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Clinical Case 3
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Objectives:

  • Identify metabolic alkalosis
  • Utilize urine chloride in the evaluation of metabolic alkalosis
  • Recognize various causes of metabolic alkalosis
  • Recognize the role of hypomagnesemia in treating hypokalemia



A 65-year-old male with a new diagnosis of congestive heart failure (CHF) returns to your office after starting several new medications within the last month. A cardiologist at an academic health center 100 miles away prescribed these medications, and neither you nor your patient know what the drugs are. Over that same time period, he states that he has felt “worse than I did after my heart attack.” At first he was just fatigued, but in the last few days he has developed nausea, vomiting, and body aches.

On examination, his temperature is 37.1° C, pulse 70, respiratory rate 8, and blood pressure 100/58 mm Hg. He has trace pedal edema. His lungs are clear, and his abdomen is diffusely tender. When you stand him up to check his blood pressure, he loses consciousness. He quickly recovers. Your nurse draws blood, starts an IV, and obtains an arterial blood gas on room air. ABG: pH 7.52, PaCO2 49 mm Hg, PaO2 90 mm Hg, and HCO3 39 meq/L.



1

The blood gas is consistent with the diagnosis of:
A)Metabolic alkalosis with respiratory compensation.
B)Respiratory alkalosis with metabolic compensation.
C)Mixed metabolic/respiratory alkalosis.
D)Mixed metabolic alkalosis and respiratory acidosis.
2

Which of the following urine tests will aid in determining the cause of this patient’s metabolic alkalosis?
A)Urine sodium.
B)Urine potassium.
C)Urine chloride.
D)Urine bicarbonate.
E)Urine creatinine.

You have admitted the patient and are on your way to the hospital to see him when the lab tests return. His plasma studies: Na 140 meq/L, K 2.5 meq/L, Cl 94 meq/L, BUN 18 mg/dL, creatinine 0.9 mg/dL, Ca 8.4 mg/dL, Mg 1.9 mg/dL. Urine studies: specific gravity 1.025, chloride 45 meq/L (high).



3

Of the following choices, which is (are) NOT likely to contribute to metabolic alkalosis in this patient?
A)Corticosteroids.
B)Diuretics.
C)Bartter’s syndrome.
D)Hypokalemia.
E)Vomiting or NG suction.

You are able to obtain the cardiologist’s records and your patient’s medications. He started taking captopril, furosemide, and metoprolol in the last month. He also takes aspirin and isosorbide dinitrate.



4

All of the following are appropriate interventions in this patient EXCEPT:
A)Discontinue furosemide.
B)Administer potassium chloride.
C)Administer hydrochloric acid through an NG tube.
D)Infuse normal (0.9%) saline.
E)Administer ranitidine.

Your patient is not responding to the KCl you are administering.



5

You give which of the following electrolytes to aid in repleting his potassium stores?
A)Sodium.
B)Bicarbonate.
C)Calcium.
D)Phosphate.
E)Magnesium.







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