Chapter 16-Disorders of the Immune Response Flashcards
What is the immune response?
Defense network that has evolved to protect against invading microorganisms
Prevents proliferation of cancer cells (natural killer cells)
Mediate the healing of damaged tissue
Hypersensitivity disorders
Excessive/inappropriate activation of immune system
Type 1 - immediate hypersensitivity disorders
Type 2 - antibody-mediated disorders
Type 3 - immune complex - mediated disorders
Type 4 - T cell mediated disorders
Hypersensitivity disorder Type 1
“Allergic reactions”
Begin rapidly
Mediators are released from mast cells
Phases 1. Initial or early response -vasodilation (BP v) -vascular leakage -smooth muscle contraction Occurs within 5-30 mins and subsides within 60 mins
- Secondary or late phase
- sets in about 2-8 hours later and lasts for several days
What is the antigen responsible for a Type 1 reaction called?
allergen
What is a systemic Type 1 reaction called?
Anaphylactic shock
Widespread vasodilation (BP v = not getting to organs)
Airway constriction
When mast cells degranulate, histamine is released?
True
Histamine is one of the first chemical mediators released
What are mast cells?
Granulocytes found in connective tissue
We don’t know normal function, yet
Activated when injured
Anaphylaxis
Systemic response to inflammatory mediators released in Type 1 hypersensitivity
Histamine, acetylcholine, kinins, leukotrienes, and prostaglandins all cause vasodilation
Acetylcholine, kinins, leukotrienes and prostaglandins all can cause broncho-constriction (inability to breathe)
Why give epinephrine for anaphylaxis?
Epinephrine is a potent vasoconstrictor, which will help reverse the extreme vasodilation that caused the blood pressure to decrease and not allow blood to get to the organs.
Type II sensitivity
Antibody mediated hypersensitivity reaction
ONLY SYSTEMATIC
Mediated by IgG or IgM
Blood transfusion reactions
Newborns with incompatible ABO or Rh factors (RoGam)
sometimes in drug reactions
- cell destruction (lysis)
- can be fatal
What happened if incompatible blood is given in transfusion?
Hemolysis (cells blow up)
Not only are cells not able to carry oxygen but the broken up pieces of RBCs (large) go back through kidneys and can actually block kidneys and cause renal failure
Type III hypersensitivity
Immune mediated disorder
Systemic or local
Immune complexes produce inflammatory effect - damages are tissue (deposit in tissues)
Serum sickness - insoluble complexes are deposited in vessel tissue
May cause local tissue necrosis because of deposits
Type IV hypersensitivity
Cell mediated hypersensitivity disorder
Occurs when tissue damage causes cell mediated immune responses with T-lymphocytes causing cell and tissue injury
Allergic contact dermatitis
“Atopic allergic reaction”
inflammatory process of the skin
Re-exposure to an allergen - “hives”
Autologous graft
same person transplant
Syngenetic graft
from a twin
Allogenetic graft
same species
Self tolerance
Mechanism where host recognizes what cells are self (host) cells and what are non self cells (antigen)
Alloantigens
Recognized as foreign
Graft vs host
When the host attacks and rejects the transplanted organ/tissue
T cells are central to causing the rejection
Most autoimmune diseases are more common in women than men?
True
Maybe an estrogen link
What are local autoimmune diseases?
Discoid lupus
Atropic gastritis
Autoimmune adrenalitis
Temporal arteritis
What are some systemic autoimmune diseases?
Systemic lupus erythmatosus
Rheumatoid arthritis
Scleroderma
Autoimmune hemolytic anemia
Immunodeficiency disorders of B cell function
Impairs the ability to produce antibodies
Immunodeficiency disorders of T cell function
Impairs the ability to orchestrate the immune system
Cannot protect against intracellular infection/cancer
Immunodeficiency disorders combined B and T cell dysfunction
Affect all aspects of immune function
Absence of immune system
“Bubble Boy”
Acquired immunodeficiency syndrome
AIDS
Caused by infection with HIV
Causes profound immunosuppression
Currently a pandemic (spreading)
HIV - if carrying disease
AIDS - infection
Pathophysiology of HIV
Carries genetic material in RNA (retrovirus)
HIV 1 or HIV2
most common in US is HIV 1
Infects CD4, T helper cells, macrophages and dendritic cells
CD4 + T cells are necessary for immune functions
What are the 8 steps to HIV replication?
