A 48-year-old man with decompensated cirrhosis has prothrombin time of 26 seconds against a control of 12 seconds. After five days of parenteral vitamin K therapy, the prothrombin time is unchanged. The best interpretation is:
- A Vitamin K malabsorption due to cholestasis
- B Severe hepatocellular dysfunction with inability to synthesise clotting factors ✓
- C Occult disseminated intravascular coagulation requiring heparin
- D Laboratory error, and the test should be repeated
Correct answer: B. Severe hepatocellular dysfunction with inability to synthesise clotting factors
Explanation
Prothrombin time depends on hepatic synthesis of factors II, V, VII and X. If prolongation is caused solely by vitamin K deficiency, as in cholestasis with impaired bile salt delivery, parenteral vitamin K corrects it within one to two days. Failure to respond indicates that the synthetic machinery itself has failed, marking severe hepatocellular insufficiency and poor prognosis. Factor V is not vitamin K dependent, so its assay can further separate synthesis failure from deficiency.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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