Treatment of an anaphylactic reaction from vaccination in a dog. Anaphylactic shock in animals: symptoms and treatments
Anaphylactic shock type of allergic reaction of the immediate type that occurs when the allergen is repeatedly introduced into the body. Anaphylactic shock is characterized by rapidly developing predominantly general manifestations: a decrease in blood pressure (blood pressure), body temperature, blood clotting, CNS disorder, increased vascular permeability and spasm of smooth muscle organs.
Most often, the symptoms of anaphylactic shock occur 3-15 minutes after contact with the drug. Sometimes the clinical picture of anaphylactic shock develops suddenly ("on the needle") or several hours later (0.5-2 hours, and sometimes more) after contact with the allergen.
The most typical is the generalized form of drug-induced anaphylactic shock.
This form is characterized by the sudden appearance feelings of anxiety, fear, severe general weakness, widespread skin itching skin hyperemia. Perhaps the appearance of urticaria, angioedema angioedema different localization, including in the larynx, which is manifested by hoarseness of voice, up to aphonia, difficulty in swallowing, the appearance of stridor breathing. Animals are disturbed by a pronounced feeling of lack of air, breathing becomes hoarse, wheezing is heard at a distance.
Many animals experience nausea, vomit, abdominal pain, cramps, involuntary act of urination and defecation. The pulse on the peripheral arteries is frequent, threadlike (or not detected), the level of blood pressure is reduced (or not detected), objective signs of shortness of breath are detected. Sometimes, due to severe edema of the tracheobronchial tree and total bronchospasm, there may be a “silent lung” picture on auscultation.
Animals suffering from pathology of cardio-vascular system , the course of drug anaphylactic shock is quite often complicated by cardiogenic pulmonary edema.
Despite the generalization clinical manifestations drug anaphylactic shock, depending on the leading syndrome, five of its variants are distinguished: hemodynamic (collaptoid), asphyxial, cerebral, abdominal, thromboembolic.
At different types In animals, the development of anaphylactic shock is accompanied by various circulatory and respiratory disorders. Based on the nature of the disorders of these functions, some researchers (N. N. Sirotinin, 1934; Doerr, 1922) distinguish several types of anaphylactic shock in animals. Tract anaphylactic shock in guinea pigs can be called asphyxic, since the earliest and leading symptom of anaphylactic shock in these animals is bronchospasm, which causes asphyxia; Against the background of the latter, circulatory disorders of the asphyxic type develop for the second time. Arterial pressure first rises sharply due to the excitation of the bulbar, vasomotor center during hypercapnia. In the future, paralysis of this center develops, blood pressure catastrophically falls and death occurs. In guinea pigs and rabbits, during anaphylactic shock, excitation of the respiratory center is observed, which radiates to the motor center on the vessel; in the future, inhibition of these centers occurs, which is expressed in respiratory depression and a drop in blood pressure.
In dogs, anaphylactic shock develops in a different pattern; it can be characterized as anaphylactic shock of the collapse type. Hence the name anaphylactic collapse, used by some authors. The leading manifestation of anaphylactic shock in dogs is circulatory disorders in the organs. abdominal cavity. There are stagnation in the liver, spleen, kidneys and in the vessels of the intestine.
Circulatory disorders in the abdominal organs are the result of antigen exposure to neural mechanisms regulation of vascular tone in the abdominal organs. The antigen also has a direct effect on the smooth muscles of the wall of the hepatic veins and some other blood vessels in the abdominal cavity. In many wild animals - bears, wolves, foxes - anaphylactic shock, like in dogs, proceeds through the mire of collapse. In rabbits with anaphylactic shock, circulatory disorders in the pulmonary circulation are the leading ones. There is an increase in blood pressure in pulmonary artery caused by spasm of the pulmonary arteries.
In rats and mice, anaphylactic shock is characterized by circulatory disorders in the systemic and pulmonary circulation. Anaphylaxis in these animal species is discussed in a separate section.
In cats and in wild animals of the feline order (lions, tigers, leopards, panthers, etc.), anaphylactic shock approaches the type of shock in dogs with the flow. However, due to the high excitability of the autonomic nervous system and its parasympathetic division, one of the primary signs of anaphylactic shock in these animals is a sharp slowdown in heart rate up to a short-term cardiac arrest.
Anaphylaxis is a medical term for a severe allergic reaction, which in some cases can be fatal. Most often, it is caused by the ingestion of some substances that cause rejection in the body. Sometimes they can get through food, sometimes through scratches or injections. Delay in taking relief measures can lead to anaphylactic shock, respiratory failure and heart failure. The result of inaction is death. However, help is possible.
