Exam 4

Inflammation, Infection, Cellulitis, Pressure Injury, Hypertension

Inflammatory Response

Sequential reaction to cell injury, divided into vascular response, cellular response, and healing

Vascular Response

Release of chemical mediators (histamines, prostaglandins, and kinins) by injured cells causes vasodilation, which increase capillary permeability and facilitate fluid movement into tissue. These actions cause redness, heat, and swelling at the site of injury

Fibrinogen is activated to fibrin by the products of the injured cells, which strengthens a blood clot formed by platelets. This functions to trap bacteria, prevent their spread, and serve as the framework for the healing process. Platelets release growth factors that start the healing process

Cellular Response

Neutrophils and monocytes move from circulation to the site of injury (chemotaxis). Neutrophils phagocytize bacteria, foreign material, and damaged cells. Dead neutrophils start to accumulate and mix with other debris to form pus. The bone marrow releases more bands (immature neutrophils) into circulation when it cannot keep up with the demand for segs (mature neutrophils)

Monocytes mature into macrophages help in phagocytosis of inflammatory debris, cleaning the area before healing

Lymphocytes arrive later; their primary role is related to humoral and cell-mediated immunity

Shift to the Left

Increased number of band neutrophils in circulation, indicative of acute bacterial infection

Chemotaxis

Directional migration of EBCs to the site of injury, resulting in an accumulation of neutrophils and monocytes at the site

Innate Immunity (Nonspecific)

Provides immediate defense against foreign invaders; acts as a barrier to infectious agents (skin) and produces chemical mediators that fight infection, remove foreign substances, and activate the adaptive immune system

ex) skin, enzymes on skin/tears, acid in GI tract, mucus, cough reflex

Humoral Immunity

Defense system that involves WBCs (B lymphocytes) that produce antibodies in response to antigens or pathogens circulating in the lymph and blood.The antigen-antibody reaction initiates a complex chain of events to protect the body from the invading microorganism

Enable production of inflammatory molecules such as interferon and interleukin-1, which cause fever

Cellular Immunity

Defense by WBCs against microorganisms that the body does not recognize as its own. T lymphocytes (T cells) directly attack cells displaying non self antigens (infected cells). Helper T cells release interleukins and other substances that stimulate antibody production by B cells and antigen destruction by other cells (macrophages)

Adaptive Immunity

B cells and T cells learn to differentiate between the body’s tissues and substances that are not normally found in the body. Some cells are sensitized by interactions with a specific antigen and become memory cells, so the immune response is faster and stronger when re-exposed

Passive Immunity

Occurs when a person receives an antibody produced in another body; which provides immediate but short-term protection against antigens

ex) Infants in utero or through breast milk (antigens disappear between 6-12 months)

Antibodies

Immunoglobulin molecules that recognize foreign invaders

Antigen

Any substances that provokes an adaptive immune response

Natural Active Immunity vs Artificial Active Immunity

Natural Active: Exposed to illness and gets sick, producing antibodies

Artificial Active: Acquired through vaccination (weakened or dead pathogen), body still produces antibodies

Natural Passive Immunity vs Artificial Passive Immunity

Natural Passive: receives an antibody produced in another body (e.g. breastfeeding)

Artificial Passive: Injections of ready-made antibodies, not from the body’s own immune response (e.g. IV immunoglobulin)

Droplet transmission

Mucous membranes of the respiratory tract are exposed to the secretions of an infected individual. Droplets cannot remain suspended in the air for long periods and seldom travel more than 3 feet

ex) influenza, RSV, pertussis, meningitis, pneumonia

Precautions: surgical mask and goggles for staff, single room, door closed, patient wears surgical mask during transport

Airborne transmission

Microorganisms are dispersed by air currents and inhaled or deposited on the skin of the susceptible host

ex) tuberculosis, measles, varicella

Precautions: N95 mask, eye protection in some circumstances, negative pressure room, door closed, and patient wears surgical mask or N95 during transport

Protective Isolation

Isolation protects susceptible patients, who may not be able to fight infection, from microorganisms in the environment.

ex) patients undergoing chemotherapy, irradiation, bone marrow transplantation, patients with severe burns, and patients who are immunocompromised (i.e. neutrophil count less than 500/mm³)

Contact Transmission

Microorganisms are dispersed by touching an infected person or surface of objects containing the microorganism

