Initial Management of Laryngeal Edema with Adrenaline (Epinephrine)
Immediate Action: Determine the Etiology First
The initial management of laryngeal edema depends critically on the underlying cause—anaphylactic/allergic laryngeal edema requires immediate intramuscular epinephrine (0.3-0.5 mg of 1:1000 solution), while hereditary angioedema (HAE) and ACE inhibitor-induced angioedema do NOT respond to epinephrine and require different treatments. 1, 2
Algorithm for Epinephrine Administration
If Anaphylaxis or Allergic Laryngeal Edema:
Dose and Route
- Adults and children ≥30 kg: Administer 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000 solution) intramuscularly into the anterolateral thigh (vastus lateralis muscle) 1, 3
- Children <30 kg: Administer 0.01 mg/kg (maximum 0.3 mg) intramuscularly into the anterolateral thigh 1, 3
- Repeat every 5 to 15 minutes as needed if symptoms persist or recur 1, 3
Why Intramuscular?
- Intramuscular injection is the preferred initial route because it produces rapid peak plasma epinephrine concentrations and is safer and more effective than subcutaneous administration 1
- Injection into the lateral thigh (vastus lateralis) provides the most rapid absorption 1
Alternative Routes (When IV Access Available)
- If IV line is in place and patient is in anaphylactic shock: Consider IV epinephrine 0.05 to 0.1 mg (1:10,000 solution) as a reasonable alternative 1
- IV infusion (5-15 μg/min) is a reasonable alternative to IV boluses for anaphylaxis not in cardiac arrest, allowing careful titration 1
Adjunctive Therapy for Laryngeal Edema
- Nebulized epinephrine (1 mg in 5 mL normal saline) may reduce airway edema if upper respiratory obstruction or stridor develops 1, 2, 4
- The effect of nebulized epinephrine is quick (within 30 minutes) but transient (lasting only 2 hours), requiring continued monitoring 2, 4
- Nebulized epinephrine does not replace intramuscular epinephrine for systemic anaphylaxis 5
If Hereditary Angioedema (HAE) or ACE Inhibitor-Induced Angioedema:
Epinephrine is NOT effective and should NOT be used as primary treatment 1, 2
For HAE:
- First-line therapies: Plasma-derived C1-INH (1000-2000 U or 20 U/kg), icatibant (30 mg subcutaneously), or ecallantide 2
- Standard allergic treatments (epinephrine, corticosteroids, antihistamines) do not work for HAE 2
For ACE Inhibitor-Induced Angioedema:
- Discontinue the ACE inhibitor immediately 2
- Consider icatibant (30 mg subcutaneously) or plasma-derived C1 esterase inhibitor (20 IU/kg) 2
- Standard antihistamines and corticosteroids are generally ineffective 2
If Inflammatory/Traumatic Laryngeal Edema (Post-Intubation, Hanging Injury, Direct Trauma):
Corticosteroids are the primary treatment, NOT epinephrine 1, 6, 7
Corticosteroid Dosing:
- Dexamethasone 8-10 mg IV immediately, then 8 mg IV every 6 hours for at least 12-24 hours 6, 7
- Alternative: Any steroid equivalent to 100 mg hydrocortisone every 6 hours 1, 6
- Single-dose steroids given immediately before extubation are ineffective—must be started at least 6-12 hours in advance for prevention 1, 7
Adjunctive Nebulized Epinephrine:
- If stridor develops: Nebulized epinephrine (1 mg) may provide rapid but transient relief 1, 2, 6
- Continue corticosteroids alongside nebulized epinephrine 2, 6
Critical Airway Management Principles
Immediate Referral and Monitoring
- Given the potential for rapid development of oropharyngeal or laryngeal edema, immediate referral to a health professional with expertise in advanced airway placement, including surgical airway management, is recommended 1
- All patients with laryngeal edema must be observed in a facility capable of performing intubation or tracheostomy 2
- Close hemodynamic monitoring is recommended in anaphylactic shock 1
Supportive Care
- Position patient upright and administer high-flow humidified oxygen 1, 2
- Keep patient NPO (nil per os) as laryngeal competence may be impaired despite full consciousness 1, 2
- End-tidal CO₂ monitoring is desirable 1, 2
Common Pitfalls and Caveats
Do NOT Assume All Laryngeal Edema Responds to Epinephrine
- HAE and ACE inhibitor-induced angioedema are bradykinin-mediated and do not respond to epinephrine, antihistamines, or steroids 1, 2
- Inflammatory/traumatic laryngeal edema requires corticosteroids, not epinephrine as primary treatment 1, 6
Do NOT Delay Definitive Airway Management
- If laryngeal edema is progressive or severe, do not delay intubation or surgical airway—intubation becomes increasingly difficult as swelling progresses 1, 2
- In some cases, emergency cricothyroidotomy or tracheostomy may be required 1
Do NOT Inject Epinephrine into Buttocks, Digits, Hands, or Feet
- Injection into these sites can cause tissue ischemia and necrosis 3
- Always use the anterolateral thigh (vastus lateralis muscle) 1, 3
Do NOT Rely on Nebulized Epinephrine Alone for Systemic Anaphylaxis
- Nebulized epinephrine has low and unpredictable systemic absorption and is useful only for localized laryngeal edema 5
- Intramuscular epinephrine is required for systemic symptoms 5
Recognize That Steroids Work Only for Inflammatory Edema
- Steroids reduce inflammatory airway edema from direct injury but have no effect on mechanical edema secondary to venous obstruction (e.g., neck hematoma) 1, 6
Summary of Epinephrine Dosing by Indication
| Indication | Route | Dose | Frequency |
|---|---|---|---|
| Anaphylaxis (adults/children ≥30 kg) | IM (anterolateral thigh) | 0.3-0.5 mg (1:1000) | Every 5-15 min as needed [1,3] |
| Anaphylaxis (children <30 kg) | IM (anterolateral thigh) | 0.01 mg/kg (max 0.3 mg) | Every 5-15 min as needed [1,3] |
| Anaphylactic shock (IV available) | IV | 0.05-0.1 mg (1:10,000) | Bolus or infusion 5-15 μg/min [1] |
| Laryngeal edema with stridor (adjunct) | Nebulized | 1 mg in 5 mL saline | As needed (transient effect) [1,2,4] |
| HAE or ACE inhibitor angioedema | NOT indicated | Do not use | Use specific treatments instead [1,2] |