A 74 years old man presented with a 6 days history of aqueous severe diarrhea with 4 kg weight loss and oliguria. Comorbid conditions include hypertension, diabetes mellitus and ischemic heart disease. Usual treatment include enalapril 20mg twice a day, salicylic acid 100mg a day and insulin lantus 8 UI a day. The physical examination reveals positive skinfold. Blood pressure 90/60 mm Hg, HR 115 bpm, T 37.8C. Laboratory findings include hemoglobin 14 mg/dl, with cells count 18,000, platelets 157,000, glucose 62 mg/dl, urea 240 mg/dl, Cr 5.7 mg/dl, Na 144 mEq/L, K 5.2 mEq/L, Cl 116 mEq/L.
The most frequent etiology for this acute renal failure would be:
Select one of the following: