What clinical condition likely caused a prolonged PT that corrected with intravenous vitamin K after 24 hours?

A prolonged prothrombin time (PT) that corrects with intravenous vitamin K after 24 hours indicates a deficiency in vitamin K-dependent clotting factors, which includes Factors II, VII, IX, and X. The clinical condition most likely causing this prolonged PT is obstructive jaundice.

In obstructive jaundice, bile flow from the liver is impeded, which can lead to a deficiency in fat-soluble vitamins, including vitamin K. Since vitamin K is essential for the synthesis of several clotting factors in the liver, an obstruction can lead to reduced levels of functioning clotting factors, prolonging the PT. Administration of vitamin K provides the necessary substrate for the liver to produce these factors, thereby correcting the PT.

This understanding highlights the connection between liver function, bile production, and vitamin K absorption. When the obstruction is resolved or vitamin K is administered, the vitamin K-dependent factors can be replenished, leading to normalization of the PT after 24 hours, which is why this scenario fits best.