Vitamin K Deficiency: Pathogenesis and Clinical Findings
Author:
Sean Spence
Reviewers:
Michael Blomfield, Tony Gu, Tristan Jones, Yan Yu Man-Chiu Poon* Lynn Saviole* * MD at initial time of publication
Dietary Deficiency
Small bowel bacterial overgrowth
Antibiotic use
Disruption of normal flora
↓ Gut flora synthesis
Vitamin K Deficiency
↓ vitamin K dependent gamma carboxylation of clotting factors II, VII, IX, X
Gastrointestinal mucosal diseases (e.g., Celiac disease)
Pancreatic insufficiency
Cholestasis
Malabsorption
Exposure to vitamin K antagonists (e.g., warfarin)
Inhibition of vitamin K epoxide reductase
↑ bleeding tendency
Gastrointestinal tract bleeds Intracranial bleeds Hemarthoses (bleeding into joints)
Easy bruising
Petechiae, purpura Heavy menstrual bleeds
Prolonged PT/INR
Note: PT/INR is more sensitive and validated for warfarin monitoring
↓ Activity of intrinsic clotting pathway
Prolonged PTT
↓ Activity of extrinsic clotting pathway
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Re-Published July 27, 2019 on www.thecalgaryguide.com