General Surgery UK Medical PG Flashcards - Medical Study Cards
Master General Surgery with OnCourse flashcards. These spaced repetition flashcards are designed for medical students preparing for NEET PG, USMLE Step 1, USMLE Step 2, MBBS exams, and other medical licensing examinations.
General Surgery Flashcard Deck - 10 Cards
Flashcard 421: What is the mechanism of action for unfractionated heparin?
_____
Answer: Binds to antithrombin III, causing indirect inhibition of factors IIa (thrombin) and Xa
Flashcard 422: Antiplatelet medication (e.g., Aspirin) should be continued through surgery if there is a high _____ risk (e.g., recent coronary stent).
Contrastingly, anticoagulants (e.g., Warfarin) are the medications typically temporarily replaced by heparin bridging.
Answer: thrombosis
Extra: In surgical patients, Aspirin is often continued if the risk of a major adverse cardiac event (MACE) outweighs the risk of surgical bleeding. True 'bridging' with heparin is indicated for patients on long-term anticoagulation (Warfarin) with a high risk of thromboembolism (e.g., mechanical heart valves, high-risk AF).
Flashcard 423: The reversal agent of low molecular weight heparin is _____
Answer: IV protamine sulfate
Extra: Note: Protamine sulfate completely neutralizes Unfractionated Heparin (UFH) but only partially neutralizes (approx. 60-80%) the anti-Xa activity of Low Molecular Weight Heparin (LMWH).
Flashcard 424: Patients taking DOACs undergoing surgery with a high-risk of bleeding should stop taking the DOAC _____ prior to surgery.
Answer: 48 hours
Extra: For DOACs (Apixaban, Rivaroxaban, Edoxaban, Dabigatran):
- Low bleed risk surgery: Stop 24 hours before.
- High bleed risk surgery: Stop 48 hours before.
- Note: Dabigatran may require longer cessation (up to 96 hours) if CrCl < 50 mL/min.
- Warfarin usually requires 5 days cessation. DOACs have much shorter half-lives.
Flashcard 425: What is the mechanism of action for low molecular weight heparin?
_____
Answer: Indirect inhibition of Xa via activation of antithrombin III
Flashcard 426: The reversal agent of edoxaban is _____
Answer: Andexanet alfa
Extra: Edoxaban is a direct Factor Xa inhibitor. While initial trials focused on rivaroxaban and apixaban, Andexanet alfa (a decoy receptor) is now the standard reversal agent for edoxaban-associated life-threatening bleeding.
For Dabigatran (Direct Thrombin Inhibitor), the reversal agent is Idarucizumab.
Flashcard 427: Vision loss from _____ diabetic retinopathy may result from macular oedema
Answer: nonproliferative
Flashcard 428: Vision loss from _____ diabetic retinopathy may result from complications (macular oedema, vitreous haemorrhage, tractional retinal detachment, neovascular glaucoma)
Answer: proliferative
Flashcard 429: The reversal agent of apixaban is _____
Answer: andexanet alfa (Andexxa)
Flashcard 430: Edoxaban is a direct factor _____ inhibitor
Answer: Xa
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