- Binds to CD4+ T cell
- Uncoating - RNA is injected into cell
- DNA synthesis - uses reverse transcriptase enzyme
- Integration - new DNA enters nucleus (integrase)
- transcription - DNA makes single strand RNA
- translation - ribosomal RNA uses mRNA to create polyprotein
- cleavage - protease enzyme cuts polyprotein chain into individual proteins that will make new virus
- Proteins and viral RNA are assembled into new HIV viruses and releases.
Primary phase of HIV infection
2-4 weeks after exposure
Last few days to 2 weeks
Latency phase of HIV infection
No signs or symptoms
Median time is 10 years
Can see lymphadenopathy (swollen lymphoid tissue)
Overt AIDS phase
CD4 + T cell count is less than 200 cells/microliter
Can lead to death within 2-3 years
Increases risk of opportunistic infection
Window period
Time receiving infection to when it shows up positive (about 25 days)
Symptoms of AIDS
Pheumocytosis Pneumonia
Opportunistic infections of respiratory tract
PCP pneumocystis pneumonia
TB
Opportunistic infections of the GI tract
Thrush
Herpes simplex
Esophagitis
Diarrhea (salmonella, giardia, c-difficile)
Nervous system infections caused by HIV
(usually late complications)
AIDS dementia complex
Cognitive and motor dysfunction
Opportunistic infections of the nervous system
Taxoplasmosis (parasite that invades CNS)
Karposi sarcoma
Malignancy of endothelial cells that line small blood vessels
Most frequent malignancy associated with AIDS
Lesions can be found on skin, in mouth, GI tract, lungs
Non Hodgkin lymphoma
AIDS more susceptible
Fever, night sweats, weight loss
Cervical dysplasia
Progress rapidly to cervical cancer in women with HIV
Wasting syndrome
AIDS defining illness
Involuntary weight loss of at least 10% of baseline body weight with the presence of diarrhea
Diagnosis made when no other cause can be identified (anorexia, metabolic abnormalities, endocrine dysfunction and malabsorption all contribute)
Cachectic - wasting away
Cachectic
wasting away
What is a nurses role in HIV/AIDS?
Astute infection control
Excellent respiratory assessments (lungs are usually where first infection shows up)
Hand washing
Protect not only self from infections but protect patient from opportunistic infections
What are the diagnostic methods for HIV and AIDS?
ELISA test and the Western Blot
Is there treatment for HIV or AIDS?
No cure
Multiple drug combinations are used to delay disease process, decrease severity of symptoms and in some cases, stop seroconversion
Can often be problems with compliance because there are so many pills to take and maybe not enough money to pay for them all or simply the patient does not want to take so many pills.
Urticaria
hives
Dermatitis
inflammation of the skin
What are some examples of Type III Hypersensitivity?
- “Farmer’s Lung”
- Reactive Arthritis
Histiocompatability
important for organ transplants
-Is the new organ compatible with the host body?
Discuss Autoimmune Diseases.
- immune system can no longer distinguish self from non-self antigens
- unknown etiology
- environmental factors could contribute
- genetic susceptibility could increase incidence and severity of autoimmune diseases
- not uncommon for a person to end up with multiple autoimmune diseases
Discuss Immunodeficiency Disorders.
- congenital or inherited
- renders a person susceptible to disease normally prevented by an intact immune system
- Disorders of B cell function
- Disorders of T cell function
- Combined T and B cell dysfunction
How is HIV Transmitted?
- sexual contact
- blood to blood contact
- infected mother to offspring
- Transfusions of blood products before 1985
- Needle sharing
- Occupational HIV infection among healthcare workers is uncommon (needle-stick)
- Can be transmitted even when no symptoms are present
