questions 2

Hereditary Angioedema

Topic updated on 12/31/16 8:11pm

  • A 23-year-old woman with past medical history of multiple allergies leading to facial swelling presents with marked difficulty breathing, abdominal pain, and swelling of the face and neck. On physical exam, her extremities are also noted to be markedly swollen (picture). She is immediately sedated for intubation to maintain patency of airway. Chart review reveals newly-started ACE-inhibitor. She is given epinephrine, fluids, and fresh frozen plasma.

  • Disorder of complement, causing angioedema
  • Genetics
    • autosomal dominant
  • Pathogenesis
    • C1 esterase inhibitor deficiency
      • C1 esterase inhibitor inhibits kallikrein-kinin pathway
        • remember kallikrein activates bradykinin
        • bradykinin
          • ↑ vasodilation
          • ↑ permeability
          • ↑ pain
    • ACE-inhibitors are contraindicated
      • ACE inactivates bradykinin
      • ACE-inhibitors allows ongoing bradykinin, causing angioedema
  • Epidemiology
    • attacks begin during childhood
  • Risk factors
    • family history of angioedema
    • family history of those contraindicated with ACE-inhibitors
    • autoimmune conditions
  • Symptoms/physical exam
    • recurrent episodes of angioedema without urticaria
      • as opposed to anaphylaxis, which typically has urticarial
      • angioedema of the face, oropharynx, extremities, or abdomen
      • angioedema of GI tract
        • severe abdominal pain
        • GI upset
      • worst at 24 hours
      • resolves over 48-72 hours
    • often preceded by prodrome
      • fatigue
      • flu-like symptoms
    • not responsive to epinephrine (epi-pen) or antihistamines
  • Best initial test
    • ↓ C4 and C2 levels
    • if C4 are normal, C1 inhibitor deficiency is unlikely
  • To confirm diagnosis if ↓ C4
    • ↓ C1 inhibitor antigenic levels
    • ↓ C1 inhibitor functional levels
Differential Diagnosis
  • Anaphylaxis
  • Allergic angioedema
  • Facial cellulitis
  • SVC syndrome
  • Often initially treated also for anaphylaxis given urgent nature and similarity in presentation
    • epinephrine
    • fluid replacement
    • anti-histamines
  • Assess airway
    • intubate if necessary
  • As soon as possible, administer medications for hereditary angioedema
    • plasma-derived C1 inhibitor
    • recombinant human C1 inhibitor
    • fresh frozen plasma if above are not available
Prognosis, Prevention, and Complications
  • Prognosis
    • mortaliy >30% in those with laryngeal angioedema
    • angioedema is unpredictable
  • Complications
    • small bowel obstruction
    • compartment syndrome
    • death by asphyxiation


Qbank (2 Questions)

(M1.IM.21) A 23-year-old female presents to the emergency room with diffuse swelling. Her boyfriend is especially concerned because her face has begun to swell (Figure A). Her tongue is also swollen and she is beginning to have trouble breathing. If her symptoms are due to a congenital syndrome and not a medication side effect, which of the following would be true regarding this patient's disease? Topic Review Topic
FIGURES: A          

1. Caused by deficiency in C1 esterase inhibitor
2. Caused by deficiency in C3
3. Caused by deficiency in C5-C8
4. Caused by deficiency in decay accelerating factor
5. Danazol is contraindicated in this disease as it may worsen symptoms

(M1.IM.74) A 47-year-old male presents to the emergency department with facial swelling and trouble breathing. These symptoms began this morning and progressively worsened over the past several hours. Vital signs are as follows: T 37.7, HR 108, BP 120/76, RR 20, and SpO2 96%. Physical examination reveals nonpitting swelling of the face, hands, and arms as well as edema of the tongue and mucus membranes of the mouth and pharynx. The patient reports several episodes of mild facial swelling that occurred during childhood between the ages of 5-18, but he does not recall seeing a physician or receiving treatment for this. His medical history is otherwise negative, except for mild hypertension for which his primary care physician initiated lisinopril 2 weeks ago. This patient most likely has which of the following underlying abnormalities? Topic Review Topic

1. MHC class I deficiency
2. Defective lysosomal storage proteins
3. Lack of NADPH oxidase
4. Defect in cytoskeletal glycoprotein
5. Deficiency of C1 esterase inhibitor


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