NCM 105 Infectious, Inflammatory and Immunologic Problems PDF

NCM 105 INFECTIOUS, INFLAMMATORY AND IMMUNOLOGIC PROBLEMS Cells of the Immune System Specialized cells that work together to defend the body against pathogens 1. Lymphocytes B cells: Produce antibodies that specifically target pathogens. They are part of the acquired/adaptive...

NCM 105 INFECTIOUS, INFLAMMATORY AND IMMUNOLOGIC PROBLEMS Cells of the Immune System Specialized cells that work together to defend the body against pathogens 1. Lymphocytes B cells: Produce antibodies that specifically target pathogens. They are part of the acquired/adaptive immune response and can form memory cells to provide long-term immunity.  T Cells: Helper T cells (CD4+ T cells) Cytotoxic T cells (CD8+ T cells) Regulatory T cells  Natural Killer (NK) Cells They can kill virus- infected cells and tumor cells without the need for prior activation.  2. Phagocytes Macrophages: Engulf and digest pathogens and dead cells. They also act as antigen-presenting cells (APCs), displaying pieces of the pathogen to activate T cells. Neutrophils: The most abundant white blood cells, they are the first responders to infection and can ingest and destroy pathogens. Dendritic cells: These are antigen-presenting cells that process antigens and present them to T cells to initiate the adaptive immune response Monocytes: precursors to macrophages and dendritic cells. They can also perform phagocytosis while in circulation  *Phagocytosis Process: 1. Recognition and attachment 2. Engulfment 3. Digestion 4. Waste Expulsion  3. Granulocytes Eosinophils: Primarily involved in combating parasitic infections and also play a role in allergic reactions. Basophils: Release histamine during allergic reactions and help defend against parasites. Mast cells: Found in tissues, they also release histamine and other chemicals during allergic reactions and help defend against pathogens at mucosal surfaces. 4. Other Cells Plasma Cells Memory Cells  The complement system is a crucial The Complement part of the innate System immune system, consisting of a series of small proteins that circulate in the blood. These proteins work together to identify and eliminate pathogens like bacteria, viruses, and damaged cells.  Opsonization Key Functions Chemotaxis of the Complement System Cell Lysis Agglutination Inflammation:  IgG (75% of Total Immunoglobulin) Appears in serum and tissues Major (interstitial fluid) Characteristics Assumes a major role in of the bloodborne and tissue infections Immunoglobulins Activates the complement system Enhances phagocytosis Crosses the placenta  IgA (15% of Total Immunoglobulin) Appears in body fluids (blood, saliva, tears, and breast milk, as Major well as pulmonary, gastrointestinal, prostatic, and Characteristics vaginal secretions) of the Protects against respiratory, Immunoglobulins gastrointestinal, and genitourinary infections Prevents absorption of antigens from food Passes to neonate in breast milk for protection  IgM (10% of Total Immunoglobulin) Appears mostly in Major intravascular serum Characteristics Appears as the first of the immunoglobulin produced Immunoglobulins in response to bacterial and viral infections Activates the complement system  IgD (0.2% of Total Immunoglobulin) Major Appears in small Characteristics amounts in serum of the Possibly influences B- Immunoglobulins lymphocyte differentiation, but role is unclear  IgE (0.004% of Total Immunoglobulin) Major Appears in serum Characteristics Takes part in allergic and of the some hypersensitivity Immunoglobulins reactions Combats parasitic infections  Recognition: The immune system identifies the invader through innate pattern recognition and Stages of the antigen presentation. Immune Response Activation: The innate immune response begins, followed by the activation of the adaptive immune system (T-cells and B-cells).  Elimination: Pathogens are neutralized and destroyed through antibodies, cell- mediated cytotoxicity, and Stages of the phagocytosis. Immune Resolution and Memory: The Response immune response winds down, healing begins, and memory cells remain for quicker responses in the future.  Infectious Problems in Adults  infectious disease has been pervasive throughout history modern medicine, THE CLIENT antibiotic therapy, WITH AN immunizations & other public health measures to INFECTION protect food & water supplies have significantly reduced the prevalence of infectious diseases in the world  however, many infections like malaria, STDs & TB remain prevalent THE CLIENT WITH AN INFECTION modern medicine contributed to antibiotic-resistant strains of microorganisms Pathophysiology (Chain of Infection) I. Etiologic / microorganism responsible for Pathogenic / the infection; causative organisms that agent: create pathologic processes in the human host; rely on the host to survive  1. Bacteria: prokaryotic, single-celled microorganisms that differ from all other organisms in lacking a true nucleus & organelles such as mitochondria, chloroplasts & lysosomes ▪ CLASSIFICATIONS a. by shape: spherical (cocci), rod-shaped (bacilli), corkscrew (spirochete) b. by reaction to gram stain A. TYPES: o Gram stain (+) - have a thick cell wall that resists discoloration (loss of color);stain violet o Gram stain (-) – have a chemically more complex cell wall that can be decolorized by alcohol; do not stain violet c. by need of oxygen o aerobic – requires oxygen to live o anaerobic – does not require