Patho Ch 16

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SelinaBell
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287471
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Patho Ch 16
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2014-10-30 21:57:41
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Pathophysiology
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Exam #4 Disorders of the Immune Response
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  1. Disorders of Immune Function (3)
    Hypersensitivity (too much of a response):

    exaggerated immune response to a foreign substance. 

    Autoimmune:

    mistakes self as non-self (will fight itself)

    Immunodeficiency:

    inadequate immune reaction
  2. Hypersensitivity

    What is the body damaged by as opposed of?

    What are the four types?
    Excessive or inappropriate activation of the immune response

    The body is damaged by the immune response, rather than by the antigen, (often called allergen)

    Commonly divided into four types (I, II, III, IV)

    • Type I: Immediate Hypersensitivity Disorders
    • Type II: Antibody-Mediated Disorders
    • Type III: Immune Complex-Mediated Disorders
    • Type IV: Cell-Mediated Hypersensitivity Disorders

    Differ in terms of type of immune response and nature/location of the antigen that is the target
  3. Type I Hypersensitivity

    What type of mediated response? Binds to what kind of cells?
    What is it commonly called?
    What type of treatment is necessary?
    • Commonly called "allergic reactions"; produces an immediate response (within minutes of an antigen challenge)
    • Systemic or anaphylactic; local or atopic reaction
    • Allergen activate IgE which bind to mast cells
    • At next exposure, the antigen binds with the surface of IgE releasing mediators and triggering the complement system 

    examples: 

    -hay fever, food allergies, hives, atopic dermatitis and anaphylaxis (high risk of death)

    Treatment: includes epinephrine, antihistamines, corticosteroids, and desensitizing injections

    ______________________

    desensitizing injections = allergy shots. 

    exposed to something and then exposed a second time to produce a response

    Eosinophils, mast cells, and B cells
  4. Type I Allergies are Mediated by IgE

    What two types of cells are involved?
    What kind of cells are they?
    What are released to initiate response and what do they contain?
    What are mast cells sources of?
    Two types of cells involved: type 2 helper T and mast cells or basophils

    Mast cells are tissue cells; basophils are blood cells derived from hematopoietic precursor cells; both have granules that contain mediators that are released to initiate the response

    Type 1 reaction begins with mast cell or basophil sensitization; allergen-specific IgE antibodies attach to cell receptors; with subsequent exposure, the allergen binds and triggers a series of events that lead to degranulation

    • Mast cells are source of prostaglandins (hormone-like lipid compounds), histamine (contraction of smooth muscle, and dilation of capillaries), acetylcholine (causes constriction of the lungs, difficulty breathing), adenosine (treats irregular hearbeat), chemotactic mediators, leukotrienes, and cytokines (important for cell signaling).
    • That continue the rxn
  5. Histamine is one of the first chemical mediators released during the inflammatory response as a result of...
    Mast cell degranulation.

    Mast cell stabilizers (used to treat asthma) prevent the histamine from being released; antihistamines (compete with histamine receptors; used to treat allergies) compete with histamine for receptor sites, lessening the inflammatory response.
  6. Anaphylaxis

    What type of reaction is it?
    What is it a response to?
    What produces vasodilation? bronchoconstriction?

    What will happen when arterioles vasodilate throughout the body? 
    What will happen when the bronchioles constrict?
    Systemic response to the inflammatory mediators released in type 1 hypersensitivity

    - histamine, acetylcholine, kinins, leukotrienes, and prostaglandins all cause vasodilation

    - acetylcholine, kinins, leukotrienes, and protaglandins all can cause bronchoconstriction 

    ______________________

    Life-threatening hypersensitivity reaction characterized by widespread edema, difficulty breathing, and vascular shock secondary to vasodilation.

    Rapid vasodilation lowers blood pressure so HR will increase to compensate.

    Constriction of bronchioles will impair airway which means less oxygen for the body
  7. Management of Anaphylaxis

    What should you initially do?

    If happened in the past, what are some ways to manage?
    Initial management:

    • stable airway (getting them breathing is important)
    • IV access (fluid=volume to help BP)
    • administer epinephrine (dilation of airways and constriction of blood vessels)

    If history:

    • need preloaded syringes
    • prevent exposure
    • educate family
    • wear medical alert bracelet
  8. Type II 

    What type of reaction is this? What are the antibodies and what does it react to?

    What occurs in blood cells?

