A 65-year-old man comes to the physician for increasing nocturnal urinary incontinence that began one month ago. His current medications are metoprolol, verapamil, and amitriptyline. Blood pressure is 145/90. Laboratory studies show:
Serum creatinine 1.6 mg/dL
Urine protein 1+
Urine WBCs 1-2/hpf
Urine RBCs 1-2/hpf
Which of the following is the most likely explanation for these findings?
Blockade of cation channels
Decreased cAMP
Diminution of renal perfusion
Increased Bowman capsule hydrostatic pressure
Non-enzymatic glycosylation of glomerular basement membrane