oxygen to live  2. Fungi: eukaryotic, single-celled microorganisms marked by the absence of a rigid cell wall in some stage of the life A. Types: cycle & reproduction by means of spores 3. Yeast: single-celled, nucleated, usually round fungi that reproduce by budding  4. Parasite: microorganisms that lies in or on another & obtains nourishment from it 5 Viruses: A. Types: microorganisms consisting of genetic material, which may be either DNA or RNA & is surrounded by a protein coat & in some viruses, by a membranous envelope B. FACTORS / CHARACTERISTICS 1.Mode of Action a.direct damage b.toxin production c.intracellular pathogens (viruses) B. Factors/Characteristics 2. Infectivity: ability of the pathogenic agent to invade & multiply in the host; depends on the defenses of the host (immunocompetence) * Pathogen: produces enzymes that facilitate invasiveness a. Coagulase – extracellular enzyme that causes coagulation b. Streptokinase – dissolves fibrin clots allowing agent to spread to surrounding tissues c. Hyaluronidase – breaks down connective tissue & increase tissue permeability d. Collagenase – degrades collagen to facilitate deep invasion of pathogens into tendons, cartilage & bone B. FACTORS / CHARACTERISTICS 3. Virulence: dises severity & invasiveness; ability to enter & move through tissue; # of microbes, length of contact 4. Antigenicity: ability to induce an immune response in the host; those who have none will evade WBC in a period of time B. FACTORS / CHARACTERISTICS 1.Toxigenicity: ability to produce toxins a.Hemolysin – destroys RBC b.Leukocidin – destroys WBC ▪ Exotoxins: water-soluble & distributed rapidly by the blood causing severe systemic & neurologic defects (eg. Tetanus, botulism & diphtheria) ▪ Endotoxin: cause inflammation & local destruction of tissues; weakly toxic, relatively stable & not antigenic (eg. Staphylococcal food poisoning & cholera) C. FACTORS THAT MAY PRODUCE DISEASE number of microorganisms virulence of the microorganisms competence of the person’s immune system length & intimacy of the contact between an individual & the microorganisms  The environment in which the infectious agent can survive ▪ source: endogenous / exogenous (other humans, patient’s own microorganisms., II. RESERVOIR: plants, animals, general environment – soil, food, water) ▪ where pathogen lives & multiplies ▪ carriers – harbor the pathogen without showing evidence of clinical disease  the method by which organisms leave III. PORTAL the reservoir OF EXIT Respiratory Tract Nose/mouth: sneezing, coughing, breathing, FROM THE talking RESERVOIR Endotracheal tubes Tracheostomies Gastrointestinal Tract Mouth: saliva, vomitus Anus/ostomies: feces Drainage tubes (NGT, T-tubes) Urinary Tract Urethral meatus Urinary diversion ostomies  the method by which organisms III. PORTAL leave the reservoir OF EXIT Reproductive Tract FROM THE Vaginal discharges RESERVOIR Urethral meatus Semen Urine Blood Open wound Needle puncture site Any disruption of intact skin or mucous membrane surfaces Tissues  the way microorganisms reach another person or host Direct Transmission: touching biting, kissing, sneezing, coughing, spitting, talking Airborne Transmission: transmitted by air currents – droplet nuclei, dust particles IV. METHOD OF TRANSMISSION: Indirect Transmission Vehicle-borne: inanimate objects (water, food, milk, blood, serum, plasma) *5 F’s: food fingers, fomites, flies, feces Vector-borne: animate objects (flying or crawling insects, ticks) V. PORTAL OF the way microorganisms ENTRY TO THE enter the body; usually the SUSCEPTIBLE same way they exit from HOST the reservoir  The final link in the chain of infection A person at risk for infection from microorganisms Factors that enable the host to resist the infection include the following: a. Physical barriers such as the skin & mucous VI. membranes SUSCEPTIBLE b. Hostile environment created by acidic stomach conditions, urine & vaginal secretions HOST c. Antimicrobial factors in saliva, tears & prostatic fluid d. Respiratory defenses including humidification, filtration, mucociliary escalator, cough reflex & alveolar macrophages e. Specific & nonspecific immune responses to pathogenic invasion  1. Age 2. Inadequate primary defenses 3. Inadequate secondary defenses 4. Inadequate active immunity FACTORS 5. Tissue destruction INFLUENCING 6. Increased environmental exposure DEV’T OF AN 7. Invasive procedures INFECTION 8. Chronic Diseases 9. Malnutrition 10.Trauma 11.Pharmaceutic agents 12.Rupture of amniotic membranes 13.Insufficient knowledge to avoid exposure to microorganisms  Also called Health Care Associated Infections (HAI) NOSOCOMIAL INFECTIONS (NI) infections associated with the delivery of health care services in a health care facility that develop during patient’s hospital stay or after discharge  possible use of biological weapons by terrorist BIOLOGICAL THREAT INFECTIONS most likely pathogens to be used for this purpose include anthrax, smallpox, botulism, pneumonic plague & viral hemorrhagic fevers  GIT: impaired swallow reflex, decrease gastric acidity & INFECTIOUS delayed gastric emptying thus PROCESS IN increased risk of aspiration OLDER ADULTS Thymus gland atrophies & by age 50-60 yrs, thymic hormone levels are undetectable, cell-mediated immune function declines  Leading Causes of Mortality Cardiovascular Respiratory Cancer Diabetes Diseases Diseases Infectious Accidents and Neurological Chronic Liver Diseases Injuries Disorders Diseases