CC: tongue swelling, drooling

ID: 40 yo woman with HTN, GERD, anxiety disorder presents with throat swelling, subjective fevers, and drooling for 3 days.  She presented to an urgent care clinic 2 days ago with the same complaints and was given clindamycin without any improvement in her symptoms.  Home medications included amlodipin, omeprazole, and paroxetine.  She denied a family history of any swelling.  A thorough workup, including C4, auto-antibodies, C1 esterase inhibitor levels and function all returned normal.  She was finally deemed to have idiopathic angioedema after extensive evaluation for underlying rheumatologic and malignant disease

Don’t forget:

• Anaphylaxis can be diagnosed if any of the following 3 clinical criteria are met (this confers 95% specificity for anaphylaxis).  Remember that respiratory compromise or hypotension are notable features in anaphylaxis.
  1. acute onset skin/mucosal involvement AND respiratory compromise or hypotension
  2. exposure to a likely allergen AND 2 of the following 4
     • skin/mucosal involvement
     • respiratory compromise
     • hypotension
     • persistent GI symptoms
  3. exposure to a known allergen AND hypotension
• Urticaria is localized areas of edema associated with pruritis and affects the superficial dermis.  It is usually transient and evanescent (< 24 hrs).  Angioedema is a deeper form of localized urticaria and affects the subcutaneous tissue, typically lasting slightly longer (48-72 hrs).

Pearls from morning report:

• Mast cell mediated angioedema is associated with urticaria, pruritis, flushing, bronchospasm, throat tightness and hypotension.  Bradykinin mediated angioedema is NOT associated with urticaria or pruritis.
• Initial laboratory workup for angioedema should include: CBC, CMP, CRP, ESR, C4.  Decreased C4 levels should prompt evaluation for C1 inhibitor deficiency – consider measuring levels of C1 inhibitor antigen and C1 inhibitor functional levels.
• Early complement deficiencies (C1, C2, C3) can predispose to autoimmune disease.  Late complement deficiencies (C5 – C9) cause recurrent bacterial infections.

Random trivia:

Trauma can sometimes precipitate angioedema in a patient taking ACEi by way of direct tissue injury activation of bradykinin.  Angioedema was first described by Dr. Heinrich Quincke (of “Quincke’s pulse” – a sign of aortic insufficiency) in 1882 and was postulated to have a hereditary basis by Sir William Osler in 1888.

Want to read more?

Urticaria and angioedema (Allergy, Asthma, & Clinical Immunology)
Urticaria and angioedema: A practical approach (American Family Physician)

References: 

Zuraw BL. Clinical practice: Hereditary angioedema. N Engl J Med. 2008;359(10):1027-36.

Zuraw B, Bingham CO. An overview of angioedema: Pathogenesis and cause. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on February 1, 2017)