What substances can cause anaphylaxis in dogs?
In fact, there are a lot of options, but there are the most common ones. Here is a rough list of them:
- Vaccines and drugs
- food products
- Certain hormones and antibiotics
- Insect bites
Symptoms of Anaphylaxis in Dogs
Signs of anaphylaxis can be very unpleasant phenomena:
- state of shock
- convulsions
- Diarrhea
- Gums turn pale and limbs get cold
- Vomit
- The heartbeat becomes more intense, but the pulse weakens
One of the main hallmarks- swelling in the face.
Helping your dog with anaphylaxis
In view of advanced level The danger of this disease from the owners needs special promptness. Contact your veterinarian as soon as possible. You will need to enter adrenaline (epinephrine), and urgently. A few minutes of delay can cost lives. Sometimes the veterinarian may administer drugs (fluid/oxygen) intravenously as appropriate.
Is it possible to prevent anaphylaxis in dogs?
Unfortunately, it is almost impossible to predict the substance-allergen. And if anaphylaxis, rash or Quincke's edema has already occurred in a dog, it remains only to be observant and notice which substances caused these phenomena. In particular, it is important to cooperate with the veterinarian in the use of drugs and vaccines that caused allergies in the dog. Information about this must be entered in her medical card.
A dog may experience discomfort during vaccination. And if, in addition, it is observed allergic reaction, then the specialist needs to take the situation under enhanced control. If the dog needs to be vaccinated, an antihistamine should be given first. And only then, after the introduction of the vaccine, you can observe the reaction for about 20-30 minutes. In some cases, you can replace certain vaccines with others.
Do you know that…
Vaccines sometimes contain antibiotics as preservatives. And if your dog is allergic to some antibiotics, it is worth checking the vaccines for their presence. If you do this in advance, before use, you can avoid problems.
Situation. Your pet is not suffering from food and medicine, but is too sensitive to insect bites. What to do?
1. First of all, even before a critical problem arises in connection with a bite, a consultation with a veterinarian is required. He will suggest options for prompt assistance in case of angioedema or angioedema. acute form anaphylactic reaction.
2. You may be advised to have a disposable syringe with a dose of adrenaline. If a reaction starts to develop, you can use it for first aid even before the veterinarian arrives. Since it is only sold by prescription, you cannot buy it without a doctor's recommendation.
It is especially important to have a plan emergency care during a trip when prompt intervention by a veterinarian is not possible. It is also impossible to completely protect a pet from bites.
NOTE! An anaphylactic reaction sometimes occurs not after the first, but after reintroduction vaccines. Therefore, if everything went well the first time, this does not mean that there will be no allergies. Even after 3, 5 or 10 injections, an anaphylactic reaction may first appear.
The intensity of the anaphylactic reaction does not depend on how old the animal is. However, the dog's general predisposition to allergies should encourage owners to special attention treat possible manifestations anaphylaxis. If skin rashes or swelling have already appeared, an anaphylactic reaction to medications can occur at any time.
Due to the wide distribution food additives, flavorings and preservatives, the current century can rightfully be called the "era of allergy", since this pathology is found almost everywhere. And not only among people, but also among our smaller brothers. This condition is extremely dangerous. For example, anaphylactic shock in dogs often leads to the death of a pet, since the owners are far from always aware of the signs that should immediately take the animal to the veterinary clinic.
This is the name of the extremely difficult pathological condition. In fact, this is a strong, generalized allergic reaction that develops as a response to repeated exposure to a sensitive animal. specific antigen. By the way, for the first time, anaphylaxis was studied precisely on the example of dogs. If you disassemble the term, then it consists of two parts: "Ana", that is, "reverse" and "Philax", that means - "protection". That is, the word of this can be translated as "Abnormal, excessive protection." In general, the way it is, because anaphylactic shock occurs with an inadequate, excessive response of the body's immune system to some substance that has fallen into it. For the first time, such a phenomenon was recorded when the experimental dogs were subcutaneously injected with an extract from the tentacles of sea anemones.
Main types
Depending on the “leading” lesion, experts distinguish five variants of anaphylactic shock in dogs at once:
- Collapse (hemodynamic variety).
- Asphyxial.
- Cerebral.
- Abdominal.
- Thromboembolic.
