A 64-year-old man comes to the emergency department due to severe abdominal pain, nausea, and vomiting. He has a history of hypertension, myocardial infarction, and systolic heart failure. His blood pressure is 100/60 mm Hg, pulse is 116/min and irregular, and respirations are 24/min. Examination shows a soft, mildly distended, and tender abdomen. Laboratory results are as follows: CT scan of the abdomen reveals distal ileal wall thickening and lack of enhancement with intravenous contrast. Decreased activity of which of the following enzymes best explains the acid-base disorder in this patient?

Question

A 64-year-old man comes to the emergency department due to severe abdominal pain, nausea, and vomiting.  He has a history of hypertension, myocardial infarction, and systolic heart failure.  His blood pressure is 100/60 mm Hg, pulse is 116/min and irregular, and respirations are 24/min.  Examination shows a soft, mildly distended, and tender abdomen.  Laboratory results are as follows:  CT scan of the abdomen reveals distal ileal wall thickening and lack of enhancement with intravenous contrast.  Decreased activity of which of the following enzymes best explains the acid-base disorder in this patient?

Quizplus · Accepted Answer

Eductional Objective: In the presence of oxygen, pyruvate produced during glycolysis is converted by pyruvate dehydrogenase to acetyl coenzyme A, which is subsequently metabolized by oxidative phosphorylation.  However, if inadequate oxygen is present in the tissues, pyruvate is converted to lactate by lactate dehydrogenase, leading to lactic acidosis.

A 64-Year-Old Man Comes to the Emergency Department Due to Severe