Pathophysiology and management of pediatric ascites.

Ascites accumulation is the product of a complex process involving hepatic, renal, systemic, hemodynamic, and neurohormonal factors. The main pathophysiologic theories of ascites formation include the "underfill," "overflow," and peripheral arterial vasodilation hypotheses. These theories are not necessarily mutually exclusive and are linked at some level by a common pathophysiologic thread: The body senses a decreased effective arterial blood volume, leading to stimulation of the sympathetic nervous system, arginine-vasopressin feedback loops, and the renin-angiotensin-aldosterone system. Cornerstones of ascites management include dietary sodium restriction and diuretics. Spironolactone is generally tried initially, with furosemide added if clinical response is suboptimal. More refractory patients require large-volume paracentesis (LVP) accompanied by volume expansion with albumin. Placement of a transjugular intrahepatic portosystemic shunt is reserved for individuals with compensated liver function who require very frequent sessions of LVP. Peritoneovenous shunts are not used in contemporary ascites management. Liver transplantation remains the definitive therapy for refractory ascites. Although treatment of ascites fails to improve survival, it benefits quality of life and limits the development of such complications as spontaneous bacterial peritonitis.