angioedema

see also:

• hereditary angioedema (HAE)
• anaphylaxis
• Emedicine - angioedema
• RCH guideline - angioedema - C1 esterase inhibitor deficiency

• angioneurotic oedema is the acute swelling of mucosal surfaces due to release of inflammatory mediators
• it may be rapidly life threatening if it involves airway structures
• most cases are associated with urticaria and are due to hypersensitivity reactions and can be managed as per anaphylaxis
• 10% of cases occur without urticaria and are considered to be kinin mediated rather than hypersensitivity mediated, and require specific prophylaxis and management.

• Mx as per anaphylaxis

• ~500 patients in Australia
• Mx as per hereditary angioedema (HAE)

• ACE is an enzyme which also metabolises bradykinin and Substance P, hence patients on ACEIs are at risk of raised bradykinin in certain situations which can then cause angiooedema, particularly of the tongue.
• theoretically angiotensin II receptor antagonists should not affect bradykinin metabolism however there have been many case reports of angioedema developing in patients on these as well.¹⁾
• can Mx as per anaphylaxis with adrenaline im, hydrocortisone and antihistamines
• fresh frozen plasma has been successfully used in treating patients with severe ACE inhibitor-induced angioedema that has not responded to other treatments
• new agents such as icatibant (a selective bradykinin receptor B2 antagonist) and DX-8831 (a kallikrein inhibitor) are currently in clinical trials for the treatment of acute attacks of hereditary angioedema, and may in the future have a role to play in the treatment of ACE inhibitor-induced angioedema.
• cease ACEIs and AGII blockers and start alternative antihypertensives:
  • do NOT start beta adrenergic blockers until angioedema has totally resolved as it will cause problems with adrenaline Rx
  • better to use other antihypertensives such as calcium channel blockers or thiazides

• rare - only 150 cases reported worldwide
• acquired angioedema without urticaria type I:
  • associated with other diseases, most commonly B-cell lymphoproliferative disorders
  • these disorders produce complement-activating factors, idiotype/anti-idiotype antibodies, or other immune complexes that destroy C1-INH function.
• acquired angioedema without urticaria type II:
  • is an autoimmune process defined by the presence of an autoantibody directed against the C1 inhibitor molecule (C1-INH).