Question

A 58-year-old patient has prolonged PT and factor IX deficiency. Parenteral vitamin K is planned. In which condition will this help?

• A. Hepatitis A
• B. Pernicious anemia
• C. Hemophilia B
• D. Bile duct obstruction

Hint:

Vitamin K deficiency can occur in bile duct obstruction because vitamin K is fat-soluble and needs bile for absorption.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question relates to Vitamin K deficiency and the conditions that cause it. We need to identify which of the listed conditions will respond to parenteral Vitamin K supplementation.
Step 2: Detailed Explanation:

Vitamin K Physiology: Vitamin K is a fat-soluble vitamin. Its absorption requires bile salts to emulsify fats in the intestine. Factors II, VII, IX, and X are Vitamin K-dependent.

Bile Duct Obstruction (Obstructive Jaundice): If the bile duct is blocked (e.g., by a stone or tumor), bile does not reach the intestine. This leads to malabsorption of fat-soluble vitamins (A, D, E, K). Without Vitamin K, the liver cannot produce the active forms of coagulation factors, resulting in a prolonged Prothrombin Time (PT).

Treatment Response: Because the liver itself is usually functional in early obstructive jaundice, giving Vitamin K parenterally (bypassing the gut) will allow the liver to resume synthesis of the factors, thus correcting the PT.

Why not others?
- Hepatitis A (A): PT prolongation here is due to intrinsic liver cell damage. The liver is "broken" and cannot use Vitamin K effectively; therefore, Vitamin K supplementation usually doesn't correct the PT in severe hepatitis.
- Hemophilia B (C): This is a genetic deficiency of Factor IX. No amount of Vitamin K will help because the genetic instruction to build the protein is missing.
- Pernicious Anemia (B): Vitamin B12 deficiency, unrelated to Vitamin K or clotting.

Step 3: Final Answer:
Parenteral Vitamin K will correct coagulopathy in bile duct obstruction because the underlying issue is malabsorption, not liver failure or a genetic defect.