    What type of treatment is necessary?
    Cytotoxic Hypersensitivity Reaction

    IgG or IgM type antibodies that react to foreign tissue of cells

    Lysis (breaking/bursting) of blood cells occurs because of the activation of the complement

    Usually immediate responses

    Ex: blood transfusion reaction and erythroblastosis fetalis (Rh disease); drug reactions

    Treatment includes ensuring blood compatibility and administering medication to prevent maternal antibody development
  9. Type III

    What type of reaction is this? What type of antibodies and what do they do?
    What happens to blood vessels?
    (flow through blood and gets stuck in tissues)

    A systemic or local reaction

    Immune complex-mediated hypersensitivity reaction

    Circulating antigen-antibody complexes accumulate and are deposited in the tissue

    Triggers the complement system and inflammation

    • Ex: 
    • Autoimmune conditions (e.g. systemic lupus erythematosus); Autoimmune vasculitis; Glomerulonephritis; Serum sickness

    Treatment is disease specific

    • Systemic: IgM, IgG, and occasionally IgA
    • Local: IgG
    • _______________________

    • immune complexes deposit on walls of blood vessels and activate complement.
    • blood vessels are damaged
  10. Type IV

    What type of reaction is this?
    What two types are there and what is there corresponding T cell?
    cell-mediated hypersensitivity reaction

    Cell-mediated: sensitized T cells attack antigen

    • Direct cell-mediated cytotoxicity (CD8 Tcells)
    • --Viral reactions

    • Delayed-type hypersensitivity (activated CD4 helper Tcells)
    • --Tuberculin Test
    • --Allergic contact dermatitis: ex: "poison ivy", reaction to metal in jewelry
    • --hypersensitivity pneumotitis 

    Treatment is disease specific

    ______________________

    takes 48-72 hours to develop symptoms of delayed-type hypersensitivity
  11. Autoimmune Diseases

    What happens? What is destroyed?
    What appears in the blood?
    Immune system attacks self-antigens

    **Normally, self-reactive immune cells are killed in the lymphoid organs or suppressed by regulatory T cells

    • In autoimmunity, this self-tolerance breaks down
    • Immune system destroys body tissues

    Anti-tissue antibodies appear in blood (e.g. antithyroid antibodies)
  12. Autoimmune Disorders

    What happens to the immune system?
    Defenses are against...
    What are the known characteristics (4)
    Immune system looses the ability to recognize self

    Defenses are directed against host

    Can affect any tissue

    Mechanism that triggers this response is not clear

    • Known characteristics:
    • --Genetics play a role
    • --More prevalent in females
    • --Onset is frequently associated with an abnormal stressor, either physical or psychological
    • --Are frequent progressive disorders characterized by periods of exacerbation (worsening) and remission (improvement)
  13. Transplants

    What assures best chance of success?
    Donor sources
    What are the 3 categories of transplants?
    Best match of tissue antigens helps assure best chance of success (so the body will not fight the tissue coming in)

    Donor sources may be living or a cadaver

    • 3 categories:
    • --Allogenic-donor and recipient are related or unrelated, but share similar tissue types
    • --Synergenic-donor and recipient are identical twins
    • --Autologous-donor and recipient are the same person; most successful
  14. Patterns of Transplant Rejections

    What are the three types of rejections?
    Manifestations?
    • Hyperacute
    • --immediate or 3 days after transplant; circulating antibodies react to graft.
    • --produced by existing recipient antibodies to graft antigens that initiate a type III

    • Acute
    • --Most common; treatable; occurs between 4 days and 3 months after transplant; Exposure to transplant causes activation of immune system, especially T cells
    • --T cells cause direct lysis of graft cells and recruit and activate inflammatory cells that injure the graft.
    • --Manifestations; fever, erythema, edema, site tenderness, and impaired function of organ

    • Chronic
    • --Occurs 4 months to years after transplant; likely antibody-mediated response; Antibodies and complements deposit in vessel walls of transplanted tissue, resulting in ischemia
    • --It manifests with dense intimal fibrosis of blood vessels of the transplanted organ.
  15. Host VS Graft
    Host Vs Graft Disease

    -host fights the graft

    -The recipient's immune system attempts to eliminate the donor cells
  16. Graft VS Host

    When does this occur
    What transplant is this common?
    What has to occur for GVHD to develop?
    What are the acute organs and how are they effected?
    Transplanted immune cells attack host

    • --Graft fights the host
    • --Frequent and potentially fatal complication of bone marrow transplants
    • --Occurs when immunocompetent fatal cells recognize host tissue as foreign and mount a cell-mediated immune response
    • --Host usually immunocompromised and unable to fight graft cells, and the host's cells are destroyed

    Acute or chronic

    _____________________

    Acute

    Skin: Most commonly effected; frequent desquamation (skin peeling)

    GI: Nausea, bloody diarrhea, and abdominal pain

    Liver: Painless jaundice, hyperbilirubinemia, sepsis, coma
  17. Immunodeficiency (low response or no response)

    What can this make people susceptible to?
    Two classifications.
    Diminished or absent immune response

    Renders the person susceptible to disease normally prevented; Opportunistic infections

    May be acute or chronic

    • Classifications:
    • --Primary: B-cell deficiencies; Ig deficiencies; T-cell deficiencies; Combined immunodeficiencies
    • --Secondary (Acquired): HIV
  18. HIV

    What type of deficiency is this?
    What does it infect?
    What are the two types?
    How is it transmitted? (3)
    What age group is HIV high in?
    Secondary Acquired Immunodeficiency 

    --Parasitic retrovirus that infects CD4 and macropahges upon entry

    • Two primary types:
    • --Type 1 is the most common strain
    • --Type 2 is more common in West Africa; progresses to disease more slowly

    In the US, rates rising among women and African Americans

    _______________

    • Transmitted by body fluids (anything sticky)
    • --sexual contact
    • --breast milk
    • --blood-to-blood contact - contaminated needles, transfusions, during pregnancy or birth

    HIV high in elderly
  19. Course of HIV Infection

    (How HIV infection progresses)

    What are the three different stages?
    Course varies from person-to-person

    Without treatment most HIV+ progress to AIDS in 7-10 years.

