Anaphylaxis Flashcards
What is anaphylaxis?
A severe, life threatening hypersensitivity reaction involving the airways, breathing and circulation
What type of hypersensitivity reaction is anaphylaxis?
Type 1
What happens during the first exposure to an antigen?
IL-4 is released which causes B cells to switch their production of IgM to IgE
IgE binds to mast cells and basophils making the cells sensitised
What happens during the second exposure to an antigen?
Cross linkage of the sensitized cells cause mast cell degranulation
This results in bronchoconstriction and vasodilation
What are the risk factors for anaphylaxis?
Asthma
Mast cell disorders
Allergies to things that people are commonly exposed to
What are the differentials of anaphylaxis?
Severe asthma attack
Septic shock
Hereditary angioedema
Panic attack
Idiopathic urticaria or angioedema
What is the presentation of anaphylaxis?
Wheezing
Tachycardia
Face swelling
Abdominal pain
Vomiting
Urticaria
Pruritis
Flushed skin
What is the most important treatment of anaphylaxis?
IM adrenaline (1:1000)
What is the general treatment of anaphylaxis?
Call for help
Remove trigger
Lie patient flat and raise legs
Adminster adrenaline
What doses of adrenaline are given to different age children?
6 months - 6 years = 150 mcg
6 years to 12 years = 300 mcg
12+ years = 500mcg
