Anaphylactic shock | Anaphylaxis
What is anaphylactic shock?
Among the most common causes of anaphylactic shock is penicillin (1 response to 5000 exposures), insect venom and application of radiocontrast agents. Anaphylaxis is an acute, life-threatening syndrome with multisystemic manifestations. Anaphylactic shock is the maximum form of early allergic reactions (type I reaction) with acute systemic symptoms and possible lethal (fatal) outcome with the shock. Resulting in a hypersensitive patient (when the patient has already been in touch with the appropriate allergen that lead to hypersensitivity) by entering the antigen (usually parenterally - injection, infusion, insect bite and rarely via oral foodstuffs, drugs).
Possible causes are:
- Drugs (antibiotics, sulfonamides, local anesthetics)
- Serum (gamma globulin)
- Poisons insects (bees, wasps, hornets, ants)
- Hyposensitized solution (eg pollen allergens during immunotherapy)
- Hormones (insulin, estradiol, methylprednisolone)
- Enzymes (streptokinase, trypsin)
- Foods (nuts, flour, milk, fish, shellfish, egg, kiwi)
- Rubber or latex which is located in a surgical glove or gloves in the household.
How to recognize anaphylactic shock?
Commonly occurring are skin lesions: itching, redness, urticaria, angioedema. Swelling of the mucous membranes, itchy eyes, nose and mouth are common symptoms as well as swelling of the lips or tongue which may cause difficulty in breathing and swallowing. Severe signs of anaphylactic reactions are manifested in the form of obstruction of the lower and upper respiratory tract.
Clinical presentation begins immediately after entering the allergen (parenteral intake) or delayed (oral intake). Most reactions occur within one hour of exposure to the antigen. There may occur initial symptoms such as itching skin, numbness of the oral mucosa. Severe signs of anaphylactic reactions are manifested in the form of upper respiratory tract obstruction due to edema of the larynx (throat), epiglottis and surrounding tissues, and bronchoconstriction of the lower respiratory tract with the development of hypoxia. Development of cardiovascular collapse accompanied by hypotension, tachycardia (rapid heartbeat), which can lead to severe arrhythmias.
Because of affecting on gastrointestinal tract it may occur: nausea, vomiting, cramps and diarrhea. Due to reduced blood flow to the brain, and a direct toxic effect of the released mediators there can come to dizziness, restlessness, loss of consciousness.
The main symptoms of anaphylaxis:
- itching, redness, urticaria, angioedema
- dyspnea (difficulty breathing), cough
- rhinorrhea may also occurr (snuffles), "wheezing" (asthmatically breathing)
- difficulty swallowing
- nausea, vomiting, diarrhea, abdominal pain, bloating
- tachycardia (rapid, weak pulse stuffed), hypotension (low blood pressure), arrhythmia (irregular heartbeat), shock
- weakness, chills
- mydriasis (dilated pupils)
- anxiety (feeling of anxiety, fear), tremors (shivering), disturbance of consciousness, syncope (fainting), coma.
Have you ever had anaphylactic shock or someone you know? Share your experience.
Have you had anaphylactic shock?
What should be done - urgently seek medical help!
In patients who are at increased risk of anaphylactic reactions (eg people who have had an anaphylactic reaction to an insect bite or food) should always carry a self-help (eg, EPI-PEN, ANA-KIT).
Development of anaphylaxis is extremely rapid and unexpected. In such situations it is necessary to rapidly identify anaphylactic situation, because it might soon turn into anaphylactic shock, which may end fatally. It is necessary to immediately suspend the application of the drug (if that is the cause of anaphylactic reactions), to prevent further absorption of the drug, monitor vital functions (frequency and rhythm of the heart, blood pressure, heart rate, rhythm and depth of breathing), to ensure adequate oxygenation of the patient and to organize the rapid transport of patients the nearest emergency room or hospital. In patients who are at increased risk of anaphylactic reactions (eg patients who have had an anaphylactic reaction to an insect bite or food) should always carry a self-help (eg EPI-PEN, ANA-KIT). EPI-PEN is a system with a syringe needle and adrenaline for single intramuscular administration. ANA-KIT contains two doses of adrenaline pills chlorphenamine (antihistamine) for chewing. In patients with anaphylactic reactions to insect venom should undergo hyposensitization.
Treatment of anaphylactic shock
1.Adrenaline (epinephrine) vials of 1% solution of 1 cc, at a dose of 0.01 mg / kg subcutaneously or intramuscularly. In particularly difficult situations slowly intravenously diluted with saline at a ratio of 1:10. If necessary, repeat the dose every 10 - 20 minutes for up to 1 - 2 times. Immediately after application of adrenaline to find a vein while collapse hasn't yet occurred, and continue to collapse infusion of 0.9% NaCl and 5% Glucosae in the ratio 1:2.
2. Intravenous antihistamines (eg Synopen 0.5 mg / kg slowly over 5-minutes).
3. Aminophylline intravenously 5-7 mg / kg for 10-20 minutes only if it got developed laryngospasm or bronchospasm. Continue infusion mg/kg/24h 15-25. It can be given micronefrin inhalation or some selective beta2 sympathomimetic fast acting (salbutamol or procaterol).
4. Norepinephrine infusion (4-8 mg in l000 ml) with special system for regulating the speed, if the pressure remained low after all the previous interventions. Infusion rate from 0.5 to 3 ml / min. If that's not enough, it can be given dopamine 1-10 mcg / kg / min with pressure control.
5. Corticosteroids are not the treatment of acute anaphylactic shock due to slow action, but are given to prevent further development of allergic reactions.
Along with drug therapy is necessary to:
Lay patient down
Oxygen - through a mask or nasal catheter (5 L / min), as necessary to ensure the airway via oropharyngeal or endotracheal tube. If intubation is not possible due to severe edema required cricoidotomy.
Aspirated secretion from the respiratory tract, occasionally.
Aspirated gastric contents (probe) due to the risk of aspiration with possible vomiting.
Repeated control of blood pressure and pulse.
If cardiac arrest occurs it is required cardiac massage with artificial respiration.
The best prevention of anaphylactic shock is a good anamnesis. Before each injection ask the patient about possible allergic manifestations to him and his family. Nurse, who is first experiencing anaphylaxis, should be trained to have prepared antishock therapy, and to know how to give epinephrine.
Who's got the greatest risk for anaphylaxis?
Everyone who has already survived anaphylactic shock is a potential candidate to have the reaction again. People allergic to food (especially to shellfish, peanuts and nuts) and asthma are at increased risk for the occurrence of life-threatening anaphylaxis. These people are especially vulnerable because it is known that they don’t need to take daily anti-allergic medications and often don’t recognize the early symptoms.