Allergic Reactions Flashcards
anaphylaxis mechanisms
Immunologic
In the immunologic mechanism, immunoglobulin E (IgE) binds to the antigen (the foreign material that provokes the allergic reaction). Antigen-bound IgE then activates FcεRI receptors on mast cells and basophils. This leads to the release of inflammatory mediators such as histamine. These mediators subsequently increase the contraction of bronchial smooth muscles, trigger vasodilation, increase the leakage of fluid from blood vessels, and cause heart muscle depression. There is also an immunologic mechanism that does not rely on IgE, but it is not known if this occurs in humans.
Non-immunologic
Non-immunologic mechanisms involved substances that directly cause the degranulation of mast cells and basophils. These include agents such as contrast medium, opioids, temperature (hot or cold), and vibration.
humoral immunity
(also called the antibody-mediated system) is the aspect of immunity that is mediated by macromolecules (as opposed to cell-mediated immunity) found in extracellular fluids such as secreted antibodies, complement proteins and certain antimicrobial peptides. Humoral immunity is so named because it involves substances found in the humours, or body fluids.
cell mediated immunity
Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria. It also plays a major role in transplant rejection.
immune response that does not involve antibodies but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. Historically, the immune system was separated into two branches: humoral immunity, for which the protective function of immunization could be found in the humor (cell-free bodily fluid or serum) and cellular immunity, for which the protective function of immunization was associated with cells. CD4 cells or helper T cells provide protection against different pathogens. Cytotoxic T cells cause death by apoptosis without using cytokines, therefore in cell mediated immunity cytokines are not always present.
ALLERGEN
substance causing an exaggerated immune response
ANAPHYLAXIS
Exaggerated immune response
allergen binds to IgE
IgE binds to mast cell
mast cell degranulation
release histamine
effects of histamine (H1 and H2 receptors)
inflammation - swelling
bronchconstriction
vasodilatation
histamine
released by body in anaphylaxis
- contraction of bronchial smooth muscles,
- stimulation of vascular permeability, and
leukotiene
other chemical released by the body in anaphylaxis
They exhibit a number of biological effects such as - contraction of bronchial smooth muscles,
- stimulation of vascular permeability, and
- attraction and activation of leukocytes.
Compared to histamine, which causes constriction of airways and edema formation, the leukotrienes are three to four orders of magnitude more potent and the effects have longer duration
H1 RECEPTORs on our lungs cause
When stimulated it causes bronchoconstriction
What effect H2 RECEPTORs have on our GI tract & Blood Vessels
Throwing up or Diarrehea - on the blood vessels they dilate
What position should a patient having an allergic Rx be in?
lay them flat
What drug is a histamine blocker
benedryl
Dosage of epinephrine
epinephriene
adult 0.3mg pedi 0.15mg
bronchodialator
vasoconstrictor
name 2 of the allergens
ant, bee, shellfish, peanuts….. Common allergens
sound a patient having anaphylaxis might make
wheezing
adult dose epi
.3mg
pedi dose
.15 mg
list symptoms
swelling, flushing, warm, tingling feeling in face, mouth, chest, feet or hands
for a pt epi is only given when they have trouble breathing or blood pressure bad
epi
you respond to a child with hives and good blood pressure
take to hospital and monitor in route
anaphylaxis
respiratory arrest or signs and symptoms of shock
side effects of epi
Epinephrine is a chemical that narrows blood vessels and opens airways in the lungs. These effects can reverse severe low blood pressure, wheezing, severe skin itching, hives, and other symptoms of an allergic reaction.
- Increased heart rate
- Increased cardiac workload
Allergic Reactions
• Immune system naturally responds to foreign substances in body
Allergic reaction
exaggerated response to foreign substance