Summary of "Chp 21 Allergy and Anaphylaxis"
Summary of “Chp 21 Allergy and Anaphylaxis”
This chapter, presented by John from Jacksonville, provides a comprehensive overview of allergies and anaphylaxis, focusing on the immunological basis, clinical presentation, assessment, and emergency management of allergic reactions, particularly life-threatening anaphylaxis. The content is targeted primarily at EMTs and other prehospital providers.
Main Ideas and Concepts
Immunology and Allergic Reactions
- Allergic reactions are exaggerated immune responses to foreign substances (allergens) involving histamine and leukotriene release.
- The immune system normally protects the body from invaders, but in allergies, it overreacts.
- Allergic reactions vary from mild (e.g., runny nose) to severe (anaphylaxis).
Anaphylaxis
- A life-threatening systemic allergic reaction involving multiple organ systems.
- Can cause airway obstruction, cardiovascular collapse, shock, and death if untreated.
- Shock from anaphylaxis is progressive and requires immediate intervention.
- Common signs include:
- Urticaria (hives)
- Angioedema (swelling of face, lips, tongue)
- Wheezing (exhalation)
- Stridor (inhalation)
- Hypotension
- Nausea, vomiting, abdominal cramps
- Rapid deterioration is common; more than two-thirds of deaths occur within 30 minutes.
Common Allergens
- Foods: shellfish, nuts (especially peanuts)
- Medications: penicillin, NSAIDs
- Plants: pollen, ragweed, dust
- Chemicals: latex, makeup, soaps
- Insect bites/stings: bees, wasps, hornets, fire ants Venomous insect allergies cause significant morbidity and mortality; many victims have no prior known allergy.
Pathophysiology
- Allergic reactions result from the release of histamines and leukotrienes.
- Epinephrine reverses vasodilation and bronchoconstriction and increases cardiac output by mimicking the sympathetic “fight or flight” response.
Assessment and Recognition
Signs and Symptoms
- Skin: urticaria (red, blotchy, raised wheals), angioedema
- Respiratory: wheezing (lower airway, exhalation), stridor (upper airway, inhalation), use of accessory muscles, nasal flaring, tripod position
- Cardiovascular: hypotension, tachycardia
- Other: nausea, vomiting, abdominal cramps, anxiety, sense of impending doom, dizziness
Distinguishing Severity
- Mild allergic reaction: localized symptoms without respiratory or cardiovascular compromise
- Anaphylaxis: systemic involvement with respiratory distress, hypotension, shock There is no moderate category; reactions are classified as mild or severe.
History Taking
- Identify possible allergen exposure (foods, medications, insect stings).
- Ask about previous allergic reactions or epinephrine use.
- Look for medical alert tags.
Emergency Management and Treatment
Scene Safety
- Ensure the scene is safe from ongoing threats (e.g., insects).
- Use standard precautions (gloves, eye protection).
Primary Assessment
- Assess airway, breathing, and circulation (ABCs).
- Look for signs of airway obstruction and respiratory distress.
- Position patient upright if breathing is difficult; supine if in shock.
- Administer high-flow oxygen; consider bag-valve-mask ventilation if breathing is inadequate.
Removal of Insect Stingers
- Scrape stinger off with a flat object (e.g., credit card).
- Avoid tweezers or squeezing to prevent venom injection.
- Clean site and apply cold packs.
- Remove tight jewelry to prevent circulation problems from swelling.
Epinephrine Administration
- Epinephrine is the primary treatment for anaphylaxis.
- Auto-injector doses:
- 0.3 mg for adults
- 0.15 mg (EpiPen Jr.) for children
- Hold injector in place for 10 seconds to ensure full dose delivery.
- Epinephrine effects:
- Vasoconstriction
- Increased heart contractility
- Bronchodilation
- Side effects may include tachycardia, hypertension, anxiety, headache, dizziness, chest pain.
- Do not administer epinephrine without signs of respiratory compromise or hypotension.
- Follow local protocols for assisting with epinephrine administration.
- Always transport patients after epinephrine administration because symptoms can recur.
Ongoing Care
- Monitor vital signs frequently (every 5 minutes if unstable, every 15 if stable).
- Repeat assessment of airway and breathing.
- Provide supportive care for shock (blanket, elevate legs if tolerated).
- Communicate clearly and document all findings, treatments, and patient responses.
Key Points and Reminders
- Anaphylaxis is a medical emergency requiring rapid recognition and treatment.
- Epinephrine is life-saving but must be used appropriately.
- Not all allergic reactions require epinephrine; only those with systemic involvement.
- Patient history and physical exam are critical for diagnosis.
- Scene safety and provider protection are essential.
- Always transport patients after treatment.
- Documentation and communication are crucial for continuity of care and legal protection.
Methodology / Instructions for EMTs
Scene Management
- Ensure scene safety.
- Use standard precautions.
Assessment
- Obtain SAMPLE history (Signs/Symptoms, Allergies, Medications, Past medical history, Last oral intake, Events leading up).
- Perform primary survey (ABCs).
- Look for signs of shock and respiratory distress.
- Check for medical alert tags.
Treatment
- Remove insect stingers by scraping.
- Administer oxygen.
- Assist with or administer epinephrine if indicated.
- Position patient appropriately.
- Provide supportive care for shock.
- Prepare for rapid transport and call ALS backup.
Post-Treatment
- Monitor vital signs frequently.
- Reassess airway and breathing.
- Document all care and patient response.
- Communicate clearly with receiving facility.
Speakers / Sources Featured
- John from Jacksonville – Primary speaker and instructor throughout the video.
This summary encapsulates the critical teaching points on allergy and anaphylaxis management for EMTs, emphasizing recognition, treatment, and the importance of rapid response to prevent fatal outcomes.
Category
Educational
