Chapter 25: Ready for Review
• An antigen is a substance the body recognizes as foreign. This recognition causes the body
to produce antibodies to destroy the foreign substance.
• The immune system is responsible for the antigen–antibody response.
• An allergic response occurs when the body produces the antigen–antibody response when
exposed to a substance that is usually harmless. An allergic response is usually limited to
one body system or a local area.
• Anaphylaxis is an extreme form of systemic allergic response involving two or more body
systems.
• A person must be sensitized to an antigen before an allergic or anaphylactic reaction can
occur.
• An anaphylactoid reaction may occur without the patient being previously exposed to the
offending agent.
• The routes of exposure to an antigen include injection, absorption, inhalation, and ingestion.
• Mast cells release chemical mediators to stimulate the allergic reaction.
• Chemical mediators produce signs and symptoms through their effects on the skin,
cardiovascular, respiratory, neurologic, and gastrointestinal systems.
• Skin effects include erythema, urticaria, and pruritis. Cyanosis and pallor may also be
present.
• Cardiovascular effects include vasodilation, hypotension, decreased cardiac output, cardiac
ischemia, and dysrhythmias.
• Respiratory effects include upper airway edema and stridor, hoarseness,
bronchoconstriction, increased bronchial secretions, wheezes, and hypoxia.
• Neurologic symptoms include altered level of consciousness, anxiety, restlessness,
combativeness, and unconsciousness.
• Gastrointestinal symptoms include nausea, vomiting, diarrhea, and cramping.
• As part of your assessment, you should evaluate the scene, patient history, level of
consciousness, upper airway, lower airway, skin, and vital signs.
• Treatment of anaphylaxis includes removing the offending agent; maintaining the airway;
administering medications such as epinephrine, antihistamines (diphenhydramine,
cimetidine, ranitidine), corticosteroids, inhaled beta-adrenergic agents, and vasopressors;
resuscitating with IV fluids; and initiating rapid transport.
• Epinephrine is first-line drug therapy for anaphylaxis.
• Patient education to prevent reexposure, to understand symptoms, and to understand the
need to use an anaphylaxis kit is essential.
• Collagen vascular diseases and other autoimmune diseases may require treatment that
involves administering medications to suppress the immune system and decrease the attack.
• Organ transplant disorders can present a multitude of problems in patients. It is important to
know the treatment priorities when you care for patients who have undergone organ
transplants.