E3 Hypersensitivity Flashcards
Hypersensitivity is a ______ immune response that is _____
normal
inappropriately triggered or excessive or produces undesired effects on the body
Hypersensitivity type I, II, III = mediated by
B cell Plasma cell antibodies
Hypersensitivity type IV = mediated by
T-cells
Type I Key characteristics
-Immediate response (15-20 mins)
-Reaction occurs after being sensitized to an antigen
-Environmental (pets dander, bee stings)
-Foods (nuts, seafood, eggs)
-Medications (penicillin, contrast dye)
Type 1 Key cells involved:
- B lymphocytes
- IgE
- Mast cells (granulocyte)
Talk through the Type 1 pathogenesis
- The B cell becomes activated after 1st exposure
- the Activated B plasma cell makes larges amounts of IgE
- IgE antibodies attach to mast cells
- Next time person is exposed to the allergen it binds to the IgE antibodies triggering the release of chemical mediators from the mast cell
- Get physical response: Anaphylactic shock, atopic dermatitis, angioedema, Rhinitis, asthma, N/V/D, cramping
Chemical mediators from mast cells cause what mediator activity? (4)
- Potent vasodilation: stuffy nose, lower BP, Wheals on skin
- Increased vascular permeability (Edema, Runny nose)
- Bronchial smooth muscle contraction (Breathing difficulties, wheezing)
- Stimulates irritant receptors (Itching aka pruritis)
What is Type I Atopic reactions?
-Localized
-Inherited tendency to becomes sensitive to allergens
Ex. Allergic rhinitis, asthma, urticaria
-Most common triggers: pollen, dust, animal dander, mold
What is Type I Anaphylaxis reaction?
-Systemic release of chemical mediators
-Life threatening: Bronchial constriction, vascular collapse, airway obstruction
-Most common triggers: Meds, Bee stings, Nuts
What causes a Type II reaction?
-Exposure to antigen or foreign tissue/cells
-Antigens are located on cell surface
-Like giving somebody the wrong blood type or transplant pts or Erythroblastosis fetalis (RH factor)
Key characteristics of Type II reactions?
- Antigens stimulate antibody production
- Antibodies recognize and attach to cell surface antigens (Antigen-Antibody complex)
- Direct destruction of targeted cells that contain the antigen (Cell lysis & phagocytosis)
Immune cells involved in Type II reactions?
- IgG & IgM
- Complement (fix foreign cells & lyse it)
- WBCs
What is the major problem with type II reactions?
The debri & clumping in small vessels reduces blood supply blocking supply to small vessels
Type II Manifestations Transfusion Reaction
-Fever, chills, flushing
-Increase HR & BP
-Chest pain or back pain
-N/V
-Restlessness & Anxiety
-Headache
What is Type III reaction?
-Autoimmune attack (Rhematoid arthritis)
-Low grade infection (bacteria or viruses
-Inhaled antigens from molds or contaminated plants
Key characteristics of Type III reations?
- Antigen-Antibody complexs form
- These are deposited into tissues
- Inflammatory response causes tissue damage
Key immune cells involved in type III
- IgG & IgM clump w/ antigens
- Complement
- Neutrophils & Mast cells
Clinical manifestations of Type III depends on _____
where the complexes are deposited in the tissue
1. Rheumatoid arthritis (Primarily the joints)
2. Glomerulonephritis (kidney failure)
3. Systemic lupus erythematosus (skin & many organs)
What is the main difference between Type II & III?
Type II-reactions occur on the cell surface and result in direct cell death or malfunction
Type III- Immune complexes are deposited into tissues and the resulting INFLAMMATION destroys the tissue
What is Type IV Hypersensitivity?
-Plant oils (Poison Ivy)
-Tuberculin antigen (Positive TB skin test)
-Jellyfish sting
-Allergic reaction to jewelry
-Gluten (Crohns disease)
-Organ transplant or skin graft
-Adhesives
Key characteristics of Type IV?
-Delayed hypersensitivity response 48-72 hrs)
-No antibody involvement
Key Immune cells of Type IV?
- T cells
- Cytokines
- Mast cells & macrophages
Steps of a Type IV response?
- Small, incomplete antigen, Hapten penetrates the skin
- Hapten combines with human protein (APC) to form complete antigen
- APC alerts T cells of antigen
- T cells attack the antigen via:
-Direct attack of the T cells
-Release of cytokines (inflammation)
-Macrophages (cell destruction)
Type IV contact dermatitis manifestations
Redness, edema, itching, blisters
Type IV Tuberculin hypersensitivity
Redness, Induration, Inflammation
Antihistamines
Suppress histamine mediator activity
Immunosuppressants (including corticosteroids)
Suppresses cell-mediated immunity
-Anti-inflammatory
Epinephrine MOA
Halts mediatory activity from mast cells
Classification of Epinephrine
Vasopressor
Bronchodilator
Anti-asthmatic
Vasoconstrictor
Indication of Epinephrine
Severe allergic reaction
Cardiac arrest
Severe asthmatic attack
Major side effects of epinephrine
Angina
Arrhythmias
Hypertension
Tachycardia
Nervousness
Restlessness
Tremor
Route of epinephrine
All EXCEPT PO
Overdose can be FATAL
Nursing considerations for epinephrine
-Monitor vitals closely
-Monitor for reversal of symptoms
-Overdose can be fatal: heart attack
-Have coworker recheck dose
-Contact clinician directly after taking this
