Step 1 Question of the Week – Metabolism

This week’s USMLE-Rx Step 1 question comes from the area of metabolism.  See if you can answer the question and then watch the video to learn the correct answer as well as the rationales for all of the options.  The video comes from a recent edition of the Rx Question Lab, so if you like it, we encourage you to register and tune in every Tuesday.
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Metabolism

A 55-year-old man with a history of chronic alcohol abuse comes to the emergency department because of nausea, vomiting, abdominal pain, and altered mental status. He says that he was fired from his job a couple days ago and drank to “drown his sorrows.” He has no significant medical history other than moderate hypertension, for which he takes a ?-blocker. On physical examination, he is tachycardic, is breathing rapidly, and his abdomen is tender throughout. His blood alcohol level is significantly increased. Laboratory studies show:

Na+: 135 mEq/L
K+: 3.3 mEq/L
Cl-: 95 mEq/L
HCO3–: 9 mEq/L
Glucose: 40 mg/dL
Serum pH: 7.1
Lactate: 9.5 mmoL/L

Which of the following metabolic abnormalities is most likely in this patient?

A. Decreased levels of glycerol-3-phosphate

B. Elevated pyruvate levels

C. Inappropriate induction of gluconeogenesis

D. Overproduction of reduced nicotinamide adenine dinucleotide (NADH)

E. Thiamine deficiency

We invite you to leave a comment with your answer as well as your rationale.  When you’re ready to check your work, watch the video!
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Discussion

1 thought on “Step 1 Question of the Week – Metabolism”

  1. In my opinion the answer is D ( overproduction of NADH ).
    In alcoholism the overproduction of NADH will shift a few metabolisms to other pathways which in summary can cause lactic acidosis, triglyceride production and hypoglycemia. So A and C will be ruled out. As for B, there won’t be any elevated pyruvate levels since pyruvate will undergo lactic acid synthesis and triglyceride production ( instead of entering the TCA). As E, I don’t think there’s no thiamine deficiency since the key findings in thiamine deficiency ( Wernicke’s syndrome ) are ataxia, ophthalmoplegia and confusion, and the patient is showing non other than altered mental status and GI symptoms.

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