Immune Disorders Flashcards
Types of Immune Responses:
Altered Immune Responses:
Type I: IgE-mediated Anaphylactic reactions
-anaphylaxis, angioedema, atopic reactions (allergic rhinitis, eczema, asthma), urticaria
Type II: Cytolytic/toxic reactions
-hemolytic blood transfusion reaction
Type III: Immune Complex reactions
-autoimmune diseases (SLE)
Delayed Hypersensitivity Reactions:
Type IV: Cell-mediated response (contact dermatitis)
Immunocompetence
the body is able to identify, inactivate and destroy foreign substances
appropriate way to respond
Altered Immune Response:
Incompetent/under-responsive: severe infection, immunodeficiency disease, malignancy may occur
Overresponsive:
hypersensitivity, allergies, autoimmune diseases
Type I: Overview
occurs in pts who are highly susceptible to certain allergens
first exposure: IgE antibodies form and attach to mast cells and basophils
second and subsequent exposure: allergens attach to IgE causing cells to release chemicals-histamine, ECF-A, leukotrienes, serotonin, kinin, bradykinin which target organs/tissues and cause sx
Type I: Sx
Smooth muscle contraction increased vascular permeability Vasodilation Hypotension Pruritis increased mucus production
Type 1: Anaphylactic Reactions
Anaphylaxis:
usually occurs w/in minutes
life threatening d/t bronchial constriction and vascular collapse
if d/t injection or insect bite initially will see itching, edema, erythema at site
Shock (vascular collapse): rapid weak pulse decrease BP dilated pupils dyspnea possible cyanosis
Bronchial and angioedema
Type 1: Tx
ABC's O2 Epinephrine (0.5ml every 5-10min) Antihistamine IV steroid
*these vasoconstrict and increase BP
Type 1: Angioedema
swelling in deeper layers of skin (eyelids, lips, tongue, larynx, hands, feet, GI tract, genitalia)
progression
skin may appear normal or have reddish hue
if lesions may be itchy
several hours to days
Type 1: Atopic Reaction
occurs in 20% of population
form of allergy which is hypersensitive and occurs in part of the body that is not in contact with the allergen
inherited tendency to be sensitive to environmental allergies includes: allergic rhinitis, asthma, atopic dermatitis/eczema, urticaria
Type 1: Asthma
bronchial action d/t ECF -A (slow reacting substance of anaphylaxis) & histamine
bronchial smooth muscle contraction
excessive mucus
edema of bronchial mucosa
Type 1: Atopic Dermatitis
Eczema: chronic inherited skin disorder caused by environmental allergens an "itch that rashes" skin reaction is more generalized or can be patchy-redness, swelling, cracking, weeping of clear fluid, scaling and crusting
Tx: hydrocortison, moisturizer, hydration
Type 1: Urticaria
acute skin reaction to systemic allergen occurring in atopic person
sx: transient wheals varying in size and shape with flaring caused by histamine
rapid development post-exposure
lasting minutes to hours
itching
tx: antihistamines, epinephrine if sever and no response to antihistamine
Type II: Cytotoxic and Cytolytic Reactions Overview
Reaction d/t activated complement system which mediates the reaction - involves IgG and IgM
causes cell destruction-erythrocytes, leukocytes, platelets
seen in:
- ABO and Rh incompatibility blood transfusion reactions
- autoimmune and drug related hemolytic anemias, leukopenia, thrombocytopenia
Type II: Acute Hemolytic Transfusion Reaction Overview
90% d/t mislabeled blood product or wrong pt
develop in first 15 min of starting blood product transfusion
agglutination of RBC obstructs capillaries which blocks clotting factors and can allow bleeding
RBC destruction releases Hgb which is filtered by kidney
Kidney tubules blocked can lead to Acute Renal Injury (ARI)