5 Cardinal Signs of Inflammation

Heat, Pain, Swelling, Redness/Hyperpigmentation, and Loss of Function

Inflammation of the Liver

Increased ammonia in blood

Decreased albumin in blood

Increased bilirubin in blood

Drugs stay in the body longer

Decreased absorption of nutrients from food

Takes longer for blood to form a clot

Decrease Inflammatory Response

Local: Rest, Ice, Compression, Elevation (RICE)

Systemic: Antipyretics, NSAIDs, Corticosteroids

Allergic: Antihistamines and Decongestants

Normal Differential Lab Ranges

Neutrophils (Segs): 55 - 70%

Bands: 5%

Monocytes: 2 - 8%

Lymphocytes: 20 - 40%

Eosinophils: 1 - 4%

Basophils: 0.5 - 1%

Cytokines

Small hormone-like proteins produced by the many leukocytes (and some other tissues) that help modify inflammation and immunity

Human Leukocyte Antigens (HLAs)

Unique surface proteins that present on all of a person’s cells that are specific to that person (AKA person’s tissue type)

Memory Cells

A sensitized B lymphocyte that produces specific antibodies on all subsequent exposures to the initial sensitizing antigen 

Plasma Cells

A sensitized B lymphocyte that immediately starts to produce antibodies against the sensitizing antigen

Stem Cells

Immature undifferentiated cells produced in the bone marrow that are pluripotent with the potential to mature into any blood cell type

Self-Tolerance

The special ability of immune system cells to recognize self virus non-self and avoid actions that would harm self cells

Inflammation - Immune Functions of Specific Leukocytes

Neutrophil: Nonspecific ingestion and phagocytosis of microorganisms and foreign proteins

Macrophage: Nonspecific recognition of foreign proteins and microorganisms; ingestion and phagocytosis. Assists with antibody-mediated immunity and cell-mediated immunity

Monocyte: Destruction of bacteria and cellular debris; matures into macrophage

Eosinophil: Releases vasoactive amines during allergic reactions and in response to parasite infestations

Basophil: Release histamines, kinins, and heparin in areas of tissue damage

Antibody-Mediated Immunity - Immune Functions of Specific Leukocytes

B Lymphocyte: Becomes sensitized to foreign cells and proteins with the assistance of macrophages and helper T cells

Plasma Cells: Secretes immunoglobulins in response to the presence of a specific antigen

Memory Cells: Remains sensitized to a specific antigen and can secrete increased amounts of immunoglobulins specific to the antigen on re-exposure

Cell-Mediated Immunity - Immune Functions of Specific Leukocytes

Helper T Cells: Enhances immune activity of all parts of general and specific immunity through secretion of various factors, cytokines, and lymphokines

Cytotoxic T Cells: Selectively attacks and destroys non-self cells, including virally infected cells, grafts, and transplanted organs

Regulator T Cells: Regulates a balance between offensive and defensive inflammation and immunity actions and maintains self-tolerance

Natural Killer Cells: Non-selectively attacks non-self cells, especially body cells that have undergone mutation and become malignant; also attacks grafts and transplanted organs

Tissue Mast Cells

Originate in the bone marrow, but differentiate and mature in tissues (especially near blood vessels, lung tissue, skin, and mucous membranes)

Have binding sites for the stems of IgE molecules and when activated are involved in allergic reactions. Respond to inflammatory products released by T lymphocytes by maintaining and prolonging inflammation and allergic reactions

Neutrophilia

Increased number of circulating neutrophils

IgA

“Secretory” antibody that is present in high concentrations in the secretions of mucous membranes and the intestinal mucosa to provide mucosal immunity

Most responsible for preventing infection in the upper and lower respiratory tracts, the GI tracts, and the genitourinary tract

IgD

Acts as a B-cell antigen receptor

IgE

Associated with antibody-mediated immediate hypersensitivity reactions

Provides protection against parasite infestations, especially helminths

IgG

Accounts for the largest amount of circulating antibodies

Is heavily expressed on second and subsequent exposures to antigens to provide sustained, long-term immunity against invading microorganisms

Activates classic complement pathway and enhances neutrophil and macrophage actions

IgM

First antibody formed by a newly sensitized B-lymphocyte plasma cell

Effective at the antibody actions of agglutination and precipitation because of having 10 binding sites per molecule

Activates complement pathway