Pain at the transfusion site, when not associated with acute hemolytic transfusion reactions, is most commonly due to the release of bradykinin from venule endothelium, and it is also possibly potassium-related. Bradykinin is formed from the cleavage of high molecular weight kininogen (HMWK) by kallikrein in the kinin-kallikrein system, and is among a few other things a potent vasodilator and alterer of capillary permeability via its interactions with prostacyclin, nitric oxide and endothelium-derived hyperploarization factor (EDHF), which hyperpolarizes vascular smooth muscle to the point of relaxation. Bradykinin concentration is increased with the administration of ACE inhibitor medications, which prevent its degradation by ACE (a kininase enzyme); therefore, note should be taken of those ACE inhibitors with the shortest half-lives, if discontinuation of the drug class is contra-indicated: captopril (Capoten) has a half-life of 1.9 hours, while ramipril (Altace) has a half-life of 2-4 hours.
Posted in Clinical Pathology Tagged: blood bank
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Sign in nowI already knew this. I learned this in medical school in our second year. I’m pretty sure it was on the USMLE Step 1. But, I’m glad you learned that today.
Bottom line: never ever trust an on-call intern….Amen!
I can dig it.
Please don’t also forget to restick the patient just in case it is a mechanical issue with the stick.
Excellent point, Doctor.