Hereditary angioedema is a type of angioedema caused due to the deficiency of a blood protein called C1 esterase inhibitor. This article provides information about the causes, symptoms, and various treatment options available for this condition.
Hereditary angioedema, which is also referred to as Quincke’s disease, is a rare immune system disorder. It is inherited in an autosomal dominant pattern, in which, the child inherits a faulty gene from one of the parent. In this condition, there are 50% chances of the parents passing this disease to the offspring. The disorder is caused due to an inadequate amount of a blood protein called C1 esterase inhibitor (CEI). The deficiency leads to the swelling in different parts of the body, especially the face and the airways.
Improper functioning or inadequate level of CEI in the blood, causes this hereditary condition. Swelling in the body is controlled by CEI, whenever there is an injury. The gene associated with C1 esterase inhibitor, SERPING1, is situated on the 11th chromosome. Mutation of this gene leads to the deficiency and dysfunction of CEI. This deficiency, further causes swelling in various body parts such as the voice box, windpipe, hands, feet, face, and the intestinal tract. Swelling of the passage that joins stomach and anus, causes pain in the form of cramps. The condition can be fatal, if the swelling takes place in the windpipe. The patient may have a hitherto unnoticed family history of the disease. Surgery, dental operation, and certain illnesses (cold and flu) are also considered as trigger factor in some cases. There are three types of hereditary angioedema, as given in the table below.
|Type 1||Low level of C1 inhibitor|
|Type 2||Normal or increased level of C1 inhibitor that does not function properly.|
|Type 3||Related to estrogen (female sex hormone) – only women are affected.|
Many times, it happens that an individual born with this condition does not show any symptom, until he/she reaches puberty. The symptoms are sudden and are referred to as an ‘attack’. The symptoms could occur due to anxiety, illness, injury, and surgery. It is noticed that the symptoms of the attack persist for at least 5 days, and it takes one to three days for the swelling to reduce completely. The following symptoms are observed in this condition:
- Swelling of body parts such as legs, arms, lips, tongue, or throat
- Unexplained pain in the stomach
- Vomiting or diarrhea due to the swelling of the intestine
- Difficulty in swallowing, breathing, and hoarseness due to swelling of the airway
The condition can be diagnosed by blood tests and genetic tests. As the swelling in the body parts can be a result of many other problems, blood and genetic tests are the only two tests that can confirm this condition. The blood test aims at finding out the amount of CEI in the blood, and verifying whether it is functioning properly or not. The gene test can help in revealing any defect in chromosome 11. If the level of CEI is very low, then this condition is confirmed.
The treatment depends on the area which has swollen. Swelling of the windpipe can be serious, and may need urgent treatment. Medications that are usually used to reduce the swelling, do not prove helpful in case of hereditary angioedema. Preventive medications like danazol and oxandrolone are recommended to people who get frequent attacks. Medications are also available to prevent swelling caused due to this condition after surgery. Some drugs are available, which can be used during an attack, i.e., soon after the swelling. Medications are available to treat the symptoms such as nausea, vomiting, etc. Blood transfusion is also given in some cases.
The condition is rare, with 1 in every 10,000 – 50,000 people in the US being affected by it. Though it is a rare genetic disorder, it may prove fatal in certain cases. Individuals having a family history of this condition should consult their physician for preventive measures.
Disclaimer: This HealthHearty article is for informative purposes only, and should not be used as a replacement for expert medical advice.