gastric acid Bile Salivary and pancreatic secretions Filtration system of nasopharynx Mucociliary blanket Bronchial, cervical, urethral, and prostatic secretions Neutrophils Monocytes Complement Stationary mononuclear phagocyte system Immunoglobulins Cell-mediated immunity

21. Route of penetration of infection

22. PATHOGENESIS HOW CAN INFECTIOUS AGENTS CAUSE DAMAGE? Direct damage Release of Exotoxins, Endotoxins and/or irritant enzymes/proteins Induction of host immune response

23. VIRAL INFECTIONS IMMUNE RESPONSE TO VIRAL INFECTIONS Natural Killer Cell Cytokine Release boosts the immune response directly inhibits viral replication Cytotoxic T Cell B cells - Neutralizing antibodies

24. BACTERIAL INFECTIONS Virulence Endotoxins Exotoxins Potent enzymes (Flesh-eating bacteria, Group A Strep) Ability to survive and proliferate intracellularly (T b ) Spread in the Host Macrophages may aid in spread (T b ) Bloodstream and Lymphatics ( almost all bacteria ) Motility and Chemotaxis ( Vibrio cholerae ) Cell and Tissue Damage

25. Virulence Factors Adhesins Capsular material Proteins (Protein F, Protein M) Lipotechoic acids Fimbriae & Pili Endotoxins Gram negative LPS cell wall components (Lipid A and Core Sugars) Exotoxins Can be produced by either Gram (+) or Gram (-) o rganisms

26. Special consideration for Mycobacteria Distinctive waxy cell coat requiring Acid Fast Stains Virulence is related to cell wall ” C o rd factor” which inhibits phagosome - lysosome fusion Lipid cell wall components help initiate delayed cell-mediated hypersensitivity response in the host - GRANULOMAS Special culture methods used; may take up to 6 weeks

27. FUNG AL INFECTIONS Only a few commonly infect man increasingly important with the rise in Immunocompromised patients Route of Infection - Almost always the LUNGS +/- clinical pulmonary symptoms & signs pulmonary disease may be subclinical, mild, or severe F ungi may produce toxins ( Mycotoxins ) Immune Response : Essential in clearing infections - CLASSICALLY GRANULOMATOUS

28. PARASITIC INFECTIONS MECHANISMS of INJURY Mechanical Injury ( ie . hookworm larvae) Eliciting an Immune Response (i.e. hookw orm larvae in the lungs cause eosinophilic pneumonia) Nutritional depletion Adult hookworms Ascaris Giardia lamblia Digestion of host tissues ( ie . Entabmoeba histolytica ) Toxins and toxic metabolites ( ie . Plasmodium in Malaria ) Combinations of the above are common

29. HOST RESPONSE TO INFEC T IOUS AGENTS Acute Inflammatory Response ( exudative; suppurative) Necrotizing Inflammation Granulomatous I nflammation Mononuclear Inflammatory Re s ponse (Chronic Inflammation & Scarring) Cytopathic- Cytoproliferative Inflammation

30. Manifestation of infect ours diseases

31. Manifestation of Infection in Diseases

32. Blood manifestations: Leukocytosis: an increase in the number of leukocytes in the blood (mostly bacterial) Neutropenia : insufficient circulating neutrophils (salmonelosis, brucellosis, pertussis, and some viral and rickettsial infections) Anemia: insufficient circulating erythrocytes (clostridium, malaria, mycoplasma, chronic infections) DIC: disseminated intravascular coagulation (bacteria, virus)

33. Organisms in blood: Bacteremia : Few b acteria in the bloodstream, whether or not they are causing disease Viremia . Septicemia: Bacteria traveling around the body via the blood Infected blood causes severe disease Pyemia : Pyemia is a seldom-used term which means "pyogenic organisms" (staphylococcus, streptococcus, gram-negative rods) infecting the blood

34. Manifestations of infections of diseases in systems: Renal manifestations Immune Complex Glomerulonephritis Hepatic manifestations Icter ( Jaundice ) Central nervous system manifestations Cerebral malfunctions ( confusion , convulsions , coma ) Cardiovascular manifestations Septic shock , endocarditis SYSTEMIC manifestations = multiorgan dysfunction

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