Immunology - Anaphylaxis Flashcards
What is anaphylaxis?
Life threatening medical emergency caused by severe type 1 hypersensitivity reaction
What is the physiology behind anaphylaxis?
IgE stimulates mast cells to rapidly release histamine and other pro-inflammatory (mast cell degranulation) causing rapid onset of symptoms
What key feature differentiates anaphylaxis from a non-anaphylactic allergic reaction?
Airway, breathing or circulatory compromise
How does anaphylaxis present?
History of allergenic exposure
- Urticaria
- Itching
- Angio-oedema
- Abdominal pain
Some additional symptoms may be
- SOB
- Wheeze
- Swelling of larynx causing stridor
- Tachycardia
- Collapse
- Light-headed
What medications are given in anaphylaxis?
IM adrenaline- repeated after 5 minutes if needed
Antihistamines - chlorphenamine or cetirizine
Steroids - IV hydrocortisone
Why must children be closely monitored after an anaphylactic reaction?
Biphasic reactions
Can have a second anaphylactic reaction after successful treatment of first
Where should children be monitored after an anaphylactic reaction?
Paediatric unit
How can anaphylaxis be confirmed?
Serum mast cell tryptase within 6 hours
Tryptase released during mast cell degranulation, stays in blood for 6 hours
What must be done with parents after anaphylaxis?
Education and follow-up
Need to be educated on allergy, avoidance and how to spots signs of anaphylaxis
Training in BLS
Specialist referral for kids and training to use adrenaline auto-injector
What is an adrenaline auto injector?
Epipen
Jext
Emerade
What are the indications of an adrenaline auto-injector?
All children and adolescents with anaphylactic reactions
Considered in generalised allergic reactions e.g.
- Asthma needing steroids
- Poor medical treatment access (rural areas)
- Higher risk adolescents
- Nut or insect sting allergies
- Significant co-morbidities e.g. CVD
What colours are the safety caps and needles in EpiPens and Jext adrenaline injectors?
EpiPen
Cap - Blue
Needle -Orange
Jext
Cap - Yellow
Needle - Black
After administering adrenaline what should the parents do?
Massage area for 10 seconds
Phone emergency services
Second dose can be given after 5 minutes if needed
