Anaphylaxis Flashcards
What type of reaction causes Anaphylaxis?
Type 1 Hypersensitivity reaction
What is the pathophysiology of Anaphylaxis?
IgE stimulates Mast cells to release Histamine (aka Mast cell degranulation)
How is the Dx of Anaphylaxis made?
Clinical
What is the key CF that differentiates Anaphylaxis from non-anaphylactic allergic reaction?
Airway / breathing / circulation compromise
(ABC)
What can the CF of Anaphylaxis be divided into?
ABCDE
(emergency examination tings)
What are the AIRWAY CF of Anaphylaxis? (5 things)
- Lip / tongue / pharynx / epiglottis swelling
- Cough
- Swallowing difficulty
- Hoarse voice
- Stridor
What are the BREATHING CF of Anaphylaxis? (9 things)
- Tachypnoea
- Wheezing
- Cough
- Chest tightness
- SOB
- Hypoxia
- Hypercapnia
- Laryngeal oedema
- Bronchospasm
What are the CIRCULATION CF of Anaphylaxis? (10 things)
- Dizziness
- Pallor
- Tachycardia
- Clammy skin
- Drowsiness
- Collapse
- Hypotension
- Prolonged CRT
- Shock
- Arrhythmias / ECG changes
Why do you get Circulation CF in Anaphylaxis? (3 steps)
- Peripheral vasodilation + Increased permeability
- Plasma leakage from circulation
- Decreased intravascular volume
What are the DISABILITY / OTHER CF of Anaphylaxis? (6 things)
- Neuro: Confusion / Anxiety / Collapse
- GI: Abd cramping / DnV
- Other: Feeling of impending death
What are the EXPOSURE CF of Anaphylaxis? (4 things)
- Urticaria (see pic)
- Angioedema (puffy lips / eyes)
- Pruritis (itchy skin)
- Erythema
What can the Differential Dx similar to Anaphylaxis be divided into? (2 things)
- Life threatening DDx
- Non-life threatening DDx
What are the Life threatening DDx that present similarly to Anaphylaxis? (3 things)
- Life-threatening Asthma
- Septic shock
- Hereditary Angioedema
What makes Life threatening Asthma different from Anaphylaxis? (2 things)
- Resp features
- No Skin / CVS / GI features
What makes Septic shock different from Anaphylaxis?
Temp below 36 / above 38
(temp usually normal in anaphylaxis)
What makes Hereditary Angioedema different from Anaphylaxis?
No urticaria
What are the NON-Life threatening DDx that present similarly to Anaphylaxis? (4 things)
- Vasovagal episode
- Panic attack
- Breath-holding episode
- Idiopathic (non-allergic) urticaria / angioedema
What is a Breath-holding episode?
When a kid invol holds their breath after being angry / frustrated / startled / in pain
What makes a Vasovagal episode different from Anaphylaxis? (4 things)
- No urticaria / angioedema / hoarseness / wheezing
- Bradycardia (instead of tachy in anaphylaxis)
- Pallor (instead of erythema in anaphylaxis)
- Improves on lying down
What makes a Panic attack different from Anaphylaxis? (3 things)
No urticaria / hypotension / wheeze
What makes a Breath-holding episode different from Anaphylaxis?
Usually resolves within 1 min
What makes Idiopathic (non-allergic) urticaria / angioedema different from Anaphylaxis?
Skin changes only, no other CF
What are the immediate Mx options for sus Anaphylaxis? (5 things)
- A: Secure Airway
- B: 100% High flow O2 // Salbutamol if wheezing
- C: IV fluids
- D: Lie pt flat (to improve cerebral perfusion)
- E: Look for flushing / urticaria / angioedema
How do you confirm Dx of Anaphylaxis?
Serum Mast Cell Tryptase within 6 hours of event
(impressive knowledge)
What is Tryptase? (2 points)
- Something released during Mast Cell degranulation
- Stays in blood for 6 hours
What meds should you give once Anaphylaxis Dx confirmed? (3 things)
- IM Adrenaline
- Antihistamines
- Steroids
When should you repeat IM Adrenaline PRN?
Every 5 mins
What effects does Adrenaline have? (4 things)
- A-adrenergic action: Increases BP
- B-agonist adrenergic action: Increases contractility + HR + Bronchiole dilation
What Antihistamines can you give in Anaphylaxis? (2 things)
- Chlorphenamine
- Cetirizine
What Steroids can you give in Anaphylaxis?
IV Hydrocortisone
What should you do with the kid after Anaphylaxis and Tx is over?
Admit for assessment + observation
Why should you admit kids for assessment + observation after Anaphylaxis and Tx is over?
Bc they might have a Biphasic Reaction
(second anaphylaxis within 72 hours even with no allergen exposure)
What should you offer parents of a Anaphylaxis kid?
EpiPen (adrenaline autoinjector)
What is a complication of Anaphylaxis?
Anaphylactic shock
What does Anaphylactic shock involve? (3 things)
- Resp: Upper + Lower Airway narrowing
- CVS: Shock vasodilation / Increased Vasc Perm
