Acquired coagulopathies: liver disease, vitamin K deficiency and DIC

13 DOH Abu Dhabi (HAAD) lab licensing practice questions on Acquired coagulopathies: liver disease, vitamin K deficiency and DIC, part of Coagulation and Hemostasis. The first 13 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Hard

   A 34-year-old construction worker collapses outdoors at midday in summer with a core temperature of 41.8 °C. Six hours after cooling, he is oozing from cannula sites. Results: platelets 41 × 10^9/L (reference 150-400), PT 22.5 s (11.0-13.5 s), APTT 54 s (25-35 s), fibrinogen 0.8 g/L (80 mg/dL; 2.0-4.0 g/L), D-dimer 18.5 mg/L FEU (below 0.5), factor V 32%, factor VII 38% and factor VIII 29% (all 50-150%), and ALT 210 U/L (below 45). The blood film shows occasional schistocytes. The coagulation results are best explained by:

   1. APrimary hyperfibrinolysis
   2. BAcute DIC triggered by heat stroke
   3. CVitamin K deficiency
   4. DReduced synthesis from acute liver injury

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   Answer: B · Acute DIC triggered by heat stroke

   A low platelet count, low fibrinogen, prolonged PT and APTT and a very high D-dimer together show consumption of platelets and factors with secondary fibrinolysis, which is acute DIC; heat stroke is a well-known trigger. Factor VIII is the key result: it is made mainly by endothelial cells rather than hepatocytes, so it stays normal or high in liver injury and falls when it is consumed. The raised ALT shows heat-related liver damage, but reduced synthesis alone would not lower factor VIII and the platelets this fast or raise the D-dimer this much. Vitamin K deficiency spares factor V and fibrinogen, and primary hyperfibrinolysis leaves the platelets normal with only a small D-dimer rise. Platelets, PT, fibrinogen and D-dimer should be repeated every few hours to follow the DIC.

   • A: Primary hyperfibrinolysis leaves the platelet count normal, with little D-dimer rise.
   • C: Vitamin K deficiency spares factor V and fibrinogen and leaves platelets normal.
   • D: Liver injury alone keeps factor VIII normal or high and does not raise D-dimer this much.

2. Question 2 · Hard

   Three days after a large paracetamol (acetaminophen) overdose, a 24-year-old woman has: INR 4.6 (reference 0.9-1.1), factor V 14%, factor VII 9%, factor VIII 190% (all 50-150%), platelets 150 × 10^9/L and fibrinogen 1.5 g/L (150 mg/dL; reference 2.0-4.0 g/L). Which mechanism best explains these results?

   1. AFailure of hepatic factor synthesis
   2. BAn acquired antibody against factor V
   3. CLack of vitamin K for carboxylation
   4. DConsumption of factors in acute DIC

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   Answer: A · Failure of hepatic factor synthesis

   Paracetamol overdose can cause acute hepatocyte necrosis, and the failing liver stops making factors with short half-lives such as factors VII and V, so the INR rises quickly. A very low factor V separates synthetic failure from vitamin K deficiency, because factor V is made by hepatocytes but does not depend on vitamin K. Factor VIII, made by endothelial cells, stays high, and the near-normal platelet count argues against DIC. The INR and factor V are followed closely and help decide on referral for liver transplantation.

   • B: A factor V inhibitor would not explain the very low factor VII.
   • C: Vitamin K deficiency lowers factors II, VII, IX and X but not factor V.
   • D: DIC would consume factor VIII and usually lower the platelet count.

3. Question 3 · Hard

   A 55-year-old man with known cirrhosis develops septic shock. His baseline INR is 1.7, platelets 85 × 10^9/L and D-dimer mildly raised. Which new result best shows that DIC has developed on top of his liver disease (factor reference 50-150%)?

   1. AINR rising from 1.7 to 2.0
   2. BFactor V falling from 55% to 45%
   3. CPlatelets falling from 85 to 70 × 10^9/L
   4. DFactor VIII falling from 180% to 40%

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   Answer: D · Factor VIII falling from 180% to 40%

   Factor VIII is made by endothelial cells and is normal or high in cirrhosis, so a marked fall points to consumption by DIC. The INR, platelet count, factor V and D-dimer are already abnormal in cirrhosis and drift with worsening liver function, so small changes in them are hard to interpret. Serial results matter more than single values: a falling platelet count and fibrinogen with a rising D-dimer together support DIC. Sepsis is a common trigger of DIC in patients with cirrhosis.

   • A: A small INR rise can come from worsening liver synthesis alone.
   • B: Factor V falls with worsening liver synthesis as well as in DIC.
   • C: A small platelet fall is common in cirrhosis with splenic pooling and does not separate the two.

4. Question 4 · Hard

   A 61-year-old man has painless jaundice from a pancreatic head mass blocking the bile duct. Results: INR 2.0 (reference 0.9-1.1), APTT 39 s (25-35 s), fibrinogen 3.6 g/L (360 mg/dL; reference 2.0-4.0 g/L), platelets 245 × 10^9/L, factor V 96% and factor VII 22% (both 50-150%). What is the most likely cause of the abnormal PT?

