Makindo Medical Notes

Untreated individuals may experience an attack every 1 to 2 weeks, with most episodes lasting about 3 to 4 days.

About

• Hereditary Angio-Oedema (HAE) incidence is approximately 1 in 50,000 individuals.

Aetiology

• Autosomal dominant inheritance pattern due to a mutation in the C1 inhibitor gene (C1-INH).
• This leads to a deficiency of the complement component C1 esterase inhibitor.
• Approximately 25% of cases arise from new mutations, resulting in excessive bradykinin production, which causes angioedema.

Clinical Presentation

• Attacks are often triggered by stress, surgery, hormonal changes, or certain foods.
• Symptoms typically begin in the teenage years.
• Swelling of the face, lips, tongue, pharynx, and larynx, which can lead to airway obstruction in severe cases.
• Red but non-itchy rash, often mistaken for allergic reactions.
• Colicky abdominal pain due to swelling of the gastrointestinal tract.

Investigations

• Reduced C1-INH Plasma Levels: Diagnostic marker for HAE.
• Genetic Testing: Can confirm a mutation in the C1-INH gene.

Management

• Emergency Care: Administer oxygen and fluids as necessary. Follow ABC protocol for airway management in cases of laryngeal swelling.
• Icatibant: A bradykinin receptor antagonist that shortens the duration of attacks by blocking the effects of bradykinin.
• C1 Esterase Inhibitor: Can be administered during an attack or used prophylactically to prevent future attacks.
• Ecallantide (Kalbitor): A kallikrein inhibitor used to treat acute HAE attacks and sometimes for blood loss prevention in surgery. It works by blocking the production of bradykinin.
• Fresh Frozen Plasma (FFP): May be used to replace C1-INH in emergency situations.
• Danazol and Stanazol: These anabolic steroids can induce the production of more C1-INH, reducing the frequency of attacks.
• Tranexamic Acid: Sometimes used as a preventative treatment to reduce attacks.