Diagram: portal hypertension leads to splanchnic vasoconstriction, which decreases effective cirulatory volume. This activates the renin–angiotensin–aldosterone system, which leads to ascites due to kidney sodium avidity and hepatorenal syndrome due to kidney vasoconstriction.
Diagram: ascites, diuretic-resistant ascites and hepatorenal syndrome are a spectrum of clinical features. Portal hypertension is associated with all three. Splanchnic vasodilation is associated with all but ascites. Kidney vasoconstriction is associated only with HRS.
Hepatorenal Syndrome... Seen in Patients with Advanced Liver Disease, cirrhosis, and/or Portal Hypertension with Elevated BUN/Creatinine... Precipitated by GI bleeds (from varices)... FeNa less than 1% (urine Na less than 10 mEq/L)... Clean Urine, No RBC's, protein, or casts in the urine... Lack of improvement in renal function with IV Fluids... The Renal Injury is due to RENAL HYPOPERFUSION... Occurs due to increased Nitric Oxide causing systemic vasodilation