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Glanzmann’s thrombasthenia
5%
1/21
Vitamin K deficiency
90%
19/21
Disseminated intravascular coagulation
0%
0/21
Hemophilia A
Hemophilia B
Select Answer to see Preferred Response
An infant presenting with easy bleeding and bruising, in the setting of increased aPTT and PT, but normal bleeding time, is likely suffering from vitamin K deficiency. Vitamin K deficiency is a common cause of bleeding disorders in the very young and very elderly (and malnourished) population. Vitamin K deficiency is important for the synthesis of clotting factors II, VII, IX, and X in the liver. Its deficiency, therefore, results in a prolonged aPTT and PT without affecting the bleeding time. It can be found in many green leafy vegetables, but is provided in an intramuscular form to neonates. Ballas et al. discuss the causes of bleeding and bruising. They describe many causes for vitamin K deficiency, including malabsorption (bacterial overgrowth), celiac disease, chronic pancreatitis, bowel resection, poor diet (alcoholism, TPN), or drugs that bind vitamin K. Another common cause in the infant population is maternal anticonvulsant use, which can be commonly treated with vitamin K repletion if the child is otherwise asymptomatic. Cornelissen et al. report on the incidence of vitamin K deficiency in infants with maternal anticonvulsant use (control) compared to mothers treated with antenatal vitamin K1. The measure of use was PIVKA-II (protein induced by vitamin K absence for factor II) which is elevated with vitamin K deficiency. The study found that none of samples where mother was treated with antenatal vitamin K contained PIVKA-II, compared with 13 of 20 in controls (p<0.001). The study also found the median cord vitamin K1 level was 530 pg/ml in treatment group compared with below detection limit in most controls. Figure A shows petechiae on the arm of an infant. Illustration A shows the coagulation cascade. Incorrect Answers: Answer 1: Glanzmann's thombasthenia is an inherited platelet disorder and would result in increased bleeding time. Answer 3: The child has normal vitals, and therefore is likely not suffering from DIC. DIC would also result in an elevation of bleeding time along with PT and PTT. Answer 4 and 5: Both hemophilia A and B result from clotting factor (VIII and IX, respectively) deficiencies. They would present with elevated aPTT, but PT and bleeding time would be normal.
4.3
(4)
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