Read also: Encephalitic tick in dogs
Hemodynamic shock is characterized by a sharp change in the volume of circulating blood (the appearance of collapse), as well as other phenomena that are caused by circulatory disorders in the pulmonary circulation (including pulmonary edema). However, the latter is more characteristic of the asphyxic variety, when spasms of the respiratory tract are especially pronounced. The most uncharacteristic is the cerebral variant, when the dog has serious mental disorders. She becomes unusually active, can run in circles without stopping or showing signs of fatigue (classic symptoms of brain damage). As a rule, everything ends with subsequent death from deep functional disorders in the cerebral cortex. In a lighter version, the dog shows signs of intense fear, sweats, whines and hides in the most remote and dark nooks and crannies.
Signs of the abdominal form at first are very similar to the symptoms of an aggravated: the dog whines due to severe pain, does not allow to probe the stomach, the visible mucous membranes turn pale, become cold. Often happens
Michaet S. Lagutchik, D.V.M. answers questions about anaphylaxis.
1. What is systemic anaphylaxis?
Systemic anaphylaxis is an acute, life-threatening reaction resulting from the formation and release of endogenous chemical mediators and the action of these mediators on various organ systems (mainly the cardiovascular and pulmonary systems).
2. Name the forms of anaphylaxis. Which of them develops the most severe emergency?
Anaphylaxis can be systemic or local. The term anaphylaxis is commonly used to describe three separate clinical conditions: systemic anaphylaxis, urticaria and angioedema. Systemic anaphylaxis resulting from a generalized massive release of mast cell mediators is the most severe form. Urticaria and angioedema - local manifestations immediate hypersensitivity reactions. Urticaria is characterized by blistering or rash, involvement of superficial dermal vessels, and varying degrees itching. With angioedema, the deep vessels of the skin are involved in the process with the formation of edema in the deeper layers of the skin and subcutaneous tissues. Although uncommon, urticaria and angioedema may progress to systemic anaphylaxis.
3. What are the main mechanisms for the development of anaphylaxis?
Two main mechanisms cause activation of mast cells and basophils and hence anaphylaxis. Anaphylaxis is most often caused by immune processes. Non-immune mechanisms lead to anaphylaxis much less frequently, and this syndrome is called an anaphylactoid reaction. Essentially, there is no difference in treatment, but recognition of the mechanism allows a better understanding of potential causes and leads to a faster diagnosis.
4. What is the pathophysiological mechanism of immune (classic) anaphylaxis?
At the first contact of sensitive individuals with the antigen, immunoglobulin E (IgE) is produced, which binds to the surface receptors of effector cells (mast cells, basophils). Upon repeated exposure to an antigen, the antigen-antibody complex induces calcium flow into the effector cell and an intracellular cascade of reactions leading to degranulation of previously synthesized mediators and the formation of new mediators. These mediators are responsible for the pathophysiological reactions in anaphylaxis.
5. What is the pathophysiological mechanism of non-immune anaphylaxis?
The development of anaphylactoid reactions occurs by two mechanisms. In most cases, there is direct activation of mast cells and basophils by drugs and other chemicals(i.e., idiosyncratic pharmacological or drug reactions). The subsequent effects are similar to the classic anaphylaxis described above. With this form of anaphylaxis, prior exposure to the antigen is not required. More rarely, activation of the complement cascade leads to the formation of anaphylatoxins (C3a, C5a), which cause degranulation of mast cells with the release of histamine, increase smooth muscle contraction and promote the release of hydrolytic enzymes from polymorphonuclear leukocytes.
6. Tell us about the mediators of pathophysiological reactions in anaphylaxis.
Anaphylaxis mediators are divided into: 1) primary (previously synthesized) and 2) secondary. Primary mediators include histamine (vasodilation; increased vascular permeability; contraction of bronchial, gastrointestinal, and coronary arteries); heparin (anticoagulation; possible bronchospasm, urticaria, fever and anticomplementary activity); chemotactic factors of eosinophils and neutrophils (chemotactic for eosinophils and neutrophils); proteolytic enzymes (formation of kinins, initiation of disseminated intravascular coagulation; activation of the complement cascade); serotonin (vascular responses) and adenosine (bronchospasm, regulation of mast cell degranulation).
Secondary mediators are also produced by eosinophils and neutrophils through other mechanisms after being activated by primary mediators. The main secondary mediators are metabolites of arachidonic acid (prostaglandins and leukotrienes) and platelet activating factor. These mediators include prostaglandins E2, D2 and I2 (prostacyclin); leukotrienes B4, C4, D4 and J4; thromboxane A2 and platelet activating factor. Most of these mediators cause vasodilation; increase vascular permeability; enhance the formation of histamine, bradykinin, leukotrienes and chemotactic factors; lead to bronchospasm; promote platelet aggregation; stimulate chemotaxis of eosinophils and neutrophils; cause cardiodepression; increase the formation of bronchial mucus; cause the release of platelets; enhance the release of granules of polymorphonuclear cells. Some mediators (prostaglandin D2, prostaglandin I2, and eosinophil products) limit the hypersensitivity reaction.
