Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Type 1 -IgE Mediated Response Mast cells (which lie near the skin, respiratory tract, GI tract, and mucous membranesplaces in the body exposed to environmental allergens) and basocells (which are blood cells) release potent mediators of allergic reactions (histamine, acetylcholine). They do this when allergens bind to the IgE antibodies for what is called the second exposure. Granulation occurs on these subsequent exposures and that is when these inflammatory mediators are released. On the first exposure to the allergen the desensitization and granulation does not occur. Therefore mediators are not released. Systemic Anaphylactic disorders Examples of mediators/allergens 1. PCN 2. Radiocontrast dyes 3. Bee or wasp stings 4. Seafood 5. Nuts legumes What you’ll see Bronchospasm Angiodema (swelling of then face) Massive vasodilatation- (circulatory shock) Treat: Treat symptoms of airway constriction and circulatory collapse with epinephrine for its B2 effects on airway, and vasoconstrictive effects on arterial system, and lots of fluids for vascular space as well. Antihistamines (Benadryl) Localized atopic disorders (high levels of IgE & exquisitely reactive to mediators) Examples of mediators/allergens 1. Allergic Rhinitis 2. Pollens 3. Ragweed 4. Grass/weeds 5. Spores 6. House dust mites 7. Animal dander What you’ll see Nasal symptoms Sneezing, itching watery discharge from eyes Attacks accompanied by malaise and fatigue “Hay fever” seasonal Household allergen- worse at night Treat: symptomatic relief, antihistamines, decongestants, intranasal corticosteroids Food allergies: Examples of mediators/allergens 1. Milk 2. Eggs 3. Peanuts 4. Soy 5. Tree nuts 6. Fish 7. Shellfish What you’ll see Acute reaction=anaphylaxis Chronic reaction=asthma, atopic dermatitis, GI disorders Diagnosis of food allergies requires a careful history, and “provacative diet testing”. This means the suspected food needs to be eliminated from the diet for a period of time to see if symptoms disappear. Then re-introduce foods to see if they reappear. One food is tested at a time. Treat: Avoidance of the food responsible for the allergy. Type 11- Antibody Mediated Cytotoxic Disorders Result of IgG and IgM class antibodies interacting with tissue/cell surface antigens. Subsequent activation of “complement” or cellmediated cytotoxicity (the cell is doomed) occurs. Examples: 1. Mismatched blood transfusions 2. Hemolytic disease of the newborn caused by ABO or Rh incompatibility 3. Certain drug reactions—The binding of the allergic drug to the surface of the RBC or WBC elicits an antibody and complement response that lyses the drug coated cell. POW! (Lytic drug reactions can produce anemia, leucopenia, thromboctypenia) What you may see Vasodilation Hypotension Flushing tachycardia. You may also see: headache, chest pain chills pain or burning along the vein back pain fever dyspnea Treat: Stop the transfusion! Stop giving the drug! Type 111 –Immune Complex Disorders Immune complex disorders are mediated by the formation of antigen-antibody complexes (immune complexes) that in turn activate complement. Activation of complement (which causes release of Vasoactive mediators) causes tissue damage by altering blood flow, increasing vascular permeability, and by the destructive action of inflammatory cells. Immune complexes produce damage both in the vascular lining itself and the organs where they may deposit (kidney, lung, joints) and causing an inflammatory response. The harmful effects are indirect, secondary to the inflammatory response induced by complement. Examples of antigens that cause immune complex related injury: 1. Exogenous antigens- viral proteins and bacterial proteins Acute glomerulonephritis that follows a streptococcal infection 2. Endogenous antigens- self antigens associated with autoimmune disorders Systemic lupus erythematosus (SLE) Urticaria Patchy or generalized rash Extensive edema (face, neck, and joints) Fever Damage can be temporary and resolve within a few days or prolonged and continuous and lead to irreversible damage. Type 1V Cell- Mediated Hypersensitivity Occurs 24-72 hours after exposure to the offending antigen. It is mediated by T-cells that are Cytotoxic and release inflammatory chemicals in the surrounding tissue. These substances attract T or B lymphocytes. The coagulation cascade is activated causing formation and deposition of fibrin. P.S. It is these Cytotoxic T-cells that that destroy cancer cells. Examples: 1. Reaction to the tuberculin test 2. Allergic contact dermatitis 3. Latex allergy 4. Poison ivy 5. Transplant reaction 6. Crohn’s disease Modulation of symptoms Corticosteroids Immunosuppressive drugs