Spontaneous Bacterial Peritonitis is a bacterial infection that occurs in patients with cirrhosis that have ascites. Symptoms include abdominal pain, fever, altered mental status, diarrhea and ileus. Paracentesis in SBP yields greater than or equal to 250 neutrophils in the ascitic fluid, regardless if culture positive or not. Common organisms include E coli and Klebsiella. Treatment is with a 3rd generation cephalosporin, classically Cefotaxime. To help prevent the occurence of Hepatorenal Syndrome, 25 % albumin in recommended in addition to antibiotics when treating SBP. SBP causes splanchnic vasodilation, which causes decreased systemic vascular resistance, which decreases renal perfusion. This activates the Renin-Angiotensin-Aldosterone System, which causes sodium and water absorption in the kidney, thus causing a urine sodium concentration is HRS that is typically < 10 meq/L. This can be differentiated from ATN in which urine sodium is > 40.