What is the protocol for treating anaphylaxis?

Anaphylaxis Protocol

Epinephrine is the first-line treatment for anaphylaxis and should be administered promptly at the onset of symptoms, with no contraindication to its use in anaphylactic patients. 1

Recognition of Anaphylaxis

Anaphylaxis is an acute life-threatening systemic reaction resulting from the sudden release of mediators from mast cells and basophils. Early recognition is crucial for effective management.

Signs and Symptoms:

• Cutaneous: Urticaria, angioedema, flushing, pruritus (most common but may be delayed or absent in rapidly progressive cases)
• Respiratory: Dyspnea, wheezing, stridor, throat tightness, hoarseness, cough
• Cardiovascular: Hypotension, tachycardia, weak pulse, dizziness, collapse
• Gastrointestinal: Nausea, vomiting, abdominal cramps, diarrhea
• Neurological: Lightheadedness, feeling of impending doom, unconsciousness

Note: The more rapidly anaphylaxis develops, the more likely it is to be severe and potentially life-threatening. 1

Treatment Protocol

Immediate Actions:

1. Assess ABCs (Airway, Breathing, Circulation)
2. Administer epinephrine immediately
   • Dose: 0.01 mg/kg of 1:1000 (1 mg/mL) solution
   • Route: Intramuscular (IM) in the anterolateral thigh (vastus lateralis muscle)
   • Adult dose: 0.3-0.5 mg
   • Pediatric dose: 0.01 mg/kg (maximum 0.3 mg)
   • May repeat every 5 minutes as necessary 1, 2, 3
3. Activate emergency response system 1
4. Position patient appropriately (supine with legs elevated for hypotension; sitting up if respiratory distress)

Secondary Interventions:

1. Oxygen administration for patients with prolonged reactions, pre-existing hypoxemia, or requiring multiple epinephrine doses 1
2. IV access and fluid resuscitation for hypotension
   • Crystalloids or colloids as appropriate
   • Rapid fluid bolus (1L for adults) for hypotension 1
3. Adjunctive medications (only after epinephrine):
   • H₁-antihistamines (e.g., diphenhydramine 1-2 mg/kg IV/IM, max 50 mg)
   • H₂-antihistamines (e.g., ranitidine 1 mg/kg IV if available)
   • Corticosteroids (e.g., methylprednisolone 1-2 mg/kg IV) 1, 4
4. Inhaled beta-2 agonists (e.g., albuterol) for persistent bronchospasm 1

Special Considerations:

• Beta-blockers: May cause refractory anaphylaxis and decreased response to epinephrine
  • Consider glucagon (1-5 mg IV followed by infusion) for patients on beta-blockers 1
• Pregnant patients: Use epinephrine with caution but do not withhold (benefits outweigh risks) 2
• Elderly patients: Consider starting with lower doses due to potential sensitivity to effects 2
• Biphasic reactions: Monitor patients for at least 4-6 hours after symptom resolution 4, 5

Equipment and Medications for Anaphylaxis Management

Every medical facility should have an established protocol and appropriate equipment for treating anaphylaxis 1:

• Stethoscope and sphygmomanometer
• Tourniquet, syringes, needles, and IV catheters (14-18 gauge)
• Epinephrine 1:1000 (1 mg/mL)
• Oxygen and delivery devices
• IV fluid setup
• Injectable antihistamines (H₁ and H₂)
• Injectable corticosteroids
• Airway management equipment
• Glucagon kit (for patients on beta-blockers)

Common Pitfalls to Avoid

1. Delaying epinephrine administration - This is the most common and dangerous error in anaphylaxis management 4, 6
2. Using incorrect route - Subcutaneous administration results in slower absorption; intramuscular in the thigh is preferred 1, 7
3. Injecting into inappropriate locations - Avoid injections into digits, hands, feet, or buttocks 2
4. Relying solely on antihistamines - These should never replace epinephrine as first-line treatment 4, 8
5. Failing to monitor for biphasic reactions - Symptoms may recur without re-exposure to the allergen 5

Post-Treatment Care

1. Observation period of 4-12 hours depending on severity and risk factors 5
2. Referral to allergist-immunologist for follow-up evaluation 1, 4
3. Prescription for epinephrine autoinjector and training on proper use 4
4. Patient education on trigger avoidance and emergency action plan 5

Remember that prompt recognition and early administration of epinephrine are the most critical factors in preventing fatal outcomes in anaphylaxis.