Treatment:

 Control airway early if tongue swelling:
  • Consider flex/fiber optic visualization
  • Be prepared for surgical airway
  • Consider ketamine for awake intubation, fiber optic nasopharyngeal intubation
  • LMA is insufficient

If cause unknown, treat as histamine related with epinephrine, H1 & H2 blockers, and corticosteroids.

Meds:

  • Epinephrine- IM preferred due to longer action
    • 0.01 mg/kg of 1:1000, max 0.5 mg IM
    • Do not withhold due to hx heart disease
  • Steroids
    • 60-120 mg Methylpredinisolone IV
    • Dexamethasone is a good alternative
  • FFP may be of use in ACE inhibitor related angioedema
    • FFP has been (rarely) reported to worsen herditary angioedema
  • Novel therapies (icatibant, ecallantide, C1-inh concentrate) are effective in HAE.
    • May be effective in ACE inhibitor related cases, but data limited.

Classification:

 Anaphylaxis
  • Common triggers include foods, insect stings, and drugs; IgE mediated
  • Symptoms include wheezing, chest tightness, and hypotension 
Histaminergic  angioedema without anaphylaxis (allergic and idiopathic) –
  • Common triggers include foods, insect stings, and drugs;
  • Presents as rash;
  • Mast cell degranulation or IgE mediated

Non-histaminergic (bradykinin mediated):

  • No urticaria
  • More likely to have abdominal symptoms
  • Frequently involves upper airway
  • Does not responded to corticosteroids or antihistamines
  • Poorly responsive to epinephrine
  • Lasts 2-5 days
  • 3 subtypes- Hereditary Angioedema, ACE-induced, and Acquired C1-Inh def.
 Non-histaminergic Subtypes:
1) Drug related:
  • Angiotensin receptor blockers and renin antagonists also shown to cause angioedema through and unknown mechanism.
  • Up to 30% Ace-inhibitor induced, of these18% admission rate
  • 0.1% to 0.7% on ACE get angioedema
  • Highest incidence during first 30 days of therapy but can occur anytime
  • Most common among African Americans
  • Cyclooxygenase inhibitors lead to increased leukotriene mediators seen in NSAID reactions
2) Hereditary Angioedema:
  • Two types caused by abnormal C1-INH gene function resulting in increased production of bradykinin.
  • Type 1:
    • Low levels of C1-Inhibitor protein production
    • Rare, 1:50,000
    • Begins in childhood and may worsen in puberty
    • 50% with recurring symptoms or abdominal pain by age 10
    • Common prodrome symptom is erythema marginatum (not urticaria)
  • Type 2:
    • More rare than type 1
    • Usually presents older, >40 yo
    • More common in women
    • More involvement of face and tongue
    • Estrogen containing products increase attacks
    • Respond to same meds as type 1, presumed to be bradykinin related
    • High C1-inh levels but dysfunctional
3) Acquired C1-Inhibitor deficiency:
  • Protein is consumed due to underlying lymphoproliferative disorder or antibody in 15% of cases
  • Other malignancies can be related
  • age >40
Labs:
  • C4 levels are low in HAE during an attack.
    • normal C4 in a patient not on C1-acement, during an attack, excludes HAE.
    • if C4 is low, follow up testing includes C1-Inh level and function
  • Tryptase levels are high in mast cell mediated disorders
    • normal in HAE
  • Labs are not helpful for ED treatment, but can be helpful for follow up care
  
Souce:
Moellman JJ, Bernstein JA, Lindsell C, et al. A consensus parameter for the evaluation and management of angioedema in the emergency department. Acad Emerg Med. 2014;21(4):469-84. PubMed
ABEM LLSA 2017

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