7. What are the most common causes development of anaphylaxis in dogs and cats?
8. What are the target organs of an anaphylactic reaction in cats and dogs?
The main target organs depend on the type of anaphylaxis. Local anaphylaxis (urticaria and angioedema) usually causes skin and gastrointestinal reactions. The most common skin symptoms- itching, swelling, erythema, characteristic rash and inflammatory hyperemia. The most common gastrointestinal symptoms are nausea, vomiting, tenesmus, and diarrhea. The main target organs for systemic anaphylaxis in cats are the respiratory and gastrointestinal tract; in dogs, the liver.
9. What are the clinical symptoms of an anaphylactic reaction in dogs and cats?
The clinical manifestations of systemic anaphylaxis in dogs and cats differ considerably.
In dogs, the earliest signs of anaphylaxis are agitation with vomiting, defecation, and urination. As the reaction progresses, breathing is inhibited or disturbed, a collapse develops associated with muscle weakness, and cardiovascular collapse. Death can occur quickly (within about 1 hour). Autopsy reveals severe liver congestion with portal hypertension because the liver is the main target organ in dogs. An appropriate examination of the liver before death to identify this symptom is rarely possible.
Cats have the most early sign anaphylaxis - itching, especially on the face and head. Typical manifestations of anaphylaxis in cats are bronchospasm, pulmonary edema and, as a result, severe respiratory distress. Other symptoms include laryngeal edema and upper airway obstruction, profuse salivation, vomiting, and loss of coordination. Severe violation of respiratory and cardiac activity leads to collapse and death.
10. What is anaphylactic shock?
Anaphylactic shock is the terminal phase of anaphylaxis, which develops as a result of neurogenic and endotoxic changes in many organ systems, especially the cardiovascular and pulmonary. Primary and secondary mediators cause changes in microcirculation, which leads to the accumulation of 60-80% of the blood volume in the peripheral bloodstream. Important factor with anaphylaxis - an increase in vascular permeability and the release of fluid from the vessels. Mediators also cause hypovolemia, arrhythmias, decreased myocardial contractility, and pulmonary hypotension, which eventually lead to tissue hypoxia, metabolic acidosis, and cell death. Clinical signs of anaphylactic shock are not pathognomonic; they are similar to those of severe cardiopulmonary collapse from any other cause.
11. How soon does anaphylaxis develop?
Usually almost immediately or within a few minutes after exposure to the agent causing it. However, the reaction may be delayed by several hours. In humans, anaphylaxis reaches its maximum severity within 5-30 minutes.
12. How to diagnose systemic anaphylaxis?
Diagnosis is based on history, physical examination and clinical picture. Constant vigilance for anaphylaxis is necessary for rapid diagnosis and start treatment. The key point in the diagnosis of systemic anaphylaxis is the rapid progression clinical signs target organ damage in animals of each species and history of recent exposure of the animal to a substance that causes anaphylaxis.
13. Immediate recognition and treatment is the criterion for successful treatment of anaphylaxis. What is the differential diagnosis for this?
Conditions that should be ruled out as soon as possible when examining animals with symptoms of severe systemic anaphylaxis include acute diseases respiratory system(asthma attack, pulmonary edema, pulmonary embolism, spontaneous pneumothorax, aspiration foreign body and paralysis of the larynx) and acute cardiac problems (supraventricular and ventricular tachyarrhythmias, septic and cardiogenic shock).
14. What is initial treatment systemic anaphylaxis?
Emergency treatment for anaphylaxis includes airway and vascular access, intensive fluid therapy, and adrenaline administration. Depending on the severity of the condition, respiratory care ranges from oxygen therapy through a face mask to orotracheal intubation; sometimes a tracheostomy is required. AT artificial ventilation animals may need severe defeat respiratory tract, pulmonary edema and bronchospasm. For the introduction of solutions and drugs, it is important to provide vascular access, preferably central venous. Infusion therapy prescribed based on severity of shock, but veterinarian should be prepared to administer shock doses of isotonic crystalloid solutions and possibly colloids. The use of adrenaline is a cornerstone in the treatment of anaphylaxis, as it eliminates bronchospasm, maintains blood pressure, inhibits further degranulation of mast cells, increases myocardial contractility and heart rate, and improves coronary blood flow. The recommended dose is 0.01-0.02 mg/kg intravenously. This corresponds to 0.01-0.02 ml/kg 1:1000 adrenaline hydrochloride solution. If venous access fails, a double dose can be administered intratracheally. In severe cases, with persistent hypotension and bronchial constriction, the dose is repeated every 5-10 minutes or epinephrine is administered by continuous infusion at a rate of 1-4 mcg / kg / min.
