A 64-year-old man with type 2 diabetes, hypertension, and chronic kidney disease (CKD) presented with new weakness. Six months ago he had a myocardial infarction complicated by heart failure with an ejection fraction of 35%. His medications were lisinopril, metoprolol succinate, insulin, and furosemide. One week ago, he was diagnosed with cellulitis of the right leg and prescribed a 7-day course of trimethoprim-sulfamethoxazole. Two days ago he noticed generalized weakness, which had worsened over the last 24 hours. Physical examination showed resolving cellulitis on the right leg. Other than symmetrical 3/5 strength in the upper and lower extremities, his neurologic examination results were normal. An electrocardiogram was unchanged from 2 months ago. Laboratory results are shown in the Table.
Palmer BF, Clegg DJ. Hyperkalemia. JAMA. 2015;314(22):2405-2406. doi:10.1001/jama.2015.9230