Hereditary angioedema

Hereditary angioedema (HAE)
Other namesHereditary angioneurotic edema (HANE),[1] familial angioneurotic edema[2]
Swollen right hand during a hereditary angioedema attack.
SpecialtyHematology
SymptomsRecurrent attacks of severe swelling[3]
Usual onsetChildhood[3]
DurationAttacks last a few days[3]
TypesType I, II, III[3]
CausesGenetic disorder (autosomal dominant)[3]
Diagnostic methodMeasuring C4 and C1-inhibitor levels.[2]
Differential diagnosisIntestinal obstruction, other types of angioedema[2]
PreventionC1 inhibitor[1]
TreatmentSupportive care, medications[1]
MedicationC1 inhibitor, ecallantide, icatibant[1]
Prognosis25% risk of death if airway involved (without treatment)[2]
Frequency~1 in 50,000[3]

Hereditary angioedema (HAE) is a disorder that results in recurrent attacks of severe swelling.[3] The swelling most commonly affects the arms, legs, face, intestinal tract, and airway.[3] If the intestinal tract is affected, abdominal pain and vomiting may occur.[1] Swelling of the airway can result in its obstruction and trouble breathing.[1] Without preventive treatment, attacks typically occur every two weeks and last for a few days.[3]

There are three main types of HAE.[3] Types I and II are caused by a mutation in the SERPING1 gene, which encodes the C1 inhibitor protein, while type III is often due to a mutation in the F12 (factor XII) gene.[3] The result is increased levels of bradykinin, which promotes swelling.[3] The condition may be inherited in an autosomal dominant manner or occur as a new mutation.[3] Triggers for an attack may include minor trauma or stress, but attacks often occur without any obvious preceding event.[3] Diagnosis of types I and II is based on measurement of C4 and C1-inhibitor levels.[2]

Management of HAE involves efforts to prevent attacks and the treatment of attacks if they occur.[1] During an attack, supportive care such as intravenous fluids and airway support may be required.[1] C1 inhibitor medications can be used for both prevention and treatment, while ecallantide and icatibant can be used to treat acute attacks.[1]

HAE affects approximately 1 in 50,000 people.[3] The condition is typically first noticed in childhood.[3] Type I and II affects females and males equally,[4] while type III affects females more often than males.[2] When the airway is involved, without treatment, the risk of death is about 25%.[2] With treatment, outcomes are generally good.[2] The condition was first described in 1888 by Canadian physician William Osler.[5]

  1. ^ a b c d e f g h i "Hereditary angioedema". GARD. 2017. Archived from the original on 4 July 2017. Retrieved 10 July 2017.
  2. ^ a b c d e f g h "Orphanet: Hereditary angioedema". www.orpha.net. August 2011. Archived from the original on 9 October 2015. Retrieved 10 July 2017.
  3. ^ a b c d e f g h i j k l m n o p Reference GH (5 July 2017). "hereditary angioedema". Genetics Home Reference. Archived from the original on 10 July 2017. Retrieved 10 July 2017.
  4. ^ "Hereditary Angioedema - NORD (National Organization for Rare Disorders)". NORD (National Organization for Rare Disorders). 2008. Archived from the original on 14 July 2017. Retrieved 10 July 2017.
  5. ^ Levin AV, Enzenauer RW (2017). The Eye in Pediatric Systemic Disease. Springer. p. 71. ISBN 9783319183893. Archived from the original on 10 September 2017.