   1. AChronic DIC caused by the tumor
   2. BAcquired inhibitor of factor VII
   3. CMalabsorption of vitamin K
   4. DHepatocellular synthetic failure

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   Answer: C · Malabsorption of vitamin K

   Bile salts are needed to absorb fat-soluble vitamin K, so complete biliary obstruction causes vitamin K deficiency. Factor VII has the shortest half-life of the vitamin K-dependent factors, so it falls first and the PT rises more than the APTT. A normal factor V, which is made by hepatocytes but does not need vitamin K, shows that liver synthesis is intact, and normal fibrinogen and platelets argue against DIC. Parenteral vitamin K should correct the INR within about a day, whereas oral vitamin K may not be absorbed.

   • A: Chronic DIC usually leaves the PT near normal and would not lower factor VII while sparing factor V.
   • B: Acquired factor VII inhibitors are very rare, and the setting points to vitamin K malabsorption.
   • D: Liver failure would lower factor V as well as factor VII.

5. Question 5 · Hard

   A woman at 36 weeks' gestation has a placental abruption with vaginal bleeding. Results: platelets 110 × 10^9/L, PT 14.5 s (reference 11.0-14.0 s), fibrinogen 2.1 g/L (210 mg/dL; nonpregnant reference 2.0-4.0 g/L) and a markedly raised D-dimer. The best interpretation of the fibrinogen is:

   1. ARaised, as expected in pregnancy
   2. BNormal, so DIC is unlikely
   3. CLow from the hemodilution of pregnancy
   4. DLow for late pregnancy, suggesting consumption

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   Answer: D · Low for late pregnancy, suggesting consumption

   Fibrinogen rises steadily in pregnancy and is commonly about 4 to 6 g/L at term, so 2.1 g/L, although inside the nonpregnant range, means a large amount has been used. Placental abruption releases tissue factor-rich placental material into the maternal circulation and is a classic cause of acute DIC. In obstetric hemorrhage a fibrinogen below about 2 g/L predicts severe bleeding, so this result needs urgent action. Results in pregnancy should be judged against pregnancy-specific ranges and repeated to follow the trend.

   • A: Fibrinogen is expected to be raised at term, and 2.1 g/L is not raised.
   • B: The value is inside the nonpregnant range but far below the level expected at term.
   • C: Fibrinogen concentration rises in pregnancy despite the larger plasma volume, so dilution does not explain a fall.

6. Question 6 · Medium

   In chronic liver disease, a prolonged thrombin time and reptilase time with a normal fibrinogen antigen level are most often caused by:

   1. AFibrinogen with excess sialic acid
   2. BLow antithrombin levels
   3. CHeparin contamination of the sample
   4. DAcquired factor XIII deficiency

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7. Question 7 · Easy

   Unlike most clotting factors, factor VIII is made mainly by:

   1. AMonocytes
   2. BEndothelial cells
   3. CHepatocytes
   4. DMegakaryocytes

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8. Question 8 · Easy

   In sepsis-associated DIC, which change mainly starts the widespread thrombin generation?

   1. ATissue factor expressed on monocytes and endothelium
   2. BAntibodies to platelet factor 4-heparin complexes
   3. CAutoantibodies that block ADAMTS13 activity
   4. DRelease of plasmin from damaged hepatocytes

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9. Question 9 · Medium

   In stable cirrhosis, a raised INR is a poor guide to bleeding risk mainly because:

   1. AProtein C and antithrombin fall as well
   2. BPlatelet counts rise to make up for factor loss
   3. CFactor VIII falls along with the other factors
   4. DFibrinolysis is switched off in cirrhosis

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10. Question 10 · Medium

    At diagnosis of acute promyelocytic leukemia, which coagulation result pattern is most typical?

    1. AVery low fibrinogen with a high D-dimer
    2. BNormal fibrinogen with an isolated prolonged PT
    3. CHigh fibrinogen with a normal D-dimer
    4. DIsolated prolonged APTT that corrects on mixing

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11. Question 11 · Hard

    A 4-year-old with meningococcal sepsis develops spreading purpura with skin necrosis. Results: platelets 30 × 10^9/L, PT 26 s (reference 11-14 s), fibrinogen 0.7 g/L (70 mg/dL; reference 2.0-4.0 g/L) and a markedly raised D-dimer. Which further result is most typical of this picture?

    1. AMarkedly low protein C activity
    2. BADAMTS13 activity below 10%
    3. CA strongly positive PF4-heparin antibody
    4. DAntithrombin above the reference range

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12. Question 12 · Medium

    An ICU patient who has eaten nothing for 10 days and is on broad-spectrum antibiotics has an INR of 2.4 (reference 0.9-1.1). Twelve hours after 10 mg of intravenous vitamin K, the INR is 1.2. This response points to:

    1. AA lupus anticoagulant
    2. BConsumption in DIC
    3. CVitamin K deficiency
    4. DHepatocellular failure

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13. Question 13 · Medium

    Prolonged PT and aPTT, low platelets, low fibrinogen and a raised D-dimer suggest which condition?

    1. AVitamin K deficiency or warfarin effect
    2. BImmune thrombocytopenia (ITP)
    3. CHemophilia A (factor VIII deficiency)
    4. DDisseminated intravascular coagulation

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