MEDizzy - A 65-year-old diabetic male with a creatinine of 1.6 was

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Nephrology

A 65-year-old diabetic male with a creatinine of 1.6 was started on an angiotensin-converting enzyme inhibitor for hypertension and presents to the emergency room with weakness. His other medications include ator- vastatin for hypercholesterolemia, metoprolol and spironolactone for con- gestive heart failure, insulin for diabetes, and aspirin. Laboratory studies include K: 7.2 mEq/L Creatinine: 1.8 mg/dL Glucose: 250 mg/dL CK: 400 IU/L Which of the following is the most likely cause of hyperkalemia in this patient?

ExplanationThe syndrome of hyporeninemic hypoaldosteronism occurs in older diabetic patients, particularly males with congestive heart failure. The syndrome often presents when aggravating drugs are added. Beta-blockers impair renin secretion; ACE inhibitors decrease aldosterone levels; and spironolactone competes for the aldosterone receptor. Combined with diabetes and mild renal insufficiency, the result may be life-threatening hyperkalemia. Moderate renal insufficiency per se is unlikely to cause such severe hyperkalemia. Hypertonicity caused by hyperglycemia could aggravate hyperkalemia, but a blood glucose of 250 mg/dL should not cause severe hyperkalemia. Statin drugs may cause muscle injury and rhabdomyolysis, but a CK of 400 IU/L is a modest elevation (probably caused by renal insufficiency) and would not cause severe hyperkalemia. A high potassium diet may contribute modestly to hyperkalemia but is rarely a major factor by itself.