A 64-year-old woman comes to the emergency room complaining of tremors in all extremities, palpitations and confusion for the last 3 days. Her current medical history is significant for peptic ulcer disease, diabetes and bladder cancer. Her current medications include omeprazole for peptic ulcer disease, metformin for diabetes and cisplatin for bladder cancer. Review of systems is significant for occasional heart burns and daily loose bowel movements since she was started on metformin.She drinks three alcoholic drinks per day and smokes half a pack of cigarettes. On physical examination, tapping in front of the woman’s ears leads to ipsilateral facial muscle contracture. The inflation of a blood pressure cuff on her right arm leads to right-sided carpal spasm after 1 minute. She was admitted to the hospital. Laboratory findings show low calcium, low potassium, high phosphate and normal magnesium levels. ECG demonstrates widening of the QRS complex, peaked T waves, and prolonged PR interval. Despite repeated intravenous administrations of calcium and potassium, the patient’s hypocalcemia and hypokalemia have not been corrected. Which of the following is the best explanation for the refractory hypocalcemia and hypokalemia in this patient?
