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Anaphylactic shock is an allergic reaction which is characterized by the most violent course. It often happens after the parenteral administration of a drug or contrast agent during an X-ray examination. Symptoms of shock appear a few seconds after contact with the allergen (paling of the skin, drop in pressure, loss of consciousness, hives). Shock is a direct threat to life, so get help immediately.
Anaphylactic shock – characteristics
Anaphylactic shock (anaphylaxis) is a quick-onset and life-threatening hypersensitivity reaction in the body in response to an agent (usually food, medicine, or a bee or wasp sting). It occurs in about 3 percent. people each year. It is more common in young women and children, the cause of which is the most frequently consumed food.
Anaphylactic shock usually causes a marked reduction in blood pressure. The table below lists the most common causes of anaphylaxis, but it is important to know that this reaction may also occur in response to other, less frequent factors.
The shock may be allergic (e.g. if you are allergic to peanut allergens) or non-allergic (if you have a reaction to e.g. cold).
The most common mechanism of anaphylactic shock is sensitization to some allergen, which causes an IgE-dependent reaction and then stimulation of the so-called mast cells, which by secreting various powerful substances (primarily histamine and tryptase) cause its symptoms. Other factors can directly stimulate mast cells and other cells.
Anaphylactic shock is an allergic reaction that occurs very quickly as a result of the body coming into contact with an allergen, e.g. drugs, bee or wasp venom, or food. Symptoms of anaphylactic shock appear a few seconds after the allergen has been administered. The patient’s blood pressure drops sharply, the heart rate accelerates, the skin turns pale, the patient loses consciousness, convulsions, involuntary urination and stools may occur. On the skin – hives. Shock may be allergic or non-allergic in nature (e.g. reaction to cold). Anaphylactic shock is a direct threat to life. You should call an ambulance immediately.
Anaphylactic shock may appear already during the allergy test, but also during a longer series of injections. The person performing this procedure, e.g. at the patient’s home, should always have the so-called shock-absorbing kitbecause it allows the patient to be saved even before the ambulance arrives.
The causes of anaphylactic shock
The most common factors causing anaphylactic shock include:
1. Drugs: antibiotics (e.g., tetracycline, penicillin, aminoglycosides); non-steroidal anti-inflammatory drugs (e.g. naproxen, aspirin, ibuprofen); cytostatics (e.g., drugs for the treatment of cancer); contrast agents used in radiology; morphine; insulin; preparations used for anesthesia.
2. Inhaled allergens: here cat or dog hair and latex play a major role.
3. Foods: in adults, allergies are most often caused by peanuts, citrus and crustaceans, while in children they are chicken eggs, cow’s milk, wheat, fish, soybeans or cold and hazelnuts. Spices in the form of preservatives and dyes found in store products also have an allergenic effect.
4. Vaccines and sera: subcutaneous desensitisation injections, anti-viral vaccines and anti-tetanus serum.
5. Insect venom: wasps, hornets, bees, ants.
6. Stress.
7. Physical effort.
8. Reaction to cold or heat.
9. Blood transfusion.
Symptoms of anaphylactic shock
The action of the allergenic factor leads to various kinds of disease symptoms. They usually appear within a few minutes (sometimes seconds) and usually disappear on their own. It should be remembered that there are relapses, i.e. late reactions, appearing up to 72 hours after the first allergic reaction. In most people, anaphylactic shock causes a skin rash (hives) after taking some food or medicine. Equally dangerous are:
- palpitations,
- dizziness,
- strong weakness,
- hoarseness, dry cough
- wheezing
- shortness of breath
- diarrhea and abdominal pain
- increased heart rate, abnormal heart rhythm,
- a runny nose
- nausea and vomiting
- lowering blood pressure,
- pale skin,
- loss of consciousness and even death (usually due to severe swelling of the tissues in the throat)
- swelling of the lips and tongue.
The occurrence of complications is favored by diseases of the respiratory system (especially asthma) and the circulatory system. Preparations used by the patient may not only induce shock, but also make treatment more difficult.
Patients or their relatives should be trained in administering adrenaline to provide first aid in the event of symptoms. This is all the more important as it has been shown that the most common cause of death due to anaphylactic shock is precisely the late administration of adrenaline. Adrenaline, which is naturally secreted in our body, mobilizes it very strongly in stressful situations. It causes the blood vessels to tighten, which automatically increases the blood pressure and reduces swelling. Thus, epinephrine alleviates / reverses the effects of anaphylactic shock.