15. What is adjuvant therapy with systemic anaphylaxis?
Adjuvant therapy for anaphylaxis includes the use of antihistamines, glucocorticoids, and, if necessary, additional supportive measures to treat hypotension, pulmonary edema, bronchoconstriction, and arrhythmias. Although antihistamines and glucocorticoids act slowly enough and may not be useful in the initial period of anaphylaxis treatment, they play a role. important role in the prevention of late reactions and complications caused by secondary mediators. The most commonly used antihistamine is diphenhydramine (5-50 mg/kg, slowly intravenously 2 times a day). Some authors recommend the competitive use of H2 antagonists (eg, cimetidine 5–10 mg/kg orally every 8 hours). Of the glucocorticoids, dexamethasone sodium phosphate (1-4 mg/kg intravenously) and prednisolone sodium succinate (10-25 mg/kg intravenously) are most often prescribed. Cdopamine (2-10 mcg/kg/min) is often used to support blood pressure and heart function. Aminophylline (5-10 mg/kg intramuscularly or slowly intravenously) is recommended in cases of persistent bronchoconstriction.
16. If the initial treatment of systemic anaphylaxis was successful, does this mean that the animal escaped the threat of death?
Of course, it is not safe to let the animal go home. Delayed reactions are often noted in animals that have experienced the immediate effects of systemic anaphylaxis. Such conditions are caused by secondary mediators and occur 6-12 hours after the first attack. To prevent these potentially lethal reactions, careful observation of the animal, intensive treatment for shock, and pulmonary complications, use antihistamines and glucocorticoids. It is advised to hospitalize the animal for at least 24 hours and monitor closely for signs of possible complications.
An anaphylactic reaction or anaphylactic shock is a hypersensitivity reaction to a foreign substance, especially a protein.
What causes anaphylactic shock?
Before anaphylactic shock occurs, the animal must be under the influence of the allergen. A typical example is a dog stung by a bee, which subsequently develops hypersensitivity to bee stings. After the first sting, there is usually a local reaction to the bite, also called the humoral reaction. This reaction causes the immune system to produce immunoglobulin E, which binds mast cells. The massive cells are responsible for the redness and swelling (urticaria) you see at the bite site. The patient is also said to be sensitive to bee toxins. After the dog's second sting, the sensitive mast cells recognize the foreign protein (bee toxins) and start a process called degranulation. In mild cases of anaphylactic shock, there is a local reaction, such as severe swelling at the site of the bite. In severe cases, released a large number of mast cells throughout the body, leading to somatic anaphylactic shock. As a rule, local reactions of anaphylaxis are observed, severe anaphylactic shock is extremely rare.
Theoretically, any foreign substance can lead to an anaphylactic reaction. The most common are food proteins, insect bites, medications, vaccine, contaminated Environment and various chemicals.
It is important to note that this is an abnormal reaction of the body. The immune system reacts too strongly to a foreign substance or protein, which leads to a reaction. In most cases, anaphylaxis is thought to be hereditary.
What are the clinical symptoms of anaphylactic shock?
Clinical symptoms depend on the method of exposure (through the mouth, skin, injection, etc.), the amount of antigen, the level of immunoglobulin in the animal.
The most common symptoms of anaphylactic shock are itching, red swelling, swelling of the skin, blisters, swelling of the face or muzzle, excessive salivation, vomiting, and diarrhea. In a severe anaphylactic reaction, the dog will have trouble breathing and his tongue and gums will turn blue.
How to diagnose anaphylaxis?
Anaphylactic shock is diagnosed by identifying recent exposure to an allergen and by characteristic clinical symptoms. Intradermal testing and blood tests for immunoglobulin are also performed to identify specific allergens.
How is anaphylactic shock treated?
An anaphylactic reaction requires immediate medical care and treatment. The first step is to remove the foreign substance, if possible. Further, to stabilize the animal, minimize the likelihood of severe anaphylaxis, control Airways and blood pressure. Drugs such as epinephrine, corticosteroids, atropine, or aminophylline are often used. In mild cases, application may be sufficient. antihistamines, and possibly corticosteroids, followed by observation of the dog for 24 or 48 hours.
What are the predictions?
The initial forecast is always restrained. It is impossible to know whether the reaction will be localized or will progress to severe.
The anaphylactic reaction escalates with each subsequent exposure to the allergen, so the main goal should be to prevent re-exposure.