Review Question - QID 108732

This patient who presents with epistaxis, bleeding gums, and oozing from her surgical site in the setting of malnutrition and broad-spectrum antibiotic use most likely has iatrogenic vitamin K deficiency.

Vitamin K is a required cofactor in the gamma-carboxylation of factors IX, X, VII, and II as well as proteins C and S. These coagulation factors are responsible for achieving hemostasis so patients will present with ecchymosis, hematomas, and prolonged bleeding. Vitamin K deficiency can occur in the setting of fat malabsorption (pancreatitis and Crohn's disease), malnutrition (homeless and elderly), and broad-spectrum antibiotic use. Broad-spectrum antibiotics can kill gut flora which are producers of vitamin K thus resulting in iatrogenic vitamin K deficiency. Laboratory tests in patients with vitamin K deficiency will show a prolonged PT and aPTT as well as a normal D-dimer level. Vitamin K deficient patients should be treated with vitamin K replacement (phytonadione) in mild cases or prothrombin complex concentrate (factors IX, X, VII, II) in cases of severe uncontrollable bleeding.

Aziz and Patil studied whether prophylactic treatment with vitamin K is indicated in patients on broad-spectrum antibiotic therapy. They found that up to 15% of patients on long-term antibiotic therapy became vitamin K deficient but that a single prophylactic dose was not effective in preventing this condition. They recommend monitoring vitamin K levels and repleting as necessary.

Incorrect Answers:
Answer 2: Bacterial infection of the bloodstream describes sepsis, which would present with continued fever as well as instability of vitals with notable hypotension and tachycardia. This is possible given the patient's history of bacterial endocarditis but not likely to be the cause of her coagulation abnormalities 5 days after surgical removal of vegetations and the use of broad-spectrum antibiotics, which are the treatment for sepsis.

Answer 3: Coagulation cascade activation describes the pathology of disseminated intravascular coagulation (DIC). DIC presents with similar symptoms as this patient (bleeding from IV sites, epistaxis, and bleeding gums) but is associated with abnormal platelet levels and D-dimer levels given the consumption of platelets and diffuse formation of microthrombi. Treatment is supportive and reversal of the inciting etiology.

Answer 4: Deficiency of Von Willebrand factor (vWF) presents with bleeding from mucosal surfaces (as in this patient) as well as a prolonged aPTT because vWF stabilizes factor VIII. This disorder would not occur suddenly in an acute hospital stay but rather would present in a more chronic manner. Treatment is with factor repletion.

Answer 5: Factor VIII deficiency describes hemophilia A. Hemophilia A presents with factor-style bleeding (easy bruising and hemarthrosis) and a more chronic picture versus this acute presentation associated with antibiotic use. Treatment is with the repletion of the deficient coagulation factor.

Bullet Summary:
Vitamin K deficiency presents with easy bruising, hemarthrosis, and bleeding from IV and surgical sites and is associated with poor nutrition and broad-spectrum antibiotic use.