Sample Question

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CASE:

A 55-year-old Caucasian man presents for yearly physical. On review of systems, he admits intermittent allergies that are worse with dust, weight loss, excessive hunger, intermittent back pain only with lifting, and new excessive, frequent urination. His vitals are blood pressure 138/88, respirations 16, pulse 70, weight 258 lb, 5’9″, height Sp02 96%, temperature 97.8°F. Labs show normal electrolytes, ALT of 10 U/L, AST of 18 U/L, and random glucose of 207 mg/dL. You check some additional labs, then explain his new diagnosis that you made based on his lab work and tell him you are going to start him on a chronic medication for his condition. You want to make sure there are no contraindications.

STEM:

In which of the following cases would it still be acceptable to use the first-line therapy drug?

ANSWER CHOICES:

  • a. Elevation of islet-specific autoantibodies
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  • b. Active alcohol abuse
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  • c. Acute heart failure
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  • d. Chronic kidney disease stage 3A
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    EXPLANATION

    The patient’s presentation of weight loss and polyuria with random glucose over 200 confirm a diagnosis of diabetes. The patient’s obesity and age, as well as disease prevalence, suggest that this is likely type 2 rather than type 1 diabetes. Metformin is the first-line drug for the management of diabetes mellitus (DM) type 2. Contraindications include estimated glomerular filtration (eGFR) rate <30%, hypersensitivity to metformin or any of its components, and factors that predispose to lactic acidosis, a rare but very serious adverse effect. A patient with chronic kidney disease (CKD) stage 3A has an eGFR of 45-60%. It is still acceptable to start metformin at eGFR >45%. In CKD stage 3B (eGFR 30-45%), metformin is used with caution, and many providers will only use half the dose or not use it at all. Metformin is contraindicated in patients with eGFR <30%.  

    Elevation of islet-specific autoantibodies suggests diabetes mellitus (DM) type 1. Metformin will not be effective in this case because it works by increasing insulin sensitivity, which is not the problem in DM type 1.

    Active alcohol abuse predisposes to lactic acidosis and alcohol should not be combined with metformin (Risk X: avoid combination).

    Acute heart failure predisposes to lactic acidosis. Unstable chronic heart failure patients should not be treated with metformin either.

    Ketones in urinalysis suggest diabetic ketoacidosis. Metformin is contraindicated in any patient with acute or chronic metabolic acidosis.

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    REFERENCES

    1. Levitsky L, Misra M. Epidemiology, presentation, and diagnosis of type 1 diabetes mellitus in children and adolescents. UpToDate. Published February 13, 2017. Available at: uptodate.com/contents/epidemiology-presentation-and-diagnosis-of-type-1-diabetes-mellitus-in-children-and-adolescents. Accessed February 23, 2017.
    2. McCulloch D. Metformin in the treatment of adults with type 2 diabetes mellitus. UpToDate. Published February 02, 2017. Available at: uptodate.com/contents/metformin-in-the-treatment-of-adults-with-type-2-diabetes-mellitus. Accessed February 23, 2017.
    3. Metformin: Drug Information. UpToDate. Available at: uptodate.com/contents/metformin-drug-information. Accessed February 23, 2017.
  • e. Ketones found in urinalysis
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