Angioedema

A distinction is made between histamine and bradykinin-induced angioedema. In bradykinin-mediated angioedema, swelling occurs without itching or redness. Attacks affecting the upper airways can lead to respiratory distress and, in the worst case, suffocation. Swelling in the area of the gastrointestinal tract can lead to colicky pain in the upper abdomen.

These angioedema do not improve after treatment with antihistamines or glucocorticosteroids.

Bradykinin-induced angioedema includes these:

• Hereditary angioedema (HAE)
• Acquired Angioedema (AAE)
• ACE inhibitor/sartan-induced angioedema
• Idiopathic bradykinin-induced angioedema

The term HAE describes a rare group of diseases (incidence 1:50000) with similar pathophysiology, clinical presentation and treatment. HAE is either inherited over generations or may occur as a spontaneous mutation

Clinical appearance
It is not possible to distinguish between the different types of HAE on the basis of the clinical picture.

HAE is characterized by recurrent swelling of the skin, mucous membranes including the gastrointestinal tract and upper respiratory tract. The attacks can be extremely painful and, if they occur in the upper respiratory tract, can be fatal. The skin swellings do not itch or form wheals.

Pathophysiology
The C1-esterase inhibitor is the only enzyme in the human body that can inhibit the production of bradykinin. Bradykinin increases vascular permeability. A reduced amount or a dysfunctional C1-esterase inhibitor leads to increased bradykinin concentrations and thus to angioedema.

The most common form of HAE is the so-called type I (reduced C1-esterase inhibitor production) and type II (production of a functionally defective C1-esterase inhibitor).

Triggers for HAE attacks include stress, infections, hormonal changes, trauma, surgery and drugs such as ACE inhibitors and Sartane.

Diagnosis
To make a diagnosis, a laboratory chemical examination of the complement system is carried out, as well as a further genetic analysis if necessary.

Treatment options for HAE
Attacks of HAE can be treated either by substitution of the C1-esterase inhibitor, by inhibition of the bradykinin receptor or by inhibition of kallikrein, a protein involved in bradykinin formation.

Patients with high attack frequency, severe attacks or a pronounced reduction in quality of life may also be treated prophylactically. For this purpose, intravenous or subcutaneous application of recombinant or human C1-esterase inhibitors, subcutaneous application of a bradykinin receptor inhibitor, as well as subcutaneous prophylaxis with a monoclonal kallikrein antibody are available.

This type of angioedema often occurs in connection with hemato-oncological diseases or certain autoimmune diseases. Due to autoantibodies, there is an increased consumption of C1-esterase inhibitor and thus a lack of C1-esterase inhibitor.

ACE inhibitors or Sartane are frequently prescribed drugs for high blood pressure. They lead to a reduced breakdown of bradykinin and can consecutively cause swelling. Every year, approximately 30,000 patients in Germany suffer from ACE inhibitor/sartan-induced angioedema. On average, patients have already been taking the corresponding medication for three years. In addition, the attacks frequently occur in the head and neck region.

• Hereditary angioedema (HAE)
• Acquired Angioedema (AAE)
• ACE inhibitors or Sartan-associated angioedema
• Idiopathic Angioedema