Electrolyte Disorders USMLE Step 1 Practice Question
A 63-year-old man with poorly controlled diabetes mellitus presents with weakness and palpitations. ECG shows peaked T waves and widening of the QRS complex. Laboratory studies show potassium 7.2 mEq/L, bicarbonate 18 mEq/L, and creatinine 3.1 mg/dL. Which of the following is the most immediate life threatening effect of this electrolyte disturbance?
Answer choices
- ANephrolithiasis due to increased urinary calcium
- BCardiac arrhythmia due to altered membrane excitabilityCorrect answer
- CTetany due to spontaneous neuronal firing
- DCentral pontine myelinolysis due to osmotic injury
- EHemolysis due to red cell membrane fragility
- FRhabdomyolysis due to muscle membrane depolarization
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