Anaphylaxis

Symptoms

The clinical symptoms of anaphylactic shock depend on the individual characteristics of the patient's body (sensitivity of the immune system to a particular allergen, age, the presence of concomitant diseases, etc.), the method of penetration of a substance with antigenic properties (parenterally, through the respiratory tract or digestive tract), the predominant "shock organ" (heart and blood vessels, respiratory tract, skin). At the same time, characteristic symptoms can develop both at lightning speed (during the parenteral administration of the drug), and 2-4 hours after meeting with the allergen.

Anaphylaxis is characterised by acute disorders of the cardiovascular system, including myocardial infarction (pain behind the sternum, fear of death, hypotension), tachycardia, extrasystole, atrial fibrillation, and a drop in blood pressure with the onset of dizziness, weakness, and fainting. Asphyxia, wheezing, bronchospasm, dysphonia, rhinorrhea, and severe shortness of breath are all respiratory symptoms of anaphylactic shock. The symptoms of neuropsychiatric illnesses include a severe headache, convulsive syndrome, psychomotor agitation, fear, and anxiety. Uncontrollable urination and defecation are symptoms of malfunction in the pelvic organs. Anaphylaxis skin indicators include erythema, urticaria, and angioedema.

Depending on how severe the anaphylaxis is, the clinical picture will change. There are four severity degrees:

•    With i degree of shock, blood pressure (bp) is decreased by 20–40 mm hg despite the small breaches. Art. There may be a rash on the skin, dryness in the throat, a cough, soreness below the sternum, a sense of heat, overall anxiousness, and no disruption of consciousness.

•    For the ii degree of anaphylactic shock, the complications are often more severe. Systolic and diastolic blood pressure both fall to 60 to 80 mm hg at the same time. Fearful feelings, overall weakness, dizziness, rhinoconjunctivitis symptoms, skin rash with itching, quincke's edoema, trouble swallowing and speaking, lower back and belly discomfort, feeling heavy behind the sternum, and shortness of breath at rest are all causes for concern. Repeated vomiting is common, and urine and faeces are difficult to manage.

•    Iii degree: a drop in systolic blood pressure to 40–60 mm hg art. And a rise in diastolic pressure to 0 are indicators of the severity of shock. Loss of consciousness occurs together with other symptoms including dilated pupils, chilly, sticky skin, thready pulse, and convulsive syndrome.

•    Iv degree: occurs quite quickly. As a result of the patient's unconsciousness, it is impossible to assess the patient's blood pressure, pulse, cardiac activity, or breathing. The patient needs immediate resuscitation in order to survive.

After emerging from shock, the patient is still weak, listless, feverish, myalgic, arthralgic, short of breath, and experiencing heart discomfort. There might be stomach discomfort, nausea, and vomiting. After the immediate symptoms of anaphylactic shock have subsided (in the first 2-4 weeks), sequelae frequently appear in the form of periarteritis nodosa, allergic myocarditis, hepatitis, glomerulonephritis, bronchial asthma, and recurrent urticaria.
 

Causes

Any substance that enters the human body can become an allergen leading to the development of an anaphylactic reaction. Anaphylactic reactions often develop in the presence of a hereditary predisposition (there is an increase in the reactivity of the immune system - both cellular and humoral). Anaphylactic shock is most frequently caused on by:

•    Introduction of medications. These are antibacterial (antibiotics and sulfonamides), hormonal agents (insulin, adrenocorticotropic hormone, corticotropin and progesterone), enzyme preparations, anesthetics, heterologous sera and vaccines. An overreaction of the immune system can also develop on the introduction of radiopaque preparations used in instrumental studies.

•    Bites and stings. The bites of snakes and insects (bees, bumblebees, hornets, and ants) are other causes of anaphylactic shock. In 20–40% of bee sting incidents, beekeepers experience anaphylaxis.

