Anaphylaxis

Question 1

What is anaphylaxis?

Answer 1

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

Question 2

Describe the pathophysiology of anaphylaxis

Answer 2

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

Question 3

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

Answer 3

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

Question 4

What is the clinical criteria for anaphylaxis?

Answer 4

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)

Question 5

What are patterns of anaphylactic reactions?

Answer 5

There are three patterns:

1. Uniphasic
2. Biphasic
3. Protracted

Question 6

Describe the uniphasic pattern of anaphylaxis

Answer 6

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

Question 7

Describe the biphasic pattern of anaphylaxis

Answer 7

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

Question 8

Describe the protracted pattern of anaphylaxis

Answer 8

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

Question 9

What are the signs and symptoms of anaphylaxis?

Answer 9

Cutaneous reactions
Respiratory reactions
Gastrointestinal reactions
Cardiovascular reactions
Other reactions

Question 10

What are signs and symptoms of anaphylaxis specific to children?

Answer 10

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

Question 11

What are common triggers?

Answer 11

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)
Latex

Question 12

How is anaphylaxis treated?

Answer 12

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

Question 13

How does epinephrine help treat anaphylaxis?

Answer 13

It opens airways, relieves histamine attack

Question 14

What are the two delivery systems available in Canada?

Answer 14

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

Question 15

What are common adverse effects of epinephrine?

Answer 15

Anxiety
Tremors
Pallor (decrease in skin colour)
Tachycardia

Question 16

What are the cutaneous signs and symptoms?

Answer 16

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

Question 17

What are the respiratory signs and symptoms?

Answer 17

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)

Question 18

What are the GI signs and symptoms?

Answer 18

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

Question 19

What are the cardiovascular signs and symptoms?

Answer 19

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

Question 20

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

Answer 20

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