Anaphylactic shock

Anaphylactic shock (anaphylaxis) is a systemic allergic reaction of the immediate type, resulting from a rapid massive IgE- mediated release of mediators from tissue basophils and peripheral blood basal cells upon repeated body contact with an allergen.

Pathogenesis of anaphylactic shock.

There are two main mechanisms of degranulation a large number of tissue basophils (mast cells):

1) IgE -dependent (true allergic): ingestion of specific allergens -> binding to IgE molecules fixed on the surface of basophils -> activation of membrane phospholipids with the production of inositol-triphosphate and diacyl-glycerol -> activation of phosphokinase -> phosphorylation of cytoplasmic proteins, changing the ratio of cAMP and cGMF – -> increase in cytosolic Ca2 + -> basophil degranulation-> histamine secretion (-> vasodilation, increase in vascular permeability with the release of plasma from the vascular bed in the tissue and the development of edema, bronchospasm, hypersecretion of bronchial mucus and hydrochloric acid in the stomach, increased gastrointestinal motility), tryptase , chymase , carboxypeptidase A, heparin, chemotactic factors -> synthesis by basophils of new factors (prostaglandins , leukotrienes , IL-3, IL-4, IL-5, IL-10, GM-CSF, etc.)

2) independent of IgE (pseudo-allergic) – Various tissue cell and basophil activation factors , opiates, cytostatics , aspirin and other NSAIDs, muscle relaxants , autoAT to IgE , physical factors, etc. take part in its implementation .

Anaphylactic shock clinic: rapidly developing usually immediately after exposure to an allergen, generalized reactions, including pruritus, urticaria, angioedema (especially laryngeal edema), arterial hypotension, wheezing and bronchospasm , nausea, vomiting, abdominal pain, diarrhea, uterine contractions, abnormal heart function; the body’s reaction usually appears a few minutes after exposure to the causative agent and progresses explosively. Objectively: reddening of the face, urticaria, swelling of the lips, uvula, tongue or other areas, wheezing during exhalation and/or inhaled stridor , cyanosis.

The dynamics of anaphylaxis symptoms are usually the following: first, erythema or itching occurs, progressing to urticaria and angioedema, accompanied by a feeling of impending death, then complaints of dizziness, fainting, gastrointestinal symptoms (nausea, vomiting, tenesmus and diarrhea), respiratory symptoms append pathways (hoarseness, dysphonia or shortness of breath), etc.

Laboratory data confirming the case of anaphylaxis:

1. Detection of specific IgE for a suspected allergen (skin tests, immunolaboratory tests)
2. Determination of the level of histamine in the blood plasma (maximum for 10-15 minutes of anaphylaxis, returns to the initial level after 30-60 minutes), beta- tryptase (neutral protease in the secretory granules of mast cells released by degranulation ; in normal blood is not determined (<1ng / ml), with anaphylaxis, the level is maximum 1-2 h after the onset of anaphylaxis, then decreases with a half-life of about 2 h;the harder the anaphylaxis, the greater the level of beta- tryptase )

A set of necessary equipment for emergency care for anaphylaxis: 1) a stethoscope and a sphygmomanometer; 2) turnstiles, syringes, needles for subcutaneous and intravenous infusions; 3) rr adrenaline hydrochloride 0.1%; 4) oxygen and equipment for its supply; 5) pts for IV infusions and related equipment; 6) oral air ducts; 7) diphenhydramine (diphenhydramine); 8) inhaled or systemic bronchiolitics ; 9) systemic GCS; 10) vasoconstrictor agents; 11) vasoconstrictors; 12) means for maintaining cardiac activity.

Emergency care for anaphylaxis (stopping anaphylactic shock):

1. Put the patient in a horizontal position and lift the lower limbs.
2. Every 2-5 minutes check the parameters of the vital functions of the body (pulse, blood pressure, breathing)
3. If anaphylaxis has developed after injection of the drug, inject 0.15-0.3 ml of a 0.1% solution of epinephrine hydrochloride into the previous injection site (to reduce further absorption of the allergenic drug)
4. 0.1% solution of adrenaline hydrochloride 0.01 ml / kg up to a maximum dose of 0.2-0.5 ml of a sc or v / m, if necessary, repeat after 10-15 minutes ( vasoconstriction of arterioles, decrease capillary permeability, bronchodilation , suppression of mast cell degranulation )
5. Maintaining free airway, inhalation of oxygen at a rate of 8-10 l / min
6. 5 mg / kg hydrocortisone (about 250 mg) i / v jet ;repeat every 6 hours if necessary
7. Anti-histamine drugs: 25-50 mg diphenhydramine (dimedrol) parenterally.
8. In the presence of bronchospasm : euphyllin 2.4% pp 10 ml IV slowly or eufillin 24% pp 1-2 ml i / m
9. Hospitalization of the patient in the hospital (due to the possibility of recurrence of anaphylaxis, as well as for a full examination of the patient and drawing up a plan for his long-term treatment)

After stopping an anaphylaxis attack, the patient should be taught to provide self-help (self-administered adrenaline), and to avoid contact with a specific allergen.

Emergency care for anaphylactic shock should be provided when the first symptoms appear, as it can lead to the death of the victim. When this condition occurs, all body systems are affected. If a person recurs a shock reaction, it proceeds much harder than the first time.

The consequences of anaphylactic shock can occur in the form of disorders of the heart, nervous system, vestibular apparatus, the appearance of jaundice, and glomerulonephritis .

Treatment

First aid for anaphylactic shock is necessary to cause even with minimal allergies, which are accompanied by a decrease in blood pressure and a change in pulse. Patients need immediate hospitalization in reanimation, where they will be provided with qualified medical assistance in case of anaphylactic shock.

First aid for anaphylactic shock should be provided immediately before the arrival of the ambulance team and include the following actions:

• Eliminate the effects of the allergen: ventilate the room, stop administering the drug, apply a tourniquet above the injection site or bite, treat the wound with an antiseptic, apply cold.
• Lay the victim horizontally, with a decrease in pressure with slightly raised legs, turn his head to the side, extend the lower jaw, remove dentures from his mouth.
• Follow the pulse, pressure, breathing of the patient.
• To force him to take an antihistamine that is available (tavegil, suprastin, fenkarol ).
• After the arrival of the doctors, provide them with information on the exact time of the onset of the reaction, the symptoms, the help provided, the history, if known.

Emergency assistance for anaphylactic shock, which the ambulance team at the scene provides, includes the following activities:

• All drugs are administered intravenously or intramuscularly.
• The injection site of the substance that caused the allergy is cut off with a 0.1% solution of adrenaline in the amount of 1 ml.If there is no increase in blood pressure, it is administered again at a dose of 0.5 ml.
• Glucocorticosteroid hormones: prednisone 1-2 mg / kg patient weight, hydrocortisone 150-300 mg.
• Assisting with anaphylactic shock includes the introduction of antihistamines: 2% suprastin solution 2 ml, 1% dimedrol 5 ml.
• Bronchospasm is stopped by the introduction of a 24% solution of aminophylline 2 ml.
• Heart failure is eliminated by diuretics ( diacarb , lasix, furosemide) and cardiac glycosides ( digoxin , strophanthin ).
• If anaphylactic shock is caused by the use of penicillin, the enzyme penicillinase is used in the amount of 1 million units.
• Free the airways from mucus.
• Through the nasal catheter injected oxygen.
• The algorithm of assistance for anaphylactic shock involves the re-introduction of medication every 15 minutes until the proper effect occurs.

Resuscitative actions during anaphylactic shock include artificial respiration, closed heart massage, tracheostomy , artificial ventilation of the lungs, catheterization of the central vein, and adrenaline injection into the heart. After elimination of the acute effects, the victim should undergo desensitization therapy for another 2 weeks.