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Vitamin K deficiency



Hematological system


Heme synthesis disorders
Coagulation disorders
Platelet disorders
Mixed platelet and coagulation disorders
Thrombosis syndromes (hypercoagulability)
Leukemoid reaction
Dysplastic and proliferative disorders
Plasma cell dyscrasias
Hematological system pathology review

Vitamin K deficiency


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High Yield Notes
4 pages

Vitamin K deficiency

9 flashcards

USMLE® Step 1 style questions USMLE

3 questions

A 6-day-old boy is brought to the emergency department by his parents because of easy bruising. The infant was born at 38 weeks to a 23-year-old primigravida woman via normal vaginal delivery at home. This is his first medical evaluation. The patient’s mother took prenatal vitamins and maintained a healthy diet during pregnancy. Family history is unremarkable. Vitals are within normal limits. Physical examination reveals an alert infant. Examination shows multiple ecchymoses visible on upper and lower extremities. The remainder of the examination is unremarkable. Laboratory results are shown.

 Laboratory features 
 Laboratory value  Result 
 Platelet count    230,000/mm3 
 Bleeding time  5 minutes 
 Prothrombin time   27 seconds 
 Activated partial thromboplastin time  42 seconds 

Which of the following is the most likely cause of this infant’s presentation?


Vitamin K deficiency is a form of avitaminosis resulting from insufficient vitamin K1 or vitamin K2 or both. It can develop as a result of low vitamin K stores, a sterile gut, gestational use of coumarin-like anticoagulants, chronic use of antibiotics, and prolonged diarrhea. Symptoms include bruising, petechiae, hematomas, oozing of blood at surgical or puncture sites, stomach pains, risk of massive uncontrolled bleeding, cartilage calcification, and severe malformation of developing bone or deposition of insoluble calcium salts in the walls of arteries. In infants, it can cause some birth defects such as an underdeveloped face, nose, bones, and fingers. Treatment involves administration of vitamin K, as well as intake of vitamin K-rich foods.