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Flashcards in Anaphylaxis Deck (20):

What is anaphylaxis?

"A serious, life-threatening generalized or systemic hypersensitivity reaction" and "a serious allergic reaction that is rapid in onset and might cause death"


Describe the pathophysiology of anaphylaxis

Anaphylaxis is an acute, systemic allergic reaction
For an immunologic reaction:
1. During an initial exposure, an individual will form IgE antibodies to an antigen = sensitization (typically no reaction)
2. Subsequently, when the individual is exposed to the antigen, it will bind to the IgE antibodies. This triggers the release of vasoactive and inflammatory mediators from mast cells and basophils (histamine, platelet activating factors, glucotrienes, etc.)
3. This leads to the potential development of urticaria, angioedema (swelling of deep tissue), bronchospasm, hypotension and/or GI symptoms
Often, signs and symptoms occur within 30 minutes after exposure, but sometimes may not appear for several hours


The World Allergy Organization has divided human anaphylaxis into three categories. Name them:

Immunologic (which can be further divided into IgE mediated and non-IgE mediated)


What is the clinical criteria for anaphylaxis?

Any one of the following three criteria fulfilled:
a. Acute onset of an illness (minutes to several hours) with the involvement of the skin, mucosal tissue or both AND at least one of the following:
-respiratory compromise
-reduced blood pressure or associated symptoms of end-organ dysfunction
b. Two or more of the following that occur rapidly after exposure to a likely allergen (minutes to several hours)
-involvement of skin/mucosal tissue
-respiratory compromise
-reduced blood pressure or associate symptoms
-persistent gastrointestinal symptoms
c. Reduced blood pressure after exposure to known allergen (minutes to several hours)


What are patterns of anaphylactic reactions?

There are three patterns:
1. Uniphasic
2. Biphasic
3. Protracted


Describe the uniphasic pattern of anaphylaxis

Isolated reaction with signs and symptoms usually appearing within 30 minutes of exposure to allergic and spontaneously settles or resolves with treatment, generally within 1 to 2 hours


Describe the biphasic pattern of anaphylaxis

Anaphylactic reaction resolves, then symptoms begin again usually within 8 hours of first symptoms. Occurs in up to 20% of patients experiencing anaphylaxis


Describe the protracted pattern of anaphylaxis

Severe reaction that lasts for an extended time (24 to 32 hours)


What are the signs and symptoms of anaphylaxis?

Cutaneous reactions
Respiratory reactions
Gastrointestinal reactions
Cardiovascular reactions
Other reactions


What are signs and symptoms of anaphylaxis specific to children?

Sudden behavioural changes (irritability, stop playing, cling to parent)


What are common triggers?

Foods (peanuts, tree nuts, shellfish, fish, milk, eggs, sesame, food additives)
Drugs (antibiotics, NSAIDS and biologics)
Insect stings (honeybees, yellow jackets, hornets, wasps and fire ants)


How is anaphylaxis treated?

CPR (if breathing is affected)
Epinephrine (inject immediately, hold injector for 10 seconds- repeat after 10 minutes if needed)
Seek medical attention


How does epinephrine help treat anaphylaxis?

It opens airways, relieves histamine attack


What are the two delivery systems available in Canada?

Allerject (has an electronic voice instruction system)
Ensure to always council on the proper use of self-injectors. Also be aware that they expire


What are common adverse effects of epinephrine?

Pallor (decrease in skin colour)


What are the cutaneous signs and symptoms?

Hives or welts, severe itching, flushing or redness of the skin, swelling


What are the respiratory signs and symptoms?

Throat and chest tightness, difficulty breathing, wheeze, cough or swelling of the tongue, lips, uvula/palate, itching of the throat, nose (itchy, congestion, runny and sneezing)


What are the GI signs and symptoms?

Difficult or painful swallowing, nausea or vomiting, abdominal cramping, diarrhea


What are the cardiovascular signs and symptoms?

Hypotension, chest pain, dysrhythmias, palpitations, tachycardia, bradycardia


Besides cutaneous, respiratory, GI and CV, what are other signs and symptoms?

Lightheadedness, dizziness, sweating, feeling of impending doom, uneasiness, headache, confusion, tunnel vision, uterine contractions