Bleeding in a patient recently on antibiotics is most commonly due to which deficiency?

Bleeding in a patient recently on antibiotics is most commonly due to which deficiency?

• A. factor VII deficiency
• B. vitamin E deficiency
• C. factor XIII deficiency
• D. vitamin K deficiency

Answer: (D)

When antibiotics disrupt gut bacteria, bleeding tendency can arise from vitamin K deficiency. Vitamin K is needed to activate clotting factors II, VII, IX, and X through gamma-carboxylation; without enough vitamin K, these factors function poorly and the coagulation cascade is impaired. The extrinsic pathway is affected early because factor VII has the shortest half-life, so the prothrombin time (PT) is often prolonged first, signaling a coagulopathy. The other deficiencies don’t fit the typical antibiotic-associated pattern. Factor VII or XIII deficiencies aren’t commonly linked to recent antibiotic use, and their clinical or lab presentations don’t align with a straightforward antibiotic-induced coagulopathy. Vitamin E deficiency isn’t a standard cause of acute bleeding in this context. Thus, vitamin K deficiency best explains bleeding after starting antibiotics.

When antibiotics disrupt gut bacteria, bleeding tendency can arise from vitamin K deficiency. Vitamin K is needed to activate clotting factors II, VII, IX, and X through gamma-carboxylation; without enough vitamin K, these factors function poorly and the coagulation cascade is impaired. The extrinsic pathway is affected early because factor VII has the shortest half-life, so the prothrombin time (PT) is often prolonged first, signaling a coagulopathy.

The other deficiencies don’t fit the typical antibiotic-associated pattern. Factor VII or XIII deficiencies aren’t commonly linked to recent antibiotic use, and their clinical or lab presentations don’t align with a straightforward antibiotic-induced coagulopathy. Vitamin E deficiency isn’t a standard cause of acute bleeding in this context. Thus, vitamin K deficiency best explains bleeding after starting antibiotics.