    1) Stage 1/Primary infection phase:

    • Signs of systematic infection; fever, fatigue, myalgias, sore throat, night sweats, GI problems, swollen lymph nodes, rash, headache
    • --Seroconversion: immune system responds and antibodies against HIV appear (1 month - 6 months); high viral loads

    2) Stage 2/Latency (chronic asymptomatic) phase

    Virus is replicating, TH cell count gradually falls: may last 10-11 years or longer

    3) Stage 3/Overt AIDS:

    • Without therapy usually leads to death in 2-3 years. 
    • Infections begin as the viral number rise destroying the CD4
    • --TH cell count <200 cells/mL or AIDS-defining illness

    _____________

    It takes a while for the immune system to let the world know you have HIV

    asymptomatic- w/o symptoms

    Overt- obvious
  20. AIDS Classification System

    What are the two types of systems?
    What are the 3 sub categories in these systems?
    Two systems, one based on lab findings and the other based on clinical manifestations

    *Laboratory Findings:

    • --Category 1: >500 cells/microL
    • --Category 2: 200-499
    • --Category 3: <200

    *Clinical

    • --Category A: asymptomatic
    • --Category B: some less serious manifestations of immune deficiency
    • --Category C: AIDS defining illnesses present
  21. AIDS Treatment

    Is there a cure?
    What therapy works best?
    What is the leading cause of death with HIV?
    What do people with AIDS need?
    No cure

    Combination therapy works best⇢Highly Active Antiretroviral Therapy (HAART)

    May have to change meds because of viral adaptation

    Other meds and vaccines will be used to prevent (prophylactic) opportunistic infections as needed

    Screen for TB; tuberculosis leading cause of death for people with HIV worldwide; often first manifestation

    Vaccinations

    Transmission prevention

    Emotional support (make people aware of their options and medications)

    Hopsice (for anyone w/ a diagnosis and prognosis of 6mos or less)

    ________________

    messed up immune system
  22. AIDS-Associated Illnesses

    (AIDS-Defining)

    What are the three systems of opportunistic infections?
    What are some malignancies associated?
    What is wasting syndrome?
    What are some metabolic disorders?

    What is TORCHES?
    Opportunistic Infections:

    • --Respiratory: bacterial pneumonia, P.Jiroveci pneumonia, TB
    • --Gastrointestinal: esophageal candiasis, CMV, herpes simplex, mouth ulcers, diarrhea, gastroenteritis, cryptospiridium
    • --Nervous system: toxoplasmosis (cat poop/liter), leukoencephlopathy, neurocognitive disorders, AIDS dementia complex; neuropathies

    Malignancies:

    --Non-Hodgkin lymphoma, Kaposi Sarcoma; noninvasive cervical carcinoma; function of impaired cell-mediated immunity

    Wasting Syndrome (losing weight; "wasting away"):

    --AIDS-defining illness; involuntary weight loss of at least 10% in presence of diarrhea, >2 stools per day, or chronic weakness and fever.

    Metabolic Disorders:

    --many associated with treatment; lipodystrophy a problem, insulin-resistance/diabetes, hyperlipidemia, mitochondrial disorders

    ____________________

    TORCHES

    • toxoplasmosis, other infections, rubella, cytomegalovirus infection, and herpes simplex
    • Epstein-Bar, and syphilis
  23. At-Risk Individuals for Immune Dysfunction
    • Very young and very old
    • Poor nutrition (good nutrition necessary)
    • Impaired skin integrity (break in skin)
    • Circulatory issues (imflammatory reaction, blood needs to get there and clean everything out)
    • Alterations in normal flora due to antibiotic therapy
    • Chronic diseases especially diabetes mellitus
    • Corticosteroid therapy (steroid that stops inflammation)
    • Chemotherapy
    • Smoking (causes vasoconstriction; can mess up vitamin C)
    • Alcohol consumption (liver)
    • Immunodeficiency states
  24. Optimize your Immune Health


    (Also good for nursing students)
    • Maintain adequate fluid intake
    • Balanced diet high in monosaturated fats, whole grains, fruits, vegetables
    • Moderate exercise
    • Weight control
    • Limit caffeine and refined sugar
    • Increase antioxidants, daily source of Vitamin C
    • Increase protein intake (to make antibodies)
    • Get adequate sleep
    • Good hygiene practices
    • Manage stress
    • Avoid toxins: negativity, environmental pollution, smoking

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