#Medtwitter, I have another good #inpatientpearl for today!
This one’s about angioedema.
(And lest you forget, I’ve included a lovely sketch of this swelling pattern, by an artist named Paul Moncus. Google is wonderful.)
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This one’s about angioedema.
(And lest you forget, I’ve included a lovely sketch of this swelling pattern, by an artist named Paul Moncus. Google is wonderful.)
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Ok. Let’s say you’re called to a code for a patient with rapidly developing angioedema. On chart review, you see they’re on lisinopril and have never had any allergic reactions before.
Airway & patient stability permitting, what is ONE high-yield question you should ask?
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Airway & patient stability permitting, what is ONE high-yield question you should ask?
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Make sure to ask about itchiness or urticaria!
This helps you differentiate between bradykinin-mediated and mast-cell mediated forms of angioedema.
To understand why, let’s take a step back to pathophysiology (it’ll be relatively painless, I promise).
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This helps you differentiate between bradykinin-mediated and mast-cell mediated forms of angioedema.
To understand why, let’s take a step back to pathophysiology (it’ll be relatively painless, I promise).
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Recall that ACE inhibitors like lisinopril inhibit ACE (duh).
Aside from working within the RAAS axis to regulate sodium and water balance, ACE plays a second role - it helps break down a substance called bradykinin.
Bradykinin, in turn, causes vasodilation (and edema!)
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Aside from working within the RAAS axis to regulate sodium and water balance, ACE plays a second role - it helps break down a substance called bradykinin.
Bradykinin, in turn, causes vasodilation (and edema!)
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To sum up:
- Patient takes ACEi.
- No ACE means too much bradykinin. - Too much bradykinin means too much capillary leakage.
Boom! Swelling.
This is the mechanism by which ACEi can cause bradykinin-mediated angioedema. Notice: nowhere have we mentioned itching (yet).
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- Patient takes ACEi.
- No ACE means too much bradykinin. - Too much bradykinin means too much capillary leakage.
Boom! Swelling.
This is the mechanism by which ACEi can cause bradykinin-mediated angioedema. Notice: nowhere have we mentioned itching (yet).
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Angioedema WITH itching suggests mast-cell mediated angioedema.
The pathophys is familiar: mast cells release histamine, causing vasodilation & pruritus.
Like with any allergic rxn, there are many triggers: foods, insects, & yes - medications. Including ACE inhibitors!
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The pathophys is familiar: mast cells release histamine, causing vasodilation & pruritus.
Like with any allergic rxn, there are many triggers: foods, insects, & yes - medications. Including ACE inhibitors!
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Turns out, mast cell-mediated angioedema is much more common than bradykinin-mediated angioedema.
(Note: I wasn’t able to find any literature on whether ACE inhibitors are more likely to cause mast-cell or bradykinin-mediated angioedema).
ncbi.nlm.nih.gov/pmc/articles/P…
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(Note: I wasn’t able to find any literature on whether ACE inhibitors are more likely to cause mast-cell or bradykinin-mediated angioedema).
ncbi.nlm.nih.gov/pmc/articles/P…
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Aside from letting us use the word bradykinin over and over, why does this distinction matter?
Turns out, the two etiologies of angioedema have different treatments.
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Turns out, the two etiologies of angioedema have different treatments.
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In bradykinin-mediated AE, you need only remove the offending agent (AKA lisinopril). As ACE regenerates, it’ll break down the bradykinin and stop the swelling.
But for mast cell-mediated AE, you’ll want to bring steroids and antihistamines on board, too.
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But for mast cell-mediated AE, you’ll want to bring steroids and antihistamines on board, too.
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IN SUMMARY:
Whenever feasible, ask your angioedematous patients about itching or urticaria.
This is a key symptom that helps you distinguish between etiologies of angioedema and can materially guide your management.
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Whenever feasible, ask your angioedematous patients about itching or urticaria.
This is a key symptom that helps you distinguish between etiologies of angioedema and can materially guide your management.
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And the bonus review tweet! Did we like this?
