Frequently Asked Questions

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Hereditary Angioedema (HAE) is a genetic conditionated illness clinically characterized by episodes of edema in body parts, high airways edema, gastrointestinal edema.
HAE is caused by a genetic defect of C1 inhibitor esterase (C1-INH). HAE is rare, occuring in about 1/10,000 to 1/50,000 individuals. Without therapy, the mortality rate is 20-30%.

Because the defect is inherited with 50% probability if one genitor is affected. Lack of familial history though, does not eliminate the possibility of HAE. 20% of the HAE cases, result from patients who had a spontaneous mutation of the C1 inhibitor gene at conception. These patients can pass the defective gene to their offspring.

HAE is caused by a genetic defect of C1 inhibitor esterase (C1-INH). This protein is involved in complement activation and plays an important role in blood coagulation control.

The attack can spontaneously occur, sometimes in patients without any previous symptoms, and sometimes preceded by anxiety or emotionally stress.
Hereditary angioedema patients are particularly vulnerable to minor trauma, infections and some drugs. Dental procedures can induce hereditary angioedema attacks. Some patients have also reported swelling in extremities following typing, prolonged writing and other physical activities. Women are more susceptible to hereditary angioedema attacks during menstruation. During pregnancy the frequency of attacks can be higher. Use of oral contraceptives is associated with an increase in the frequency and severity of attacks.

First episodes occur often during childhood, half of the patients beings symptomatic during the first 10 years of their life, and a third during the second decade. There also seems to be an e\increased frequency of attacks during puberty or adolescence.

Symptoms appear during the first couple of hours and slowly ameliorates during the next 24-72h. Some cases, the edema disappear only after a week.

The frequency of attacks varies considerably, from once-a-week to more than a year.

The hereditary angioedema attacks are particularly dangerous if they appear in the upper airways. In the laryngeal edema, obstruction is lethal without medical treatment and intubation or thracheostomy. Abdominal attacks cause severe pain, nausea, vomiting. They often mimic a surgical abdomen leading to unnecessary exploratory surgery.

There are two types of therapy: (1) preventive treatment and (2) treatment of acute attacks.

Though swelling of the extremities is uncomfortable and sometimes painful, it is not dangerous. Long term preventive therapy is necessary for patients with respiratory hereditary angioedema with more than one attack per moth or with impaired respiratory activity.

Thranexamic acid, Danazol are the most frequently used. The large number of side effects require a cautious use and management of these hormones.

Short term therapy necessary for preventing hereditary angioedema attacks in patients facing dental procedures, surgery or endoscopy.

Yes. Any localization of HAE attack is well controlled by C1-INH concentrate, icatibant and ecallantide. When these are not available fresh frozen plasma can be used. Adrenaline, antihistamines and corticosteroids are not effective in treating angioedema caused by C1-INH deficiency.

Laryngeal edema is a medical/surgical emergency no matter what causes it. The hoarseness and difficult swallowing are the first alarming symptoms that drive the patient to the physician. C1-INH i.v. or a dose of fresh frozen plasma can prevent the hereditary angioedema attack.

We should consider hereditary angioedema in case of episodic hypodermal edema of the extremities, in the absence of urticaria, upper airways edema and gastrointestinal edema, specially when it occurs in other family members. Laboratory analysis of blood samples or genetic testing is required to establish the hereditary angioedema diagnosis. There are two specific blood tests that confirm hereditary angioedema: (1) C1-inhibitor quantitative (antigenic) and (2) C1-inhibitor functional.
Traditionally, hereditary angioedema has been classified in two types: hereditary angioedema type 1 - C1-INH absent or reduced in serum and hereditary angioedema type 2 - C1-INH normal in serum, but has abnormal function.

The are five companies that conduct clinical trials with new drugs:
1. CSL Behring produce Berinert-P, C1-INH concentrate;
2. DX-88 (Dyax Corp.) kallikrein inhibitor, used in HAE acute attack;
3. Icatibant (Jerini AG) ß2 bradykinin receptor antagonist, for hypodermal use;
4. Lev Pharma is conducting a clinical tryal with a C1-INH product;
5. Pharming NV realized a C1-INH recombinant product.