Figure 1: A 65-year-old male with edema of the hands and feet after general weakness for 1 week. On renal ultrasonography, the right kidney is enlarged (12.8 cm), with diffusely and slightly increased cortical echogenicity and hypoechoic renal pyramids, suggesting acute kidney injury (blood urea nitrogen/creatinine = 97.2/18.7 mg/dL, K = 6.4 mmol/L, and activated partial thromboplastin time = 33.1 s). K: Potassium