Drug of choice for acute attack of hereditary angioneurotic edema is
**Core Concept**
Hereditary angioneurotic edema (HAE) is a rare genetic disorder characterized by recurring episodes of severe swelling, primarily affecting the skin and mucous membranes. This condition is caused by a deficiency or dysfunction of the C1 esterase inhibitor (C1-INH) enzyme, leading to uncontrolled activation of the complement system and subsequent release of bradykinin, a potent vasodilator.
**Why the Correct Answer is Right**
The drug of choice for acute attacks of HAE is **C1 esterase inhibitor (C1-INH) concentrate**, which replaces the deficient or dysfunctional enzyme and effectively inhibits the complement system. This leads to a reduction in bradykinin levels, resulting in decreased vasodilation and edema. C1-INH concentrate is administered intravenously and is generally effective within 15-30 minutes, providing rapid relief from symptoms.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because antihistamines, such as diphenhydramine, are not effective in treating the underlying cause of HAE and may even exacerbate symptoms due to their anticholinergic effects.
* **Option B:** This option is incorrect because corticosteroids, such as prednisone, may provide some relief from inflammation but are not sufficient to treat the acute attack of HAE.
* **Option D:** This option is incorrect because epinephrine, although used in anaphylaxis, is not the drug of choice for acute attacks of HAE and may even worsen symptoms due to its vasopressor effects.
**Clinical Pearl / High-Yield Fact**
C1 esterase inhibitor concentrate is the only FDA-approved treatment for acute attacks of hereditary angioneurotic edema.
**Correct Answer:** C. C1 esterase inhibitor (C1-INH) concentrate