血管性水肿

症狀

The skin of the face, normally around the mouth, and the mucosa of the mouth and/or throat, as well as the tongue, swell over the period of minutes to hours. The swelling can also occur elsewhere, typically in the hands.  The swelling can be itchy or painful.  There may also be slightly decreased sensation in the affected areas due to compression of the nerves. Urticaria (hives) may develop simultaneously.
In severe cases, stridor of the airway occurs, with gasping or wheezy inspiratory breath sounds and decreasing oxygen levels. Tracheal intubation is required in these situations to prevent respiratory arrest and risk of death.
Sometimes, the cause is recent exposure to an allergen (e.g. peanuts), but more often it is either idiopathic (unknown) or only weakly correlated to allergen exposure.
In hereditary angioedema, often no direct cause is identifiable, although mild trauma, including dental work and other stimuli, can cause attacks. There is usually no associated itch or urticaria, as it is not an allergic response.  Patients with HAE can also have recurrent episodes (often called "attacks") of abdominal pain, usually accompanied by intense vomiting, weakness, and in some cases, watery diarrhea, and an unraised, nonitchy splotchy/swirly rash.  These stomach attacks can last one to five days on average, and can require hospitalization for aggressive pain management and hydration. Abdominal attacks have also been known to cause a significant increase in the patient's white blood cell count, usually in the vicinity of 13,000 to 30,000.  As the symptoms begin to diminish, the white count slowly begins to decrease, returning to normal when the attack subsides. As the symptoms and diagnostic tests are almost indistinguishable from an acute abdomen (e.g. perforated appendicitis) it is possible for undiagnosed HAE patients to undergo laparotomy (operations on the abdomen) or laparoscopy (keyhole surgery) that turns out to have been unnecessary.
HAE may also cause swelling in a variety of other locations, most commonly the limbs, genitals, neck, throat and face. The pain associated with these swellings varies from mildly uncomfortable to agonizing pain, depending on its location and severity. Predicting where and when the next episode of edema will occur is impossible. Most patients have an average of one episode per month, but there are also patients who have weekly episodes or only one or two episodes per year. The triggers can vary and include infections, minor injuries, mechanical irritation, operations or stress. In most cases, edema develops over a period of 12–36 hours and then subsides within 2–5 days.

診斷

The diagnosis is made on the clinical picture. Routine blood tests (complete blood count, electrolytes, renal function, liver enzymes) are typically performed. Mast cell tryptase levels may be elevated if the attack was due to an acute allergic (anaphylactic) reaction. When the patient has been stabilized, particular investigations may clarify the exact cause; complement levels, especially depletion of complement factors 2 and 4, may indicate deficiency of C1-inhibitor. HAE type III is a diagnosis of exclusion consisting of observed angioedema along with normal C1 levels and function.
The hereditary form (HAE) often goes undetected for a long time, as its symptoms resemble those of more common disorders, such as allergy or intestinal colic. An important clue is the failure of hereditary angioedema to respond to antihistamines or steroids, a characteristic that distinguishes it from allergic reactions. It is particularly difficult to diagnose HAE in patients whose episodes are confined to the gastrointestinal tract. Besides a family history of the disease, only a laboratory analysis can provide final confirmation. In this analysis, it is usually a reduced complement factor C4, rather than the C1-INH deficiency itself, that is detected. The former is used during the reaction cascade in the complement system of immune defense, which is permanently overactive due to the lack of regulation by C1-INH.
Angioedema is classified as either hereditary or acquired.

獲得性血管性水腫

Acquired angioedema (AAE) can be immunologic, nonimmunologic, or idiopathic. It is usually caused by allergy and occurs together with other allergic symptoms and urticaria. It can also occur as a side effect to certain medications, particularly ACE inhibitors. It is characterized by repetitive episodes of swelling, frequently of the face, lips, tongue, limbs, and genitals. Edema of the gastrointestinal mucosa typically leads to severe abdominal pain; in the upper respiratory tract, it can be life-threatening.

