A 64-year-old man undergoes an emergency colonic resection for extensive ischemic colitis. He lives alone and consumes large amounts of alcohol. His family history is noncontributory. The patient is extubated on the 4th postoperative day. After extubation, he has episodes of confusion and agitation treated with lorazepam and haloperidol. He is also receiving piperacillin with tazobactam. The patient has had nothing by mouth since the surgery. On postoperative day 7, the nurse notices bleeding from a venipuncture site. His temperature is 36.7 C (98 F), blood pressure is 121/76 mm Hg, pulse is 80/min, and respirations are 16/min. Laboratory results are as follows: Which of the following is the most likely cause of this patient's current condition?

Question

A 64-year-old man undergoes an emergency colonic resection for extensive ischemic colitis.  He lives alone and consumes large amounts of alcohol.  His family history is noncontributory.  The patient is extubated on the 4th postoperative day.  After extubation, he has episodes of confusion and agitation treated with lorazepam and haloperidol.  He is also receiving piperacillin with tazobactam.  The patient has had nothing by mouth since the surgery.  On postoperative day 7, the nurse notices bleeding from a venipuncture site.  His temperature is 36.7 C (98 F), blood pressure is 121/76 mm Hg, pulse is 80/min, and respirations are 16/min.  Laboratory results are as follows:  Which of the following is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

This patient's clinical presentation suggests an acquired bleeding disorder, most likely due to vitamin K deficiency. Vitamin K is a fat-soluble vitamin that plays an important role in hemostasis by serving as a cofactor in the enzymatic carboxylation of glutamic acid residues on prothrombin complex proteins. The body obtains vitamin K exogenously from intestinal absorption of dietary Vitamin K and endogenously from bacterial production of vitamin K in the intestine. Vitamin K deficiency is most commonly due to inadequate dietary intake, intestinal malabsorption, or hepatocellular disease causing loss of storage sites. The liver can normally store a 30-day supply of vitamin K, but an acutely ill person with underlying liver disease can become vitamin K deficient in as little as 7-10 days. This patient received no enteral nutrition postoperatively and was given a broad-spectrum antibiotic, and so both natural sources of vitamin K were compromised. In addition, he also likely has alcoholic liver disease, further limiting his vitamin K stores. Vitamin K deficiency decreases plasma levels of all the prothrombin complex proteins (factors 2, 7, 9, 10, and protein C and S). This initially increases the prothrombin time (PT), followed by prolongation of the partial thromboplastin time (PTT). Administration of vitamin K rapidly replenishes the stores in 8-10 hours, and fresh frozen plasma may be used for the management of acute hemorrhage in the interim. (Choice A) Disseminated intravascular coagulation causes depletion of clotting factors and secondary fibrinolysis. This causes bleeding, acute kidney and liver injury, hypotension, and tachycardia. Testing shows thrombocytopenia, prolonged PT and PTT, decreased fibrinogen, and schistocytes on peripheral smear. Although this patient's PT and PTT are prolonged, he is hemodynamically stable and has a normal platelet count. (Choices B and E) Lupus anticoagulant (LAC) is an antiphospholipid antibody that prolongs the PTT during diagnostic testing. However, patients with LAC are actually hypercoagulable with increased risk for venous thrombosis. Factor V Leiden causes a hypercoagulable state due to activated protein C resistance. This patient's increased bleeding makes these unlikely. (Choice C) Factor VIII deficiency is an X-linked inherited plasma coagulation disorder that primarily prolongs the PTT. It would usually be apparent earlier in life. (Choice D) Hypersplenism can occur in patients with cirrhosis, portal hypertension, and splenomegaly. Splenic sequestration leads to thrombocytopenia, and patients rarely develop clinical bleeding or prolonged PT/PTT. (Choice F) Thrombotic thrombocytopenic purpura is a rare form of consumptive thrombocytopenia caused by widespread platelet thrombi that form in the microcirculation. It typically presents with thrombocytopenia, microangiopathic hemolytic anemia, fever, and neurologic findings (eg, altered mental status). (Choice H) von Willebrand disease is the most frequently diagnosed inherited bleeding disorder in adults. Laboratory testing usually shows increased bleeding time and PTT. However, the PT will be normal. Educational objective: Vitamin K deficiency is usually due to inadequate dietary intake, intestinal malabsorption, or hepatocellular disease. An acutely ill patient with underlying liver disease can become vitamin K deficient in 7-10 days. Laboratory studies usually show prolonged prothrombin time followed by prolonged partial thromboplastin time.

A 64-Year-Old Man Undergoes an Emergency Colonic Resection for Extensive