Anaphylactic shock – management
1. First of all, contact the patient with the factor that caused the shock should be severed, eg by removing the insect’s sting.
2. Then the patient should receive adrenaline intramuscularly, eg into the thigh. It can also be given by a trained person.
3. People who have been prescribed an antihistamine – should take it as soon as possible. The drug is given only in conscious people.
4. The patient should be placed in a lying position with the legs elevated.
5. After completing the above steps, the next step is to call an ambulance. Under no circumstances should the patient drive to the hospital by car alone, as this may lead to sudden loss of consciousness and catastrophic consequences.
6. If the patient has experienced respiratory or circulatory arrest – start a resuscitation action. Do not wait, because delaying the death of the sick person.
7. A patient with anaphylactic shock should remain under observation in the hospital for at least 8 hours. More severe cases are hospitalized in the intensive care unit.
8. Upon discharge from hospital, patients should be given a written plan to deal with another shock, and a prescription for epinephrine and medication.
Anaphylactic shock diagnosis
The diagnosis of anaphylactic shock is based primarily on the observation of symptoms often associated with a drop in blood pressure. The symptoms of shock are quite specific, therefore the diagnosis is not a major problem. Of course, it may happen that the patient does not pay attention to vomiting and the drop in blood pressure after eating a food. Mistakes happen – shock may be confused with, for example, bronchial asthma or food poisoning. The challenge for the physician is to determine what caused the anaphylactic shock.
As a rule, during severe shock, there is no time to investigate histamine levelsto confirm the suspicion of an anaphylactic shock. This examination should be performed up to an hour after the onset of symptoms. In addition, examination is used for diagnosis trypases in the blood. Trypase levels may be normal in patients with food allergies. In addition, the levels of these substances can fluctuate very quickly, which also makes it difficult to recognize a shock. Hence, diagnosis is made mainly on the basis of the symptoms present.
Treatment of anaphylactic shock
Treatment of anaphylactic shock, as mentioned above, requires, first of all, the fastest possible administration of adrenaline. Adults are usually administered intramuscularly from 0,3 to 0,5 mg in a dilution of 1: 1000. In addition to epinephrine, antihistamines such as clemastine and glucocorticosteroids are administered. Their main task is to alleviate and stop the build-up of symptoms. The former – soothe itching and rash, while the latter have a strong anti-allergic effect, but only start working after a few hours. They mainly prevent recurrence of anaphylactic shock.
Bronchodilators are used in people with shortness of breath. In order to prevent hypoxia of the body, the patient is given oxygen for breathing. The swelling of the tissues in the throat that occurs in anaphylactic shock makes it difficult to breathe and may cause suffocation. In this case, intubation should be performed in the patient, thanks to which breathing will be enabled. Sometimes the swelling is so large that it is necessary to perform a cricothyrotomy (insert a small tube directly through the skin of the neck into the windpipe).
Fluids are infused intravenously to avoid a large drop in blood pressure.
Symptoms of anaphylactic shock may disappear on their own in some people, and symptoms may worsen rapidly and die in others. Some people are unaware that a certain factor can trigger anaphylactic shock in them.
Persons experiencing shock may lead a normal life, but bear in mind that symptoms of shock may recur. Therefore, a complete recovery is impossible.
Anaphylactic shock – prevention
It is very important to prevent anaphylactic shock as it is a medical emergency. The main thing is to identify the trigger of the allergic reaction, and then avoid contact with it. However, this is not always possible. Therefore, before having the vaccine or receiving the drug, tell your doctor if you have had a shock in the past. Thanks to this, the doctor will be properly prepared in the event of a reoccurrence of the reaction. If you are allergic to insect venom – you can get adrenaline pre-filled syringes, which you can inject yourself intramuscularly. People at risk of shock should also carry one of the first aid kits:
- Ann-KIt – the kit includes a syringe and needle with a double dose of epinephrine, antihistamine tablets, a tourniquet and alcohol swabs;
- Epi-Pen – in the set, instead of a syringe, there is a spring-loaded pen, which is activated by pressing firmly against the skin.
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