Anaphylactic shock is a shock associated with a reaction of the organism against a particular antigen. This is therefore an immunological reaction antigen-antibody (IgE) and not a nonspecific histamine release by the action of a molecule on the membrane causes mast cell degranulation her. For example, atracurium (curare) has the distinction of being histamine particularly when it is injected quickly, it is not an anaphylactic reaction, but a non-specific histamine release in this case. However, there is a molecule that can trigger a true anaphylactic reaction.
Anaphylactic shock is an emergency
The allergens most frequently implicated are the products of iodinated contrast, quaternary ammonium compounds (curare), the beta-lactams, the wasp venom, latex, sulfites …
Anaphylactic shock is classified into four grades, depending on the size of the reaction:

Grade I : Observe mainly skin reactions with swelling, hives without marked haemodynamic compromise, sometimes preceded by premonitory symptoms such itching, burning

Grade II: In addition to a fall in blood pressure accompanied by tachycardia reaction, the patient begins to experience difficulty breathing, coughing

Grade III: The patient shows signs of previous grades with a respiratory distress, bronchospame from laryngospasm, arrhythmias and conduction

Grade IV: cardio-circulatory arrest

Pathophysiology:
Hypersensitivity type I
Step One: Awareness
First contact with antigen (Ag) With production of antibodies (Ab) of IgE will bind to the membranes of basophils and mast cells;
Second step: contact the following:
Attachment of Ag and IgE bridge formation on the membranes of target cells,
Massive release of histamine: cutaneous vasodilation, bronchoconstriction, collapse, inhibiting the release of norepinephrine

Treatment:
Shock Grade I:

  • Stop the administration of the antigenic substance suspected
  • Surveillance monitoring: TA, rhythm, saturation, respiratory rate and ST segment analysis
  • Intravenous
  • Supine, legs elevated


Shock Grade II:
I ditto + epinephrine 10 to 20 min γ/1-2 (γ = microgram) and oxygen mask, high concentration

Shock Grade III:
adrenaline from 100 to 200 min γ/1-2

Shock Grade IV:
MCE / BAVU + adrenaline 1mg/2-3 min (some authors recommend 5mg from the third reinjection).
In shock grade II, III and IV filled with concomitant isotonic crystalloid and colloid.
C as individuals:
In pregnant women:
Setting the left lateral position to avoid vena cava and start with ephedrine (αβ indirect) than 10mg/kg. If ineffective, switch to the adrenaline.

Bronchospamse predominant:
Use of inhaled salbutamol (β2 +), if inefficient relay 100 micrograms IV bolus IV then SAP.
Inhaled nebulized epinephrine, Bricanyl
Steroids are not the first line treatment of bronchospasm
Laryngospasm predominant:
If no improvement with the combination of adrenaline and IV nebullisation, intubation in rapid sequence induction

Patient beta-blocker:
Increasing doses of epinephrine
Glucagon 1-2mg IVD / 5 min

Allergy testing:
Tryptase at 30 min 120 + / – histamine (but degrades very quickly)
Doubt whether specific IgE (eg quaternary ammonium IgE if curare suspect)
Urinary methyl-histamine after 3 to 4 hours
Investigations allergy 6-8 weeks

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