These reactions may be due to activation of complement without immune complex formation, e. While radiocontrast agents have traditionally felt to be nonimmunologic, some of the newer, low-osmolar agents may involve IgE-mediated reactions. We may find, with more research, that both immunologic and nonimmunologic anaphylaxis occur concurrently in some patients. For clinicians and patients, the important takeaway message is that anaphylaxis, regardless of the underlying mechanism, is a serious and potentially life-threatening event that must be treated immediately with epinephrine.
International consensus on ICON anaphylaxis. World Allergy Organ J. Bradykinin is also thought to be much more powerful than histamine. Almost all of the signs and symptoms of anaphylaxis can be primarily related to a few major pathophysiologic factors occurring during the reaction: 1 increase in vascular permeability; 2 vasodilation; and 3 bronchiole smooth muscle contraction. Signs, symptoms and etiology are listed as follows by organ system:. An increase in vascular permeability results in urticaria hives , pruritis itching and angioedema a deeper cutaneous swelling , especially around the mouth, eyes and to the extremities.
Vasodilation will produce tingling, warmth, flushing and diffuse redness. An increase in vascular permeability, vasodilation and stimulation of nerve endings will produce rhinitis and laryngeal edema. Signs and symptoms of rhinitis are nasal congestion, itchy nose, sneezing and rhinorrhea nasal drainage.
Laryngeal edema produces hoarseness, sensation of the throat tightening, dyspnea, stridor and excessive salivation. Bronchiole smooth muscle contraction, which leads to bronchospasm, in addition to vasodilation and an increase in vascular permeability, affects the lower respiratory tract. The signs and symptoms are wheezing, cough, chest tightness, rhonchi, tachypnea, respiratory distress and cyanosis.
Circulatory collapse is produced as a result of an increase in vascular permeability with a loss of plasma volume out of the intravascular space, vasodilation and decreased cardiac output. Signs and symptoms include tachycardia, hypotension, weakness, syncope and light-headedness. The patient may also present with dysrhythmias. Cerebral hypoxia results from a decrease in cerebral perfusion from the loss of intravascular volume associated with an increase in vascular permeability and vasodilation, and hypoxia resulting from laryngeal edema and bronchospasm.
The patient becomes apprehensive and anxious, and may present with headache, confusion, altered mental status, seizures rare and coma. GI signs and symptoms are caused by gut smooth muscle contraction and an increase in mucus secretion. Common signs and symptoms are diarrhea, abdominal cramping, nausea, vomiting and difficulty swallowing dysphagia.
Other signs and symptoms that may occur include pelvic pain, vaginal bleeding and urinary incontinence from contraction of the smooth muscle in the uterus and bladder. Itchy, red, watery eyes result from stimulation of nerve endings. Emergency care of a patient suffering from an anaphylactic reaction is geared toward supporting vital functions while eliminating the three primary factors vasodilation, increased vascular permeability and bronchoconstriction that are producing the pathophysiologic condition and the signs and symptoms.
Aggressive airway management, ventilation, if necessary, and oxygenation must be performed immediately. If the patient is hypotensive, run the fluids wide open. Place the patient on a continuous ECG monitor and pulse oximeter. The drug of choice in anaphylaxis is epinephrine, which contains alpha and beta properties. The alpha properties will reverse vasodilation and vascular permeability; beta 1 will increase myocardial contractility; and the beta 2 properties will reverse the bronchoconstriction by promoting bronchiole smooth muscle dilation.
Diphenhydramine Benadryl may also be administered to block the histamine receptors. Corticosteroids may be used to stabilize mast cell membranes and reduce release of chemical mediators. Antibiotics penicillin, cephalosporins Foods milk, egg whites, shellfish, nuts, chocolate, grains, beets Foreign proteins latex, venom, glue Therapeutic agents anesthetics, egg-based vaccines Physical or environmental factors exercise, cold Idiopathic.
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Online Product Guide. Contact Us. Advisory Board. About Us. Copied to clipboard. Pathophysiology Sensitization involves an immunologic process that occurs when the body views a substance as foreign.
Assessment Almost all of the signs and symptoms of anaphylaxis can be primarily related to a few major pathophysiologic factors occurring during the reaction: 1 increase in vascular permeability; 2 vasodilation; and 3 bronchiole smooth muscle contraction. Signs, symptoms and etiology are listed as follows by organ system: Cutaneous Skin An increase in vascular permeability results in urticaria hives , pruritis itching and angioedema a deeper cutaneous swelling , especially around the mouth, eyes and to the extremities.
Upper Respiratory Tract An increase in vascular permeability, vasodilation and stimulation of nerve endings will produce rhinitis and laryngeal edema. Lower Respiratory Tract Bronchiole smooth muscle contraction, which leads to bronchospasm, in addition to vasodilation and an increase in vascular permeability, affects the lower respiratory tract.
Cardiovascular System Circulatory collapse is produced as a result of an increase in vascular permeability with a loss of plasma volume out of the intravascular space, vasodilation and decreased cardiac output.
Central Nervous System Cerebral hypoxia results from a decrease in cerebral perfusion from the loss of intravascular volume associated with an increase in vascular permeability and vasodilation, and hypoxia resulting from laryngeal edema and bronchospasm.
Gastrointestinal Tract GI signs and symptoms are caused by gut smooth muscle contraction and an increase in mucus secretion. Management Emergency care of a patient suffering from an anaphylactic reaction is geared toward supporting vital functions while eliminating the three primary factors vasodilation, increased vascular permeability and bronchoconstriction that are producing the pathophysiologic condition and the signs and symptoms.
Textbook of Medical Physiology, 10th edition. Philadelphia, PA: W. Saunders, Understanding Pathophysiology, 3rd edition. St Louis, MO: Mosby, Anatomy and Physiology for Emergency Care. Rodak BF. It's just about people understanding the risk," she said. We acknowledge Aboriginal and Torres Strait Islander peoples as the First Australians and Traditional Custodians of the lands where we live, learn, and work.
So what exactly is anaphylaxis and what can you do to stop it? What is anaphylaxis? What causes anaphylaxis? More on:.
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