Angioedema

Background

• Angioedema is paroxysmal, nondemarcated swelling of dermal or submucosal layers of skin or mucosa
  • Swelling is asymmetric, nonpitting, and nonpruritic
• 4 etiologies:
  • 1. Congenital or acquired loss of C1 esterase inhibitor
  • 2. IgE–mediated type I allergic reaction
  • 3. ACEI adverse reaction
  • 4. Idiopathic

Hereditary Angioedema

Background

• Due to C1 esterase inhibitor deficiency
  • Leads to unregulated activity of vasoactive mediators (bradykinin) associated with complement pathway
  • Autosomal dominant

Diagnosis

• Suspect in patients with history of recurrent peripheral angioedema and abdominal pain
  • 75% experience onset of symptoms before age 15yr
• C4 level screens for HAE (suspect if low)
• Decreased levels of C1 and C4 esterase inhibitors confirms diagnosis

Treatment

• Strongly consider definitive airway if voice change, hoarseness, stridor, dyspnea - arrange transfer to OR if not crashing
• Epinephrine can produce some improvement in early acute attacks associated with anaphylaxis, however, HAE is bradykinin mediated and the role of steroids and H1/H2 blockers is limited
• If available - C1 esterase inhibitors (Berinert 20u/kg IV), kallikrein/bradykinin inhibitors (ecallantide 30mg SQ), or bradykinin receptor antagonist (icantibant 30mg SQ)
• FFP
  • Replaces the missing inhibitor protein
  • Not recommended in life-threatening laryngeal edema (some pts may become more edematous)
    • Instead, pt should undergo fiberoptic intubation w/ preparation for surgical airway

ACE Inhibitor-induced Angioedema

Background

• Incidence is highest within the first month; however, may occur at anytime
• Incidence is 0.1-2.2% (more common in blacks)
• Physiology more closely related to bradykinin-mediated pathway than IgE-mediated pathway, therefore current treatments may be insufficient

Treatment

• Airway management as above, consider awake fiberoptic intubation
• Epinephrine 0.3mg IM q15-20min prn
• Consider glucagon 1-5mg IV if pt on B-blockers and not responding to epi
• Diphenhydramine 50mg IV OR cetirizine 10mg PO
• Methylprednisolone 125mg IV
• H2 blocker IV or PO

Differential Diagnosis

Acute allergic reaction

• Allergic reaction/urticaria
• Anaphylaxis
• Angioedema
• Anxiety attack
• Asthma exacerbation
• Carcinoid syndrome
• Cold urticaria
• Contrast induced allergic reaction
• Scombroid
• Shock
• Transfusion reaction

Disposition

• Consider discharge after 4-6 hrs obs if there is no airway edema and pt improves
• 24 hrs obs if epi given
• Ishoo Staging (based on retrospective study)
  • Stage 1 - face/lip
    • 48% outpatient, 52% floor, 0% ICU or advanced airway
  • Stage 2 - soft palate
    • 60% outpt, 40% floor, 0 ICU or advanced airway
  • Stage 3 - tongue
    • 26% outpt, 67% ICU, 7% advanced airway
  • Stage 4 - larynx
    • 100% ICU, 24% advanced airway

See Also

• Anaphylaxis
• Tongue pathology

Source

• Tintinalli
• EB Medicine "Angioedema in the Emergency Department: An Evidence Based Review" Nov 2012
• Ishoo, et al, 1999, "Predicting Airway Risk in Angioedema: staging system based on presentation" in Otolaryngology - Head and Neck Surgery