1. A 70-year-old man with atrial fibrillation is taking warfarin for stroke prevention. He presents with a spontaneous nosebleed and INR of 5.5. What is the most appropriate next step?

• Withhold warfarin and administer vitamin K orally
• Continue warfarin and monitor INR weekly
• Withhold warfarin and start low molecular weight heparin (LMWH)
• Refer for emergency warfarin reversal with prothrombin complex concentrate (PCC)

Answer: Withhold warfarin and administer vitamin K orally

If INR is >5 but <8 without serious bleeding, oral vitamin K and holding warfarin is standard. PCC is for life-threatening bleeds.

2. A 65-year-old woman on rivaroxaban for venous thromboembolism presents with minor bleeding. What is the most appropriate test to assess anticoagulation levels?

• PT/INR
• Anti-Xa activity assay
• aPTT
• Thrombin time

Answer: Anti-Xa activity assay

For factor Xa inhibitors (rivaroxaban, apixaban), an anti-Xa assay is the most accurate measure of anticoagulant effect.

3. A 60-year-old woman receiving enoxaparin for DVT develops severe bleeding. What is the most appropriate initial management?

• Stop enoxaparin and administer protamine sulphate
• Stop enoxaparin and administer vitamin K
• Administer prothrombin complex concentrate (PCC)
• Transfuse fresh frozen plasma (FFP)

Answer: Stop enoxaparin and administer protamine sulphate

In cases of major bleeding on LMWH, discontinuing the drug and using protamine sulphate can help partially reverse its anticoagulant effects.

4. What is the primary mechanism of action of unfractionated heparin (UFH)?

• Inhibits factor Xa and thrombin by enhancing antithrombin activity
• Directly inhibits thrombin activity
• Reduces platelet aggregation by blocking glycoprotein IIb/IIIa
• Blocks the synthesis of vitamin K-dependent clotting factors

Answer: Inhibits factor Xa and thrombin by enhancing antithrombin activity

Unfractionated heparin binds to antithrombin, accelerating its inactivation of factor Xa and thrombin, thus reducing clot formation.

5. A 10-year-old boy with haemophilia A presents with joint swelling and severe pain after a minor fall. What is the most appropriate immediate management?

• Administer factor VIII concentrate
• Start tranexamic acid and monitor closely
• Immobilise the joint and monitor for improvement
• Refer for urgent joint aspiration

Answer: Administer factor VIII concentrate

Prompt factor VIII replacement is critical for haemarthrosis management in haemophilia A to prevent permanent joint damage.

6. What is the most common long-term complication of recurrent haemarthrosis in haemophilia B?

• Joint destruction and chronic arthropathy
• Increased risk of venous thromboembolism
• Hepatotoxicity due to factor IX replacement therapy
• Immune tolerance induction failure

Answer: Joint destruction and chronic arthropathy

Recurrent joint bleeds lead to cartilage and bone damage, causing progressive arthropathy, a major cause of morbidity in haemophilia.

7. A 70-year-old man on dabigatran for atrial fibrillation develops gastrointestinal bleeding. What is the most specific reversal agent?

• Andexanet alfa
• Idarucizumab
• Vitamin K
• Fresh frozen plasma (FFP)

Answer: Idarucizumab

Idarucizumab (Praxbind) is a monoclonal antibody fragment that specifically binds dabigatran, rapidly reversing its anticoagulant action.

8. A 68-year-old man taking rivaroxaban for DVT asks if he needs routine INR monitoring. What is the most appropriate response?

• No routine INR monitoring is required
• INR monitoring is needed every 4 weeks
• INR should be monitored weekly during initiation
• Routine monitoring is only needed for high-risk patients

Answer: No routine INR monitoring is required

Rivaroxaban’s anticoagulant effect does not require the frequent INR checks needed by warfarin therapy.

9. A 45-year-old woman receiving enoxaparin develops significant bruising and a platelet count of 40,000/µL. What is the most likely diagnosis?

• Heparin-induced thrombocytopenia (HIT)
• Immune thrombocytopenic purpura (ITP)
• Disseminated intravascular coagulation (DIC)
• Bone marrow failure

Answer: Heparin-induced thrombocytopenia (HIT)

HIT is a severe complication of heparin/LMWH exposure, with thrombocytopenia and paradoxical increased clotting risk.

10. A 75-year-old woman on warfarin presents with a life-threatening intracranial haemorrhage. What is the most appropriate initial management?

• Administer prothrombin complex concentrate (PCC)
• Administer IV vitamin K
• Start tranexamic acid
• Perform an emergency craniotomy

Answer: Administer prothrombin complex concentrate (PCC)

PCC quickly replenishes vitamin K-dependent clotting factors, vital for reversing life-threatening bleeds. Vitamin K is also given but is slower acting.