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38 Cards in this Set
- Front
- Back
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How many people in Canada are thought to have anaphylaxis?
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It is estimated that up to 3 million people may be at risk of anaphylaxis.
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What can cause anaphylaxis?
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Drugs - Penicillin, other antibiotics, aspirin, some anesthetics, colloids etc
Insect stings - Bee's yellow jackets, hornets, wasps and ants. Foods - Peanuts, Tree nuts, fish and shellfish, fruits, eggs, soy and milk Latex - Gloves and other materials made of latex Animals - Fur, dander, animal serum products |
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What is the most common cause of anaphylaxis?
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Food allergies.
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What are the two types of normal immune response?
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Cellular immunity - the body produces T-cells that attack and destroy invaders.
Humoural Immunity - Antibodies dissolved in the plasma and lymph are used to fight invading organisms. The cells producing the immunity are located in the lymph nodes, spleen and GI tract. |
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What are the routes of entry for allergens?
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Injection
Absorption Inhalation Ingestion |
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What happens when a foreign substance enters the body?
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The body initiates a series of responses.
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What is the primary response?
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Cells greet, confront and engulf the invading cell to see if they are allowed to be in the body.
If the invading substance is not permitted the body creates proteins called antibodies intended to match up with the invading antigen and inactivate it. |
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What is sensitivity?
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Developed from the primary response.
The body records details of the encounter with the substance to assist in future identification of the substance and production of antibodies to fit the invading antigen. |
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What are basophils and mast cells?
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They contain the body's chemical weapons or chemical mediators.
They remain inactive until an antigen combines with an antibody. The chemical mediators launch and maintain the immune response. |
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How do the mediators do this?
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The summon more white blood cells to fight the invaders and also increase blood flow to the area under attack.
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What is secondary response?
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This is where the immune system is activated in response to the detection of of a previously encountered invader.
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What is acquired immunity?
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The administration of a vaccine allows the body to produce antibodies without experiencing the disease.
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What is natural immunity?
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The body encounters the antigen and experiences a full immune response with all the pathology of the disease.
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What are abnormal immune reactions?
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The immune system can sometimes be overzealous in defending the body.
The resulting problems can range from hay fever to anaphylaxis. |
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What happens during these abnormal reactions?
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The immune system becomes hypersensitive to one or more substances.
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What implications does this have for the patient?
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While the immune system can also recognize and react to dangerous invaders like bacteria or viruses. They also react to things like strawberries and penicillin.
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What do the mast cells do?
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They start to release mediators. Histamine one of these mediators causes blood vessels to dilate and capillaries to leak.
White blood cells are called to the area and platelets begin to clump together. |
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What happens in most cases?
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The overreaction is restricted to the local area being invaded. The runny itchy nose and swollen eyes associated with hay fever is an example of a local reaction.
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What is anaphylaxis?
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The bodies defense forces do not restrict their activities to just the local area.
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What happens?
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The histamine release causes vasodilation which presents as flushed skin and hypotension.
Vascular permiability is increased leading to tissue swelling and fluid secretion. |
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How can tissue swelling present?
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As hives, narrowing of the airway or increased fluids in the airway.
Histamine release can also cause smooth muscle cramping. |
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What does the smooth muscle cramping do?
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The cramping of the smooth muscle can result in laryngospasm or bronchospasm and abdominal cramping.
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What can histamine do to the heart?
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It decreases the contractility of the heart.
When this is combined with vasodilation it can result in hypotension. Arrhythmias due to hypoperfusion and hypoxia are common. |
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What do leukotrienes do?
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They are more powerful mediators and compound the effects of histamine.
They cause coronary vasoconstriction compounding arrhythmias and increased vascular permiability contributing to hypoperfusion. |
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What are the clinical symptoms of anaphylaxis?
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Skin - warm, flushed, itching, swollen eyes, swelling of face and tongue, swelling of hands and feet, hives
Respiratory - dyspnea, tightness in throat and chest, stridor, hoarseness, lump in throat, wheezes, crackles, coughing, sneezing Cardiovascular - Arrhythmias, hypotension, tachycardia Gastrointestinal - Cramping, nausea, bloating, vomiting, distension, profuse watery diarrhea Central nervous - Headache, dizziness, confusion, anxiety and restlessness, sense of impending doom, altered metal state. |
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What should you be doing with the scene assessment?
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Looking for exposure problems. What was the patient doing (gardening and bees for example). If at a restaurant what were they eating. Are they taking any new medications?
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What about LOC?
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The status of the brain is a direct reflection of the patients oxygenation status. A restless, confused, anxious or combative patient is likely hypoxic.
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What if the patient is unresponsive?
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If the patient cannot speak assess the airway for patency before assuming a neurological problem.
Any change in mental state should prompt you to examine the the airway and breathing. |
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What to look for in the upper airway?
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Noisy airways can be a sign of impending airway occlusion due to swelling. Listen for stridor or hoarseness. Patient may complain of feeling tightness or a lump in their throat.
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What to look for in the lower airway?
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Look for tachypnea, laboured breathing, accessory muscle use., abnormal retractions, prolonged expiration.
You may hear wheezing followed by diminished lung sounds. Silent lungs are a very bad finding. |
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What are some history questions to ask the patient?
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Does the patient have any allergies?
Have they had an allergic or anaphylactic reaction before? How severe? How rapid did it progress? When did symptoms begin? Ask about breathing and dyspnea? Determine if any treatment has been provided either in the form of an epipen or B2 agonist or benadryl |
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What are some vital signs you will see with anaphylaxis?
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Tachypnea, tachycardia and hypotension.
When these these signs are present with flushed skin and hives anaphylaxis should be one of the major considerations |
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What is the classic presentation of anaphylaxis?
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Respiratory symptoms and hypotension
Gastrointestinal symptoms such as cramping, nausea, vomiting and diarrhea. |
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What interventions should be performed for anaphylaxis?
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O2 - high flow
12 lead to monitor possible arrhythmias IV - to combat hypotension Epinephrine as soon as possible Salbutamol - to help with any brochospasm that may be present |
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Why is epinephrine the drug of choice for anaphylaxis?
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It stops the process of mast cell degranulation. It also reverses the effects of the mediators by causing
vasoconstriction increases heart contractility This helps to relieve the hypotension that a patient is experiencing |
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Why can patients with beta blockers cause a problem?
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They can have more frequent and severe anaphylactic reactions and can develop a paradoxical reaction to epinephrine. Glucagon and ipratropium should be considered instead.
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What are the two groups for management of allergic reactions?
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Patients who have an allergic reaction with no respiratory distress.
Patients with signs of an allergic reaction and dyspnea. |
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What do these patients require?
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O2, epinephrine and antihistamines.
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