Anaphylactic shock – how to recognize it and how to proceed?

Generalized erythema, itching, hives, edema? These are often the first symptoms of anaphylaxis, a sudden and severe allergic or non-allergic hypersensitivity reaction that is life-threatening. In the event of an anaphylactic shock, you cannot wait – every minute counts. The “prescription” is adrenaline, served as soon as possible …

Patomechanism anafilaksji

What exactly is anaphylaxis? The word itself comes from Greek: ana means “opposite” and phyl means “protection”. According to the definition of the European Academy of Allergology and Clinical Immunology (EAACI), anaphylaxis is a severe, life-threatening, systemic or generalized immediate hypersensitivity reaction [1]. According to various sources, the incidence of anaphylactic reactions ranges from 30 to 950 cases per 100000 people per year, with the mortality rate not exceeding 1%. [2]. Children, adolescents, women, as well as people suffering from atopic diseases, in the case of whom even a small contact with a sensitizing substance can potentially cause a severe allergic reaction, are in the highest risk group [3].

Most often, anaphylaxis associated with allergic reactions, mainly IgE-dependent, may also be associated with non-allergic hypersensitivity, in the course of which no immune mechanisms are involved. In the case of allergic anaphylactic reactions, symptoms appear after repeated contact with the allergen. However, in the case of non-allergic anaphylactic reactions, symptoms may appear at the first contact with the triggering agent. Importantly, regardless of the pathomechanism of the anaphylactic reaction, the treatment procedure is the same [4].

Food, drugs, venom …

Just about any substance can cause an anaphylactic reaction. In the case of children, it is most often food. In turn, among adults, these are drugs, especially antibiotics, as well as insect venom from bites or stings. Less common anaphylaxis is caused by latex or food additives such as monosodium glutamate or food dyes. According to various observations, in about 1/3 of cases the cause remains unknown (idiopathic anaphylaxis) [5].

The most common foods that trigger anaphylaxis are: nuts of various kinds, mainly peanuts, seafood, fish meat, cow’s milk, chicken eggs, sesame seeds, soybeans and wheat, less often fruits and vegetables. In children who develop an anaphylactic reaction caused by an allergen contained in food, it is possible that the allergy subsides with age [6].

In terms of medications, anaphylaxis most often occurs with beta-lactam antibiotics such as penicillin, aspirin, and non-steroidal anti-inflammatory drugs. Apart from drugs, anaphylactic reactions can be caused by contrast agents, blood preparations, blood substitutes (mainly dextran), sera, and latex [4].

Hymenoptera insects are the most common insects whose venom causes anaphylaxis: bees, wasps, hornets and ants [4].

Warning signals

The first symptoms of anaphylaxis usually appear several to several dozen minutes after the triggering stimulus was triggered. In the case of food, the reaction may occur up to several hours after a meal [4]. The most commonly affected parts of the body are skin (80-90%), lungs and airways (70%), stomach and intestines (30-45%), heart and blood vessels (10-45%) and central nervous system (10-15%) [8].

In most patients, the first symptoms of an anaphylactic reaction affect the skin and mucous membranes. Generalized erythema, pruritus, hives or edema, which may be preceded by tingling in the hands and feet, is observed [4].

Respiratory symptoms may be related to the presence of rhinitis, swelling of the tongue, mouth, throat, larynx (upper respiratory tract edema) and bronchial obstruction [4]. The most common ones are: short and difficult breathing, hoarseness, laryngeal wheezing (stridor), cough, shortness of breath, blockage and runny nose.

Gastrointestinal symptoms such as nausea, vomiting, cramping abdominal pain, loose stools, or the genitourinary system: urinary bladder pressure, urinary incontinence are much less common [4].

In cases of severe anaphylaxis, symptoms of tissue blood flow impairment are observed. The skin of patients in anaphylactic shock is pale, cool, moist, subcutaneous veins are collapsed, a drop in blood pressure (hypotonia), threadlike pulse, impaired consciousness, convulsions, oliguria or anuria are observed [9].

All these symptoms can be classified according to their severity, which allows to distinguish four stages of reaction. In the initial stage of anaphylaxis, there is a reaction at the point of contact with the sensitizing factor, i.e. redness, skin changes, slight swelling. These reactions are often accompanied by feelings of dread, anxiety and headache. The second stage is more dangerous – in addition to changes in the skin, there may be heart palpitations, shortness of breath, nausea, abdominal pain, vomiting and fear of death. In the third stage, all the symptoms listed above are present, in addition, there are swelling of the throat and larynx, impaired consciousness, and a state of reduced muscle tone. In the fourth stage, there is cardiopulmonary failure and, as a result, death [10].

SOS for the sick

There is no difference in the management of anaphylactic shock symptoms in children and adults – it includes general measures and symptomatic treatment.

The general procedure is to stop exposure to the trigger and reduce its penetration by applying a tourniquet above the exposure site and cooling it down. In the event of a bee sting, the sting should be properly removed to prevent further amounts of venom from reaching the skin. In addition, the patient should be placed in a supine position with elevated limbs, except in cases with predominant symptoms of airway obstruction. Maintaining constant verbal contact with the patient is also an element of the general procedure. It is important for two reasons – firstly, it facilitates monitoring of his condition, and secondly, it reduces the feeling of fear of death [11].

In emergency procedures, it is necessary to assess and ensure the patency of the airways, assess respiratory efficiency and blood circulation. Properly early application of oxygen therapy prevents hypoxia of tissues and organs and enables the proper operation of symptomatic drugs. The most important interventions, however, include the administration of adrenaline as soon as possible, not without reason called a life-saving drug. It can be administered subcutaneously, intramuscularly, intravenously or in the form of nebulization. There are many benefits to using adrenaline intramuscularly. First of all, it does not require intravenous puncture and can be administered quickly and safely [4].

“Recipe for shock”

According to experts, an element of preventive health care and a life-saving solution for patients with an increased risk of anaphylaxis is an automatic disposable injector with adrenaline (epinephrine), which you can always have with you. The pen is used intramuscularly in the anterolateral part of the thigh and it does not even require taking off your clothes. The procedure for administering the drug is very simple. In the event of an anaphylactic shock, the solution should be administered intramuscularly according to the following rules:

1. remove the cap from the tube,
2. hold the auto-injector in your hand and remove the protective cap,
3. lift the pen about 10 cm from the thigh,
4. hit the orange tip on the anterolateral part of the thigh (through clothes) at a 90-degree angle,
5. hold down after you hear a click (the solution will be dispensed automatically),
6. pull out the pen
7. massage the injection area for about 10 seconds in order to distribute the solution more quickly over the body,
8. if there is no clear improvement, repeat the application of the solution after 5-15 minutes,
9. After dispensing the solution, carefully insert the auto-injector with the needle first into the tube which has a built-in needle guard. Then screw the cap tightly on the tube and dispose of the pen safely [12].

The pen is available for both children and adults.