•    Food allergy. Anaphylaxis often develops on food allergens (eggs, dairy products, fish and seafood, soy and peanuts , food additives, dyes and flavors, as well as biological products used to process vegetables and fruits). Thus, in the united states, more than 90% of cases of severe anaphylactic reactions develop on hazelnuts. In recent years, the number of cases of the development of anaphylactic shock on sulfites, food additives used for a longer preservation of the product, has become more frequent. 
•    Physical factors. The sickness can also be brought on by a combination of certain meals (most frequently prawns, almonds, chicken meat, celery, white bread), following physical activity, and other physical elements (work connected with muscular stress, sports training, cold and heat). Activities (gardening, sports, swimming, running, etc.)

•    Allergy to latex. Cases of anaphylaxis to latex products (rubber gloves, catheters, tire products, etc.) Are becoming more frequent, and cross- allergy to latex and some fruits (avocados, bananas, kiwi) is often observed.

Treatment

Treatment is carried out in the clinic and consists of three stages:
•    Etiotropic therapy. It is aimed at the rapid elimination of the cause of the pathological condition - the irritant that provoked the allergic reaction. It is necessary to stop contact with the allergen - rinse the stomach with oral medication or use of an allergenic product, pull out a bee sting or pull the limb with a medical tourniquet 5-6 cm above the site of the snake bite (injection).

•    Pathogenic therapy. It is focused on stopping anaphylaxis, correcting metabolic, cardiological, respiratory, hormonal or other disorders. The patient is injected intramuscularly or subcutaneously with a solution of adrenaline . Single adult dose - 0.5 ml, children - 0.3 ml. In a serious condition, adrenaline is administered intravenously through a dropper. To restore homeostasis - the volume, composition of extracellular and intracellular fluids - colloidal solutions are parenterally injected into the bloodstream. Large doses of injectable glucocorticosteroids are used to stop spasms, reduce vascular permeability, achieve a positive inotropic effect (increase in the strength of heart contractions). Unlike uncomplicated types of allergies, antihistamines are very rarely used in anaphylactic shock.due to lack of efficiency. In severe cases, the patient is connected to resuscitation equipment.

•    Symptomatic therapy. It is carried out taking into account the diagnosed deviations. With bronchospasm, aerosol bronchodilators are prescribed ( salbutamol , fenoterol), with persistent hypotension - drugs for low blood pressure , with severe edema - diuretics .
The patient is transferred from the intensive care unit to a regular ward for 2-3 days, and is discharged from the clinic for 7-10 days. Further treatment depends on the identified or predicted complications. The patient is sent under the supervision of the attending physician at the place of residence (with dispensary registration).
 

Tests Required for Diagnosis

The diagnosis is based on clinical symptoms, since there is usually no time for a detailed examination of the patient. A description of the circumstances under which the development of anaphylaxis began - a bee sting, taking a medicine, or eating a culinary dish - can help the doctor. If the patient cannot speak, the anamnesis is compiled from the words of relatives, friends or passers-by.
The inspection includes:
•    Evaluation of the state of the skin and mucous membranes;Determination of reflexes, clarity of consciousness;
•    Measurement of blood pressure, pulse, depth and frequency of breathing;
•    Auscultation of the chest.
A comprehensive examination is carried out after the provision of emergency medical care.
Diagnostic methods
When the patient returns to a stable state, appoint:
•    Lab tests. In the blood, the concentration of histamine and the enzyme tryptase, ph, coagulogram, leukocytes, erythrocytes, total and specific ige are determined. In the urine - histamine metabolites.
•    Allergy tests. Include skin tests to identify a specific allergen, provocative tests for an irritating factor.
•    Functional research. To assess the state of the cardiovascular and respiratory systems, an ecg, daily monitoring of blood pressure, holter monitoring, pulse oximetry, chest x-ray, and capnogram are performed.
Additional diagnostic procedures are prescribed based on the patient's well-being.

Differential diagnosis
Anaphylaxis and anaphylactic shock should be distinguished from other conditions:
•    An acute attack of bronchial asthma - usually develops within a few days, there are no skin symptoms, blood pressure is within normal limits or elevated;
•    Fainting - there are no skin and respiratory symptoms, sometimes bradycardia is observed;
•    Angioedema - in this condition, the injected glucocorticosteroid is little effective or does not help at all ;
•    Other types of shock - traumatic (after injury), posthemorrhagic (after blood loss), septic (against a severe infection).