Hypovitaminosis K

Hypovitaminosis K (also known as vitamin K deficiency) is caused by a lack of vitamin K in the body.

Clinical presentation

The main symptoms and signs are related to a clotting dyscrasia as vitamin K is vital as a cofactor for the enzymatic activation of several key components of the clotting pathway, including the prothrombogenic proteins, prothrombin, factors VII, IX, and X, and the anticoagulant molecules, proteins C, S and Z.

• bleeding tendency
  • spontaneous hematomas
  • mucosal bleeding
  • hematochezia and melena
  • hematuria
  • menorrhagia
  • anemia

More concerning nowadays is possible deleterious sequelae of chronic subclinical vitamin K deficiency as it becomes clear that vitamin K is important for processes in the body other than clotting:

• increased fracture risk: vitamin K required for osteocalcin, a key molecule in osteogenesis
• increased risk of some cancers, e.g. HCC
• may be increased vascular calcification, and thus myocardial ischemia

Pathology

Etiology

• fat malabsorption
• chronic broad spectrum antibiotics
  • in particular sulbactam/cefoperazone, cefamandole, cefmetazole, and cefotetan (antibiotics with an N-methyl-tetrazole-thiol side group)
• dietary fat insufficiency

Treatment and prognosis

• vitamin K supplementation produces a rapid resolution of the clotting dysfunction