Glossary of terms Flashcards
Anaphylaxis
exaggerated IgE mediated response to an allergen, with a hypersensitivity reaction involving several of the bodily systems, which classically manifests in profound hypotension and airway and respiratory compromise. Anaphylaxis is considered a severe life-threatening reaction that may cause death if not treated with epinephrine in a timely manner. Rapid onset within ten minutes (vaccines typically within 30 mins). Can be up to six hours!
Results from sudden, systemic release of allergenic mediators (histamine, leukotrienes, prostaglandins, tryptase) from mast cells and basophils.
Increased vascular permeability allows transfer of up to 50% of intravascular fluid to extravascular space.
Hemodynamic collapse could ocure with little or no cutaneous or respiratory symptoms.
Antibody
Proteins that are made by the immune system that attack foreign substances (antigens) such as bacteria, viruses, cancer cells and allergens. They are specific to each type of foreign substance.
Antigen
A substance that is capable of triggering the production of an antibody.
Basophils
A type of white blood cell. These cells help fight infections by releasing histamine and other chemicals that help dilate blood vessels when the immune response is triggered.
Exercise-induced anaphylaxis
An exercise induced lowering of the mast cell degranulation threshold causes the release of histamine and other mediators and leads to the symptoms of anaphylaxis. Unlike the food-dependent subset, this process is not influenced by Immunoglobulin E (IgE). The mechanism by which exercise lowers the mast cell degranulation threshold is unknown.
Hemodynamic collapse/shock
circulatory failure that results in inadequate oxygen delivery to meet tissue metabolic demand
Hemodynamic instability
A state requiring pharmacologic or mechanical support to maintain a normal BP or adequate cardiac output.
Idiopathic anaphylaxis
the cause of idiopathic anaphylaxis remains unknown. The symptoms do not differ from those of other types of anaphylaxis.
Diagnosis is by exclusion.
Clients with idiopathic anaphylaxis are categorized in four ways:
Idiopathic anaphylaxis – Generalized – infrequent
Idiopathic anaphylaxis – Generalized – frequent
Idiopathic anaphylaxis – angioedema infrequent
Idiopathic anaphylaxis – angioedema frequent
IgE
Immunoglobulin E. A class of Immunoglobulins that includes the antibodies that are elicited by an allergic substance (allergen). These antibodies attack the invading allergen. A person who has an allergy usually has elevated levels of IgE.
Mast cell
connective tissue cell whose normal function is unknown but which is frequently injured in allergic reactions, releasing chemicals including histamine that are very irritating and cause itching, swelling and fluid leakage from cells. These allergic chemicals may also cause muscle spasm and lead to lung and throat tightening.
Epinephrine
Epinephrine is the drug form of a hormone (adrenaline) that the body produces on its own. It helps to reverse symptoms of an allergic reaction by: Opening the airways. Improving blood pressure. Accelerating heart rate.
Acting on smooth muscle of the bronchial tree to reduce bronchospasm
Counteracting histamine-induced vasodilation
Increasing cardiac output
Reducing histamine release
dimenhydrinate (not indicated!)
Epinephrine is first-line treatment for anaphylaxis and there is no known equivalent substitute. H1‐antihistamines (e.g., Benadryl) relieve localized and less severe systemic allergic reactions and are not indicated as initial first-line treatment in the emergency management of anaphylaxis, as there is no effect on respiratory or cardiovascular symptoms; they are of little clinical importance in life-threatening anaphylaxis based on current evidence
