Anaphylaxis and Medical Errors Flashcards
What is anaphylaxis
- An acute allergic reaction to an antigen (e.g. bee sting) to which the body has become hypersensitive
Describe what happens in the first exposure to an allergen
- Allergen
- causes TH1 to be released
- causes TH2 to be release d
- causes interleukins
- produce IL4
- produces B cells
- IgE is produced from B cells
describe what happens in the second exposure to an allergen
- IgE antibody is produce
- bridging takes place
- produces basophils and mast cells
What happens when basophils and mast cells degranulate
- they vasoactive and lead to mediator and cytokine release
- this causes release of histamine, leukotrienes, PgD2, platelet activating factor, complement system, eosinophils and neutrophil chemotactic factors, nitric oxide and tryptase
What does histamine cause to happen
- tachycardia
- headaches
- mucus secretion
- rhinorrhea
- bronchospasm
What does nitric oxide cause
- bronchospasm
- vasodilation
What does PgD2 do
- bronchospasm
- pain
- oedema
- vasodilation
What does the complement system do
- vasodilation
- bronchospasm
what does tryptase do
- proteolysis
What does platelet activating factor
- oedema
- vasodilation
- bowel contraction
- bronchospasm
- thrombi and microthrombi
How do you manage an anaphylactic reaction
- ABCDE
- diagnosis - acute onset of illness, life-threatening airway and breathing or circulation, usually skin changes
Call for help
- lie patient flat
- raise the patients legs
Adrenaline
how and how much adrenaline should you give
- adult or child more than 12 years
- child 6-12 years
- child 6 months to 6 years
- child less than 6 months
- Adrenaline (give IM unless experienced with IV adrenaline), IM doses of 1:1000 adrenaline (repeat after 5 minutes if no better)
- Adult = 500 micrograms IM
- Child more than 12 years = 500 micrograms IM
- child 6-12 years - 300 micrograms IM
- child less than 6 yers = 150 micrograms
what levels of chlorphenamine should you give
- adult or child more than 12 years
- child 6-12 years
- child 6 months to 6 years
- child less than 6 months
- adult or child more than 12 years = 10mg
- child 6-12 years = 5mg
- child 6 months to 6 years - 2.5mg
- child less than 6 months - 250 micrograms/kg
how much hydrocortisone should you give
- adult or child more than 12 years
- child 6-12 years
- child 6 months to 6 years
- child less than 6 months
- adult or child more than 12 years = 200mg
- child 6-12 years = 100mg
- child 6 months to 6 years = 50mg
- child less than 6 months = 25mg
what should you do post anaphylaxis
- consider 3 days of anti-histamines and oral steroids
- observe on HDU for at least 6 hours then review by a senior clinical
- report drug reactions to the MHRA
what post anaphylaxis investigations should you carry out
- 12 lead ECG
- CXR
- Bloods
- ABG
- urine output
- mast cell tryptase
What is the specific test for the diagnosis of anaphylaxis
- mast cell tryptase
What is mast cell tyrptase
- major protein component of mast cell secretary granules - increases in anaphylaxis
When does mast cell tryptase peak
- peak levels 1-2 hours after event
how often should you do mast cell tryptase
- three timed samples ASAP after event, 1-2 hours after the event and 24 hours after the event
What is a biphasic reactions
- recurrent epsiode
- 8-12 hours post event
- 5-25% of anaphylactic patients
- difficult to predict
What is the management of anaphylaxis
- post discharge follow up
- EPIPEN
- consider steroids/anti-histamines 3 days
- review by senior clinician before discharge
- as for initial reaction with observation >24 hours
What patients are still at risk of an anaphylaxis
- Allergen still in system
- severe slow onset idiopathic reactions
- poor access to A+E
- sever asthmatics
- previous biphasic reaction
Who should you give adrenaline auto injections to
- patients at increased risk of reaction
What happens in the allergy clinic
- RAST testing
- skin allergy testing - different allergens tested on skin and reaction monitored
- education on signs, symptoms and actions to take if reaction occurs
