Transcript Anaphylaxis
Severe Allergic Reaction (Anaphylactic Shock) 过敏性休克 Fang Hong 方 红 1st Affiliated Hospital, Zhejiang University Overview • Anaphylaxis is a severe allergic reaction that occurs rapidly and causes a life-threatening response involving the whole body. This reaction can lead to difficulty breathing and shock ultimately leading to death. • An anaphylactic reaction occurs when the body's immune system overreacts to an antigen, which it recognizes as an "invader" or foreign substance. • The reaction usually occurs within seconds to minutes of exposure. Causes Triggers of allergic reactions may include: • Drugs, prescription and over-the-counter medication and blood or blood products; • Venom of stinging insects; • Foods, especially high-protein foods , most commonly, fish, nuts, fruit, wheat, milk, eggs, soy products; • Food additives, such as sulfites; • Other substances ,such as latex (natural rubber); • Dyes and contrast materials, used during radiologic procedures or tests; • Often, however, the trigger is unknown. Pathogenesis • The body's white blood cells produce antibodies as a reaction to that antigen. The antibodies circulate in the bloodstream and attach themselves to mast cells in the body. • In an allergic reaction, the antibody is called immunoglobulin E, or IgE. • When the antibodies come in contact with the antigen, they signal other cells to produce mediators. Histamine is an one of the mediators. • The effects of these mediators on organs and tissues of the body cause the symptoms of the reaction. Symptoms • The symptoms of anaphylaxis can vary. In some people, the reaction begins very slowly, but in most the symptoms appear rapidly and abruptly. • The most severe and life-threatening symptoms are difficulty breathing and loss of consciousness. • Difficulty breathing is due to swelling and/or spasm in the airways. In very rare cases, breathing can stop altogether. • Loss of consciousness is due to dangerously low blood pressure, which is called "shock." • In the most serious cases, the heart can stop pumping altogether. • These events can lead to death from anaphylaxis. Symptoms • Generally, a reaction must involve at least two different body systems, such as skin and heart. • Skin: Most anaphylactic reactions involve the skin. • Wheals (raised bumps): Hives can cause severe itching; • Generalized erythema (redness); • Swelling in the face, eyelids, lips, tongue, throat, hands, and feet. Symptoms • Breathing: Difficulty breathing, wheezing, chest tightness, coughing, hoarseness, nasal congestion, sneezing; • Cardiovascular: Blood pressure may drop to dangerously low levels, rapid or irregular heart beat; dizziness, faintness; loss of consciousness, collapse; • General: Tingling or sensation of warmth, difficulty swallowing; Nausea, vomiting; Diarrhea, abdominal cramping, bloating; Anxiety, fear, feeling that you are going to die. Medical Care • Anaphylaxis is a medical emergency and requires immediate treatment in an emergency department of a hospital. • If swelling develops rapidly, particularly involving the mouth or throat, and the patient has trouble in breathing or feels dizzy, light-headed, or faint, go immediately to the nearest emergency department or call an ambulance. Treatment • The first priority in the emergency department is to protect the airway (breathing) and maintain adequate blood pressure. • The emergency team will make sure that your airway is open and that you are getting adequate oxygen. • Oxygen may be given through tubes into the nose or by face mask. • In severe respiratory distress, mechanical ventilation may be required. Treatment • If blood pressure is dangerously low, medication to increase blood pressure will be given. • An intravenous (IV) catheter may be inserted in order to give saline solution to help boost blood pressure. • The IV line may also be used to give medication. Treatment Medications include: • Epinephrine (0.5ml) should be given by injection into the muscle, through an IV line, or by injection under the skin; • H1-receptor blockers/antihistamines: May be given by IV, by injection in the muscle, or by mouth; • Inhaled beta-agonists: Used to treat bronchospasm (spasms in the lung) and dilate the airways; • Corticosteroids: Help to decrease the severity and recurrence of symptoms; may be given orally, injected in muscle, or by IV line; • If low blood pressure does not improve, additional medications, such as dopamine, may be given. Keywords • Severe allergic reaction (anaphylactic shock); • Allergy; • Antibodies, antibody, antigen; • Immunoglobulin E, IgE; • Epinephrine. Question • Please describe your experience with anaphylaxis.