Emergency Treatment of HAE

Emergency treatment of HAE during an acute attack can be extremely challenging because, unlike an allergic reaction, swelling related to HAE does not respond to epinephrine, antihistamines, or glucocorticoids. In Canada and several European countries, C1 esterase inhibitor (C1-INH) is used for treating acute attacks of HAE or for short-term prophylaxis. In countries such as the U.S., where no C1-INH is available, fresh-frozen plasma (FFP) is used. However, there are side effects related to use of replacement therapies, especially FFP.

The most important urgent acute HAE attacks are those involving laryngeal swelling, which is potentially lethal. Attacks of this type must be treated immediately in the hospital—not a local clinic—in case emergency intubation or tracheotomy is necessary. Involvement of the upper airway usually begins slowly but cases of progression within 20 minutes have been reported. Voice alteration and dysphagia indicate high risk of total airway obstruction. If there is suspicion of airway involvement, FFP or C1-INH concentrate should be given promptly. Administration of C1-INH concentrate in particular shortens the duration of attacks by about a third and halves the time to the beginning of the relief of symptoms. In very severe cases, emergency tracheotomy or tracheal intubation should be performed at once.

Severe pain can often accompany abdominal attacks. In fact, an acute HAE attack can mimic appendicitis, a bowel rupture, or an obstruction. In addition, the white blood cell count may increase during an attack, further complicating the clinical scenario. Many patients have undergone unnecessary surgeries before HAE was correctly diagnosed. As with any group of people, those with HAE can indeed develop appendicitis or other acute bowel symptoms, so caution is advised.

In abdominal HAE attacks where severe pain is noticeable, pain management using nonsteroidal antiinflammatory drugs (NSAIDs) is often effective. It is very important that HAE be correctly diagnosed in such cases. Often, an abdominal attack presents similarly to such disorders as appendicitis, a bowel rupture or an obstruction.

For more information about diagnosis and treatment of HAE see: