A 19-year-old man has recurrent attacks of gastrointestinal colic and swelling of his face and legs. There is no relationship of the attacks to any foods or activity. His father has a similar syndrome. Which of the following is the most likely cause of death in this disease?
First, I need to figure out what disease this is. Recurrent abdominal pain and swelling (angioedema) with a family history makes me think of hereditary angioedema (HAE). HAE is an autosomal dominant disorder caused by C1 esterase inhibitor deficiency. The symptoms include episodic swelling of the skin, GI tract, and sometimes the airway. The key here is the family history and the absence of triggers like food or activity, which are more common in allergic reactions.
Now, the question is about the cause of death. In HAE, the most dangerous complication is laryngeal edema, which can lead to airway obstruction and death. So the answer is likely airway obstruction. Let me check the options. The correct answer should be the one related to airway issues. Let's see, the options aren't listed here, but based on the scenario, the correct answer is airway obstruction.
Other options might include things like GI bleeding or anaphylaxis. But GI bleeding isn't the main cause in HAE. Anaphylaxis is allergic, which is different from hereditary causes. Also, C1 esterase inhibitor deficiency leads to bradykinin-mediated swelling, not IgE-mediated. So the wrong options would be those not related to airway. The clinical pearl here is that HAE can be fatal if the airway is involved. So the answer must be airway obstruction.
**Core Concept**
This question tests recognition of hereditary angioedema (HAE), an autosomal dominant disorder caused by C1 esterase inhibitor deficiency. The condition leads to bradykinin-mediated vascular leakage, causing recurrent angioedema and abdominal attacks. Fatal laryngeal edema is the primary cause of mortality.
**Why the Correct Answer is Right**
Laryngeal angioedema in HAE can progress to airway obstruction, a life-threatening emergency. Unlike allergic reactions (which involve IgE), HAE involves dysregulation of the kallikrein-kinin system, leading to uncontrolled bradykinin production. This causes subcutaneous and submucosal edema in the airway, gastrointestinal tract, and skin. Prompt recognition and treatment with bradykinin receptor antagonists or C1 esterase inhibitors are critical to prevent death.
**Why Each Wrong Option is Incorrect**
**Option A:** GI bleeding is not a direct cause of death in HAE; abdominal pain and swelling occur but do not typically lead to fatal hemorrhage.
**Option B:** Anaphylaxis is IgE-mediated and unrelated to HAE. HAE attacks are non-allergic and not triggered by allergens.
**Option C:** Renal failure is not a feature of HAE; the condition primarily affects vascular permeability, not renal function.
**Clinical Pearl / High-Yield Fact**
Never forget that HAE can mimic allergic reactions but requires different treatment. Classic features include non-pitting edema, family history, and absence of urticaria. Airway involvement is the red flag for life-threatening complications.