Question Number 0005 A 35 year old man has been kept on long term parenteral nutrition in an intensive care unit after incurring severe head and abdominal injuries in a traffic accident. He has been receiving broad-spectrum antibiotics for prolonged periods due to recurrent chest and abdominal infections. He develops a hemorrhaagic diathesis. His Prothrombin time is found to be increased. These manifestations are most likely secondary to a deficiency of a) Vitamin A Correct Answer: D Explanation: The PT is more sensitive than the aPTT in detecting vitamin K deficiency states because Factor VII, the only one of the vitamin K-dependent factors that is in the extrinsic pathway of coagulation, is the most labile of these proteins.The two major sources of vitamin K are dietary intake and synthesis by the bacterial flora of the intestine. Therefore, in the absence of malabsorption, nutritional deficiency alone rarely causes clinically significant vitamin K deficiency. However, such a condition can arise when eradication of gut flora is combined with inadequate dietary intake. This situation typically occurs in critically ill patients in intensive care units who have no oral intake and are receiving broad-spectrum antibiotics for prolonged periods. Vitamin K deficiency can also develop in patients receiving total parenteral nutrition unless the infusions are supplemented with vitamin K Related Questions A 35 year old man has been kept on long term parenteralAn 80 year old complains of a severe scalyA three year old old boy with known renal failureA 55 year old complains of a scaly and reddened rashA woman in her second trimester of pregnancy presents |
Labels: Heamatology, MRCP Part 1 MCQ, physiology, USMLE 01