Anaphylactic shock

What is
anaphylactic shock?

Anaphylactic shock is a severe, generalised, systemic hypersensitivity (or allergic) reaction which can be life-threatening.

This reaction is characterised by sudden-onset upper or lower airway and/or cardiovascular involvement and is potentially fatal.

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A unique symptom:
Quincke’s oedema

Quincke’s oedema is a severe form of allergy. It is characterised by facial oedema, especially affecting the eyelids and lips, associated with a sensation of heat.

The onset of itching of the pharynx, voice changes and inspiratory breathing difficulties are manifestations of the pharyngeal-laryngeal involvement and the imminent risk of breathing difficulties. The oedema can affect other parts of the body. It can be isolated or associated with an urticaria attack.

Aetiology

General aspects – pathophysiology

The major risk of anaphylactic shock is due to the cardiac and respiratory complications. The drop in blood pressure can lead to loss of consciousness or even a cardiac arrest. These symptoms are increased in the event of associated respiratory involvement (asthma).

List of allergens responsible for anaphylactic shock

The substances that can be held responsible for severe manifestations of immediate hypersensitivity are as follows:

General anaesthetics and certain forms of curare

Hymenoptera stings (bees, wasps, hornets)

Nuts: peanuts, walnuts, hazelnuts, etc.

Painkillers: aspirin, lidocaine, morphine derivatives

Injectable iodine contrast media

Antibiotics, particularly penicillins

But also latex, foods (fish, shellfish, egg, milk, cold meats, etc.), plasma volume expanders, ACE inhibitors, etc.

Management

As soon as the symptoms are recognised, an ambulance must be called (dial 15).

 

If the patient is known to be allergic, a dose of adrenaline must be injected. This comes in the form of an easy-to-use auto-injector pen.

 

The pen must be held in the dominant hand, then the needle and injection trigger button covers must be removed. The injection must be made into the thigh muscle, directly or through clothing. The pen must be held in place for ten seconds. The injection site must then be rubbed.

 

In certain cases, if the symptoms do not improve, a second injection is necessary. It can be given 5-10 minutes after the first.

Useful links

French association for allergy prevention
https://allergies.afpral.fr/

Asthma and allergy association
http://asthme-allergies.org/

National agency for drug and health product safety
ansm.sante.fr