遺傳型血管性水腫

Hereditary angioedema (HAE) exists in three forms, all of which are caused by a genetic mutation inherited in an autosomal dominant form. They are distinguished by the underlying genetic abnormality. Types I and II are caused by mutations in the SERPING1 gene, which result in either diminished levels of the C1-inhibitor protein (type I HAE) or dysfunctional forms of the same protein (type II HAE). Type III HAE has been linked with mutations in the F12 gene, which encodes the coagulation protein factor XII. All forms of HAE lead to abnormal activation of the complement system, and all forms can cause swelling elsewhere in the body, such as the digestive tract. If HAE involves the larynx, it can cause life-threatening asphyxiation. The pathogenesis of this disorder is suspected to be related to unopposed activation of the contact pathway by the initial generation of kallikrein and/or clotting factor XII by damaged endothelial cells. The end product of this cascade, bradykinin, is produced in large amounts and is believed to be the predominant mediator leading to increased vascular permeability and vasodilation that induces typical angioedema "attacks".

過敏

In allergic angioedema, avoidance of the allergen and use of antihistamines may prevent future attacks. Cetirizine is a commonly prescribed antihistamine for angioedema.  Some patients have reported success with the combination of a nightly low dose of cetirizine to moderate the frequency and severity of attacks, followed by a much higher dose when an attack does appear.  Severe angioedema cases may require desensitization to the putative allergen, as mortality can occur. Chronic cases require steroid therapy, which generally leads to a good response. In cases where allergic attack is progressing towards airway obstruction, epinephrine may be life-saving.

藥物導致

ACE inhibitors can induce angioedema. ACE inhibitors block the enzyme ACE so it can no longer degrade bradykinin; thus, bradykinin accumulates and causes angioedema. This complication appears more common in African-Americans. In people with ACE inhibitor angioedema, the drug needs to be discontinued and an alternative treatment needs to be found, such as an angiotensin II receptor blocker (ARB) which has a similar mechanism but does not affect bradykinin. However, this is controversial, as small studies have shown some patients with ACE inhibitor angioedema can develop it with ARBs, as well.

遺傳性

In hereditary angioedema, specific stimuli that have previously led to attacks may need to be avoided in the future. It does not respond to antihistamines, corticosteroids, or epinephrine. Acute treatment consists of C1-INH (C1-esterase inhibitor) concentrate from donor blood, which must be administered intravenously. In an emergency, fresh frozen blood plasma, which also contains C1-INH, can also be used. However, in most European countries, C1-INH concentrate is only available to patients who are participating in special programmes. The medications ecallantide and icatibant may be used to treat attacks. In 2017 these medications cost between 5,700 and 14,000 美元 per dose in the United States, prices that tripled in two years.
Future attacks of hereditary angioedema can be prevented by the use of androgens such as danazol, oxandrolone or methyltestosterone. These agents increase the level of aminopeptidase P, an enzyme that inactivates kinins; kinins (especially bradykinin) are responsible for the manifestations of angioedema.
活性減弱的雄性激素如達那唑、司坦唑（康力龍）、羥甲烯龍（康復龍）等治療先天性C1INH缺陷，可糾正其生化缺損並有預防發作的效用，但不能用於小兒和孕婦。

獲得性

獲得性血管神經性水腫、HAE的I型與II型、以及非組胺血管神經性水腫性，抗纖維蛋白溶酶藥物如氨甲環酸或ε-氨基己酸有時可控制自然發作，也適用於小兒和孕婦。桂利嗪可用於抗C4活化，適用於有肝病不能使用雄性激素的患者。

歷史

1882年，Heinrich Quincke首次臨床報告此病。 雖然有些更早的臨床描述。
1888年，William Osler認為某些是由於遺傳導致的，稱「遺傳性血管神經性水腫」。
1963年證實了C1酯酶抑制劑匱乏是病因。

流行病學

在美國，急診室年度就診患者中有80,000至112,000是血管神經性水腫，是過敏導致就醫中的首位。