Anaphylaxis Abdullatiff Sami Al-Rashed

Group No.: 3

Objectives Allergic reactions

( hypersensitivity ).

Anaphylaxis.

Allergic Reactions Allergic reactions are sensitivities to substances called

allergens that come into contact with the skin, nose, eyes, respiratory tract, and gastrointestinal tract. They can be breathed into the lungs, swallowed, or injected.

In an allergic reaction, the immune system starts fighting substances that are usually harmless as though these substances were trying to attack the body.

Many allergic reactions are mild, while others can be severe and life-threatening and the manifestation that happen according to the severity of the reaction.

An allergic reaction is more serious when severe allergic reaction (anaphylaxis) occurs

Types of hypersensitivity ( Allergic Reaction )

Type I: Immediate

Hypersensitivity

Type II: Cytotoxic

Hypersensitivity

Type III: Immune Complex

Hypersensitivity

Type IV: Delayed

Hypersensitivity

Type I

IgE Mediated

Classic Allergy

Type II

IgG/IgM Mediated

rbc lysis

Type III

IgG Mediated

Immune complexDisease

Type IV

T cell

Delayed Type

Hypersensitivity

Gel and Coombs classification of hypersensitivities.

Anaphylaxis Anaphylaxis is a sudden,

severe allergic reaction that can be life-threatening. It is a medical emergency case.

It can occur within seconds or minutes of exposure to something someone is allergic to

Anaphylaxis is under hypersensitivity type 1

Anaphylaxis baby

Etiology Our immune system produces antibodies that defend against

foreign substances.

This is good when a foreign substance is harmful (such as certain bacteria or viruses).

But some people's immune systems overreact to substances that shouldn't cause an allergic reaction.

When this occurs, the immune system sets off a chemical chain reaction, leading to allergy symptoms.

Normally, allergy symptoms are not life-threatening.

But some people have a severe allergic reaction that can lead to anaphylaxis.

Etiology Anaphylaxis can occur in response to almost any foreign

substance h.

The most common causes of anaphylactic shock are:

1. Certain medications, especially penicillin

2. Foods, such as peanuts, tree nuts (walnuts, pecans), fish, shellfish, milk and eggs

3. Insect stings from bees, yellow jackets, wasps, hornets and fire ants

Less common causes of anaphylaxis include:

1. Exercise, often after eating certain foods.

Anaphylaxis usually happens within minutes of exposure and almost always within two hours

Pathophysiology Anaphylaxis is a severe allergic

reaction of rapid onset affecting many body systems.

It is due to the release of inflammatory mediators and cytokines from mast cells and basophils, typically due to an immunologic reaction but sometimes non-immunologic mechanism.

Cont..http://www.youtube.com/watch?

v=G9D-Vfmbt4s

Risk factors There aren't many known risk factors for anaphylaxis,

but some things that may increase your risk include:

1. A personal history of anaphylaxis: If you've experienced anaphylaxis once, your risk of having this serious reaction is increased. Future reactions may be more severe than the first reaction.

2. Allergies or asthma: People who have either condition are at increased risk of having anaphylaxis.

3. A family history: If you have family members who have experienced exercised-induced anaphylaxis, your risk of developing this type of anaphylaxis is higher than it is for someone without a family history.

Sign & Symptoms Anaphylaxis symptoms include:1. Skin reactions, including hives along with

itching, flushed or pale skin (almost always present with anaphylaxis)

2. A feeling of warmth3. The sensation of a lump in your throat4. Constriction of the airways and a swollen

tongue or throat, which can cause wheezing and trouble breathing

5. A feeling of impending doom6. A weak and rapid pulse7. Nausea, vomiting or diarrhea8. Dizziness or fainting

Cont..Heart and circulation: Dizziness,

weakness, fainting, rapid, slow, or irregular heart rate, or hypotension.

Digestive system: Nausea, vomiting, abdominal cramps, or diarrhea

Nervous system: Anxiety, confusion, or a sense of impending doom

hives Swelling of conjunctiva

Investigation Allergy testing is ordered to help

in determining the trigger.

Skin allergy testing (such as patch testing) is available for certain foods and venoms. Blood testing for specific IgE can be useful to confirm milk, egg, peanut, tree nut and fish allergies.

Diagnosis Anaphylaxis is diagnosed based on clinical criteria.

When any one of the following three occurs within minutes/hours of exposure to an allergen there is a high likelihood of anaphylaxis:

1. Involvement of the skin or mucosal tissue plus either respiratory difficulty or hypotension.

2. Two or more of the following symptoms:

a. Involvement of the skin or mucosa b. Respiratory difficulties c. Low blood pressure d. Gastrointestinal symptom

3. Low blood pressure after exposure to a known allerge.

Cont..During an attack, blood tests for

tryptase or histamine (released from mast cells) might be useful in diagnosing anaphylaxis due to insect stings or medications. However these tests are of limited utility if the cause is food or and they are not specific for the diagnosis.

Treatment During an anaphylactic attack, an emergency medical

team may perform cardiopulmonary resuscitation (CPR) if the patient stops breathing or his heart stops beating. He/she may be given medications including:

1. Epinephrine (adrenaline) to reduce the body's allergic response.

2. Oxygen, to help compensate for restricted breathing.

3. Intravenous (IV) antihistamines and cortisone to reduce inflammation of air passages and improve breathing.

4. A beta agonist (such as albuterol) to relieve breathing symptoms.

Complication of AnaphylaxisAirway blockageCardiac arrest (no effective

heartbeat)Respiratory arrest (no breathing)Shock

Prevention The best way to prevent

anaphylaxis is to avoid substances that cause this severe reaction.

First Aid If you're with someone having an allergic reaction

with signs of anaphylaxis:

1. Immediately call your local medical emergency number.

2. Ask the person if he or she is carrying an epinephrine autoinjector to treat an allergic attack (for example, EpiPen, Twinject).

3. If the person says he or she needs to use an autoinjector, ask whether you should help inject the medication. This is usually done by pressing the autoinjector against the person's thigh.

4. Have the person lie still on his or her back.

Cont..5. Loosen tight clothing and cover the person with a

blanket. Don't give the person anything to drink.

6. If there's vomiting or bleeding from the mouth, turn the person on his or her side to prevent choking.

7. If there are no signs of breathing, coughing or movement, begin CPR. Do uninterrupted chest presses — about 100 every minute — until paramedics arrive.

8. Get emergency treatment even if symptoms start to improve. After anaphylaxis, it's possible for symptoms to recur. Monitoring in a hospital setting for several hours is usually necessary.

References http://www.mayoclinic.com/healt

h/anaphylaxis/DS00009

http://www.medscape.com/viewarticle/497498_8

https://www.mja.com.au/journal/2006/185/5/2-anaphylaxis-diagnosis-and-management

Thank You